Spade
Mini Shell
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reserved.
--
-- This program is free software; you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation; version 2 of the License.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program; if not, write to the Free Software
-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
USA.
-- DO NOT EDIT THIS FILE. It is generated automatically.
-- To use this file, load its contents into the mysql database. For
example,
-- with the mysql client program, process the file like this, where
-- file_name is the name of this file:
-- mysql -u root -p mysql < file_name
set names 'utf8';
set sql_log_bin = 0;
use mysql;
delete from help_topic;
delete from help_category;
delete from help_keyword;
delete from help_relation;
lock tables help_topic write, help_category write, help_keyword write,
help_relation write;
insert into help_category (help_category_id,name,parent_category_id,url)
values (1,'Contents',0,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (2,'Polygon Properties',34,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (3,'WKT',34,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (4,'Numeric Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (5,'Plugins',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (6,'MBR',34,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (7,'Control Flow Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (8,'Transactions',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (9,'Help Metadata',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (10,'Account Management',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (11,'Point Properties',34,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (12,'Encryption Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (13,'LineString Properties',34,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (14,'Miscellaneous Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (15,'Logical Operators',47,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (16,'Functions and Modifiers for Use with GROUP
BY',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (17,'Information Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (18,'Assignment Operators',47,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (19,'Comparison Operators',47,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (20,'Bit Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (21,'Table Maintenance',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (22,'User-Defined Functions',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (23,'Data Types',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (24,'Compound Statements',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (25,'Geometry Constructors',34,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (26,'Administration',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (27,'Data Manipulation',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (28,'Utility',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (29,'Language Structure',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (30,'Geometry Relations',34,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (31,'Date and Time Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (32,'WKB',34,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (33,'Procedures',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (34,'Geographic Features',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (35,'Geometry Properties',34,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (36,'String Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (37,'Functions',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (38,'Data Definition',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (39,'Sequences',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (40,'JSON Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (41,'Window Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (42,'Spider Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (43,'Dynamic Column Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (44,'Galera Functions',37,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (45,'Temporal Tables',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (46,'GeoJSON',34,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (47,'Operators',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (48,'Arithmetic Operators',47,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (49,'Replication',1,'');
insert into help_category (help_category_id,name,parent_category_id,url)
values (50,'Prepared Statements',1,'');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(1,9,'HELP_DATE','Help Contents generated from the MariaDB
Knowledge Base on 23 January 2023.','','');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(2,9,'HELP_VERSION','Help Contents generated for MariaDB
10.6 from the MariaDB Knowledge Base on 23 January
2023.','','');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(3,2,'AREA','A synonym for ST_AREA.\n\nURL:
https://mariadb.com/kb/en/polygon-properties-area/','','https://mariadb.com/kb/en/polygon-properties-area/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(4,2,'CENTROID','A synonym for ST_CENTROID.\n\nURL:
https://mariadb.com/kb/en/centroid/','','https://mariadb.com/kb/en/centroid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(5,2,'ExteriorRing','A synonym for ST_ExteriorRing.\n\nURL:
https://mariadb.com/kb/en/polygon-properties-exteriorring/','','https://mariadb.com/kb/en/polygon-properties-exteriorring/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(6,2,'InteriorRingN','A synonym for
ST_InteriorRingN.\n\nURL:
https://mariadb.com/kb/en/polygon-properties-interiorringn/','','https://mariadb.com/kb/en/polygon-properties-interiorringn/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(7,2,'NumInteriorRings','A synonym for
ST_NumInteriorRings.\n\nURL:
https://mariadb.com/kb/en/polygon-properties-numinteriorrings/','','https://mariadb.com/kb/en/polygon-properties-numinteriorrings/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(8,2,'ST_AREA','Syntax\n------\n\nST_Area(poly)\nArea(poly)\n\nDescription\n-----------\n\nReturns
as a double-precision number the area of the Polygon value poly,
as\nmeasured in its spatial reference system.\n\nST_Area() and Area() are
synonyms.\n\nExamples\n--------\n\nSET @poly = \'Polygon((0 0,0 3,3
0,0 0),(1 1,1 2,2 1,1 1))\';\n\nSELECT
Area(GeomFromText(@poly));\n+---------------------------+\n|
Area(GeomFromText(@poly)) |\n+---------------------------+\n|
4 |\n+---------------------------+\n\nURL:
https://mariadb.com/kb/en/st_area/','','https://mariadb.com/kb/en/st_area/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(9,2,'ST_CENTROID','Syntax\n------\n\nST_Centroid(mpoly)\nCentroid(mpoly)\n\nDescription\n-----------\n\nReturns
a point reflecting the mathematical centroid (geometric center) for\nthe
MultiPolygon mpoly. The resulting point will not necessarily be on
the\nMultiPolygon.\n\nST_Centroid() and Centroid() are
synonyms.\n\nExamples\n--------\n\nSET @poly =
ST_GeomFromText(\'POLYGON((0 0,20 0,20 20,0 20,0 0))\');\nSELECT
ST_AsText(ST_Centroid(@poly)) AS center;\n+--------------+\n| center
|\n+--------------+\n| POINT(10 10) |\n+--------------+\n\nURL:
https://mariadb.com/kb/en/st_centroid/','','https://mariadb.com/kb/en/st_centroid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(10,2,'ST_ExteriorRing','Syntax\n------\n\nST_ExteriorRing(poly)\nExteriorRing(poly)\n\nDescription\n-----------\n\nReturns
the exterior ring of the Polygon value poly as a
LineString.\n\nST_ExteriorRing() and ExteriorRing() are
synonyms.\n\nExamples\n--------\n\nSET @poly = \'Polygon((0 0,0 3,3
3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))\';\n\nSELECT
AsText(ExteriorRing(GeomFromText(@poly)));\n+-------------------------------------------+\n|
AsText(ExteriorRing(GeomFromText(@poly)))
|\n+-------------------------------------------+\n| LINESTRING(0 0,0 3,3
3,3 0,0 0)
|\n+-------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_exteriorring/','','https://mariadb.com/kb/en/st_exteriorring/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(11,2,'ST_InteriorRingN','Syntax\n------\n\nST_InteriorRingN(poly,N)\nInteriorRingN(poly,N)\n\nDescription\n-----------\n\nReturns
the N-th interior ring for the Polygon value poly as a LineString.\nRings
are numbered beginning with 1.\n\nST_InteriorRingN() and InteriorRingN()
are synonyms.\n\nExamples\n--------\n\nSET @poly = \'Polygon((0 0,0
3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))\';\n\nSELECT
AsText(InteriorRingN(GeomFromText(@poly),1));\n+----------------------------------------------+\n|
AsText(InteriorRingN(GeomFromText(@poly),1))
|\n+----------------------------------------------+\n| LINESTRING(1 1,1 2,2
2,2 1,1 1)
|\n+----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_interiorringn/','','https://mariadb.com/kb/en/st_interiorringn/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(12,2,'ST_NumInteriorRings','Syntax\n------\n\nST_NumInteriorRings(poly)\nNumInteriorRings(poly)\n\nDescription\n-----------\n\nReturns
an integer containing the number of interior rings in the Polygon\nvalue
poly.\n\nNote that according the the OpenGIS standard, a POLYGON should
have exactly\none ExteriorRing and all other rings should lie within that
ExteriorRing and\nthus be the InteriorRings. Practically, however, some
systems, including\nMariaDB\'s, permit polygons to have several
\'ExteriorRings\'. In the case of\nthere being multiple,
non-overlapping exterior rings ST_NumInteriorRings()\nwill return
1.\n\nST_NumInteriorRings() and NumInteriorRings() are
synonyms.\n\nExamples\n--------\n\nSET @poly = \'Polygon((0 0,0 3,3
3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))\';\n\nSELECT
NumInteriorRings(GeomFromText(@poly));\n+---------------------------------------+\n|
NumInteriorRings(GeomFromText(@poly))
|\n+---------------------------------------+\n|
1 |\n+---------------------------------------+\n\nNon-overlapping
\'polygon\':\n\nSELECT
ST_NumInteriorRings(ST_PolyFromText(\'POLYGON((0 0,10 0,10 10,0 10,0
0),\n (-1 -1,-5 -1,-5 -5,-1 -5,-1 -1))\')) AS
NumInteriorRings;\n+------------------+\n| NumInteriorRings
|\n+------------------+\n| 1 |\n+------------------+\n\nURL:
https://mariadb.com/kb/en/st_numinteriorrings/','','https://mariadb.com/kb/en/st_numinteriorrings/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(13,3,'WKT Definition','Description\n-----------\n\nThe
Well-Known Text (WKT) representation of Geometry is designed to
exchange\ngeometry data in ASCII form. Examples of the basic geometry types
include:\n\n+-----------------------------------------------------------------------------+\n|
Geometry Types
|\n+-----------------------------------------------------------------------------+\n|
POINT
|\n+-----------------------------------------------------------------------------+\n|
LINESTRING
|\n+-----------------------------------------------------------------------------+\n|
POLYGON
|\n+-----------------------------------------------------------------------------+\n|
MULTIPOINT
|\n+-----------------------------------------------------------------------------+\n|
MULTILINESTRING
|\n+-----------------------------------------------------------------------------+\n|
MULTIPOLYGON
|\n+-----------------------------------------------------------------------------+\n|
GEOMETRYCOLLECTION
|\n+-----------------------------------------------------------------------------+\n|
GEOMETRY
|\n+-----------------------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/wkt-definition/','','https://mariadb.com/kb/en/wkt-definition/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(14,3,'AsText','A synonym for ST_AsText().\n\nURL:
https://mariadb.com/kb/en/wkt-astext/','','https://mariadb.com/kb/en/wkt-astext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(15,3,'AsWKT','A synonym for ST_AsText().\n\nURL:
https://mariadb.com/kb/en/wkt-aswkt/','','https://mariadb.com/kb/en/wkt-aswkt/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(16,3,'GeomCollFromText','A synonym for
ST_GeomCollFromText.\n\nURL:
https://mariadb.com/kb/en/wkt-geomcollfromtext/','','https://mariadb.com/kb/en/wkt-geomcollfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(17,3,'GeometryCollectionFromText','A synonym for
ST_GeomCollFromText.\n\nURL:
https://mariadb.com/kb/en/geometrycollectionfromtext/','','https://mariadb.com/kb/en/geometrycollectionfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(18,3,'GeometryFromText','A synonym for
ST_GeomFromText.\n\nURL:
https://mariadb.com/kb/en/geometryfromtext/','','https://mariadb.com/kb/en/geometryfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(19,3,'GeomFromText','A synonym for ST_GeomFromText.\n\nURL:
https://mariadb.com/kb/en/wkt-geomfromtext/','','https://mariadb.com/kb/en/wkt-geomfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(20,3,'LineFromText','A synonym for ST_LineFromText.\n\nURL:
https://mariadb.com/kb/en/wkt-linefromtext/','','https://mariadb.com/kb/en/wkt-linefromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(21,3,'LineStringFromText','A synonym for
ST_LineFromText.\n\nURL:
https://mariadb.com/kb/en/linestringfromtext/','','https://mariadb.com/kb/en/linestringfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(22,3,'MLineFromText','Syntax\n------\n\nMLineFromText(wkt[,srid])\nMultiLineStringFromText(wkt[,srid])\n\nDescription\n-----------\n\nConstructs
a MULTILINESTRING value using its WKT representation and
SRID.\n\nMLineFromText() and MultiLineStringFromText() are
synonyms.\n\nExamples\n--------\n\nCREATE TABLE gis_multi_line (g
MULTILINESTRING);\nSHOW FIELDS FROM gis_multi_line;\nINSERT INTO
gis_multi_line VALUES\n
(MultiLineStringFromText(\'MULTILINESTRING((10 48,10 21,10 0),(16
0,16\n23,16 48))\')),\n (MLineFromText(\'MULTILINESTRING((10
48,10 21,10 0))\')),\n (MLineFromWKB(AsWKB(MultiLineString(\n
LineString(Point(1, 2), Point(3, 5)),\n LineString(Point(2, 5), Point(5,
8), Point(21, 7))))));\n\nURL:
https://mariadb.com/kb/en/mlinefromtext/','','https://mariadb.com/kb/en/mlinefromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(23,3,'MPointFromText','Syntax\n------\n\nMPointFromText(wkt[,srid])\nMultiPointFromText(wkt[,srid])\n\nDescription\n-----------\n\nConstructs
a MULTIPOINT value using its WKT representation and
SRID.\n\nMPointFromText() and MultiPointFromText() are
synonyms.\n\nExamples\n--------\n\nCREATE TABLE gis_multi_point (g
MULTIPOINT);\nSHOW FIELDS FROM gis_multi_point;\nINSERT INTO
gis_multi_point VALUES\n (MultiPointFromText(\'MULTIPOINT(0 0,10
10,10 20,20 20)\')),\n (MPointFromText(\'MULTIPOINT(1 1,11 11,11
21,21 21)\')),\n (MPointFromWKB(AsWKB(MultiPoint(Point(3, 6),
Point(4, 10)))));\n\nURL:
https://mariadb.com/kb/en/mpointfromtext/','','https://mariadb.com/kb/en/mpointfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(24,3,'MPolyFromText','Syntax\n------\n\nMPolyFromText(wkt[,srid])\nMultiPolygonFromText(wkt[,srid])\n\nDescription\n-----------\n\nConstructs
a MULTIPOLYGON value using its WKT representation and
SRID.\n\nMPolyFromText() and MultiPolygonFromText() are
synonyms.\n\nExamples\n--------\n\nCREATE TABLE gis_multi_polygon (g
MULTIPOLYGON);\nSHOW FIELDS FROM gis_multi_polygon;\nINSERT INTO
gis_multi_polygon VALUES\n (MultiPolygonFromText(\'MULTIPOLYGON(\n
((28 26,28 0,84 0,84 42,28 26),(52 18,66 23,73 9,48 6,52 18)),\n ((59
18,67 18,67 13,59 13,59 18)))\')),\n
(MPolyFromText(\'MULTIPOLYGON(\n ((28 26,28 0,84 0,84 42,28 26),(52
18,66 23,73 9,48 6,52 18)),\n ((59 18,67 18,67 13,59 13,59
18)))\')),\n (MPolyFromWKB(AsWKB(MultiPolygon(Polygon(\n
LineString(Point(0, 3), Point(3, 3), Point(3, 0), Point(0,
3)))))));\n\nURL:
https://mariadb.com/kb/en/mpolyfromtext/','','https://mariadb.com/kb/en/mpolyfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(25,3,'MultiLineStringFromText','A synonym for
MLineFromText.\n\nURL:
https://mariadb.com/kb/en/multilinestringfromtext/','','https://mariadb.com/kb/en/multilinestringfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(26,3,'MultiPointFromText','A synonym for
MPointFromText.\n\nURL:
https://mariadb.com/kb/en/multipointfromtext/','','https://mariadb.com/kb/en/multipointfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(27,3,'MultiPolygonFromText','A synonym for
MPolyFromText.\n\nURL:
https://mariadb.com/kb/en/multipolygonfromtext/','','https://mariadb.com/kb/en/multipolygonfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(28,3,'PointFromText','A synonym for
ST_PointFromText.\n\nURL:
https://mariadb.com/kb/en/wkt-pointfromtext/','','https://mariadb.com/kb/en/wkt-pointfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(29,3,'PolyFromText','A synonym for ST_PolyFromText.\n\nURL:
https://mariadb.com/kb/en/wkt-polyfromtext/','','https://mariadb.com/kb/en/wkt-polyfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(30,3,'PolygonFromText','A synonym for
ST_PolyFromText.\n\nURL:
https://mariadb.com/kb/en/polygonfromtext/','','https://mariadb.com/kb/en/polygonfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(31,3,'ST_AsText','Syntax\n------\n\nST_AsText(g)\nAsText(g)\nST_AsWKT(g)\nAsWKT(g)\n\nDescription\n-----------\n\nConverts
a value in internal geometry format to its WKT representation and\nreturns
the string result.\n\nST_AsText(), AsText(), ST_AsWKT() and AsWKT() are all
synonyms.\n\nExamples\n--------\n\nSET @g = \'LineString(1 1,4 4,6
6)\';\n\nSELECT
ST_AsText(ST_GeomFromText(@g));\n+--------------------------------+\n|
ST_AsText(ST_GeomFromText(@g)) |\n+--------------------------------+\n|
LINESTRING(1 1,4 4,6 6)
|\n+--------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_astext/','','https://mariadb.com/kb/en/st_astext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(32,3,'ST_ASWKT','A synonym for ST_ASTEXT().\n\nURL:
https://mariadb.com/kb/en/st_aswkt/','','https://mariadb.com/kb/en/st_aswkt/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(33,3,'ST_GeomCollFromText','Syntax\n------\n\nST_GeomCollFromText(wkt[,srid])\nST_GeometryCollectionFromText(wkt[,srid])\nGeomCollFromText(wkt[,srid])\nGeometryCollectionFromText(wkt[,srid])\n\nDescription\n-----------\n\nConstructs
a GEOMETRYCOLLECTION value using its WKT representation and
SRID.\n\nST_GeomCollFromText(), ST_GeometryCollectionFromText(),
GeomCollFromText() and\nGeometryCollectionFromText() are all
synonyms.\n\nExample\n-------\n\nCREATE TABLE gis_geometrycollection (g
GEOMETRYCOLLECTION);\nSHOW FIELDS FROM gis_geometrycollection;\nINSERT INTO
gis_geometrycollection VALUES\n
(GeomCollFromText(\'GEOMETRYCOLLECTION(POINT(0 0), LINESTRING(0
0,10\n10))\')),\n (GeometryFromWKB(AsWKB(GeometryCollection(Point(44,
6),\nLineString(Point(3, 6), Point(7, 9)))))),\n
(GeomFromText(\'GeometryCollection()\')),\n
(GeomFromText(\'GeometryCollection EMPTY\'));\n\nURL:
https://mariadb.com/kb/en/st_geomcollfromtext/','','https://mariadb.com/kb/en/st_geomcollfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(34,3,'ST_GeometryCollectionFromText','A synonym for
ST_GeomCollFromText.\n\nURL:
https://mariadb.com/kb/en/st_geometrycollectionfromtext/','','https://mariadb.com/kb/en/st_geometrycollectionfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(35,3,'ST_GeometryFromText','A synonym for
ST_GeomFromText.\n\nURL:
https://mariadb.com/kb/en/st_geometryfromtext/','','https://mariadb.com/kb/en/st_geometryfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(36,3,'ST_GeomFromText','Syntax\n------\n\nST_GeomFromText(wkt[,srid])\nST_GeometryFromText(wkt[,srid])\nGeomFromText(wkt[,srid])\nGeometryFromText(wkt[,srid])\n\nDescription\n-----------\n\nConstructs
a geometry value of any type using its WKT representation and
SRID.\n\nGeomFromText(), GeometryFromText(), ST_GeomFromText()
and\nST_GeometryFromText() are all synonyms.\n\nExample\n-------\n\nSET @g
= ST_GEOMFROMTEXT(\'POLYGON((1 1,1 5,4 9,6 9,9 3,7 2,1
1))\');\n\nURL:
https://mariadb.com/kb/en/st_geomfromtext/','','https://mariadb.com/kb/en/st_geomfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(37,3,'ST_LineFromText','Syntax\n------\n\nST_LineFromText(wkt[,srid])\nST_LineStringFromText(wkt[,srid])\nLineFromText(wkt[,srid])\nLineStringFromText(wkt[,srid])\n\nDescription\n-----------\n\nConstructs
a LINESTRING value using its WKT representation and
SRID.\n\nST_LineFromText(), ST_LineStringFromText(), ST_LineFromText()
and\nST_LineStringFromText() are all
synonyms.\n\nExamples\n--------\n\nCREATE TABLE gis_line (g
LINESTRING);\nSHOW FIELDS FROM gis_line;\nINSERT INTO gis_line VALUES\n
(LineFromText(\'LINESTRING(0 0,0 10,10 0)\')),\n
(LineStringFromText(\'LINESTRING(10 10,20 10,20 20,10 20,10
10)\')),\n (LineStringFromWKB(AsWKB(LineString(Point(10, 10),
Point(40, 10)))));\n\nURL:
https://mariadb.com/kb/en/st_linefromtext/','','https://mariadb.com/kb/en/st_linefromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(38,3,'ST_LineStringFromText','A synonym for
ST_LineFromText.\n\nURL:
https://mariadb.com/kb/en/st_linestringfromtext/','','https://mariadb.com/kb/en/st_linestringfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(39,3,'ST_PointFromText','Syntax\n------\n\nST_PointFromText(wkt[,srid])\nPointFromText(wkt[,srid])\n\nDescription\n-----------\n\nConstructs
a POINT value using its WKT representation and SRID.\n\nST_PointFromText()
and PointFromText() are synonyms.\n\nExamples\n--------\n\nCREATE TABLE
gis_point (g POINT);\nSHOW FIELDS FROM gis_point;\nINSERT INTO gis_point
VALUES\n (PointFromText(\'POINT(10 10)\')),\n
(PointFromText(\'POINT(20 10)\')),\n
(PointFromText(\'POINT(20 20)\')),\n
(PointFromWKB(AsWKB(PointFromText(\'POINT(10 20)\'))));\n\nURL:
https://mariadb.com/kb/en/st_pointfromtext/','','https://mariadb.com/kb/en/st_pointfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(40,3,'ST_PolyFromText','Syntax\n------\n\nST_PolyFromText(wkt[,srid])\nST_PolygonFromText(wkt[,srid])\nPolyFromText(wkt[,srid])\nPolygonFromText(wkt[,srid])\n\nDescription\n-----------\n\nConstructs
a POLYGON value using its WKT representation and
SRID.\n\nST_PolyFromText(), ST_PolygonFromText(), PolyFromText()
and\nST_PolygonFromText() are all synonyms.\n\nExamples\n--------\n\nCREATE
TABLE gis_polygon (g POLYGON);\nINSERT INTO gis_polygon VALUES\n
(PolygonFromText(\'POLYGON((10 10,20 10,20 20,10 20,10
10))\')),\n (PolyFromText(\'POLYGON((0 0,50 0,50 50,0 50,0 0),
(10 10,20 10,20 20,10\n20,10 10))\'));\n\nURL:
https://mariadb.com/kb/en/st_polyfromtext/','','https://mariadb.com/kb/en/st_polyfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(41,3,'ST_PolygonFromText','A synonym for
ST_PolyFromText.\n\nURL:
https://mariadb.com/kb/en/st_polygonfromtext/','','https://mariadb.com/kb/en/st_polygonfromtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(42,4,'DIV','Syntax\n------\n\nDIV\n\nDescription\n-----------\n\nInteger
division. Similar to FLOOR(), but is safe with BIGINT values.\nIncorrect
results may occur for non-integer operands that exceed BIGINT range.\n\nIf
the ERROR_ON_DIVISION_BY_ZERO SQL_MODE is used, a division by zero
produces\nan error. Otherwise, it returns NULL.\n\nThe remainder of a
division can be obtained using the MOD
operator.\n\nExamples\n--------\n\nSELECT 300 DIV 7;\n+-----------+\n| 300
DIV 7 |\n+-----------+\n| 42 |\n+-----------+\n\nSELECT 300 DIV
0;\n+-----------+\n| 300 DIV 0 |\n+-----------+\n| NULL
|\n+-----------+\n\nURL:
https://mariadb.com/kb/en/div/','','https://mariadb.com/kb/en/div/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(43,4,'ABS','Syntax\n------\n\nABS(X)\n\nDescription\n-----------\n\nReturns
the absolute (non-negative) value of X. If X is not a number, it
is\nconverted to a numeric type.\n\nExamples\n--------\n\nSELECT
ABS(42);\n+---------+\n| ABS(42) |\n+---------+\n| 42
|\n+---------+\n\nSELECT ABS(-42);\n+----------+\n| ABS(-42)
|\n+----------+\n| 42 |\n+----------+\n\nSELECT ABS(DATE
\'1994-01-01\');\n+------------------------+\n| ABS(DATE
\'1994-01-01\') |\n+------------------------+\n|
19940101 |\n+------------------------+\n\nURL:
https://mariadb.com/kb/en/abs/','','https://mariadb.com/kb/en/abs/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(44,4,'ACOS','Syntax\n------\n\nACOS(X)\n\nDescription\n-----------\n\nReturns
the arc cosine of X, that is, the value whose cosine is X. Returns\nNULL if
X is not in the range -1 to 1.\n\nExamples\n--------\n\nSELECT
ACOS(1);\n+---------+\n| ACOS(1) |\n+---------+\n| 0
|\n+---------+\n\nSELECT ACOS(1.0001);\n+--------------+\n| ACOS(1.0001)
|\n+--------------+\n| NULL |\n+--------------+\n\nSELECT
ACOS(0);\n+-----------------+\n| ACOS(0) |\n+-----------------+\n|
1.5707963267949 |\n+-----------------+\n\nSELECT
ACOS(0.234);\n+------------------+\n| ACOS(0.234)
|\n+------------------+\n| 1.33460644244679 |\n+------------------+\n\nURL:
https://mariadb.com/kb/en/acos/','','https://mariadb.com/kb/en/acos/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(45,4,'ASIN','Syntax\n------\n\nASIN(X)\n\nDescription\n-----------\n\nReturns
the arc sine of X, that is, the value whose sine is X. Returns NULL if\nX
is not in the range -1 to 1.\n\nExamples\n--------\n\nSELECT
ASIN(0.2);\n+--------------------+\n| ASIN(0.2)
|\n+--------------------+\n| 0.2013579207903308
|\n+--------------------+\n\nSELECT
ASIN(\'foo\');\n+-------------+\n| ASIN(\'foo\')
|\n+-------------+\n| 0 |\n+-------------+\n\nSHOW
WARNINGS;\n+---------+------+-----------------------------------------+\n|
Level | Code | Message
|\n+---------+------+-----------------------------------------+\n| Warning
| 1292 | Truncated incorrect DOUBLE value: \'foo\'
|\n+---------+------+-----------------------------------------+\n\nURL:
https://mariadb.com/kb/en/asin/','','https://mariadb.com/kb/en/asin/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(46,4,'ATAN','Syntax\n------\n\nATAN(X)\n\nDescription\n-----------\n\nReturns
the arc tangent of X, that is, the value whose tangent is
X.\n\nExamples\n--------\n\nSELECT ATAN(2);\n+--------------------+\n|
ATAN(2) |\n+--------------------+\n| 1.1071487177940904
|\n+--------------------+\n\nSELECT ATAN(-2);\n+---------------------+\n|
ATAN(-2) |\n+---------------------+\n| -1.1071487177940904
|\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/atan/','','https://mariadb.com/kb/en/atan/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(47,4,'ATAN2','Syntax\n------\n\nATAN(Y,X),
ATAN2(Y,X)\n\nDescription\n-----------\n\nReturns the arc tangent of the
two variables X and Y. It is similar to\ncalculating the arc tangent of Y /
X, except that the signs of both arguments\nare used to determine the
quadrant of the result.\n\nExamples\n--------\n\nSELECT
ATAN(-2,2);\n+---------------------+\n| ATAN(-2,2)
|\n+---------------------+\n| -0.7853981633974483
|\n+---------------------+\n\nSELECT
ATAN2(PI(),0);\n+--------------------+\n| ATAN2(PI(),0)
|\n+--------------------+\n| 1.5707963267948966
|\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/atan2/','','https://mariadb.com/kb/en/atan2/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(48,4,'CEIL','Syntax\n------\n\nCEIL(X)\n\nDescription\n-----------\n\nCEIL()
is a synonym for CEILING().\n\nURL:
https://mariadb.com/kb/en/ceil/','','https://mariadb.com/kb/en/ceil/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(49,4,'CEILING','Syntax\n------\n\nCEILING(X)\n\nDescription\n-----------\n\nReturns
the smallest integer value not less than X.\n\nExamples\n--------\n\nSELECT
CEILING(1.23);\n+---------------+\n| CEILING(1.23) |\n+---------------+\n|
2 |\n+---------------+\n\nSELECT
CEILING(-1.23);\n+----------------+\n| CEILING(-1.23)
|\n+----------------+\n| -1 |\n+----------------+\n\nURL:
https://mariadb.com/kb/en/ceiling/','','https://mariadb.com/kb/en/ceiling/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(50,4,'CONV','Syntax\n------\n\nCONV(N,from_base,to_base)\n\nDescription\n-----------\n\nConverts
numbers between different number bases. Returns a string\nrepresentation of
the number N, converted from base from_base to base to_base.\n\nReturns
NULL if any argument is NULL, or if the second or third argument are\nnot
in the allowed range.\n\nThe argument N is interpreted as an integer, but
may be specified as an\ninteger or a string. The minimum base is 2 and the
maximum base is 36. If\nto_base is a negative number, N is regarded as a
signed number. Otherwise, N\nis treated as unsigned. CONV() works with
64-bit precision.\n\nSome shortcuts for this function are also available:
BIN(), OCT(), HEX(),\nUNHEX(). Also, MariaDB allows binary literal values
and hexadecimal literal\nvalues.\n\nExamples\n--------\n\nSELECT
CONV(\'a\',16,2);\n+----------------+\n|
CONV(\'a\',16,2) |\n+----------------+\n| 1010
|\n+----------------+\n\nSELECT
CONV(\'6E\',18,8);\n+-----------------+\n|
CONV(\'6E\',18,8) |\n+-----------------+\n| 172
|\n+-----------------+\n\nSELECT CONV(-17,10,-18);\n+------------------+\n|
CONV(-17,10,-18) |\n+------------------+\n| -H
|\n+------------------+\n\nSELECT
CONV(12+\'10\'+\'10\'+0xa,10,10);\n+------------------------------+\n|
CONV(12+\'10\'+\'10\'+0xa,10,10)
|\n+------------------------------+\n| 42
|\n+------------------------------+\n\nURL:
https://mariadb.com/kb/en/conv/','','https://mariadb.com/kb/en/conv/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(51,4,'COS','Syntax\n------\n\nCOS(X)\n\nDescription\n-----------\n\nReturns
the cosine of X, where X is given in
radians.\n\nExamples\n--------\n\nSELECT COS(PI());\n+-----------+\n|
COS(PI()) |\n+-----------+\n| -1 |\n+-----------+\n\nURL:
https://mariadb.com/kb/en/cos/','','https://mariadb.com/kb/en/cos/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(52,4,'COT','Syntax\n------\n\nCOT(X)\n\nDescription\n-----------\n\nReturns
the cotangent of X.\n\nExamples\n--------\n\nSELECT
COT(42);\n+--------------------+\n| COT(42)
|\n+--------------------+\n| 0.4364167060752729
|\n+--------------------+\n\nSELECT COT(12);\n+---------------------+\n|
COT(12) |\n+---------------------+\n| -1.5726734063976893
|\n+---------------------+\n\nSELECT COT(0);\nERROR 1690 (22003): DOUBLE
value is out of range in \'cot(0)\'\n\nURL:
https://mariadb.com/kb/en/cot/','','https://mariadb.com/kb/en/cot/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(53,4,'CRC32','Syntax\n------\n\n<= MariaDB
10.7\n\nCRC32(expr)\n\nFrom MariaDB
10.8\n\nCRC32([par,]expr)\n\nDescription\n-----------\n\nComputes a cyclic
redundancy check (CRC) value and returns a 32-bit unsigned\nvalue. The
result is NULL if the argument is NULL. The argument is expected to\nbe a
string and (if possible) is treated as one if it is not.\n\nUses the ISO
3309 polynomial that used by zlib and many others. MariaDB 10.8\nintroduced
the CRC32C() function, which uses the alternate
Castagnoli\npolynomia.\n\nMariaDB starting with
10.8\n--------------------------\nOften, CRC is computed in pieces. To
facilitate this, MariaDB 10.8.0\nintroduced an optional parameter:
CRC32(\'MariaDB\')=CRC32(CRC32(\'Maria\'),\'DB\').\n\nExamples\n--------\n\nSELECT
CRC32(\'MariaDB\');\n+------------------+\n|
CRC32(\'MariaDB\') |\n+------------------+\n| 4227209140
|\n+------------------+\n\nSELECT
CRC32(\'mariadb\');\n+------------------+\n|
CRC32(\'mariadb\') |\n+------------------+\n| 2594253378
|\n+------------------+\n\nFrom MariaDB 10.8.0\n\nSELECT
CRC32(CRC32(\'Maria\'),\'DB\');\n+----------------------------+\n|
CRC32(CRC32(\'Maria\'),\'DB\')
|\n+----------------------------+\n| 4227209140
|\n+----------------------------+\n\nURL:
https://mariadb.com/kb/en/crc32/','','https://mariadb.com/kb/en/crc32/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(54,4,'DEGREES','Syntax\n------\n\nDEGREES(X)\n\nDescription\n-----------\n\nReturns
the argument X, converted from radians to degrees.\n\nThis is the converse
of the RADIANS() function.\n\nExamples\n--------\n\nSELECT
DEGREES(PI());\n+---------------+\n| DEGREES(PI()) |\n+---------------+\n|
180 |\n+---------------+\n\nSELECT DEGREES(PI() /
2);\n+-------------------+\n| DEGREES(PI() / 2) |\n+-------------------+\n|
90 |\n+-------------------+\n\nSELECT
DEGREES(45);\n+-----------------+\n| DEGREES(45)
|\n+-----------------+\n| 2578.3100780887 |\n+-----------------+\n\nURL:
https://mariadb.com/kb/en/degrees/','','https://mariadb.com/kb/en/degrees/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(55,4,'EXP','Syntax\n------\n\nEXP(X)\n\nDescription\n-----------\n\nReturns
the value of e (the base of natural logarithms) raised to the power of\nX.
The inverse of this function is LOG() (using a single argument only)
or\nLN().\n\nIf X is NULL, this function returns
NULL.\n\nExamples\n--------\n\nSELECT EXP(2);\n+------------------+\n|
EXP(2) |\n+------------------+\n| 7.38905609893065
|\n+------------------+\n\nSELECT EXP(-2);\n+--------------------+\n|
EXP(-2) |\n+--------------------+\n| 0.1353352832366127
|\n+--------------------+\n\nSELECT EXP(0);\n+--------+\n| EXP(0)
|\n+--------+\n| 1 |\n+--------+\n\nSELECT
EXP(NULL);\n+-----------+\n| EXP(NULL) |\n+-----------+\n| NULL
|\n+-----------+\n\nURL:
https://mariadb.com/kb/en/exp/','','https://mariadb.com/kb/en/exp/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(56,4,'FLOOR','Syntax\n------\n\nFLOOR(X)\n\nDescription\n-----------\n\nReturns
the largest integer value not greater than
X.\n\nExamples\n--------\n\nSELECT FLOOR(1.23);\n+-------------+\n|
FLOOR(1.23) |\n+-------------+\n| 1 |\n+-------------+\n\nSELECT
FLOOR(-1.23);\n+--------------+\n| FLOOR(-1.23) |\n+--------------+\n|
-2 |\n+--------------+\n\nURL:
https://mariadb.com/kb/en/floor/','','https://mariadb.com/kb/en/floor/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(57,4,'LN','Syntax\n------\n\nLN(X)\n\nDescription\n-----------\n\nReturns
the natural logarithm of X; that is, the base-e logarithm of X. If X\nis
less than or equal to 0, or NULL, then NULL is returned.\n\nThe inverse of
this function is EXP().\n\nExamples\n--------\n\nSELECT
LN(2);\n+-------------------+\n| LN(2)
|\n+-------------------+\n| 0.693147180559945
|\n+-------------------+\n\nSELECT LN(-2);\n+--------+\n| LN(-2)
|\n+--------+\n| NULL |\n+--------+\n\nURL:
https://mariadb.com/kb/en/ln/','','https://mariadb.com/kb/en/ln/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(58,4,'LOG','Syntax\n------\n\nLOG(X),
LOG(B,X)\n\nDescription\n-----------\n\nIf called with one parameter, this
function returns the natural logarithm of\nX. If X is less than or equal to
0, then NULL is returned.\n\nIf called with two parameters, it returns the
logarithm of X to the base B. If\nB is <= 1 or X <= 0, the function
returns NULL.\n\nIf any argument is NULL, the function returns NULL.\n\nThe
inverse of this function (when called with a single argument) is the
EXP()\nfunction.\n\nExamples\n--------\n\nLOG(X):\n\nSELECT
LOG(2);\n+-------------------+\n| LOG(2)
|\n+-------------------+\n| 0.693147180559945
|\n+-------------------+\n\nSELECT LOG(-2);\n+---------+\n| LOG(-2)
|\n+---------+\n| NULL |\n+---------+\n\nLOG(B,X)\n\nSELECT
LOG(2,16);\n+-----------+\n| LOG(2,16) |\n+-----------+\n| 4
|\n+-----------+\n\nSELECT LOG(3,27);\n+-----------+\n| LOG(3,27)
|\n+-----------+\n| 3 |\n+-----------+\n\nSELECT
LOG(3,1);\n+----------+\n| LOG(3,1) |\n+----------+\n| 0
|\n+----------+\n\nSELECT LOG(3,0);\n+----------+\n| LOG(3,0)
|\n+----------+\n| NULL |\n+----------+\n\nURL:
https://mariadb.com/kb/en/log/','','https://mariadb.com/kb/en/log/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(59,4,'LOG10','Syntax\n------\n\nLOG10(X)\n\nDescription\n-----------\n\nReturns
the base-10 logarithm of X.\n\nExamples\n--------\n\nSELECT
LOG10(2);\n+-------------------+\n| LOG10(2)
|\n+-------------------+\n| 0.301029995663981
|\n+-------------------+\n\nSELECT LOG10(100);\n+------------+\n|
LOG10(100) |\n+------------+\n| 2 |\n+------------+\n\nSELECT
LOG10(-100);\n+-------------+\n| LOG10(-100) |\n+-------------+\n|
NULL |\n+-------------+\n\nURL:
https://mariadb.com/kb/en/log10/','','https://mariadb.com/kb/en/log10/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(60,4,'LOG2','Syntax\n------\n\nLOG2(X)\n\nDescription\n-----------\n\nReturns
the base-2 logarithm of X.\n\nExamples\n--------\n\nSELECT
LOG2(4398046511104);\n+---------------------+\n| LOG2(4398046511104)
|\n+---------------------+\n| 42
|\n+---------------------+\n\nSELECT LOG2(65536);\n+-------------+\n|
LOG2(65536) |\n+-------------+\n| 16 |\n+-------------+\n\nSELECT
LOG2(-100);\n+------------+\n| LOG2(-100) |\n+------------+\n| NULL
|\n+------------+\n\nURL:
https://mariadb.com/kb/en/log2/','','https://mariadb.com/kb/en/log2/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(61,4,'MOD','Syntax\n------\n\nMOD(N,M), N % M, N MOD
M\n\nDescription\n-----------\n\nModulo operation. Returns the remainder of
N divided by M. See also Modulo\nOperator.\n\nIf the
ERROR_ON_DIVISION_BY_ZERO SQL_MODE is used, any number modulus
zero\nproduces an error. Otherwise, it returns NULL.\n\nThe integer part of
a division can be obtained using DIV.\n\nExamples\n--------\n\nSELECT 1042
% 50;\n+-----------+\n| 1042 % 50 |\n+-----------+\n| 42
|\n+-----------+\n\nSELECT MOD(234, 10);\n+--------------+\n| MOD(234, 10)
|\n+--------------+\n| 4 |\n+--------------+\n\nSELECT 253 %
7;\n+---------+\n| 253 % 7 |\n+---------+\n| 1
|\n+---------+\n\nSELECT MOD(29,9);\n+-----------+\n| MOD(29,9)
|\n+-----------+\n| 2 |\n+-----------+\n\nSELECT 29 MOD
9;\n+----------+\n| 29 MOD 9 |\n+----------+\n| 2
|\n+----------+\n\nURL:
https://mariadb.com/kb/en/mod/','','https://mariadb.com/kb/en/mod/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(62,4,'OCT','Syntax\n------\n\nOCT(N)\n\nDescription\n-----------\n\nReturns
a string representation of the octal value of N, where N is a
longlong\n(BIGINT) number. This is equivalent to CONV(N,10,8). Returns NULL
if N is NULL.\n\nExamples\n--------\n\nSELECT OCT(34);\n+---------+\n|
OCT(34) |\n+---------+\n| 42 |\n+---------+\n\nSELECT
OCT(12);\n+---------+\n| OCT(12) |\n+---------+\n| 14
|\n+---------+\n\nURL:
https://mariadb.com/kb/en/oct/','','https://mariadb.com/kb/en/oct/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(63,4,'PI','Syntax\n------\n\nPI()\n\nDescription\n-----------\n\nReturns
the value of π (pi). The default number of decimal places displayed
is\nsix, but MariaDB uses the full double-precision value
internally.\n\nExamples\n--------\n\nSELECT PI();\n+----------+\n| PI()
|\n+----------+\n| 3.141593 |\n+----------+\n\nSELECT
PI()+0.0000000000000000000000;\n+-------------------------------+\n|
PI()+0.0000000000000000000000 |\n+-------------------------------+\n|
3.1415926535897931159980 |\n+-------------------------------+\n\nURL:
https://mariadb.com/kb/en/pi/','','https://mariadb.com/kb/en/pi/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(64,4,'POW','Syntax\n------\n\nPOW(X,Y)\n\nDescription\n-----------\n\nReturns
the value of X raised to the power of Y.\n\nPOWER() is a
synonym.\n\nExamples\n--------\n\nSELECT POW(2,3);\n+----------+\n|
POW(2,3) |\n+----------+\n| 8 |\n+----------+\n\nSELECT
POW(2,-2);\n+-----------+\n| POW(2,-2) |\n+-----------+\n| 0.25
|\n+-----------+\n\nURL:
https://mariadb.com/kb/en/pow/','','https://mariadb.com/kb/en/pow/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(65,4,'POWER','Syntax\n------\n\nPOWER(X,Y)\n\nDescription\n-----------\n\nThis
is a synonym for POW(), which returns the value of X raised to the
power\nof Y.\n\nURL:
https://mariadb.com/kb/en/power/','','https://mariadb.com/kb/en/power/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(66,4,'RADIANS','Syntax\n------\n\nRADIANS(X)\n\nDescription\n-----------\n\nReturns
the argument X, converted from degrees to radians. Note that π
radians\nequals 180 degrees.\n\nThis is the converse of the DEGREES()
function.\n\nExamples\n--------\n\nSELECT
RADIANS(45);\n+-------------------+\n| RADIANS(45)
|\n+-------------------+\n| 0.785398163397448
|\n+-------------------+\n\nSELECT RADIANS(90);\n+-----------------+\n|
RADIANS(90) |\n+-----------------+\n| 1.5707963267949
|\n+-----------------+\n\nSELECT RADIANS(PI());\n+--------------------+\n|
RADIANS(PI()) |\n+--------------------+\n| 0.0548311355616075
|\n+--------------------+\n\nSELECT RADIANS(180);\n+------------------+\n|
RADIANS(180) |\n+------------------+\n| 3.14159265358979
|\n+------------------+\n\nURL:
https://mariadb.com/kb/en/radians/','','https://mariadb.com/kb/en/radians/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(67,4,'RAND','Syntax\n------\n\nRAND(),
RAND(N)\n\nDescription\n-----------\n\nReturns a random DOUBLE precision
floating point value v in the range 0 <= v <\n1.0. If a constant
integer argument N is specified, it is used as the seed\nvalue, which
produces a repeatable sequence of column values. In the example\nbelow,
note that the sequences of values produced by RAND(3) is the same
both\nplaces where it occurs.\n\nIn a WHERE clause, RAND() is evaluated
each time the WHERE is executed.\n\nStatements using the RAND() function
are not safe for statement-based\nreplication.\n\nPractical
uses\n--------------\n\nThe expression to get a random integer from a given
range is the following:\n\nFLOOR(min_value + RAND() * (max_value -
min_value +1))\n\nRAND() is often used to read random rows from a table, as
follows:\n\nSELECT * FROM my_table ORDER BY RAND() LIMIT 10;\n\nNote,
however, that this technique should never be used on a large table as
it\nwill be extremely slow. MariaDB will read all rows in the table,
generate a\nrandom value for each of them, order them, and finally will
apply the LIMIT\nclause.\n\nExamples\n--------\n\nCREATE TABLE t (i
INT);\n\nINSERT INTO t VALUES(1),(2),(3);\n\nSELECT i, RAND() FROM
t;\n+------+-------------------+\n| i | RAND()
|\n+------+-------------------+\n| 1 | 0.255651095188829 |\n| 2 |
0.833920199269355 |\n| 3 | 0.40264774151393
|\n+------+-------------------+\n\nSELECT i, RAND(3) FROM
t;\n+------+-------------------+\n| i | RAND(3)
|\n+------+-------------------+\n| 1 | 0.90576975597606 |\n| 2 |
0.373079058130345 |\n| 3 | 0.148086053457191
|\n+------+-------------------+\n\nSELECT i, RAND() FROM
t;\n+------+-------------------+\n| i | RAND()
|\n+------+-------------------+\n| 1 | 0.511478140495232 |\n| 2 |
0.349447508668012 |\n| 3 | 0.212803152588013
|\n+------+-------------------+\n\nUsing the same seed, the same sequence
will be returned:\n\nSELECT i, RAND(3) FROM
t;\n+------+-------------------+\n| i | RAND(3)
|\n+------+-------------------+\n| 1 | 0.90576975597606 |\n| 2 |
0.373079058130345 |\n| 3 | 0.148086053457191
|\n+------+-------------------+\n\nGenerating a random number from 5 to
15:\n\nSELECT FLOOR(5 + (RAND() * 11));\n\nURL:
https://mariadb.com/kb/en/rand/','','https://mariadb.com/kb/en/rand/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(68,4,'ROUND','Syntax\n------\n\nROUND(X),
ROUND(X,D)\n\nDescription\n-----------\n\nRounds the argument X to D
decimal places. D defaults to 0 if not specified. D\ncan be negative to
cause D digits left of the decimal point of the value X to\nbecome
zero.\n\nThe rounding algorithm depends on the data type of X:\n\n* for
floating point types (FLOAT, DOUBLE) the C libraries rounding function\nis
used, so the behavior *may* differ between operating systems\n* for fixed
point types (DECIMAL, DEC/NUMBER/FIXED) the \"round half up\"
rule\nis used, meaning that e.g. a value ending in exactly .5 is always
rounded up.\n\nExamples\n--------\n\nSELECT
ROUND(-1.23);\n+--------------+\n| ROUND(-1.23) |\n+--------------+\n|
-1 |\n+--------------+\n\nSELECT ROUND(-1.58);\n+--------------+\n|
ROUND(-1.58) |\n+--------------+\n| -2
|\n+--------------+\n\nSELECT ROUND(1.58); \n+-------------+\n| ROUND(1.58)
|\n+-------------+\n| 2 |\n+-------------+\n\nSELECT ROUND(1.298,
1);\n+-----------------+\n| ROUND(1.298, 1) |\n+-----------------+\n|
1.3 |\n+-----------------+\n\nSELECT ROUND(1.298,
0);\n+-----------------+\n| ROUND(1.298, 0) |\n+-----------------+\n|
1 |\n+-----------------+\n\nSELECT ROUND(23.298,
-1);\n+-------------------+\n| ROUND(23.298, -1)
|\n+-------------------+\n| 20
|\n+-------------------+\n\nURL:
https://mariadb.com/kb/en/round/','','https://mariadb.com/kb/en/round/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(69,4,'SIGN','Syntax\n------\n\nSIGN(X)\n\nDescription\n-----------\n\nReturns
the sign of the argument as -1, 0, or 1, depending on whether X
is\nnegative, zero, or positive.\n\nExamples\n--------\n\nSELECT
SIGN(-32);\n+-----------+\n| SIGN(-32) |\n+-----------+\n| -1
|\n+-----------+\n\nSELECT SIGN(0);\n+---------+\n| SIGN(0)
|\n+---------+\n| 0 |\n+---------+\n\nSELECT
SIGN(234);\n+-----------+\n| SIGN(234) |\n+-----------+\n| 1
|\n+-----------+\n\nURL:
https://mariadb.com/kb/en/sign/','','https://mariadb.com/kb/en/sign/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(70,4,'SIN','Syntax\n------\n\nSIN(X)\n\nDescription\n-----------\n\nReturns
the sine of X, where X is given in radians.\n\nExamples\n--------\n\nSELECT
SIN(1.5707963267948966);\n+-------------------------+\n|
SIN(1.5707963267948966) |\n+-------------------------+\n|
1 |\n+-------------------------+\n\nSELECT
SIN(PI());\n+----------------------+\n| SIN(PI())
|\n+----------------------+\n| 1.22460635382238e-16
|\n+----------------------+\n\nSELECT
ROUND(SIN(PI()));\n+------------------+\n| ROUND(SIN(PI()))
|\n+------------------+\n| 0 |\n+------------------+\n\nURL:
https://mariadb.com/kb/en/sin/','','https://mariadb.com/kb/en/sin/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(71,4,'SQRT','Syntax\n------\n\nSQRT(X)\n\nDescription\n-----------\n\nReturns
the square root of X. If X is negative, NULL is
returned.\n\nExamples\n--------\n\nSELECT SQRT(4);\n+---------+\n| SQRT(4)
|\n+---------+\n| 2 |\n+---------+\n\nSELECT
SQRT(20);\n+------------------+\n| SQRT(20)
|\n+------------------+\n| 4.47213595499958
|\n+------------------+\n\nSELECT SQRT(-16);\n+-----------+\n| SQRT(-16)
|\n+-----------+\n| NULL |\n+-----------+\n\nSELECT
SQRT(1764);\n+------------+\n| SQRT(1764) |\n+------------+\n| 42
|\n+------------+\n\nURL:
https://mariadb.com/kb/en/sqrt/','','https://mariadb.com/kb/en/sqrt/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(72,4,'TAN','Syntax\n------\n\nTAN(X)\n\nDescription\n-----------\n\nReturns
the tangent of X, where X is given in
radians.\n\nExamples\n--------\n\nSELECT
TAN(0.7853981633974483);\n+-------------------------+\n|
TAN(0.7853981633974483) |\n+-------------------------+\n|
0.9999999999999999 |\n+-------------------------+\n\nSELECT
TAN(PI());\n+-----------------------+\n| TAN(PI())
|\n+-----------------------+\n| -1.22460635382238e-16
|\n+-----------------------+\n\nSELECT TAN(PI()+1);\n+-----------------+\n|
TAN(PI()+1) |\n+-----------------+\n| 1.5574077246549
|\n+-----------------+\n\nSELECT
TAN(RADIANS(PI()));\n+--------------------+\n| TAN(RADIANS(PI()))
|\n+--------------------+\n| 0.0548861508080033
|\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/tan/','','https://mariadb.com/kb/en/tan/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(73,4,'TRUNCATE','This page documents the TRUNCATE function.
See TRUNCATE TABLE for the
DDL\nstatement.\n\nSyntax\n------\n\nTRUNCATE(X,D)\n\nDescription\n-----------\n\nReturns
the number X, truncated to D decimal places. If D is 0, the result has\nno
decimal point or fractional part. D can be negative to cause D digits
left\nof the decimal point of the value X to become
zero.\n\nExamples\n--------\n\nSELECT
TRUNCATE(1.223,1);\n+-------------------+\n| TRUNCATE(1.223,1)
|\n+-------------------+\n| 1.2
|\n+-------------------+\n\nSELECT
TRUNCATE(1.999,1);\n+-------------------+\n| TRUNCATE(1.999,1)
|\n+-------------------+\n| 1.9
|\n+-------------------+\n\nSELECT TRUNCATE(1.999,0);
\n+-------------------+\n| TRUNCATE(1.999,0) |\n+-------------------+\n|
1 |\n+-------------------+\n\nSELECT
TRUNCATE(-1.999,1);\n+--------------------+\n| TRUNCATE(-1.999,1)
|\n+--------------------+\n| -1.9
|\n+--------------------+\n\nSELECT
TRUNCATE(122,-2);\n+------------------+\n| TRUNCATE(122,-2)
|\n+------------------+\n| 100
|\n+------------------+\n\nSELECT
TRUNCATE(10.28*100,0);\n+-----------------------+\n| TRUNCATE(10.28*100,0)
|\n+-----------------------+\n| 1028
|\n+-----------------------+\n\nURL:
https://mariadb.com/kb/en/truncate/','','https://mariadb.com/kb/en/truncate/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(74,5,'INSTALL PLUGIN','Syntax\n------\n\nINSTALL PLUGIN [IF
NOT EXISTS] plugin_name SONAME
\'plugin_library\'\n\nDescription\n-----------\n\nThis statement
installs an individual plugin from the specified library. To\ninstall the
whole library (which could be required), use INSTALL SONAME. See\nalso
Installing a Plugin.\n\nplugin_name is the name of the plugin as defined in
the plugin declaration\nstructure contained in the library file. Plugin
names are not case sensitive.\nFor maximal compatibility, plugin names
should be limited to ASCII letters,\ndigits, and underscore, because they
are used in C source files, shell command\nlines, M4 and Bourne shell
scripts, and SQL environments.\n\nplugin_library is the name of the shared
library that contains the plugin\ncode. The file name extension can be
omitted (which makes the statement look\nthe same on all
architectures).\n\nThe shared library must be located in the plugin
directory (that is, the\ndirectory named by the plugin_dir system
variable). The library must be in the\nplugin directory itself, not in a
subdirectory. By default, plugin_dir is\nplugin directory under the
directory named by the pkglibdir configuration\nvariable, but it can be
changed by setting the value of plugin_dir at server\nstartup. For example,
set its value in a my.cnf
file:\n\n[mysqld]\nplugin_dir=/path/to/plugin/directory\nIf the value of
plugin_dir is a relative path name, it is taken to be relative\nto the
MySQL base directory (the value of the basedir system variable).\n\nINSTALL
PLUGIN adds a line to the mysql.plugin table that describes the\nplugin.
This table contains the plugin name and library file name.\n\nINSTALL
PLUGIN causes the server to read option (my.cnf) files just as
during\nserver startup. This enables the plugin to pick up any relevant
options from\nthose files. It is possible to add plugin options to an
option file even\nbefore loading a plugin (if the loose prefix is used). It
is also possible to\nuninstall a plugin, edit my.cnf, and install the
plugin again. Restarting the\nplugin this way enables it to the new option
values without a server restart.\n\nINSTALL PLUGIN also loads and
initializes the plugin code to make the plugin\navailable for use. A plugin
is initialized by executing its initialization\nfunction, which handles any
setup that the plugin must perform before it can\nbe used.\n\nTo use
INSTALL PLUGIN, you must have the INSERT privilege for the
mysql.plugin\ntable.\n\nAt server startup, the server loads and initializes
any plugin that is listed\nin the mysql.plugin table. This means that a
plugin is installed with INSTALL\nPLUGIN only once, not every time the
server starts. Plugin loading at startup\ndoes not occur if the server is
started with the --skip-grant-tables option.\n\nWhen the server shuts down,
it executes the de-initialization function for\neach plugin that is loaded
so that the plugin has a chance to perform any\nfinal cleanup.\n\nIf you
need to load plugins for a single server startup when
the\n--skip-grant-tables option is given (which tells the server not to
read system\ntables), use the --plugin-load mysqld option.\n\nMariaDB
starting with 10.4.0\n----------------------------\n\nIF NOT
EXISTS\n-------------\n\nWhen the IF NOT EXISTS clause is used, MariaDB
will return a note instead of\nan error if the specified plugin already
exists. See SHOW WARNINGS.\n\nExamples\n--------\n\nINSTALL PLUGIN sphinx
SONAME \'ha_sphinx.so\';\n\nThe extension can also be
omitted:\n\nINSTALL PLUGIN innodb SONAME \'ha_xtradb\';\n\nFrom
MariaDB 10.4.0:\n\nINSTALL PLUGIN IF NOT EXISTS example SONAME
\'ha_example\';\nQuery OK, 0 rows affected (0.104 sec)\n\nINSTALL
PLUGIN IF NOT EXISTS example SONAME \'ha_example\';\nQuery OK, 0
rows affected, 1 warning (0.000 sec)\n\nSHOW
WARNINGS;\n+-------+------+------------------------------------+\n| Level |
Code | Message
|\n+-------+------+------------------------------------+\n| Note | 1968 |
Plugin \'example\' already installed
|\n+-------+------+------------------------------------+\n\nURL:
https://mariadb.com/kb/en/install-plugin/','','https://mariadb.com/kb/en/install-plugin/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(75,5,'UNINSTALL PLUGIN','Syntax\n------\n\nUNINSTALL PLUGIN
[IF EXISTS] plugin_name\n\nDescription\n-----------\n\nThis statement
removes a single installed plugin. To uninstall the whole\nlibrary which
contains the plugin, use UNINSTALL SONAME. You cannot uninstall\na plugin
if any table that uses it is open.\n\nplugin_name must be the name of some
plugin that is listed in the mysql.plugin\ntable. The server executes the
plugin\'s deinitialization function and removes\nthe row for the
plugin from the mysql.plugin table, so that subsequent server\nrestarts
will not load and initialize the plugin. UNINSTALL PLUGIN does not\nremove
the plugin\'s shared library file.\n\nTo use UNINSTALL PLUGIN, you
must have the DELETE privilege for the\nmysql.plugin table.\n\nMariaDB
starting with 10.4.0\n----------------------------\n\nIF
EXISTS\n---------\n\nIf the IF EXISTS clause is used, MariaDB will return a
note instead of an\nerror if the plugin does not exist. See SHOW
WARNINGS.\n\nExamples\n--------\n\nUNINSTALL PLUGIN example;\n\nFrom
MariaDB 10.4.0:\n\nUNINSTALL PLUGIN IF EXISTS example;\nQuery OK, 0 rows
affected (0.099 sec)\n\nUNINSTALL PLUGIN IF EXISTS example;\nQuery OK, 0
rows affected, 1 warning (0.000 sec)\n\nSHOW
WARNINGS;\n+-------+------+-------------------------------+\n| Level | Code
| Message
|\n+-------+------+-------------------------------+\n| Note | 1305 |
PLUGIN example does not exist
|\n+-------+------+-------------------------------+\n\nURL:
https://mariadb.com/kb/en/uninstall-plugin/','','https://mariadb.com/kb/en/uninstall-plugin/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(76,5,'INSTALL SONAME','Syntax\n------\n\nINSTALL SONAME
\'plugin_library\'\n\nDescription\n-----------\n\nThis statement
is a variant of INSTALL PLUGIN. It installs all plugins from a\ngiven
plugin_library. See INSTALL PLUGIN for details.\n\nplugin_library is the
name of the shared library that contains the plugin\ncode. The file name
extension (for example, libmyplugin.so or libmyplugin.dll)\ncan be omitted
(which makes the statement look the same on all architectures).\n\nThe
shared library must be located in the plugin directory (that is,
the\ndirectory named by the plugin_dir system variable). The library must
be in the\nplugin directory itself, not in a subdirectory. By default,
plugin_dir is\nplugin directory under the directory named by the pkglibdir
configuration\nvariable, but it can be changed by setting the value of
plugin_dir at server\nstartup. For example, set its value in a my.cnf
file:\n\n[mysqld]\nplugin_dir=/path/to/plugin/directory\nIf the value of
plugin_dir is a relative path name, it is taken to be relative\nto the
MySQL base directory (the value of the basedir system variable).\n\nINSTALL
SONAME adds one or more lines to the mysql.plugin table that describes\nthe
plugin. This table contains the plugin name and library file
name.\n\nINSTALL SONAME causes the server to read option (my.cnf) files
just as during\nserver startup. This enables the plugin to pick up any
relevant options from\nthose files. It is possible to add plugin options to
an option file even\nbefore loading a plugin (if the loose prefix is used).
It is also possible to\nuninstall a plugin, edit my.cnf, and install the
plugin again. Restarting the\nplugin this way enables it to the new option
values without a server restart.\n\nINSTALL SONAME also loads and
initializes the plugin code to make the plugin\navailable for use. A plugin
is initialized by executing its initialization\nfunction, which handles any
setup that the plugin must perform before it can\nbe used.\n\nTo use
INSTALL SONAME, you must have the INSERT privilege for the
mysql.plugin\ntable.\n\nAt server startup, the server loads and initializes
any plugin that is listed\nin the mysql.plugin table. This means that a
plugin is installed with INSTALL\nSONAME only once, not every time the
server starts. Plugin loading at startup\ndoes not occur if the server is
started with the --skip-grant-tables option.\n\nWhen the server shuts down,
it executes the de-initialization function for\neach plugin that is loaded
so that the plugin has a chance to perform any\nfinal cleanup.\n\nIf you
need to load plugins for a single server startup when
the\n--skip-grant-tables option is given (which tells the server not to
read system\ntables), use the --plugin-load mysqld option.\n\nIf you need
to install only one plugin from a library, use the INSTALL
PLUGIN\nstatement.\n\nExamples\n--------\n\nTo load the XtraDB storage
engine and all of its information_schema tables\nwith one statement,
use\n\nINSTALL SONAME \'ha_xtradb\';\n\nThis statement can be
used instead of INSTALL PLUGIN even when the library\ncontains only one
plugin:\n\nINSTALL SONAME \'ha_sequence\';\n\nURL:
https://mariadb.com/kb/en/install-soname/','','https://mariadb.com/kb/en/install-soname/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(77,5,'UNINSTALL SONAME','Syntax\n------\n\nUNINSTALL SONAME
[IF EXISTS]
\'plugin_library\'\n\nDescription\n-----------\n\nThis statement
is a variant of UNINSTALL PLUGIN statement, that removes all\nplugins
belonging to a specified plugin_library. See UNINSTALL PLUGIN
for\ndetails.\n\nplugin_library is the name of the shared library that
contains the plugin\ncode. The file name extension (for example,
libmyplugin.so or libmyplugin.dll)\ncan be omitted (which makes the
statement look the same on all architectures).\n\nTo use UNINSTALL SONAME,
you must have the DELETE privilege for the\nmysql.plugin table.\n\nMariaDB
starting with 10.4.0\n----------------------------\n\nIF
EXISTS\n---------\n\nIf the IF EXISTS clause is used, MariaDB will return a
note instead of an\nerror if the plugin library does not exist. See SHOW
WARNINGS.\n\nExamples\n--------\n\nTo uninstall the XtraDB plugin and all
of its information_schema tables with\none statement, use\n\nUNINSTALL
SONAME \'ha_xtradb\';\n\nFrom MariaDB 10.4.0:\n\nUNINSTALL SONAME
IF EXISTS \'ha_example\';\nQuery OK, 0 rows affected (0.099
sec)\n\nUNINSTALL SONAME IF EXISTS \'ha_example\';\nQuery OK, 0
rows affected, 1 warning (0.000 sec)\n\nSHOW
WARNINGS;\n+-------+------+-------------------------------------+\n| Level
| Code | Message
|\n+-------+------+-------------------------------------+\n| Note | 1305 |
SONAME ha_example.so does not exist
|\n+-------+------+-------------------------------------+\n\nURL:
https://mariadb.com/kb/en/uninstall-soname/','','https://mariadb.com/kb/en/uninstall-soname/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(78,5,'Plugin Overview','Plugins are server components that
enhance MariaDB in some way. These can be\nanything from new storage
engines, plugins for enhancing full-text parsing, or\neven small
enhancements, such as a plugin to get a timestamp as an
integer.\n\nQuerying Plugin
Information\n---------------------------\n\nThere are a number of ways to
see which plugins are currently active.\n\nA server almost always has a
large number of active plugins, because the\nserver contains a large number
of built-in plugins, which are active by\ndefault and cannot be
uninstalled.\n\nQuerying Plugin Information with SHOW
PLUGINS\n---------------------------------------------\n\nThe SHOW PLUGINS
statement can be used to query information about all
active\nplugins.\n\nFor example:\n\nSHOW
PLUGINS\\G;\n********************** 1. row **********************\n Name:
binlog\n Status: ACTIVE\n Type: STORAGE ENGINE\nLibrary: NULL\nLicense:
GPL\n********************** 2. row **********************\n Name:
mysql_native_password\n Status: ACTIVE\n Type: AUTHENTICATION\nLibrary:
NULL\nLicense: GPL\n********************** 3. row **********************\n
Name: mysql_old_password\n Status: ACTIVE\n Type: AUTHENTICATION\nLibrary:
NULL\nLicense: GPL\n...\n\nIf a plugin\'s Library column has a NULL
value, then the plugin is built-in,\nand it cannot be
uninstalled.\n\nQuerying Plugin Information with
information_schema.PLUGINS\n-----------------------------------------------------------\n\nThe
information_schema.PLUGINS table can be queried to get more
detailed\ninformation about plugins.\n\nFor example:\n\nSELECT * FROM
information_schema.PLUGINS\\G\n...\n*************************** 6. row
***************************\n PLUGIN_NAME: CSV\n PLUGIN_VERSION:
1.0\n PLUGIN_STATUS: ACTIVE\n PLUGIN_TYPE: STORAGE ENGINE\n
PLUGIN_TYPE_VERSION: 100003.0\n PLUGIN_LIBRARY:
NULL\nPLUGIN_LIBRARY_VERSION: NULL\n PLUGIN_AUTHOR: Brian Aker, MySQL
AB\n PLUGIN_DESCRIPTION: CSV storage engine\n PLUGIN_LICENSE: GPL\n
LOAD_OPTION: FORCE\n PLUGIN_MATURITY: Stable\n PLUGIN_AUTH_VERSION:
1.0\n*************************** 7. row ***************************\n
PLUGIN_NAME: MEMORY\n PLUGIN_VERSION: 1.0\n PLUGIN_STATUS: ACTIVE\n
PLUGIN_TYPE: STORAGE ENGINE\n PLUGIN_TYPE_VERSION: 100003.0\n
PLUGIN_LIBRARY: NULL\nPLUGIN_LIBRARY_VERSION: NULL\n PLUGIN_AUTHOR:
MySQL AB\n PLUGIN_DESCRIPTION: Hash based, stored in memory, useful for
temporary\ntables\n PLUGIN_LICENSE: GPL\n LOAD_OPTION: FORCE\n
PLUGIN_MATURITY: Stable\n PLUGIN_AUTH_VERSION: 1.0\n...\n\nIf a
plugin\'s PLUGIN_LIBRARY column has the NULL value, then the plugin
is\nbuilt-in, and it cannot be uninstalled.\n\nQuerying Plugin Information
with mysql.plugin\n---------------------------------------------\n\nThe
mysql.plugin table can be queried to get information about
installed\nplugins.\n\nThis table only contains information about plugins
that have been installed\nvia the following methods:\n\n* The INSTALL
SONAME statement.\n* The INSTALL PLUGIN statement.\n* The mysql_plugin
utility.\n\nThis table does not contain information about:\n\n* Built-in
plugins.\n* Plugins loaded with the --plugin-load-add option.\n* Plugins
loaded with the --plugin-load option.\n\nThis table only contains enough
information to reload the plugin when the\nserver is restarted, which means
it only contains the plugin name and the\nplugin library.\n\nFor
example:\n\nSELECT * FROM mysql.plugin;\n\n+------+------------+\n| name |
dl |\n+------+------------+\n| PBXT | libpbxt.so
|\n+------+------------+\n\nInstalling a
Plugin\n-------------------\n\nThere are three primary ways to install a
plugin:\n\n* A plugin can be installed dynamically with an SQL
statement.\n* A plugin can be installed with a mysqld option, but it
requires a server\nrestart.\n* A plugin can be installed with the
mysql_plugin utility, while the server is\ncompletely offline.\n\nWhen you
are installing a plugin, you also have to ensure that:\n\n* The
server\'s plugin directory is properly configured, and the
plugin\'s\nlibrary is in the plugin directory.\n* The server\'s
minimum plugin maturity is properly configured, and the plugin\nis mature
enough to be installed.\n\nInstalling a Plugin
Dynamically\n-------------------------------\n\nA plugin can be installed
dynamically by executing either the INSTALL SONAME\nor the INSTALL PLUGIN
statement.\n\nIf a plugin is installed with one of these statements, then a
record will be\nadded to the mysql.plugins table for the plugin. This means
that the plugin\nwill automatically be loaded every time the server
restarts, unless\nspecifically uninstalled or deactivated.\n\nInstalling a
Plugin with INSTALL SONAME\n---------------------------------------\n\nYou
can install a plugin dynamically by executing the INSTALL
SONAME\nstatement. INSTALL SONAME installs all plugins from the given
plugin library.\nThis could be required for some plugin libraries.\n\nFor
example, to install all plugins in the server_audit plugin library
(which\nis currently only the server_audit audit plugin), you could execute
the\nfollowing:\n\nINSTALL SONAME \'server_audit\';\n\nInstalling
a Plugin with INSTALL
PLUGIN\n---------------------------------------\n\nYou can install a plugin
dynamically by executing the INSTALL PLUGIN\nstatement. INSTALL PLUGIN
installs a single plugin from the given plugin\nlibrary.\n\nFor example, to
install the server_audit audit plugin from the server_audit\nplugin
library, you could execute the following:\n\nINSTALL PLUGIN server_audit
SONAME \'server_audit\';\n\nInstalling a Plugin with Plugin Load
Options\n--------------------------------------------\n\nA plugin can be
installed with a mysqld option by providing either the\n--plugin-load-add
or the --plugin-load option.\n\nIf a plugin is installed with one of these
options, then a record will not be\nadded to the mysql.plugins table for
the plugin. This means that if the server\nis restarted without the same
option set, then the plugin will not\nautomatically be
loaded.\n\nInstalling a Plugin with
--plugin-load-add\n------------------------------------------\n\nYou can
install a plugin with the --plugin-load-add option by specifying
the\noption as a command-line argument to mysqld or by specifying the
option in a\nrelevant server option group in an option file.\n\nThe
--plugin-load-add option uses the following format:\n\n* Plugins can be
specified in the format name=library, where name is the\nplugin name and
library is the plugin library. This format installs a single\nplugin from
the given plugin library.\n* Plugins can also be specified in the format
library, where library is the\nplugin library. This format installs all
plugins from the given plugin library.\n* Multiple plugins can be specified
by separating them with semicolons.\n\nFor example, to install all plugins
in the server_audit plugin library (which\nis currently only the
server_audit audit plugin) and also the ed25519\nauthentication plugin from
the auth_ed25519 plugin library, you could set the\noption to the following
values on the command-line:\n\n$ mysqld --user=mysql
--plugin-load-add=\'server_audit\'\n--plugin-load-add=\'ed25519=auth_ed25519\'\n\nYou
could also set the option to the same values in an option
file:\n\n[mariadb]\n...\nplugin_load_add = server_audit\nplugin_load_add =
ed25519=auth_ed25519\n\nSpecial care must be taken when specifying both the
--plugin-load option and\nthe --plugin-load-add option together. The
--plugin-load option resets the\nplugin load list, and this can cause
unexpected problems if you are not aware.\nThe --plugin-load-add option
does not reset the plugin load list, so it is\nmuch safer to use. See
Specifying Multiple Plugin Load Options for
more\ninformation.\n\nInstalling a Plugin with
--plugin-load\n--------------------------------------\n\nYou can install a
plugin with the --plugin-load option by specifying the\noption as a
command-line argument to mysqld or by specifying the option in a\nrelevant
server option group in an option file.\n\nThe --plugin-load option uses the
following format:\n\n* Plugins can be specified in the format name=library,
where name is the\nplugin name and library is the plugin library. This
format installs a single\nplugin from the given plugin library.\n* Plugins
can also be specified in the format library, where library is the\nplugin
library. This format installs all plugins from the given plugin library.\n*
Multiple plugins can be specified by separating them with
semicolons.\n\nFor example, to install all plugins in the server_audit
plugin library (which\nis currently only the server_audit audit plugin) and
also the ed25519\nauthentication plugin from the auth_ed25519 plugin
library, you could set the\noption to the following values on the
command-line:\n\n$ mysqld --user=mysql
--plugin-load=\'server_audit;ed25519=auth_ed25519\'\n\nYou could
also set the option to the same values in an option
file:\n\n[mariadb]\n...\nplugin_load =
server_audit;ed25519=auth_ed25519\n\nSpecial care must be taken when
specifying the --plugin-load option multiple\ntimes, or when specifying
both the --plugin-load option and the\n--plugin-load-add option together.
The --plugin-load option resets the plugin\nload list, and this can cause
unexpected problems if you are not aware. The\n--plugin-load-add option
does not reset the plugin load list, so it is much\nsafer to use. See
Specifying Multiple Plugin Load Options for more information.\n\nSpecifying
Multiple Plugin Load
Options\n---------------------------------------\n\nSpecial care must be
taken when specifying the --plugin-load option multiple\ntimes, or when
specifying both the --plugin-load option and the\n--plugin-load-add option.
The --plugin-load option resets the plugin load\nlist, and this can cause
unexpected problems if you are not aware. The\n--plugin-load-add option
does not reset the plugin load list, so it is much\nsafer to use.\n\nThis
can have the following consequences:\n\n* If the --plugin-load option is
specified multiple times, then only the last\ninstance will have any
effect. For example, in the following case, the first\ninstance of the
option is reset:\n\n[mariadb]\n...\nplugin_load = server_audit\nplugin_load
= ed25519=auth_ed25519\n\n* If the --plugin-load option is specified after
the --plugin-load-add option,\nthen it will also reset the changes made by
that option. For example, in the\nfollowing case, the --plugin-load-add
option does not do anything, because the\nsubsequent --plugin-load option
resets the plugin load list:\n\n[mariadb]\n...\nplugin_load_add =
server_audit\nplugin_load = ed25519=auth_ed25519\n\n* In contrast, if the
--plugin-load option is specified before the\n--plugin-load-add option,
then it will work fine, because the\n--plugin-load-add option does not
reset the plugin load list. For example, in\nthe following case, both
plugins are properly loaded:\n\n[mariadb]\n...\nplugin_load =
server_audit\nplugin_load_add = ed25519=auth_ed25519\n\nInstalling a Plugin
with mysql_plugin\n-------------------------------------\n\nA plugin can be
installed with the mysql_plugin utility if the server is\ncompletely
offline.\n\nThe syntax is:\n\nmysql_plugin [options] <plugin>
ENABLE|DISABLE\n\nFor example, to install the server_audit audit plugin,
you could execute the\nfollowing:\n\nmysql_plugin server_audit ENABLE\n\nIf
a plugin is installed with this utility, then a record will be added to
the\nmysql.plugins table for the plugin. This means that the plugin
will\nautomatically be loaded every time the server restarts, unless
specifically\nuninstalled or deactivated.\n\nConfiguring the Plugin
Directory\n--------------------------------\n\nWhen a plugin is being
installed, the server looks for the plugin\'s library in\nthe
server\'s plugin directory. This directory is configured by the
plugin_dir\nsystem variable. This can be specified as a command-line
argument to mysqld or\nit can be specified in a relevant server option
group in an option file. For\nexample:\n\n[mariadb]\n...\nplugin_dir =
/usr/lib64/mysql/plugin\n\nConfiguring the Minimum Plugin
Maturity\n---------------------------------------\n\nWhen a plugin is being
installed, the server compares the plugin\'s maturity\nlevel against
the server\'s minimum allowed plugin maturity. This can help\nprevent
users from using unstable plugins on production servers. This
minimum\nplugin maturity is configured by the plugin_maturity system
variable. This can\nbe specified as a command-line argument to mysqld or it
can be specified in a\nrelevant server option group in an option file. For
example:\n\n[mariadb]\n...\nplugin_maturity = stable\n\nConfiguring Plugin
Activation at Server
Startup\n-----------------------------------------------\n\nA plugin will
be loaded by default when the server starts if:\n\n* The plugin was
installed with the INSTALL SONAME statement.\n* The plugin was installed
with the INSTALL PLUGIN statement.\n* The plugin was installed with the
mysql_plugin utility.\n* The server is configured to load the plugin with
the --plugin-load-add\noption.\n* The server is configured to load the
plugin with the --plugin-load option.\n\nThis behavior can be changed with
special options that take the form\n--plugin-name. For example, for the
server_audit audit plugin, the special\noption is called
--server-audit.\n\nThe possible values for these special options
are:\n\n+---------------------------------------+------------------------------------+\n|
Option Value | Description
|\n+---------------------------------------+------------------------------------+\n|
OFF | Disables the plugin without
|\n| | removing it from the
|\n| | mysql.plugins table.
|\n+---------------------------------------+------------------------------------+\n|
ON | Enables the plugin. If the plugin
|\n| | cannot be initialized, then
the |\n| | server will still
continue |\n| | starting up,
but the plugin will |\n| | be
disabled.
|\n+---------------------------------------+------------------------------------+\n|
FORCE | Enables the plugin. If the plugin
|','','https://mariadb.com/kb/en/plugin-overview/');
update help_topic set description = CONCAT(description, '\n|
| cannot be initialized, then the |\n|
| server will fail to start with an |\n|
| error.
|\n+---------------------------------------+------------------------------------+\n|
FORCE_PLUS_PERMANENT | Enables the plugin. If the plugin
|\n| | cannot be initialized, then
the |\n| | server will fail to
start with an |\n| | error. In
addition, the plugin |\n| |
cannot be uninstalled with |\n|
| UNINSTALL SONAME or UNINSTALL |\n|
| PLUGIN while the server is |\n|
| running.
|\n+---------------------------------------+------------------------------------+\n\nA
plugin\'s status can be found by looking at the PLUGIN_STATUS column
of the\ninformation_schema.PLUGINS table.\n\nUninstalling
Plugins\n--------------------\n\nPlugins that are found in the mysql.plugin
table, that is those that were\ninstalled with INSTALL SONAME, INSTALL
PLUGIN or mysql_plugin can be\nuninstalled in one of two ways:\n\n* The
UNINSTALL SONAME or the UNINSTALL PLUGIN statement while the server
is\nrunning\n* With mysql_plugin while the server is offline.\n\nPlugins
that were enabled as a --plugin-load option do not need to be\nuninstalled.
If --plugin-load is omitted the next time the server starts, or\nthe plugin
is not listed as one of the --plugin-load entries, the plugin will\nnot be
loaded.\n\nUNINSTALL PLUGIN uninstalls a single installed plugin, while
UNINSTALL SONAME\nuninstalls all plugins belonging to a given
library.\n\nURL: https://mariadb.com/kb/en/plugin-overview/') WHERE
help_topic_id = 78;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(79,6,'MBR Definition','Description\n-----------\n\nThe MBR
(Minimum Bounding Rectangle), or Envelope is the bounding geometry,\nformed
by the minimum and maximum (X,Y)
coordinates:\n\nExamples\n--------\n\n((MINX MINY, MAXX MINY, MAXX MAXY,
MINX MAXY, MINX MINY))\n\nURL:
https://mariadb.com/kb/en/mbr-definition/','','https://mariadb.com/kb/en/mbr-definition/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(80,6,'MBRContains','Syntax\n------\n\nMBRContains(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether the Minimum Bounding Rectangle of g1\ncontains
the Minimum Bounding Rectangle of g2. This tests the opposite\nrelationship
as MBRWithin().\n\nExamples\n--------\n\nSET @g1 =
GeomFromText(\'Polygon((0 0,0 3,3 3,3 0,0 0))\');\n\nSET @g2 =
GeomFromText(\'Point(1 1)\');\n\nSELECT MBRContains(@g1,@g2),
MBRContains(@g2,@g1);\n+----------------------+----------------------+\n|
MBRContains(@g1,@g2) | MBRContains(@g2,@g1)
|\n+----------------------+----------------------+\n| 1
| 0
|\n+----------------------+----------------------+\n\nURL:
https://mariadb.com/kb/en/mbrcontains/','','https://mariadb.com/kb/en/mbrcontains/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(81,6,'MBRDisjoint','Syntax\n------\n\nMBRDisjoint(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether the Minimum Bounding Rectangles of the
two\ngeometries g1 and g2 are disjoint. Two geometries are disjoint if they
do not\nintersect, that is touch or overlap.\n\nExamples\n--------\n\nSET
@g1 = GeomFromText(\'Polygon((0 0,0 3,3 3,3 0,0 0))\');\nSET @g2
= GeomFromText(\'Polygon((4 4,4 7,7 7,7 4,4
4))\');\nSELECTmbrdisjoint(@g1,@g2);\n+----------------------+\n|
mbrdisjoint(@g1,@g2) |\n+----------------------+\n| 1
|\n+----------------------+\n\nSET @g1 = GeomFromText(\'Polygon((0 0,0
3,3 3,3 0,0 0))\');\nSET @g2 = GeomFromText(\'Polygon((3 3,3 6,6
6,6 3,3 3))\');\nSELECT
mbrdisjoint(@g1,@g2);\n+----------------------+\n| mbrdisjoint(@g1,@g2)
|\n+----------------------+\n| 0
|\n+----------------------+\n\nURL:
https://mariadb.com/kb/en/mbrdisjoint/','','https://mariadb.com/kb/en/mbrdisjoint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(82,6,'MBREqual','Syntax\n------\n\nMBREqual(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether the Minimum Bounding Rectangles of the
two\ngeometries g1 and g2 are the same.\n\nExamples\n--------\n\nSET
@g1=GEOMFROMTEXT(\'LINESTRING(0 0, 1 2)\');\nSET
@g2=GEOMFROMTEXT(\'POLYGON((0 0, 0 2, 1 2, 1 0, 0 0))\');\nSELECT
MbrEqual(@g1,@g2);\n+-------------------+\n| MbrEqual(@g1,@g2)
|\n+-------------------+\n| 1
|\n+-------------------+\n\nSET @g1=GEOMFROMTEXT(\'LINESTRING(0 0, 1
3)\');\nSET @g2=GEOMFROMTEXT(\'POLYGON((0 0, 0 2, 1 4, 1 0, 0
0))\');\nSELECT MbrEqual(@g1,@g2);\n+-------------------+\n|
MbrEqual(@g1,@g2) |\n+-------------------+\n| 0
|\n+-------------------+\n\nURL:
https://mariadb.com/kb/en/mbrequal/','','https://mariadb.com/kb/en/mbrequal/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(83,6,'MBRIntersects','Syntax\n------\n\nMBRIntersects(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether the Minimum Bounding Rectangles of the
two\ngeometries g1 and g2 intersect.\n\nExamples\n--------\n\nSET @g1 =
GeomFromText(\'Polygon((0 0,0 3,3 3,3 0,0 0))\');\nSET @g2 =
GeomFromText(\'Polygon((3 3,3 6,6 6,6 3,3 3))\');\nSELECT
mbrintersects(@g1,@g2);\n+------------------------+\n|
mbrintersects(@g1,@g2) |\n+------------------------+\n|
1 |\n+------------------------+\n\nSET @g1 =
GeomFromText(\'Polygon((0 0,0 3,3 3,3 0,0 0))\');\nSET @g2 =
GeomFromText(\'Polygon((4 4,4 7,7 7,7 4,4 4))\');\nSELECT
mbrintersects(@g1,@g2);\n+------------------------+\n|
mbrintersects(@g1,@g2) |\n+------------------------+\n|
0 |\n+------------------------+\n\nURL:
https://mariadb.com/kb/en/mbrintersects/','','https://mariadb.com/kb/en/mbrintersects/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(84,6,'MBROverlaps','Syntax\n------\n\nMBROverlaps(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether the Minimum Bounding Rectangles of the
two\ngeometries g1 and g2 overlap. The term spatially overlaps is used if
two\ngeometries intersect and their intersection results in a geometry of
the same\ndimension but not equal to either of the given
geometries.\n\nExamples\n--------\n\nSET @g1 =
GeomFromText(\'Polygon((0 0,0 3,3 3,3 0,0 0))\');\nSET @g2 =
GeomFromText(\'Polygon((4 4,4 7,7 7,7 4,4 4))\');\nSELECT
mbroverlaps(@g1,@g2);\n+----------------------+\n| mbroverlaps(@g1,@g2)
|\n+----------------------+\n| 0
|\n+----------------------+\n\nSET @g1 = GeomFromText(\'Polygon((0 0,0
3,3 3,3 0,0 0))\');\nSET @g2 = GeomFromText(\'Polygon((3 3,3 6,6
6,6 3,3 3))\');\nSELECT
mbroverlaps(@g1,@g2);\n+----------------------+\n| mbroverlaps(@g1,@g2)
|\n+----------------------+\n| 0
|\n+----------------------+\n\nSET @g1 = GeomFromText(\'Polygon((0 0,0
4,4 4,4 0,0 0))\');\nSET @g2 = GeomFromText(\'Polygon((3 3,3 6,6
6,6 3,3 3))\');\nSELECT
mbroverlaps(@g1,@g2);\n+----------------------+\n| mbroverlaps(@g1,@g2)
|\n+----------------------+\n| 1
|\n+----------------------+\n\nURL:
https://mariadb.com/kb/en/mbroverlaps/','','https://mariadb.com/kb/en/mbroverlaps/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(85,6,'MBRTouches','Syntax\n------\n\nMBRTouches(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether the Minimum Bounding Rectangles of the
two\ngeometries g1 and g2 touch. Two geometries spatially touch if the
interiors of\nthe geometries do not intersect, but the boundary of one of
the geometries\nintersects either the boundary or the interior of the
other.\n\nExamples\n--------\n\nSET @g1 = GeomFromText(\'Polygon((0
0,0 3,3 3,3 0,0 0))\');\nSET @g2 = GeomFromText(\'Polygon((4 4,4
7,7 7,7 4,4 4))\');\nSELECT
mbrtouches(@g1,@g2);\n+---------------------+\n| mbrtouches(@g1,@g2)
|\n+---------------------+\n| 0
|\n+---------------------+\n\nSET @g1 = GeomFromText(\'Polygon((0 0,0
3,3 3,3 0,0 0))\');\nSET @g2 = GeomFromText(\'Polygon((3 3,3 6,6
6,6 3,3 3))\');\nSELECT
mbrtouches(@g1,@g2);\n+---------------------+\n| mbrtouches(@g1,@g2)
|\n+---------------------+\n| 1
|\n+---------------------+\n\nSET @g1 = GeomFromText(\'Polygon((0 0,0
4,4 4,4 0,0 0))\');\nSET @g2 = GeomFromText(\'Polygon((3 3,3 6,6
6,6 3,3 3))\');\nSELECT
mbrtouches(@g1,@g2);\n+---------------------+\n| mbrtouches(@g1,@g2)
|\n+---------------------+\n| 0
|\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/mbrtouches/','','https://mariadb.com/kb/en/mbrtouches/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(86,6,'MBRWithin','Syntax\n------\n\nMBRWithin(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether the Minimum Bounding Rectangle of g1 is\nwithin
the Minimum Bounding Rectangle of g2. This tests the opposite\nrelationship
as MBRContains().\n\nExamples\n--------\n\nSET @g1 =
GeomFromText(\'Polygon((0 0,0 3,3 3,3 0,0 0))\');\nSET @g2 =
GeomFromText(\'Polygon((0 0,0 5,5 5,5 0,0 0))\');\nSELECT
MBRWithin(@g1,@g2),
MBRWithin(@g2,@g1);\n+--------------------+--------------------+\n|
MBRWithin(@g1,@g2) | MBRWithin(@g2,@g1)
|\n+--------------------+--------------------+\n| 1 |
0 |\n+--------------------+--------------------+\n\nURL:
https://mariadb.com/kb/en/mbrwithin/','','https://mariadb.com/kb/en/mbrwithin/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(87,7,'CASE OPERATOR','Syntax\n------\n\nCASE value WHEN
[compare_value] THEN result [WHEN [compare_value] THEN\nresult ...] [ELSE
result] END\n\nCASE WHEN [condition] THEN result [WHEN [condition] THEN
result ...]\n[ELSE result] END\n\nDescription\n-----------\n\nThe first
version returns the result where value=compare_value. The second\nversion
returns the result for the first condition that is true. If there was\nno
matching result value, the result after ELSE is returned, or NULL if
there\nis no ELSE part.\n\nThere is also a CASE statement, which differs
from the CASE operator described\nhere.\n\nExamples\n--------\n\nSELECT
CASE 1 WHEN 1 THEN \'one\' WHEN 2 THEN \'two\' ELSE
\'more\'
END;\n+------------------------------------------------------------+\n|
CASE 1 WHEN 1 THEN \'one\' WHEN 2 THEN \'two\' ELSE
\'more\' END
|\n+------------------------------------------------------------+\n| one
|\n+------------------------------------------------------------+\n\nSELECT
CASE WHEN 1>0 THEN \'true\' ELSE \'false\'
END;\n+--------------------------------------------+\n| CASE WHEN 1>0
THEN \'true\' ELSE \'false\' END
|\n+--------------------------------------------+\n| true
|\n+--------------------------------------------+\n\nSELECT CASE BINARY
\'B\' WHEN \'a\' THEN 1 WHEN \'b\' THEN 2
END;\n+-----------------------------------------------------+\n| CASE
BINARY \'B\' WHEN \'a\' THEN 1 WHEN \'b\'
THEN 2 END |\n+-----------------------------------------------------+\n|
NULL
|\n+-----------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/case-operator/','','https://mariadb.com/kb/en/case-operator/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(88,7,'IF
Function','Syntax\n------\n\nIF(expr1,expr2,expr3)\n\nDescription\n-----------\n\nIf
expr1 is TRUE (expr1 <> 0 and expr1 <> NULL) then IF() returns
expr2;\notherwise it returns expr3. IF() returns a numeric or string value,
depending\non the context in which it is used.\n\nNote: There is also an IF
statement which differs from the IF() function\ndescribed
here.\n\nExamples\n--------\n\nSELECT IF(1>2,2,3);\n+-------------+\n|
IF(1>2,2,3) |\n+-------------+\n| 3
|\n+-------------+\n\nSELECT
IF(1<2,\'yes\',\'no\');\n+--------------------+\n|
IF(1<2,\'yes\',\'no\') |\n+--------------------+\n|
yes |\n+--------------------+\n\nSELECT
IF(STRCMP(\'test\',\'test1\'),\'no\',\'yes\');\n+---------------------------------------+\n|
IF(STRCMP(\'test\',\'test1\'),\'no\',\'yes\')
|\n+---------------------------------------+\n| no
|\n+---------------------------------------+\n\nURL:
https://mariadb.com/kb/en/if-function/','','https://mariadb.com/kb/en/if-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(89,7,'IFNULL','Syntax\n------\n\nIFNULL(expr1,expr2)\nNVL(expr1,expr2)\n\nDescription\n-----------\n\nIf
expr1 is not NULL, IFNULL() returns expr1; otherwise it returns
expr2.\nIFNULL() returns a numeric or string value, depending on the
context in which\nit is used.\n\nFrom MariaDB 10.3, NVL() is an alias for
IFNULL().\n\nExamples\n--------\n\nSELECT IFNULL(1,0); \n+-------------+\n|
IFNULL(1,0) |\n+-------------+\n| 1 |\n+-------------+\n\nSELECT
IFNULL(NULL,10);\n+-----------------+\n| IFNULL(NULL,10)
|\n+-----------------+\n| 10 |\n+-----------------+\n\nSELECT
IFNULL(1/0,10);\n+----------------+\n| IFNULL(1/0,10)
|\n+----------------+\n| 10.0000 |\n+----------------+\n\nSELECT
IFNULL(1/0,\'yes\');\n+-------------------+\n|
IFNULL(1/0,\'yes\') |\n+-------------------+\n| yes
|\n+-------------------+\n\nURL:
https://mariadb.com/kb/en/ifnull/','','https://mariadb.com/kb/en/ifnull/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(90,7,'NULLIF','Syntax\n------\n\nNULLIF(expr1,expr2)\n\nDescription\n-----------\n\nReturns
NULL if expr1 = expr2 is true, otherwise returns expr1. This is the\nsame
as CASE WHEN expr1 = expr2 THEN NULL ELSE expr1
END.\n\nExamples\n--------\n\nSELECT NULLIF(1,1);\n+-------------+\n|
NULLIF(1,1) |\n+-------------+\n| NULL |\n+-------------+\n\nSELECT
NULLIF(1,2);\n+-------------+\n| NULLIF(1,2) |\n+-------------+\n|
1 |\n+-------------+\n\nURL:
https://mariadb.com/kb/en/nullif/','','https://mariadb.com/kb/en/nullif/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(91,7,'NVL','MariaDB starting with
10.3\n--------------------------\nFrom MariaDB 10.3, NVL is a synonym for
IFNULL.\n\nURL:
https://mariadb.com/kb/en/nvl/','','https://mariadb.com/kb/en/nvl/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(92,7,'NVL2','MariaDB starting with
10.3\n--------------------------\nThe NLV2 function was introduced in
MariaDB
10.3.0.\n\nSyntax\n------\n\nNVL2(expr1,expr2,expr3)\n\nDescription\n-----------\n\nThe
NVL2 function returns a value based on whether a specified expression
is\nNULL or not. If expr1 is not NULL, then NVL2 returns expr2. If expr1 is
NULL,\nthen NVL2 returns expr3.\n\nExamples\n--------\n\nSELECT
NVL2(NULL,1,2);\n+----------------+\n| NVL2(NULL,1,2)
|\n+----------------+\n| 2 |\n+----------------+\n\nSELECT
NVL2(\'x\',1,2);\n+---------------+\n| NVL2(\'x\',1,2)
|\n+---------------+\n| 1 |\n+---------------+\n\nURL:
https://mariadb.com/kb/en/nvl2/','','https://mariadb.com/kb/en/nvl2/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(93,8,'SET TRANSACTION','Syntax\n------\n\nSET [GLOBAL |
SESSION] TRANSACTION\n transaction_property [, transaction_property]
...\n\ntransaction_property:\n ISOLATION LEVEL level\n | READ WRITE\n |
READ ONLY\n\nlevel:\n REPEATABLE READ\n | READ COMMITTED\n | READ
UNCOMMITTED\n | SERIALIZABLE\n\nDescription\n-----------\n\nThis statement
sets the transaction isolation level or the transaction access\nmode
globally, for the current session, or for the next transaction:\n\n* With
the GLOBAL keyword, the statement sets the default\n transaction level
globally for all subsequent sessions. Existing sessions are\n
unaffected.\n* With the SESSION keyword, the statement sets the default\n
transaction level for all subsequent transactions performed within the\n
current session.\n* Without any SESSION or GLOBAL keyword,\n the statement
sets the isolation level for the next (not started) transaction\n performed
within the current session.\n\nA change to the global default isolation
level requires the SUPER privilege.\nAny session is free to change its
session isolation level (even in the middle\nof a transaction), or the
isolation level for its next transaction.\n\nIsolation
Level\n---------------\n\nTo set the global default isolation level at
server startup, use the\n--transaction-isolation=level option on the
command line or in an option file.\nValues of level for this option use
dashes rather than spaces, so the\nallowable values are READ-UNCOMMITTED,
READ-COMMITTED, REPEATABLE-READ, or\nSERIALIZABLE. For example, to set the
default isolation level to REPEATABLE\nREAD, use these lines in the
[mysqld] section of an option file:\n\n[mysqld]\ntransaction-isolation =
REPEATABLE-READ\nTo determine the global and session transaction isolation
levels at runtime,\ncheck the value of the tx_isolation system
variable:\n\nSELECT @@GLOBAL.tx_isolation, @@tx_isolation;\n\nInnoDB
supports each of the translation isolation levels described here
using\ndifferent locking strategies. The default level is REPEATABLE READ.
For\nadditional information about InnoDB record-level locks and how it uses
them to\nexecute various types of statements, see InnoDB Lock Modes,
and\nhttp://dev.mysql.com/doc/refman/en/innodb-locks-set.html.\n\nIsolation
Levels\n----------------\n\nThe following sections describe how MariaDB
supports the different transaction\nlevels.\n\nREAD
UNCOMMITTED\n----------------\n\nSELECT statements are performed in a
non-locking fashion, but a possible\nearlier version of a row might be
used. Thus, using this isolation level, such\nreads are not consistent.
This is also called a \"dirty read.\" Otherwise, this\nisolation
level works like READ COMMITTED.\n\nREAD COMMITTED\n--------------\n\nA
somewhat Oracle-like isolation level with respect to
consistent\n(non-locking) reads: Each consistent read, even within the same
transaction,\nsets and reads its own fresh snapshot.
See\nhttp://dev.mysql.com/doc/refman/en/innodb-consistent-read.html.\n\nFor
locking reads (SELECT with FOR UPDATE or LOCK IN SHARE MODE), InnoDB
locks\nonly index records, not the gaps before them, and thus allows the
free\ninsertion of new records next to locked records. For UPDATE and
DELETE\nstatements, locking depends on whether the statement uses a unique
index with\na unique search condition (such as WHERE id = 100), or a
range-type search\ncondition (such as WHERE id > 100). For a unique
index with a unique search\ncondition, InnoDB locks only the index record
found, not the gap before it.\nFor range-type searches, InnoDB locks the
index range scanned, using gap locks\nor next-key (gap plus index-record)
locks to block insertions by other\nsessions into the gaps covered by the
range. This is necessary because\n\"phantom rows\" must be
blocked for MySQL replication and recovery to work.\n\nNote: If the READ
COMMITTED isolation level is used or the\ninnodb_locks_unsafe_for_binlog
system variable is enabled, there is no InnoDB\ngap locking except for
foreign-key constraint checking and duplicate-key\nchecking. Also, record
locks for non-matching rows are released after MariaDB\nhas evaluated the
WHERE condition.If you use READ COMMITTED or
enable\ninnodb_locks_unsafe_for_binlog, you must use row-based binary
logging.\n\nREPEATABLE READ\n---------------\n\nThis is the default
isolation level for InnoDB. For consistent reads, there is\nan important
difference from the READ COMMITTED isolation level: All\nconsistent reads
within the same transaction read the snapshot established by\nthe first
read. This convention means that if you issue several plain\n(non-locking)
SELECT statements within the same transaction, these SELECT\nstatements are
consistent also with respect to each other.
See\nhttp://dev.mysql.com/doc/refman/en/innodb-consistent-read.html.\n\nFor
locking reads (SELECT with FOR UPDATE or LOCK IN SHARE MODE), UPDATE,
and\nDELETE statements, locking depends on whether the statement uses a
unique\nindex with a unique search condition, or a range-type search
condition. For a\nunique index with a unique search condition, InnoDB locks
only the index\nrecord found, not the gap before it. For other search
conditions, InnoDB locks\nthe index range scanned, using gap locks or
next-key (gap plus index-record)\nlocks to block insertions by other
sessions into the gaps covered by the range.\n\nThis is the minimum
isolation level for non-distributed XA
transactions.\n\nSERIALIZABLE\n------------\n\nThis level is like
REPEATABLE READ, but InnoDB implicitly converts all plain\nSELECT
statements to SELECT ... LOCK IN SHARE MODE if autocommit is disabled.\nIf
autocommit is enabled, the SELECT is its own transaction. It therefore
is\nknown to be read only and can be serialized if performed as a
consistent\n(non-locking) read and need not block for other transactions.
(This means that\nto force a plain SELECT to block if other transactions
have modified the\nselected rows, you should disable
autocommit.)\n\nDistributed XA transactions should always use this
isolation level.\n\nAccess Mode\n-----------\n\nThe access mode specifies
whether the transaction is allowed to write data or\nnot. By default,
transactions are in READ WRITE mode (see the tx_read_only\nsystem
variable). READ ONLY mode allows the storage engine to apply\noptimizations
that cannot be used for transactions which write data. The only\nexception
to this rule is that read only transactions can perform DDL\nstatements on
temporary tables.\n\nIt is not permitted to specify both READ WRITE and
READ ONLY in the same\nstatement.\n\nREAD WRITE and READ ONLY can also be
specified in the START TRANSACTION\nstatement, in which case the specified
mode is only valid for one transaction.\n\nExamples\n--------\n\nSET GLOBAL
TRANSACTION ISOLATION LEVEL SERIALIZABLE;\n\nAttempting to set the
isolation level within an existing transaction without\nspecifying GLOBAL
or SESSION.\n\nSTART TRANSACTION;\n\nSET TRANSACTION ISOLATION LEVEL
SERIALIZABLE;\nERROR 1568 (25001): Transaction characteristics can\'t
be changed while a\ntransaction is in progress\n\nURL:
https://mariadb.com/kb/en/set-transaction/','','https://mariadb.com/kb/en/set-transaction/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(94,8,'START TRANSACTION','Syntax\n------\n\nSTART
TRANSACTION [transaction_property [, transaction_property] ...] |
BEGIN\n[WORK]\nCOMMIT [WORK] [AND [NO] CHAIN] [[NO] RELEASE]\nROLLBACK
[WORK] [AND [NO] CHAIN] [[NO] RELEASE]\nSET autocommit = {0 |
1}\n\ntransaction_property:\n WITH CONSISTENT SNAPSHOT\n | READ WRITE\n |
READ ONLY\n\nDescription\n-----------\n\nThe START TRANSACTION or BEGIN
statement begins a new transaction. COMMIT\ncommits the current
transaction, making its changes permanent. ROLLBACK rolls\nback the current
transaction, canceling its changes. The SET autocommit\nstatement disables
or enables the default autocommit mode for the current\nsession.\n\nSTART
TRANSACTION and SET autocommit = 1 implicitly commit the
current\ntransaction, if any.\n\nThe optional WORK keyword is supported for
COMMIT and ROLLBACK, as are the\nCHAIN and RELEASE clauses. CHAIN and
RELEASE can be used for additional\ncontrol over transaction completion.
The value of the completion_type system\nvariable determines the default
completion behavior.\n\nThe AND CHAIN clause causes a new transaction to
begin as soon as the current\none ends, and the new transaction has the
same isolation level as the\njust-terminated transaction. The RELEASE
clause causes the server to\ndisconnect the current client session after
terminating the current\ntransaction. Including the NO keyword suppresses
CHAIN or RELEASE completion,\nwhich can be useful if the completion_type
system variable is set to cause\nchaining or release completion by
default.\n\nAccess Mode\n-----------\n\nThe access mode specifies whether
the transaction is allowed to write data or\nnot. By default, transactions
are in READ WRITE mode (see the tx_read_only\nsystem variable). READ ONLY
mode allows the storage engine to apply\noptimizations that cannot be used
for transactions which write data. The only\nexception to this rule is that
read only transactions can perform DDL\nstatements on temporary
tables.\n\nIt is not permitted to specify both READ WRITE and READ ONLY in
the same\nstatement.\n\nREAD WRITE and READ ONLY can also be specified in
the SET TRANSACTION\nstatement, in which case the specified mode is valid
for all sessions, or for\nall subsequent transaction used by the current
session.\n\nautocommit\n----------\n\nBy default, MariaDB runs with
autocommit mode enabled. This means that as soon\nas you execute a
statement that updates (modifies) a table, MariaDB stores the\nupdate on
disk to make it permanent. To disable autocommit mode, use the\nfollowing
statement:\n\nSET autocommit=0;\n\nAfter disabling autocommit mode by
setting the autocommit variable to zero,\nchanges to transaction-safe
tables (such as those for InnoDB or NDBCLUSTER)\nare not made permanent
immediately. You must use COMMIT to store your changes\nto disk or ROLLBACK
to ignore the changes.\n\nTo disable autocommit mode for a single series of
statements, use the START\nTRANSACTION statement.\n\nDDL
Statements\n--------------\n\nDDL statements (CREATE, ALTER, DROP) and
administrative statements (FLUSH,\nRESET, OPTIMIZE, ANALYZE, CHECK, REPAIR,
CACHE INDEX), transaction management\nstatements (BEGIN, START TRANSACTION)
and LOAD DATA INFILE, cause an implicit\nCOMMIT and start a new
transaction. An exception to this rule are the DDL that\noperate on
temporary tables: you can CREATE, ALTER and DROP them without\ncausing any
COMMIT, but those actions cannot be rolled back. This means that\nif you
call ROLLBACK, the temporary tables you created in the transaction
will\nremain, while the rest of the transaction will be rolled
back.\n\nTransactions cannot be used in Stored Functions or Triggers. In
Stored\nProcedures and Events BEGIN is not allowed, so you should use
START\nTRANSACTION instead.\n\nA transaction acquires a metadata lock on
every table it accesses to prevent\nother connections from altering their
structure. The lock is released at the\nend of the transaction. This
happens even with non-transactional storage\nengines (like MEMORY or
CONNECT), so it makes sense to use transactions with\nnon-transactional
tables.\n\nin_transaction\n--------------\n\nThe in_transaction system
variable is a session-only, read-only variable that\nreturns 1 inside a
transaction, and 0 if not in a transaction.\n\nWITH CONSISTENT
SNAPSHOT\n------------------------\n\nThe WITH CONSISTENT SNAPSHOT option
starts a consistent read for storage\nengines such as InnoDB that can do
so, the same as if a START TRANSACTION\nfollowed by a SELECT from any
InnoDB table was issued.\n\nSee Enhancements for START TRANSACTION WITH
CONSISTENT SNAPSHOT.\n\nExamples\n--------\n\nSTART TRANSACTION;\nSELECT
@A:=SUM(salary) FROM table1 WHERE type=1;\nUPDATE table2 SET summary=@A
WHERE type=1;\nCOMMIT;\n\nURL:
https://mariadb.com/kb/en/start-transaction/','','https://mariadb.com/kb/en/start-transaction/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(95,8,'COMMIT','The COMMIT statement ends a transaction,
saving any changes to the data so\nthat they become visible to subsequent
transactions. Also, unlocks metadata\nchanged by current transaction. If
autocommit is set to 1, an implicit commit\nis performed after each
statement. Otherwise, all transactions which don\'t end\nwith an
explicit COMMIT are implicitly rollbacked and the changes are lost.\nThe
ROLLBACK statement can be used to do this explicitly.\n\nThe required
syntax for the COMMIT statement is as follows:\n\nCOMMIT [WORK] [AND [NO]
CHAIN] [[NO] RELEASE]\n\nCOMMIT is the more important transaction
terminator, as well as the more\ninteresting one. The basic form of the
COMMIT statement is simply the keyword\nCOMMIT (the keyword WORK is simply
noise and can be omitted without changing\nthe effect).\n\nThe optional AND
CHAIN clause is a convenience for initiating a new\ntransaction as soon as
the old transaction terminates. If AND CHAIN is\nspecified, then there is
effectively nothing between the old and new\ntransactions, although they
remain separate. The characteristics of the new\ntransaction will be the
same as the characteristics of the old one — that is,\nthe new
transaction will have the same access mode, isolation level
and\ndiagnostics area size (we\'ll discuss all of these shortly) as
the transaction\njust terminated.\n\nRELEASE tells the server to disconnect
the client immediately after the\ncurrent transaction.\n\nThere are NO
RELEASE and AND NO CHAIN options. By default, commits do not\nRELEASE or
CHAIN, but it\'s possible to change this default behavior with
the\ncompletion_type server system variable. In this case, the AND NO CHAIN
and NO\nRELEASE options override the server default.\n\nURL:
https://mariadb.com/kb/en/commit/','','https://mariadb.com/kb/en/commit/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(96,8,'ROLLBACK','The ROLLBACK statement rolls back (ends) a
transaction, destroying any changes\nto SQL-data so that they never become
visible to subsequent transactions. The\nrequired syntax for the ROLLBACK
statement is as follows.\n\nROLLBACK [ WORK ] [ AND [ NO ] CHAIN ] \n[ TO [
SAVEPOINT ] {<savepoint name> | <simple target specification>}
]\n\nThe ROLLBACK statement will either end a transaction, destroying all
data\nchanges that happened during any of the transaction, or it will just
destroy\nany data changes that happened since you established a savepoint.
The basic\nform of the ROLLBACK statement is just the keyword ROLLBACK (the
keyword WORK\nis simply noise and can be omitted without changing the
effect).\n\nThe optional AND CHAIN clause is a convenience for initiating a
new\ntransaction as soon as the old transaction terminates. If AND CHAIN
is\nspecified, then there is effectively nothing between the old and
new\ntransactions, although they remain separate. The characteristics of
the new\ntransaction will be the same as the characteristics of the old one
— that is,\nthe new transaction will have the same access mode, isolation
level and\ndiagnostics area size (we\'ll discuss all of these shortly)
as the transaction\njust terminated. The AND NO CHAIN option just tells
your DBMS to end the\ntransaction — that is, these four SQL statements
are equivalent:\n\nROLLBACK; \nROLLBACK WORK; \nROLLBACK AND NO CHAIN;
\nROLLBACK WORK AND NO CHAIN;\n\nAll of them end a transaction without
saving any transaction characteristics.\nThe only other options, the
equivalent statements:\n\nROLLBACK AND CHAIN;\nROLLBACK WORK AND
CHAIN;\n\nboth tell your DBMS to end a transaction, but to save that
transaction\'s\ncharacteristics for the next transaction.\n\nROLLBACK
is much simpler than COMMIT: it may involve no more than a few\ndeletions
(of Cursors, locks, prepared SQL statements and log-file
entries).\nIt\'s usually assumed that ROLLBACK can\'t fail,
although such a thing is\nconceivable (for example, an encompassing
transaction might reject an attempt\nto ROLLBACK because it\'s lining
up for a COMMIT).\n\nROLLBACK cancels all effects of a transaction. It does
not cancel effects on\nobjects outside the DBMS\'s control (for
example the values in host program\nvariables or the settings made by some
SQL/CLI function calls). But in\ngeneral, it is a convenient statement for
those situations when you say \"oops,\nthis isn\'t working\"
or when you simply don\'t care whether your temporary work\nbecomes
permanent or not.\n\nHere is a moot question. If all you\'ve been
doing is SELECTs, so that there\nhave been no data changes, should you end
the transaction with ROLLBACK or\nCOMMIT? It shouldn\'t really matter
because both ROLLBACK and COMMIT do the\nsame transaction-terminating job.
However, the popular conception is that\nROLLBACK implies failure, so after
a successful series of SELECT statements\nthe convention is to end the
transaction with COMMIT rather than ROLLBACK.\n\nMariaDB (and most other
DBMSs) supports rollback of SQL-data change\nstatements, but not of
SQL-Schema statements. This means that if you use any\nof CREATE, ALTER,
DROP, GRANT, REVOKE, you are implicitly committing at\nexecution
time.\n\nINSERT INTO Table_2 VALUES(5); \nDROP TABLE Table_3 CASCADE;
\nROLLBACK;\n\nThe result will be that both the INSERT and the DROP will go
through as\nseparate transactions so the ROLLBACK will have no
effect.\n\nURL:
https://mariadb.com/kb/en/rollback/','','https://mariadb.com/kb/en/rollback/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(97,8,'LOCK TABLES','Syntax\n------\n\nLOCK TABLE[S]\n
tbl_name [[AS] alias] lock_type\n [, tbl_name [[AS] alias] lock_type]
...\n [WAIT n|NOWAIT]\n\nlock_type:\n READ [LOCAL]\n | [LOW_PRIORITY]
WRITE\n | WRITE CONCURRENT\n\nUNLOCK
TABLES\n\nDescription\n-----------\n\nThe lock_type can be one
of:\n\n+---------------------------+------------------------------------------------+\n|
Option | Description
|\n+---------------------------+------------------------------------------------+\n|
READ | Read lock, no writes allowed
|\n+---------------------------+------------------------------------------------+\n|
READ LOCAL | Read lock, but allow concurrent inserts
|\n+---------------------------+------------------------------------------------+\n|
WRITE | Exclusive write lock. No other connections
|\n| | can read or write to this table
|\n+---------------------------+------------------------------------------------+\n|
LOW_PRIORITY WRITE | Exclusive write lock, but allow new read
|\n| | locks on the table until we get the write
|\n| | lock.
|\n+---------------------------+------------------------------------------------+\n|
WRITE CONCURRENT | Exclusive write lock, but allow READ LOCAL
|\n| | locks to the table.
|\n+---------------------------+------------------------------------------------+\n\nMariaDB
enables client sessions to acquire table locks explicitly for the\npurpose
of cooperating with other sessions for access to tables, or to
prevent\nother sessions from modifying tables during periods when a session
requires\nexclusive access to them. A session can acquire or release locks
only for\nitself. One session cannot acquire locks for another session or
release locks\nheld by another session.\n\nLocks may be used to emulate
transactions or to get more speed when updating\ntables.\n\nLOCK TABLES
explicitly acquires table locks for the current client session.\nTable
locks can be acquired for base tables or views. To use LOCK TABLES,
you\nmust have the LOCK TABLES privilege, and the SELECT privilege for each
object\nto be locked. See GRANT\n\nFor view locking, LOCK TABLES adds all
base tables used in the view to the set\nof tables to be locked and locks
them automatically. If you lock a table\nexplicitly with LOCK TABLES, any
tables used in triggers are also locked\nimplicitly, as described in
Triggers and Implicit Locks.\n\nUNLOCK TABLES explicitly releases any table
locks held by the current session.\n\nMariaDB starting with
10.3.0\n----------------------------\n\nWAIT/NOWAIT\n-----------\n\nSet the
lock wait timeout. See WAIT and NOWAIT.\n\nLimitations\n-----------\n\n*
LOCK TABLES doesn\'t work when using Galera cluster. You may
experience\ncrashes or locks when used with Galera.\n* LOCK TABLES works on
XtraDB/InnoDB tables only if the innodb_table_locks\nsystem variable is set
to 1 (the default) and autocommit is set to 0 (1 is\ndefault). Please note
that no error message will be returned on LOCK TABLES\nwith
innodb_table_locks = 0.\n* LOCK TABLES implicitly commits the active
transaction, if any. Also,\nstarting a transaction always releases all
table locks acquired with LOCK\nTABLES. This means that there is no way to
have table locks and an active\ntransaction at the same time. The only
exceptions are the transactions in\nautocommit mode. To preserve the data
integrity between transactional and\nnon-transactional tables, the
GET_LOCK() function can be used.\n* When using LOCK TABLES on a TEMPORARY
table, it will always be locked with a\nWRITE lock.\n* While a connection
holds an explicit read lock on a table, it cannot modify\nit. If you try,
the following error will be produced:\n\nERROR 1099 (HY000): Table
\'tab_name\' was locked with a READ lock and can\'t
be\nupdated\n\n* While a connection holds an explicit lock on a table, it
cannot access a\nnon-locked table. If you try, the following error will be
produced:\n\nERROR 1100 (HY000): Table \'tab_name\' was not
locked with LOCK TABLES\n\n* While a connection holds an explicit lock on a
table, it cannot issue the\nfollowing: INSERT DELAYED, CREATE TABLE, CREATE
TABLE ... LIKE, and DDL\nstatements involving stored programs and views
(except for triggers). If you\ntry, the following error will be
produced:\n\nERROR 1192 (HY000): Can\'t execute the given command
because you have active\nlocked tables or an active transaction\n\n* LOCK
TABLES can not be used in stored routines - if you try, the
following\nerror will be produced on creation. This restriction was removed
in MariaDB\n10.6.2:\n\nERROR 1314 (0A000): LOCK is not allowed in stored
procedures\n\nURL:
https://mariadb.com/kb/en/lock-tables/','','https://mariadb.com/kb/en/lock-tables/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(98,8,'SAVEPOINT','Syntax\n------\n\nSAVEPOINT
identifier\nROLLBACK [WORK] TO [SAVEPOINT] identifier\nRELEASE SAVEPOINT
identifier\n\nDescription\n-----------\n\nInnoDB supports the SQL
statements SAVEPOINT, ROLLBACK TO SAVEPOINT, RELEASE\nSAVEPOINT and the
optional WORK keyword for ROLLBACK.\n\nEach savepoint must have a legal
MariaDB identifier. A savepoint is a named\nsub-transaction.\n\nNormally
ROLLBACK undoes the changes performed by the whole transaction. When\nused
with the TO clause, it undoes the changes performed after the
specified\nsavepoint, and erases all subsequent savepoints. However, all
locks that have\nbeen acquired after the save point will survive. RELEASE
SAVEPOINT does not\nrollback or commit any changes, but removes the
specified savepoint.\n\nWhen the execution of a trigger or a stored
function begins, it is not\npossible to use statements which reference a
savepoint which was defined from\nout of that stored program.\n\nWhen a
COMMIT (including implicit commits) or a ROLLBACK statement (with no
TO\nclause) is performed, they act on the whole transaction, and all
savepoints\nare removed.\n\nErrors\n------\n\nIf COMMIT or ROLLBACK is
issued and no transaction was started, no error is\nreported.\n\nIf
SAVEPOINT is issued and no transaction was started, no error is
reported\nbut no savepoint is created. When ROLLBACK TO SAVEPOINT or
RELEASE SAVEPOINT\nis called for a savepoint that does not exist, an error
like this is issued:\n\nERROR 1305 (42000): SAVEPOINT svp_name does not
exist\n\nURL:
https://mariadb.com/kb/en/savepoint/','','https://mariadb.com/kb/en/savepoint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(99,8,'Metadata Locking','MariaDB supports metadata locking.
This means that when a transaction\n(including XA transactions) uses a
table, it locks its metadata until the end\nof transaction.
Non-transactional tables are also locked, as well as views and\nobjects
which are related to locked tables/views (stored functions,
triggers,\netc). When a connection tries to use a DDL statement (like an
ALTER TABLE)\nwhich modifies a table that is locked, that connection is
queued, and has to\nwait until it\'s unlocked. Using savepoints and
performing a partial rollback\ndoes not release metadata locks.\n\nLOCK
TABLES ... WRITE are also queued. Some wrong statements which produce
an\nerror may not need to wait for the lock to be freed.\n\nThe metadata
lock\'s timeout is determined by the value of the\nlock_wait_timeout
server system variable (in seconds). However, note that its\ndefault value
is 31536000 (1 year, MariaDB <= 10.2.3), or 86400 (1 day,\nMariaDB >=
10.2.4). If this timeout is exceeded, the following error
is\nreturned:\n\nERROR 1205 (HY000): Lock wait timeout exceeded; try
restarting transaction\n\nIf the metadata_lock_info plugin is installed,
the Information Schema\nmetadata_lock_info table stores information about
existing metadata locks.\n\nMariaDB starting with
10.5.2\n----------------------------\nFrom MariaDB 10.5, the Performance
Schema metadata_locks table contains\nmetadata lock
information.\n\nExample\n-------\n\nLet\'s use the following MEMORY
(non-transactional) table:\n\nCREATE TABLE t (a INT) ENGINE =
MEMORY;\n\nConnection 1 starts a transaction, and INSERTs a row into
t:\n\nSTART TRANSACTION;\n\nINSERT INTO t SET a=1;\n\nt\'s metadata is
now locked by connection 1. Connection 2 tries to alter t, but\nhas to
wait:\n\nALTER TABLE t ADD COLUMN b INT;\n\nConnection 2\'s prompt is
blocked now.\n\nNow connection 1 ends the transaction:\n\nCOMMIT;\n\n...and
connection 2 finally gets the output of its command:\n\nQuery OK, 1 row
affected (35.23 sec)\nRecords: 1 Duplicates: 0 Warnings: 0\n\nURL:
https://mariadb.com/kb/en/metadata-locking/','','https://mariadb.com/kb/en/metadata-locking/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(100,8,'Transaction Timeouts','MariaDB has always had the
wait_timeout and interactive_timeout settings,\nwhich close connections
after a certain period of inactivity.\n\nHowever, these are by default set
to a long wait period. In situations where\ntransactions may be started,
but not committed or rolled back, more granular\ncontrol and a shorter
timeout may be desirable so as to avoid locks being held\nfor too
long.\n\nMariaDB 10.3 introduced three new variables to handle this
situation.\n\n* idle_transaction_timeout (all transactions)\n*
idle_write_transaction_timeout (write transactions -
called\nidle_readwrite_transaction_timeout until MariaDB 10.3.2)\n*
idle_readonly_transaction_timeout (read transactions)\n\nThese accept a
time in seconds to time out, by closing the connection,\ntransactions that
are idle for longer than this period. By default all are set\nto zero, or
no timeout.\n\nidle_transaction_timeout affects all
transactions,\nidle_write_transaction_timeout affects write transactions
only and\nidle_readonly_transaction_timeout affects read transactions only.
The latter\ntwo variables work independently. However, if either is set
along with\nidle_transaction_timeout, the settings for
idle_write_transaction_timeout or\nidle_readonly_transaction_timeout will
take precedence.\n\nExamples\n--------\n\nSET SESSION
idle_transaction_timeout=2;\nBEGIN;\nSELECT * FROM t;\nEmpty set (0.000
sec)\n## wait 3 seconds\nSELECT * FROM t;\nERROR 2006 (HY000): MySQL server
has gone away\n\nSET SESSION
idle_write_transaction_timeout=2;\nBEGIN;\nSELECT * FROM t;\nEmpty set
(0.000 sec)\n## wait 3 seconds\nSELECT * FROM t;\nEmpty set (0.000
sec)\nINSERT INTO t VALUES(1);\n## wait 3 seconds\nSELECT * FROM t;\nERROR
2006 (HY000): MySQL server has gone away\n\nSET SESSION
idle_transaction_timeout=2,
SESSION\nidle_readonly_transaction_timeout=10;\nBEGIN;\nSELECT * FROM
t;\nEmpty set (0.000 sec)\n ## wait 3 seconds\nSELECT * FROM t;\nEmpty set
(0.000 sec)\n## wait 11 seconds\nSELECT * FROM t;\nERROR 2006 (HY000):
MySQL server has gone away\n\nURL:
https://mariadb.com/kb/en/transaction-timeouts/','','https://mariadb.com/kb/en/transaction-timeouts/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(101,8,'UNLOCK TABLES','Syntax\n------\n\nUNLOCK
TABLES\n\nDescription\n-----------\n\nUNLOCK TABLES explicitly releases any
table locks held by the current session.\nSee LOCK TABLES for more
information.\n\nIn addition to releasing table locks acquired by the LOCK
TABLES statement,\nthe UNLOCK TABLES statement also releases the global
read lock acquired by the\nFLUSH TABLES WITH READ LOCK statement. The FLUSH
TABLES WITH READ LOCK\nstatement is very useful for performing backups. See
FLUSH for more\ninformation about FLUSH TABLES WITH READ LOCK.\n\nURL:
https://mariadb.com/kb/en/transactions-unlock-tables/','','https://mariadb.com/kb/en/transactions-unlock-tables/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(102,8,'WAIT and NOWAIT','MariaDB starting with
10.3.0\n----------------------------\nMariaDB 10.3.0 introduced extended
syntax so that it is possible to set\ninnodb_lock_wait_timeout and
lock_wait_timeout for the following statements:\n\nSyntax\n------\n\nALTER
TABLE tbl_name [WAIT n|NOWAIT] ...\nCREATE ... INDEX ON tbl_name
(index_col_name, ...) [WAIT n|NOWAIT] ...\nDROP INDEX ... [WAIT
n|NOWAIT]\nDROP TABLE tbl_name [WAIT n|NOWAIT] ...\nLOCK TABLE ... [WAIT
n|NOWAIT]\nOPTIMIZE TABLE tbl_name [WAIT n|NOWAIT]\nRENAME TABLE tbl_name
[WAIT n|NOWAIT] ...\nSELECT ... FOR UPDATE [WAIT n|NOWAIT]\nSELECT ... LOCK
IN SHARE MODE [WAIT n|NOWAIT]\nTRUNCATE TABLE tbl_name [WAIT
n|NOWAIT]\n\nDescription\n-----------\n\nThe lock wait timeout can be
explicitly set in the statement by using either\nWAIT n (to set the wait in
seconds) or NOWAIT, in which case the statement\nwill immediately fail if
the lock cannot be obtained. WAIT 0 is equivalent to\nNOWAIT.\n\nURL:
https://mariadb.com/kb/en/wait-and-nowait/','','https://mariadb.com/kb/en/wait-and-nowait/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(103,8,'XA Transactions','Overview\n--------\n\nThe MariaDB
XA implementation is based on the X/Open CAE document
Distributed\nTransaction Processing: The XA Specification. This document is
published by\nThe Open Group and available
at\nhttp://www.opengroup.org/public/pubs/catalog/c193.htm.\n\nXA
transactions are designed to allow distributed transactions, where
a\ntransaction manager (the application) controls a transaction which
involves\nmultiple resources. Such resources are usually DBMSs, but could
be resources\nof any type. The whole set of required transactional
operations is called a\nglobal transaction. Each subset of operations which
involve a single resource\nis called a local transaction. XA used a
2-phases commit (2PC). With the first\ncommit, the transaction manager
tells each resource to prepare an effective\ncommit, and waits for a
confirm message. The changes are not still made\neffective at this point.
If any of the resources encountered an error, the\ntransaction manager will
rollback the global transaction. If all resources\ncommunicate that the
first commit is successful, the transaction manager can\nrequire a second
commit, which makes the changes effective.\n\nIn MariaDB, XA transactions
can only be used with storage engines that support\nthem. At least InnoDB,
TokuDB, SPIDER and MyRocks support them. For InnoDB,\nuntil MariaDB 10.2,
XA transactions can be disabled by setting the\ninnodb_support_xa server
system variable to 0. From MariaDB 10.3, XA\ntransactions are always
supported.\n\nLike regular transactions, XA transactions create metadata
locks on accessed\ntables.\n\nXA transactions require REPEATABLE READ as a
minimum isolation level. However,\ndistributed transactions should always
use SERIALIZABLE.\n\nTrying to start more than one XA transaction at the
same time produces a 1400\nerror (SQLSTATE \'XAE09\'). The same
error is produced when attempting to start\nan XA transaction while a
regular transaction is in effect. Trying to start a\nregular transaction
while an XA transaction is in effect produces a 1399 error\n(SQLSTATE
\'XAE07\').\n\nThe statements that cause an implicit COMMIT for
regular transactions produce\na 1400 error (SQLSTATE \'XAE09\')
if a XA transaction is in effect.\n\nInternal XA vs External
XA\n--------------------------\n\nXA transactions are an overloaded term in
MariaDB. If a storage engine is\nXA-capable, it can mean one or both of
these:\n\n* It supports MariaDB\'s internal two-phase commit API. This
is transparent to\nthe user. Sometimes this is called \"internal
XA\", since MariaDB\'s internal\ntransaction coordinator log can
handle coordinating these transactions.\n\n* It supports XA transactions,
with the XA START, XA PREPARE, XA COMMIT, etc.\nstatements. Sometimes this
is called \"external XA\", since it requires the use\nof an
external transaction coordinator to use this feature
properly.\n\nTransaction Coordinator Log\n---------------------------\n\nIf
you have two or more XA-capable storage engines enabled, then a
transaction\ncoordinator log must be available.\n\nThere are currently two
implementations of the transaction coordinator log:\n\n* Binary log-based
transaction coordinator log\n* Memory-mapped file-based transaction
coordinator log\n\nIf the binary log is enabled on a server, then the
server will use the binary\nlog-based transaction coordinator log.
Otherwise, it will use the\nmemory-mapped file-based transaction
coordinator log.\n\nSee Transaction Coordinator Log for more
information.\n\nSyntax\n------\n\nXA {START|BEGIN} xid [JOIN|RESUME]\n\nXA
END xid [SUSPEND [FOR MIGRATE]]\n\nXA PREPARE xid\n\nXA COMMIT xid [ONE
PHASE]\n\nXA ROLLBACK xid\n\nXA RECOVER
[FORMAT=[\'RAW\'|\'SQL\']]\n\nxid: gtrid [, bqual [,
formatID ]]\n\nThe interface to XA transactions is a set of SQL statements
starting with XA.\nEach statement changes a transaction\'s state,
determining which actions it can\nperform. A transaction which does not
exist is in the NON-EXISTING state.\n\nXA START (or BEGIN) starts a
transaction and defines its xid (a transaction\nidentifier). The JOIN or
RESUME keywords have no effect. The new transaction\nwill be in ACTIVE
state.\n\nThe xid can have 3 components, though only the first one is
mandatory. gtrid\nis a quoted string representing a global transaction
identifier. bqual is a\nquoted string representing a local transaction
identifier. formatID is an\nunsigned integer indicating the format used for
the first two components; if\nnot specified, defaults to 1. MariaDB does
not interpret in any way these\ncomponents, and only uses them to identify
a transaction. xids of transactions\nin effect must be unique.\n\nXA END
declares that the specified ACTIVE transaction is finished and it\nchanges
its state to IDLE. SUSPEND [FOR MIGRATE] has no effect.\n\nXA PREPARE
prepares an IDLE transaction for commit, changing its state to\nPREPARED.
This is the first commit.\n\nXA COMMIT definitely commits and terminates a
transaction which has already\nbeen PREPARED. If the ONE PHASE clause is
specified, this statements performs\na 1-phase commit on an IDLE
transaction.\n\nXA ROLLBACK rolls back and terminates an IDLE or PREPARED
transaction.\n\nXA RECOVER shows information about all PREPARED
transactions.\n\nWhen trying to execute an operation which is not allowed
for the transaction\'s\ncurrent state, an error is produced:\n\nXA
COMMIT \'test\' ONE PHASE;\nERROR 1399 (XAE07): XAER_RMFAIL: The
command cannot be executed when global\ntransaction is in the ACTIVE
state\n\nXA COMMIT \'test2\';\nERROR 1399 (XAE07): XAER_RMFAIL:
The command cannot be executed when global\ntransaction is in the
NON-EXISTING state\n\nXA RECOVER\n----------\n\nThe XA RECOVER statement
shows information about all transactions which are in\nthe PREPARED state.
It does not matter which connection created the\ntransaction: if it has
been PREPARED, it appears. But this does not mean that\na connection can
commit or rollback a transaction which was started by another\nconnection.
Note that transactions using a 1-phase commit are never in the\nPREPARED
state, so they cannot be shown by XA RECOVER.\n\nXA RECOVER produces four
columns:\n\nXA
RECOVER;\n+----------+--------------+--------------+------+\n| formatID |
gtrid_length | bqual_length | data
|\n+----------+--------------+--------------+------+\n| 1 |
4 | 0 | test
|\n+----------+--------------+--------------+------+\n\nMariaDB starting
with 10.3.3\n----------------------------\nYou can use XA RECOVER
FORMAT=\'SQL\' to get the data in a human readable form\nthat can
be directly copy-pasted into XA COMMIT or XA ROLLBACK. This
is\nparticularly useful for binary xid generated by some transaction
coordinators.\n\nformatID is the formatID part of xid.\n\ndata are the
gtrid and bqual parts of xid, concatenated.\n\ngtrid_length and
bqual_length are the lengths of gtrid and bqual,
respectevely.\n\nExamples\n--------\n\n2-phases commit:\n\nXA START
\'test\';\n\nINSERT INTO t VALUES (1,2);\n\nXA END
\'test\';\n\nXA PREPARE \'test\';\n\nXA COMMIT
\'test\';\n\n1-phase commit:\n\nXA START
\'test\';\n\nINSERT INTO t VALUES (1,2);\n\nXA END
\'test\';\n\nXA COMMIT \'test\' ONE
PHASE;\n\nHuman-readable:\n\nxa start \'12\\r34\\t67\\v78\',
\'abc\\ndef\', 3;\n\ninsert t1 values (40);\n\nxa end
\'12\\r34\\t67\\v78\', \'abc\\ndef\', 3;\n\nxa prepare
\'12\\r34\\t67\\v78\', \'abc\\ndef\', 3;\n\nxa recover
format=\'RAW\';\n+----------+--------------+--------------+--------------------+\n|
formatID | gtrid_length | bqual_length | data
|\n+----------+--------------+--------------+--------------------+\n34
67v78abc 11 | 7 | 12\ndef
|\n+----------+--------------+--------------+--------------------+\n\nxa
recover
format=\'SQL\';\n+----------+--------------+--------------+-------------------------------------\n---------+\n|
formatID | gtrid_length | bqual_length | data
\n
|\n+----------+--------------+--------------+-------------------------------------\n---------+\n|
3 | 11 | 7
|\nX\'31320d3334093637763738\',X\'6162630a646566\',3
|\n+----------+--------------+--------------+-------------------------------------\n---------+\n\nxa
rollback
X\'31320d3334093637763738\',X\'6162630a646566\',3;\n\nKnown
Issues\n------------\n\nMariaDB Galera
Cluster\n----------------------\n\nMariaDB Galera Cluster does not support
XA transactions.\n\nHowever, MariaDB Galera Cluster builds include a
built-in plugin called wsrep.\nPrior to MariaDB 10.4.3, this plugin was
internally considered an XA-capable\nstorage engine. Consequently, these
MariaDB Galera Cluster builds have\nmultiple XA-capable storage engines by
default, even if the only \"real\"\nstorage engine that supports
external XA transactions enabled on these builds\nby default is InnoDB.
Therefore, when using one these builds MariaDB would be\nforced to use a
transaction coordinator log by default, which could have\nperformance
implications.\n\nSee Transaction Coordinator Log Overview: MariaDB Galera
Cluster for more\ninformation.\n\nURL:
https://mariadb.com/kb/en/xa-transactions/','','https://mariadb.com/kb/en/xa-transactions/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(104,10,'CREATE USER','Syntax\n------\n\nCREATE [OR REPLACE]
USER [IF NOT EXISTS] \n user_specification [,user_specification ...] \n
[REQUIRE {NONE | tls_option [[AND] tls_option ...] }]\n [WITH
resource_option [resource_option ...] ]\n [lock_option]
[password_option]\n\nuser_specification:\n username
[authentication_option]\n\nauthentication_option:\n IDENTIFIED BY
\'password\'\n | IDENTIFIED BY PASSWORD
\'password_hash\'\n | IDENTIFIED {VIA|WITH} authentication_rule
[OR authentication_rule ...]\n\nauthentication_rule:\n
authentication_plugin\n | authentication_plugin {USING|AS}
\'authentication_string\'\n | authentication_plugin {USING|AS}
PASSWORD(\'password\')\n\ntls_option:\n SSL\n | X509\n | CIPHER
\'cipher\'\n | ISSUER \'issuer\'\n | SUBJECT
\'subject\'\n\nresource_option:\n MAX_QUERIES_PER_HOUR count\n |
MAX_UPDATES_PER_HOUR count\n | MAX_CONNECTIONS_PER_HOUR count\n |
MAX_USER_CONNECTIONS count\n | MAX_STATEMENT_TIME
time\n\npassword_option:\n PASSWORD EXPIRE\n | PASSWORD EXPIRE DEFAULT\n |
PASSWORD EXPIRE NEVER\n | PASSWORD EXPIRE INTERVAL N DAY\n\nlock_option:\n
ACCOUNT LOCK\n | ACCOUNT UNLOCK\n}\n\nDescription\n-----------\n\nThe
CREATE USER statement creates new MariaDB accounts. To use it, you
must\nhave the global CREATE USER privilege or the INSERT privilege for the
mysql\ndatabase. For each account, CREATE USER creates a new row in
mysql.user (until\nMariaDB 10.3 this is a table, from MariaDB 10.4
it\'s a view) or\nmysql.global_priv_table (from MariaDB 10.4) that has
no privileges.\n\nIf any of the specified accounts, or any permissions for
the specified\naccounts, already exist, then the server returns ERROR 1396
(HY000). If an\nerror occurs, CREATE USER will still create the accounts
that do not result in\nan error. Only one error is produced for all users
which have not been created:\n\nERROR 1396 (HY000): \n Operation CREATE
USER failed for
\'u1\'@\'%\',\'u2\'@\'%\'\n\nCREATE
USER, DROP USER, CREATE ROLE, and DROP ROLE all produce the same
error\ncode when they fail.\n\nSee Account Names below for details on how
account names are specified.\n\nOR REPLACE\n----------\n\nIf the optional
OR REPLACE clause is used, it is basically a shortcut for:\n\nDROP USER IF
EXISTS name;\nCREATE USER name ...;\n\nFor example:\n\nCREATE USER
foo2@test IDENTIFIED BY \'password\';\nERROR 1396 (HY000):
Operation CREATE USER failed for
\'foo2\'@\'test\'\n\nCREATE OR REPLACE USER foo2@test
IDENTIFIED BY \'password\';\nQuery OK, 0 rows affected (0.00
sec)\n\nIF NOT EXISTS\n-------------\n\nWhen the IF NOT EXISTS clause is
used, MariaDB will return a warning instead\nof an error if the specified
user already exists.\n\nFor example:\n\nCREATE USER foo2@test IDENTIFIED BY
\'password\';\nERROR 1396 (HY000): Operation CREATE USER failed
for \'foo2\'@\'test\'\n\nCREATE USER IF NOT EXISTS
foo2@test IDENTIFIED BY \'password\';\nQuery OK, 0 rows affected,
1 warning (0.00 sec)\n\nSHOW
WARNINGS;\n+-------+------+----------------------------------------------------+\n|
Level | Code | Message
|\n+-------+------+----------------------------------------------------+\n|
Note | 1973 | Can\'t create user
\'foo2\'@\'test\'; it already exists
|\n+-------+------+----------------------------------------------------+\n\nAuthentication
Options\n----------------------\n\nIDENTIFIED BY
\'password\'\n------------------------\n\nThe optional IDENTIFIED
BY clause can be used to provide an account with a\npassword. The password
should be specified in plain text. It will be hashed by\nthe PASSWORD
function prior to being stored in the\nmysql.user/mysql.global_priv_table
table.\n\nFor example, if our password is mariadb, then we can create the
user with:\n\nCREATE USER foo2@test IDENTIFIED BY
\'mariadb\';\n\nIf you do not specify a password with the
IDENTIFIED BY clause, the user will\nbe able to connect without a password.
A blank password is not a wildcard to\nmatch any password. The user must
connect without providing a password if no\npassword is set.\n\nThe only
authentication plugins that this clause supports are\nmysql_native_password
and mysql_old_password.\n\nIDENTIFIED BY PASSWORD
\'password_hash\'\n--------------------------------------\n\nThe
optional IDENTIFIED BY PASSWORD clause can be used to provide an
account\nwith a password that has already been hashed. The password should
be specified\nas a hash that was provided by the PASSWORD function. It will
be stored in the\nmysql.user/mysql.global_priv_table table as-is.\n\nFor
example, if our password is mariadb, then we can find the hash
with:\n\nSELECT
PASSWORD(\'mariadb\');\n+-------------------------------------------+\n|
PASSWORD(\'mariadb\')
|\n+-------------------------------------------+\n|
*54958E764CE10E50764C2EECBB71D01F08549980
|\n+-------------------------------------------+\n1 row in set (0.00
sec)\n\nAnd then we can create a user with the hash:\n\nCREATE USER
foo2@test IDENTIFIED BY
PASSWORD\n\'*54958E764CE10E50764C2EECBB71D01F08549980\';\n\nIf
you do not specify a password with the IDENTIFIED BY clause, the user
will\nbe able to connect without a password. A blank password is not a
wildcard to\nmatch any password. The user must connect without providing a
password if no\npassword is set.\n\nThe only authentication plugins that
this clause supports are\nmysql_native_password and
mysql_old_password.\n\nIDENTIFIED {VIA|WITH}
authentication_plugin\n-------------------------------------------\n\nThe
optional IDENTIFIED VIA authentication_plugin allows you to specify
that\nthe account should be authenticated by a specific authentication
plugin. The\nplugin name must be an active authentication plugin as per
SHOW PLUGINS. If it\ndoesn\'t show up in that output, then you will
need to install it with INSTALL\nPLUGIN or INSTALL SONAME.\n\nFor example,
this could be used with the PAM authentication plugin:\n\nCREATE USER
foo2@test IDENTIFIED VIA pam;\n\nSome authentication plugins allow
additional arguments to be specified after a\nUSING or AS keyword. For
example, the PAM authentication plugin accepts a\nservice name:\n\nCREATE
USER foo2@test IDENTIFIED VIA pam USING \'mariadb\';\n\nThe exact
meaning of the additional argument would depend on the
specific\nauthentication plugin.\n\nMariaDB starting with
10.4.0\n----------------------------\nThe USING or AS keyword can also be
used to provide a plain-text password to a\nplugin if it\'s provided
as an argument to the PASSWORD() function. This is\nonly valid for
authentication plugins that have implemented a hook for the\nPASSWORD()
function. For example, the ed25519 authentication plugin
supports\nthis:\n\nCREATE USER safe@\'%\' IDENTIFIED VIA ed25519
USING PASSWORD(\'secret\');\n\nMariaDB starting with
10.4.3\n----------------------------\nOne can specify many authentication
plugins, they all work as alternatives\nways of authenticating a
user:\n\nCREATE USER safe@\'%\' IDENTIFIED VIA ed25519 USING
PASSWORD(\'secret\') OR\nunix_socket;\n\nBy default, when you
create a user without specifying an authentication\nplugin, MariaDB uses
the mysql_native_password plugin.\n\nTLS Options\n-----------\n\nBy
default, MariaDB transmits data between the server and clients
without\nencrypting it. This is generally acceptable when the server and
client run on\nthe same host or in networks where security is guaranteed
through other means.\nHowever, in cases where the server and client exist
on separate networks or\nthey are in a high-risk network, the lack of
encryption does introduce\nsecurity concerns as a malicious actor could
potentially eavesdrop on the\ntraffic as it is sent over the network
between them.\n\nTo mitigate this concern, MariaDB allows you to encrypt
data in transit\nbetween the server and clients using the Transport Layer
Security (TLS)\nprotocol. TLS was formerly known as Secure Socket Layer
(SSL), but strictly\nspeaking the SSL protocol is a predecessor to TLS and,
that version of the\nprotocol is now considered insecure. The documentation
still uses the term SSL\noften and for compatibility reasons TLS-related
server system and status\nvariables still use the prefix ssl_, but
internally, MariaDB only supports its\nsecure successors.\n\nSee Secure
Connections Overview for more information about how to determine\nwhether
your MariaDB server has TLS support.\n\nYou can set certain TLS-related
restrictions for specific user accounts. For\ninstance, you might use this
with user accounts that require access to\nsensitive data while sending it
across networks that you do not control. These\nrestrictions can be enabled
for a user account with the CREATE USER, ALTER\nUSER, or GRANT statements.
The following options are
available:\n\n+---------------------------+------------------------------------------------+\n|
Option | Description
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE NONE | TLS is not required for this account, but can
|\n| | still be used.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE SSL | The account must use TLS, but no valid X509
|\n| | certificate is required. This option
cannot |\n| | be combined with other TLS
options.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE X509 | The account must use TLS and must have a
|\n| | valid X509 certificate. This option
implies |\n| | REQUIRE SSL. This option cannot
be combined |\n| | with other TLS options.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE ISSUER \'issuer\' | The account must use TLS and must
have a |\n| | valid X509 certificate. Also,
the Certificate |\n| | Authority must be the one
specified via the |\n| | string issuer. This
option implies REQUIRE |\n| | X509. This
option can be combined with the |\n| |
SUBJECT, and CIPHER options in any order.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE SUBJECT \'subject\' | The account must use TLS and must
have a |\n| | valid X509 certificate. Also,
the |\n| | certificate\'s
Subject must be the one |\n| | specified
via the string subject. This option |\n| |
implies REQUIRE X509. This option can be |\n|
| combined with the ISSUER, and CIPHER options |\n|
| in any order.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE CIPHER \'cipher\' | The account must use TLS, but no
valid X509 |\n| | certificate is required.
Also, the encryption |\n| | used for the
connection must use a specific |\n| | cipher
method specified in the string cipher. |\n| |
This option implies REQUIRE SSL. This option |\n|
| can be combined with the ISSUER, and SUBJECT |\n|
| options in any order.
|\n+---------------------------+------------------------------------------------+\n\nThe
REQUIRE keyword must be used only once for all specified options, and
the\nAND keyword can be used to separate individual options, but it is not
required.\n\nFor example, you can create a user account that requires these
TLS options\nwith the following:\n\nCREATE USER
\'alice\'@\'%\'\n REQUIRE SUBJECT \'/CN=alice/O=My
Dom, Inc./C=US/ST=Oregon/L=Portland\'\n AND ISSUER
\'/C=FI/ST=Somewhere/L=City/ O=Some
Company/CN=Peter\nParker/emailAddress=p.parker@marvel.com\'\n AND
CIPHER \'SHA-DES-CBC3-EDH-RSA\';\n\nIf any of these options are
set for a specific user account, then any client\nwho tries to connect with
that user account will have to be configured to\nconnect with TLS.\n\nSee
Securing Connections for Client and Server for information on how
to\nenable TLS on the client and server.\n\nResource Limit
Options\n----------------------\n\nIt is possible to set per-account limits
for certain server resources. The\nfollowing table shows the values that
can be set per
account:\n\n+--------------------------------------+--------------------------------------+\n|
Limit Type | Decription
|\n+--------------------------------------+--------------------------------------+\n|
MAX_QUERIES_PER_HOUR | Number of statements that the
|\n| | account can issue per hour
|\n| | (including updates)
|\n+--------------------------------------+--------------------------------------+\n|
MAX_UPDATES_PER_HOUR | Number of updates (not queries)
|\n| | that the account can issue per
hour
|\n+--------------------------------------+--------------------------------------+\n|
MAX_CONNECTIONS_PER_HOUR | Number of connections that the
|\n| | account can start per hour
|\n+--------------------------------------+--------------------------------------+\n|
MAX_USER_CONNECTIONS | Number of simultaneous connections
|\n| | that can be accepted from the
same |\n| | account; if it is 0,
|\n| | max_connections
will be used |\n| | instead;
if max_connections is 0, |\n| |
there is no limit for this |\n|
| account\'s simultaneous connections.
|\n+--------------------------------------+--------------------------------------+\n|
MAX_STATEMENT_TIME | Timeout, in seconds, for statements
|','','https://mariadb.com/kb/en/create-user/');
update help_topic set description = CONCAT(description, '\n|
| executed by the user. See also |\n|
| Aborting Statements that Exceed a |\n|
| Certain Time to Execute.
|\n+--------------------------------------+--------------------------------------+\n\nIf
any of these limits are set to 0, then there is no limit for that
resource\nfor that user.\n\nHere is an example showing how to create a user
with resource limits:\n\nCREATE USER
\'someone\'@\'localhost\' WITH\n MAX_USER_CONNECTIONS
10\n MAX_QUERIES_PER_HOUR 200;\n\nThe resources are tracked per account,
which means \'user\'@\'server\'; not per\nuser name or
per connection.\n\nThe count can be reset for all users using FLUSH
USER_RESOURCES, FLUSH\nPRIVILEGES or mysqladmin reload.\n\nPer account
resource limits are stored in the user table, in the mysql\ndatabase.
Columns used for resources limits are named max_questions,\nmax_updates,
max_connections (for MAX_CONNECTIONS_PER_HOUR), and\nmax_user_connections
(for MAX_USER_CONNECTIONS).\n\nAccount Names\n-------------\n\nAccount
names have both a user name component and a host name component, and\nare
specified as \'user_name\'@\'host_name\'.\n\nThe user
name and host name may be unquoted, quoted as strings using double\nquotes
(\") or single quotes (\'), or quoted as identifiers using
backticks (`).\nYou must use quotes when using special characters (such as
a hyphen) or\nwildcard characters. If you quote, you must quote the user
name and host name\nseparately (for example
\'user_name\'@\'host_name\').\n\nHost Name
Component\n-------------------\n\nIf the host name is not provided, it is
assumed to be \'%\'.\n\nHost names may contain the wildcard
characters % and _. They are matched as if\nby the LIKE clause. If you need
to use a wildcard character literally (for\nexample, to match a domain name
with an underscore), prefix the character with\na backslash. See LIKE for
more information on escaping wildcard characters.\n\nHost name matches are
case-insensitive. Host names can match either domain\nnames or IP
addresses. Use \'localhost\' as the host name to allow only
local\nclient connections.\n\nYou can use a netmask to match a range of IP
addresses using \'base_ip/netmask\'\nas the host name. A user
with an IP address ip_addr will be allowed to connect\nif the following
condition is true:\n\nip_addr & netmask = base_ip\n\nFor example, given
a user:\n\nCREATE USER
\'maria\'@\'247.150.130.0/255.255.255.0\';\n\nthe IP
addresses satisfying this condition range from 247.150.130.0
to\n247.150.130.255.\n\nUsing 255.255.255.255 is equivalent to not using a
netmask at all. Netmasks\ncannot be used for IPv6 addresses.\n\nNote that
the credentials added when creating a user with the \'%\'
wildcard\nhost will not grant access in all cases. For example, some
systems come with\nan anonymous localhost user, and when connecting from
localhost this will take\nprecedence.\n\nBefore MariaDB 10.6, the host name
component could be up to 60 characters in\nlength. Starting from MariaDB
10.6, it can be up to 255 characters.\n\nUser Name
Component\n-------------------\n\nUser names must match exactly, including
case. A user name that is empty is\nknown as an anonymous account and is
allowed to match a login attempt with any\nuser name component. These are
described more in the next section.\n\nFor valid identifiers to use as user
names, see Identifier Names.\n\nIt is possible for more than one account to
match when a user connects.\nMariaDB selects the first matching account
after sorting according to the\nfollowing criteria:\n\n* Accounts with an
exact host name are sorted before accounts using a wildcard\nin the\nhost
name. Host names using a netmask are considered to be exact for sorting.\n*
Accounts with a wildcard in the host name are sorted according to
the\nposition of\nthe first wildcard character. Those with a wildcard
character later in the\nhost name\nsort before those with a wildcard
character earlier in the host name.\n* Accounts with a non-empty user name
sort before accounts with an empty user\nname.\n* Accounts with an empty
user name are sorted last. As mentioned previously,\nthese are known as
anonymous accounts. These are described more in the next\nsection.\n\nThe
following table shows a list of example account as sorted by
these\ncriteria:\n\n+---------+-------------+\n| User | Host
|\n+---------+-------------+\n| joffrey | 192.168.0.3 |\n| |
192.168.0.% |\n| joffrey | 192.168.% |\n| | 192.168.%
|\n+---------+-------------+\n\nOnce connected, you only have the
privileges granted to the account that\nmatched, not all accounts that
could have matched. For example, consider the\nfollowing
commands:\n\nCREATE USER
\'joffrey\'@\'192.168.0.3\';\nCREATE USER
\'joffrey\'@\'%\';\nGRANT SELECT ON test.t1 to
\'joffrey\'@\'192.168.0.3\';\nGRANT SELECT ON test.t2
to \'joffrey\'@\'%\';\n\nIf you connect as joffrey from
192.168.0.3, you will have the SELECT privilege\non the table test.t1, but
not on the table test.t2. If you connect as joffrey\nfrom any other IP
address, you will have the SELECT privilege on the table\ntest.t2, but not
on the table test.t1.\n\nUsernames can be up to 80 characters long before
10.6 and starting from 10.6\nit can be 128 characters long.\n\nAnonymous
Accounts\n------------------\n\nAnonymous accounts are accounts where the
user name portion of the account\nname is empty. These accounts act as
special catch-all accounts. If a user\nattempts to log into the system from
a host, and an anonymous account exists\nwith a host name portion that
matches the user\'s host, then the user will log\nin as the anonymous
account if there is no more specific account match for the\nuser name that
the user entered.\n\nFor example, here are some anonymous
accounts:\n\nCREATE USER \'\'@\'localhost\';\nCREATE
USER \'\'@\'192.168.0.3\';\n\nFixing a Legacy Default
Anonymous Account\n-----------------------------------------\n\nOn some
systems, the mysql.db table has some entries for the
\'\'@\'%\' anonymous\naccount by default.
Unfortunately, there is no matching entry in
the\nmysql.user/mysql.global_priv_table table, which means that this
anonymous\naccount doesn\'t exactly exist, but it does have
privileges--usually on the\ndefault test database created by
mysql_install_db. These account-less\nprivileges are a legacy that is
leftover from a time when MySQL\'s privilege\nsystem was less
advanced.\n\nThis situation means that you will run into errors if you try
to create a\n\'\'@\'%\' account. For example:\n\nCREATE
USER \'\'@\'%\';\nERROR 1396 (HY000): Operation CREATE
USER failed for \'\'@\'%\'\n\nThe fix is to DELETE the
row in the mysql.db table and then execute FLUSH\nPRIVILEGES:\n\nDELETE
FROM mysql.db WHERE User=\'\' AND Host=\'%\';\nFLUSH
PRIVILEGES;\n\nAnd then the account can be created:\n\nCREATE USER
\'\'@\'%\';\nQuery OK, 0 rows affected (0.01
sec)\n\nSee MDEV-13486 for more information.\n\nPassword
Expiry\n---------------\n\nMariaDB starting with
10.4.3\n----------------------------\nBesides automatic password expiry, as
determined by default_password_lifetime,\npassword expiry times can be set
on an individual user basis, overriding the\nglobal setting, for
example:\n\nCREATE USER \'monty\'@\'localhost\'
PASSWORD EXPIRE INTERVAL 120 DAY;\n\nSee User Password Expiry for more
details.\n\nAccount Locking\n---------------\n\nMariaDB starting with
10.4.2\n----------------------------\nAccount locking permits privileged
administrators to lock/unlock user\naccounts. No new client connections
will be permitted if an account is locked\n(existing connections are not
affected). For example:\n\nCREATE USER
\'marijn\'@\'localhost\' ACCOUNT LOCK;\n\nSee Account
Locking for more details.\n\nFrom MariaDB 10.4.7 and MariaDB 10.5.8, the
lock_option and password_option\nclauses can occur in either order.\n\nURL:
https://mariadb.com/kb/en/create-user/') WHERE help_topic_id = 104;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(105,10,'ALTER USER','Syntax\n------\n\nALTER USER [IF
EXISTS] \n user_specification [,user_specification] ...\n [REQUIRE {NONE |
tls_option [[AND] tls_option] ...}]\n [WITH resource_option
[resource_option] ...]\n [lock_option]
[password_option]\n\nuser_specification:\n username
[authentication_option]\n\nauthentication_option:\n IDENTIFIED BY
\'password\'\n | IDENTIFIED BY PASSWORD
\'password_hash\'\n | IDENTIFIED {VIA|WITH} authentication_rule
[OR authentication_rule] ...\n\nauthentication_rule:\n
authentication_plugin\n | authentication_plugin {USING|AS}
\'authentication_string\'\n | authentication_plugin {USING|AS}
PASSWORD(\'password\')\n\ntls_option\n SSL\n | X509\n | CIPHER
\'cipher\'\n | ISSUER \'issuer\'\n | SUBJECT
\'subject\'\n\nresource_option\n MAX_QUERIES_PER_HOUR count\n |
MAX_UPDATES_PER_HOUR count\n | MAX_CONNECTIONS_PER_HOUR count\n |
MAX_USER_CONNECTIONS count\n | MAX_STATEMENT_TIME
time\n\npassword_option:\n PASSWORD EXPIRE\n | PASSWORD EXPIRE DEFAULT\n |
PASSWORD EXPIRE NEVER\n | PASSWORD EXPIRE INTERVAL N DAY\n\nlock_option:\n
ACCOUNT LOCK\n | ACCOUNT UNLOCK\n}\n\nDescription\n-----------\n\nThe ALTER
USER statement modifies existing MariaDB accounts. To use it, you\nmust
have the global CREATE USER privilege or the UPDATE privilege for
the\nmysql database. The global SUPER privilege is also required if the
read_only\nsystem variable is enabled.\n\nIf any of the specified user
accounts do not yet exist, an error results. If\nan error occurs, ALTER
USER will still modify the accounts that do not result\nin an error. Only
one error is produced for all users which have not been\nmodified.\n\nIF
EXISTS\n---------\n\nWhen the IF EXISTS clause is used, MariaDB will return
a warning instead of an\nerror for each specified user that does not
exist.\n\nAccount Names\n-------------\n\nFor ALTER USER statements,
account names are specified as the username\nargument in the same way as
they are for CREATE USER statements. See account\nnames from the CREATE
USER page for details on how account names are specified.\n\nCURRENT_USER
or CURRENT_USER() can also be used to alter the account logged\ninto the
current session. For example, to change the current user\'s
password\nto mariadb:\n\nALTER USER CURRENT_USER() IDENTIFIED BY
\'mariadb\';\n\nAuthentication
Options\n----------------------\n\nMariaDB starting with
10.4\n--------------------------\nFrom MariaDB 10.4, it is possible to use
more than one authentication plugin\nfor each user account. For example,
this can be useful to slowly migrate users\nto the more secure ed25519
authentication plugin over time, while allowing the\nold
mysql_native_password authentication plugin as an alternative for
the\ntransitional period. See Authentication from MariaDB 10.4 for
more.\n\nWhen running ALTER USER, not specifying an authentication option
in the\nIDENTIFIED VIA clause will remove that authentication method.
(However this\nwas not the case before MariaDB 10.4.13, see
MDEV-21928)\n\nFor example, a user is created with the ability to
authenticate via both a\npassword and unix_socket:\n\nCREATE USER
\'bob\'@\'localhost\' \n IDENTIFIED VIA
mysql_native_password USING PASSWORD(\'pwd\')\n OR
unix_socket;\n\nSHOW CREATE USER
\'bob\'@\'localhost\'\\G\n***************************
1. row ***************************\nCREATE USER for bob@localhost: CREATE
USER `bob`@`localhost` \n IDENTIFIED VIA mysql_native_password\n USING
\'*975B2CD4FF9AE554FE8AD33168FBFC326D2021DD\'\n OR
unix_socket\n\nIf the user\'s password is updated, but unix_socket
authentication is not\nspecified in the IDENTIFIED VIA clause, unix_socket
authentication will no\nlonger be permitted.\n\nALTER USER
\'bob\'@\'localhost\' IDENTIFIED VIA
mysql_native_password \n USING PASSWORD(\'pwd2\');\n\nSHOW CREATE
USER
\'bob\'@\'localhost\'\\G\n***************************
1. row ***************************\nCREATE USER for bob@localhost: CREATE
USER `bob`@`localhost` \n IDENTIFIED BY PASSWORD
\'*38366FDA01695B6A5A9DD4E428D9FB8F7EB75512\'\n\nIDENTIFIED BY
\'password\'\n------------------------\n\nThe optional IDENTIFIED
BY clause can be used to provide an account with a\npassword. The password
should be specified in plain text. It will be hashed by\nthe PASSWORD
function prior to being stored to the mysql.user table.\n\nFor example, if
our password is mariadb, then we can set the account\'s\npassword
with:\n\nALTER USER foo2@test IDENTIFIED BY \'mariadb\';\n\nIf
you do not specify a password with the IDENTIFIED BY clause, the user
will\nbe able to connect without a password. A blank password is not a
wildcard to\nmatch any password. The user must connect without providing a
password if no\npassword is set.\n\nThe only authentication plugins that
this clause supports are\nmysql_native_password and
mysql_old_password.\n\nIDENTIFIED BY PASSWORD
\'password_hash\'\n--------------------------------------\n\nThe
optional IDENTIFIED BY PASSWORD clause can be used to provide an
account\nwith a password that has already been hashed. The password should
be specified\nas a hash that was provided by the PASSWORD#function. It will
be stored to the\nmysql.user table as-is.\n\nFor example, if our password
is mariadb, then we can find the hash with:\n\nSELECT
PASSWORD(\'mariadb\');\n+-------------------------------------------+\n|
PASSWORD(\'mariadb\')
|\n+-------------------------------------------+\n|
*54958E764CE10E50764C2EECBB71D01F08549980
|\n+-------------------------------------------+\n\nAnd then we can set an
account\'s password with the hash:\n\nALTER USER foo2@test \n
IDENTIFIED BY PASSWORD
\'*54958E764CE10E50764C2EECBB71D01F08549980\';\n\nIf you do not
specify a password with the IDENTIFIED BY clause, the user will\nbe able to
connect without a password. A blank password is not a wildcard to\nmatch
any password. The user must connect without providing a password if
no\npassword is set.\n\nThe only authentication plugins that this clause
supports are\nmysql_native_password and mysql_old_password.\n\nIDENTIFIED
{VIA|WITH}
authentication_plugin\n-------------------------------------------\n\nThe
optional IDENTIFIED VIA authentication_plugin allows you to specify
that\nthe account should be authenticated by a specific authentication
plugin. The\nplugin name must be an active authentication plugin as per
SHOW PLUGINS. If it\ndoesn\'t show up in that output, then you will
need to install it with INSTALL\nPLUGIN or INSTALL SONAME.\n\nFor example,
this could be used with the PAM authentication plugin:\n\nALTER USER
foo2@test IDENTIFIED VIA pam;\n\nSome authentication plugins allow
additional arguments to be specified after a\nUSING or AS keyword. For
example, the PAM authentication plugin accepts a\nservice name:\n\nALTER
USER foo2@test IDENTIFIED VIA pam USING \'mariadb\';\n\nThe exact
meaning of the additional argument would depend on the
specific\nauthentication plugin.\n\nIn MariaDB 10.4 and later, the USING or
AS keyword can also be used to provide\na plain-text password to a plugin
if it\'s provided as an argument to the\nPASSWORD() function. This is
only valid for authentication plugins that have\nimplemented a hook for the
PASSWORD() function. For example, the ed25519\nauthentication plugin
supports this:\n\nALTER USER safe@\'%\' IDENTIFIED VIA ed25519
USING PASSWORD(\'secret\');\n\nTLS Options\n-----------\n\nBy
default, MariaDB transmits data between the server and clients
without\nencrypting it. This is generally acceptable when the server and
client run on\nthe same host or in networks where security is guaranteed
through other means.\nHowever, in cases where the server and client exist
on separate networks or\nthey are in a high-risk network, the lack of
encryption does introduce\nsecurity concerns as a malicious actor could
potentially eavesdrop on the\ntraffic as it is sent over the network
between them.\n\nTo mitigate this concern, MariaDB allows you to encrypt
data in transit\nbetween the server and clients using the Transport Layer
Security (TLS)\nprotocol. TLS was formerly known as Secure Socket Layer
(SSL), but strictly\nspeaking the SSL protocol is a predecessor to TLS and,
that version of the\nprotocol is now considered insecure. The documentation
still uses the term SSL\noften and for compatibility reasons TLS-related
server system and status\nvariables still use the prefix ssl_, but
internally, MariaDB only supports its\nsecure successors.\n\nSee Secure
Connections Overview for more information about how to determine\nwhether
your MariaDB server has TLS support.\n\nYou can set certain TLS-related
restrictions for specific user accounts. For\ninstance, you might use this
with user accounts that require access to\nsensitive data while sending it
across networks that you do not control. These\nrestrictions can be enabled
for a user account with the CREATE USER, ALTER\nUSER, or GRANT statements.
The following options are
available:\n\n+---------------------------+------------------------------------------------+\n|
Option | Description
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE NONE | TLS is not required for this account, but can
|\n| | still be used.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE SSL | The account must use TLS, but no valid X509
|\n| | certificate is required. This option
cannot |\n| | be combined with other TLS
options.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE X509 | The account must use TLS and must have a
|\n| | valid X509 certificate. This option
implies |\n| | REQUIRE SSL. This option cannot
be combined |\n| | with other TLS options.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE ISSUER \'issuer\' | The account must use TLS and must
have a |\n| | valid X509 certificate. Also,
the Certificate |\n| | Authority must be the one
specified via the |\n| | string issuer. This
option implies REQUIRE |\n| | X509. This
option can be combined with the |\n| |
SUBJECT, and CIPHER options in any order.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE SUBJECT \'subject\' | The account must use TLS and must
have a |\n| | valid X509 certificate. Also,
the |\n| | certificate\'s
Subject must be the one |\n| | specified
via the string subject. This option |\n| |
implies REQUIRE X509. This option can be |\n|
| combined with the ISSUER, and CIPHER options |\n|
| in any order.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE CIPHER \'cipher\' | The account must use TLS, but no
valid X509 |\n| | certificate is required.
Also, the encryption |\n| | used for the
connection must use a specific |\n| | cipher
method specified in the string cipher. |\n| |
This option implies REQUIRE SSL. This option |\n|
| can be combined with the ISSUER, and SUBJECT |\n|
| options in any order.
|\n+---------------------------+------------------------------------------------+\n\nThe
REQUIRE keyword must be used only once for all specified options, and
the\nAND keyword can be used to separate individual options, but it is not
required.\n\nFor example, you can alter a user account to require these TLS
options with\nthe following:\n\nALTER USER
\'alice\'@\'%\'\n REQUIRE SUBJECT \'/CN=alice/O=My
Dom, Inc./C=US/ST=Oregon/L=Portland\' AND\n ISSUER
\'/C=FI/ST=Somewhere/L=City/ O=Some
Company/CN=Peter\nParker/emailAddress=p.parker@marvel.com\'\n AND
CIPHER \'SHA-DES-CBC3-EDH-RSA\';\n\nIf any of these options are
set for a specific user account, then any client\nwho tries to connect with
that user account will have to be configured to\nconnect with TLS.\n\nSee
Securing Connections for Client and Server for information on how
to\nenable TLS on the client and server.\n\nResource Limit
Options\n----------------------\n\nIt is possible to set per-account limits
for certain server resources. The\nfollowing table shows the values that
can be set per
account:\n\n+------------------------------------+---------------------------------------+\n|
Limit Type | Description
|\n+------------------------------------+---------------------------------------+\n|
MAX_QUERIES_PER_HOUR | Number of statements that the
|\n| | account can issue per hour
|\n| | (including updates)
|\n+------------------------------------+---------------------------------------+\n|
MAX_UPDATES_PER_HOUR | Number of updates (not queries) that
|\n| | the account can issue per hour
|\n+------------------------------------+---------------------------------------+\n|
MAX_CONNECTIONS_PER_HOUR | Number of connections that the
|\n| | account can start per hour
|\n+------------------------------------+---------------------------------------+\n|
MAX_USER_CONNECTIONS | Number of simultaneous connections
|\n| | that can be accepted from the
same |\n| | account; if it is 0,
max_connections |\n| | will be used
instead; if |\n| |
max_connections is 0, there is no |\n|
| limit for this account\'s |\n|
| simultaneous connections.
|','','https://mariadb.com/kb/en/alter-user/');
update help_topic set description = CONCAT(description,
'\n+------------------------------------+---------------------------------------+\n|
MAX_STATEMENT_TIME | Timeout, in seconds, for statements
|\n| | executed by the user. See also
|\n| | Aborting Statements that
Exceed a |\n| | Certain Time to
Execute.
|\n+------------------------------------+---------------------------------------+\n\nIf
any of these limits are set to 0, then there is no limit for that
resource\nfor that user.\n\nHere is an example showing how to set an
account\'s resource limits:\n\nALTER USER
\'someone\'@\'localhost\' WITH\n MAX_USER_CONNECTIONS
10\n MAX_QUERIES_PER_HOUR 200;\n\nThe resources are tracked per account,
which means \'user\'@\'server\'; not per\nuser name or
per connection.\n\nThe count can be reset for all users using FLUSH
USER_RESOURCES, FLUSH\nPRIVILEGES or mysqladmin reload.\n\nPer account
resource limits are stored in the user table, in the mysql\ndatabase.
Columns used for resources limits are named max_questions,\nmax_updates,
max_connections (for MAX_CONNECTIONS_PER_HOUR), and\nmax_user_connections
(for MAX_USER_CONNECTIONS).\n\nPassword Expiry\n---------------\n\nMariaDB
starting with 10.4.3\n----------------------------\nBesides automatic
password expiry, as determined by default_password_lifetime,\npassword
expiry times can be set on an individual user basis, overriding the\nglobal
setting, for example:\n\nALTER USER
\'monty\'@\'localhost\' PASSWORD EXPIRE INTERVAL 120
DAY;\nALTER USER \'monty\'@\'localhost\' PASSWORD
EXPIRE NEVER;\nALTER USER \'monty\'@\'localhost\'
PASSWORD EXPIRE DEFAULT;\n\nSee User Password Expiry for more
details.\n\nAccount Locking\n---------------\n\nMariaDB starting with
10.4.2\n----------------------------\nAccount locking permits privileged
administrators to lock/unlock user\naccounts. No new client connections
will be permitted if an account is locked\n(existing connections are not
affected). For example:\n\nALTER USER
\'marijn\'@\'localhost\' ACCOUNT LOCK;\n\nSee Account
Locking for more details.\n\nFrom MariaDB 10.4.7 and MariaDB 10.5.8, the
lock_option and password_option\nclauses can occur in either order.\n\nURL:
https://mariadb.com/kb/en/alter-user/') WHERE help_topic_id = 105;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(106,10,'DROP USER','Syntax\n------\n\nDROP USER [IF EXISTS]
user_name [, user_name] ...\n\nDescription\n-----------\n\nThe DROP USER
statement removes one or more MariaDB accounts. It removes\nprivilege rows
for the account from all grant tables. To use this statement,\nyou must
have the global CREATE USER privilege or the DELETE privilege for
the\nmysql database. Each account is named using the same format as for the
CREATE\nUSER statement; for example,
\'jeffrey\'@\'localhost\'. If you specify only
the\nuser name part of the account name, a host name part of
\'%\' is used. For\nadditional information about specifying
account names, see CREATE USER.\n\nNote that, if you specify an account
that is currently connected, it will not\nbe deleted until the connection
is closed. The connection will not be\nautomatically closed.\n\nIf any of
the specified user accounts do not exist, ERROR 1396 (HY000)\nresults. If
an error occurs, DROP USER will still drop the accounts that do\nnot result
in an error. Only one error is produced for all users which have\nnot been
dropped:\n\nERROR 1396 (HY000): Operation DROP USER failed for
\'u1\'@\'%\',\'u2\'@\'%\'\n\nFailed
CREATE or DROP operations, for both users and roles, produce the
same\nerror code.\n\nIF EXISTS\n---------\n\nIf the IF EXISTS clause is
used, MariaDB will return a note instead of an\nerror if the user does not
exist.\n\nExamples\n--------\n\nDROP USER bob;\n\nDROP USER
foo2@localhost,foo2@\'127.%\';\n\nIF EXISTS:\n\nDROP USER
bob;\nERROR 1396 (HY000): Operation DROP USER failed for
\'bob\'@\'%\'\n\nDROP USER IF EXISTS bob;\nQuery OK, 0
rows affected, 1 warning (0.00 sec)\n\nSHOW
WARNINGS;\n+-------+------+---------------------------------------------+\n|
Level | Code | Message
|\n+-------+------+---------------------------------------------+\n| Note
| 1974 | Can\'t drop user \'bob\'@\'%\'; it
doesn\'t exist
|\n+-------+------+---------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/drop-user/','','https://mariadb.com/kb/en/drop-user/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(107,10,'GRANT','Syntax\n------\n\nGRANT\n priv_type
[(column_list)]\n [, priv_type [(column_list)]] ...\n ON [object_type]
priv_level\n TO user_specification [ user_options
...]\n\nuser_specification:\n username [authentication_option]\n |
PUBLIC\nauthentication_option:\n IDENTIFIED BY \'password\'\n |
IDENTIFIED BY PASSWORD \'password_hash\'\n | IDENTIFIED
{VIA|WITH} authentication_rule [OR authentication_rule
...]\n\nauthentication_rule:\n authentication_plugin\n |
authentication_plugin {USING|AS} \'authentication_string\'\n |
authentication_plugin {USING|AS} PASSWORD(\'password\')\n\nGRANT
PROXY ON username\n TO user_specification [, user_specification ...]\n
[WITH GRANT OPTION]\n\nGRANT rolename TO grantee [, grantee ...]\n [WITH
ADMIN OPTION]\n\ngrantee:\n rolename\n username
[authentication_option]\n\nuser_options:\n [REQUIRE {NONE | tls_option
[[AND] tls_option] ...}]\n [WITH with_option [with_option]
...]\n\nobject_type:\n TABLE\n | FUNCTION\n | PROCEDURE\n |
PACKAGE\n\npriv_level:\n *\n | *.*\n | db_name.*\n | db_name.tbl_name\n |
tbl_name\n | db_name.routine_name\n\nwith_option:\n GRANT OPTION\n |
resource_option\n\nresource_option:\n MAX_QUERIES_PER_HOUR count\n |
MAX_UPDATES_PER_HOUR count\n | MAX_CONNECTIONS_PER_HOUR count\n |
MAX_USER_CONNECTIONS count\n | MAX_STATEMENT_TIME time\n\ntls_option:\n
SSL\n | X509\n | CIPHER \'cipher\'\n | ISSUER
\'issuer\'\n | SUBJECT
\'subject\'\n\nDescription\n-----------\n\nThe GRANT statement
allows you to grant privileges or roles to accounts. To\nuse GRANT, you
must have the GRANT OPTION privilege, and you must have the\nprivileges
that you are granting.\n\nUse the REVOKE statement to revoke privileges
granted with the GRANT statement.\n\nUse the SHOW GRANTS statement to
determine what privileges an account has.\n\nAccount
Names\n-------------\n\nFor GRANT statements, account names are specified
as the username argument in\nthe same way as they are for CREATE USER
statements. See account names from\nthe CREATE USER page for details on how
account names are specified.\n\nImplicit Account
Creation\n-------------------------\n\nThe GRANT statement also allows you
to implicitly create accounts in some\ncases.\n\nIf the account does not
yet exist, then GRANT can implicitly create it. To\nimplicitly create an
account with GRANT, a user is required to have the same\nprivileges that
would be required to explicitly create the account with the\nCREATE USER
statement.\n\nIf the NO_AUTO_CREATE_USER SQL_MODE is set, then accounts can
only be created\nif authentication information is specified, or with a
CREATE USER statement.\nIf no authentication information is provided, GRANT
will produce an error when\nthe specified account does not exist, for
example:\n\nshow variables like \'%sql_mode%\'
;\n+---------------+--------------------------------------------+\n|
Variable_name | Value
|\n+---------------+--------------------------------------------+\n|
sql_mode | NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
|\n+---------------+--------------------------------------------+\n\nGRANT
USAGE ON *.* TO \'user123\'@\'%\' IDENTIFIED BY
\'\';\nERROR 1133 (28000): Can\'t find any matching row in
the user table\n\nGRANT USAGE ON *.* TO
\'user123\'@\'%\' \n IDENTIFIED VIA PAM using
\'mariadb\' require ssl ;\nQuery OK, 0 rows affected (0.00
sec)\n\nselect host, user from mysql.user where user=\'user123\'
;\n\n+------+----------+\n| host | user |\n+------+----------+\n| %
| user123 |\n+------+----------+\n\nPrivilege
Levels\n----------------\n\nPrivileges can be set globally, for an entire
database, for a table or\nroutine, or for individual columns in a table.
Certain privileges can only be\nset at certain levels.\n\n* Global
privileges priv_type are granted using *.* for\npriv_level. Global
privileges include privileges to administer the database\nand manage user
accounts, as well as privileges for all tables, functions, and\nprocedures.
Global privileges are stored in the mysql.user table prior to\nMariaDB
10.4, and in mysql.global_priv table afterwards.\n* Database privileges
priv_type are granted using db_name.*\nfor priv_level, or using just * to
use default database. Database\nprivileges include privileges to create
tables and functions, as well as\nprivileges for all tables, functions, and
procedures in the database. Database\nprivileges are stored in the mysql.db
table.\n* Table privileges priv_type are granted using
db_name.tbl_name\nfor priv_level, or using just tbl_name to specify a table
in the default\ndatabase. The TABLE keyword is optional. Table privileges
include the\nability to select and change data in the table. Certain table
privileges can\nbe granted for individual columns.\n* Column privileges
priv_type are granted by specifying a table for\npriv_level and providing a
column list after the privilege type. They allow\nyou to control exactly
which columns in a table users can select and change.\n* Function
privileges priv_type are granted using FUNCTION db_name.routine_name\nfor
priv_level, or using just FUNCTION routine_name to specify a function\nin
the default database.\n* Procedure privileges priv_type are granted using
PROCEDURE\ndb_name.routine_name\nfor priv_level, or using just PROCEDURE
routine_name to specify a procedure\nin the default database.\n\nThe USAGE
Privilege\n-------------------\n\nThe USAGE privilege grants no real
privileges. The SHOW GRANTS statement will\nshow a global USAGE privilege
for a newly-created user. You can use USAGE with\nthe GRANT statement to
change options like GRANT OPTION and\nMAX_USER_CONNECTIONS without changing
any account privileges.\n\nThe ALL PRIVILEGES
Privilege\n----------------------------\n\nThe ALL PRIVILEGES privilege
grants all available privileges. Granting all\nprivileges only affects the
given privilege level. For example, granting all\nprivileges on a table
does not grant any privileges on the database or\nglobally.\n\nUsing ALL
PRIVILEGES does not grant the special GRANT OPTION privilege.\n\nYou can
use ALL instead of ALL PRIVILEGES.\n\nThe GRANT OPTION
Privilege\n--------------------------\n\nUse the WITH GRANT OPTION clause
to give users the ability to grant privileges\nto other users at the given
privilege level. Users with the GRANT OPTION\nprivilege can only grant
privileges they have. They cannot grant privileges at\na higher privilege
level than they have the GRANT OPTION privilege.\n\nThe GRANT OPTION
privilege cannot be set for individual columns. If you use\nWITH GRANT
OPTION when specifying column privileges, the GRANT OPTION\nprivilege will
be granted for the entire table.\n\nUsing the WITH GRANT OPTION clause is
equivalent to listing GRANT OPTION as a\nprivilege.\n\nGlobal
Privileges\n-----------------\n\nThe following table lists the privileges
that can be granted globally. You can\nalso grant all database, table, and
function privileges globally. When granted\nglobally, these privileges
apply to all databases, tables, or functions,\nincluding those created
later.\n\nTo set a global privilege, use *.* for priv_level.\n\nBINLOG
ADMIN\n------------\n\nEnables administration of the binary log, including
the PURGE BINARY LOGS\nstatement and setting the system variables:\n\n*
binlog_annotate_row_events\n* binlog_cache_size\n*
binlog_commit_wait_count\n* binlog_commit_wait_usec\n*
binlog_direct_non_transactional_updates\n* binlog_expire_logs_seconds\n*
binlog_file_cache_size\n* binlog_format\n* binlog_row_image\n*
binlog_row_metadata\n* binlog_stmt_cache_size\n* expire_logs_days\n*
log_bin_compress\n* log_bin_compress_min_len\n*
log_bin_trust_function_creators\n* max_binlog_cache_size\n*
max_binlog_size\n* max_binlog_stmt_cache_size\n* sql_log_bin and\n*
sync_binlog.\n\nAdded in MariaDB 10.5.2.\n\nBINLOG
MONITOR\n--------------\n\nNew name for REPLICATION CLIENT from MariaDB
10.5.2, (REPLICATION CLIENT still\nsupported as an alias for compatibility
purposes). Permits running SHOW\ncommands related to the binary log, in
particular the SHOW BINLOG STATUS and\nSHOW BINARY LOGS statements. Unlike
REPLICATION CLIENT prior to MariaDB 10.5,\nSHOW REPLICA STATUS isn\'t
included in this privilege, and REPLICA MONITOR is\nrequired.\n\nBINLOG
REPLAY\n-------------\n\nEnables replaying the binary log with the BINLOG
statement (generated by\nmariadb-binlog), executing SET timestamp when
secure_timestamp is set to\nreplication, and setting the session values of
system variables usually\nincluded in BINLOG output, in particular:\n\n*
gtid_domain_id\n* gtid_seq_no\n* pseudo_thread_id\n* server_id.\n\nAdded in
MariaDB 10.5.2\n\nCONNECTION ADMIN\n----------------\n\nEnables
administering connection resource limit options. This includes\nignoring
the limits specified by:\n\n* max_connections\n* max_user_connections
and\n* max_password_errors.\n\nThe statements specified in init_connect are
not executed, killing connections\nand queries owned by other users is
permitted. The following\nconnection-related system variables can be
changed:\n\n* connect_timeout\n* disconnect_on_expired_password\n*
extra_max_connections\n* init_connect\n* max_connections\n*
max_connect_errors\n* max_password_errors\n* proxy_protocol_networks\n*
secure_auth\n* slow_launch_time\n* thread_pool_exact_stats\n*
thread_pool_dedicated_listener\n* thread_pool_idle_timeout\n*
thread_pool_max_threads\n* thread_pool_min_threads\n*
thread_pool_oversubscribe\n* thread_pool_prio_kickup_timer\n*
thread_pool_priority\n* thread_pool_size, and\n*
thread_pool_stall_limit.\n\nAdded in MariaDB 10.5.2.\n\nCREATE
USER\n-----------\n\nCreate a user using the CREATE USER statement, or
implicitly create a user\nwith the GRANT statement.\n\nFEDERATED
ADMIN\n---------------\n\nExecute CREATE SERVER, ALTER SERVER, and DROP
SERVER statements. Added in\nMariaDB 10.5.2.\n\nFILE\n----\n\nRead and
write files on the server, using statements like LOAD DATA INFILE
or\nfunctions like LOAD_FILE(). Also needed to create CONNECT outward
tables.\nMariaDB server must have the permissions to access those
files.\n\nGRANT OPTION\n------------\n\nGrant global privileges. You can
only grant privileges that you have.\n\nPROCESS\n-------\n\nShow
information about the active processes, for example via SHOW
PROCESSLIST\nor mysqladmin processlist. If you have the PROCESS privilege,
you can see all\nthreads. Otherwise, you can see only your own threads
(that is, threads\nassociated with the MariaDB account that you are
using).\n\nREAD_ONLY ADMIN\n---------------\n\nUser can set the read_only
system variable and allows the user to perform\nwrite operations, even when
the read_only option is active. Added in MariaDB\n10.5.2.\n\nFrom MariaDB
10.11.0, the READ_ONLY ADMIN privilege has been removed from\nSUPER. The
benefit of this is that one can remove the READ_ONLY ADMIN\nprivilege from
all users and ensure that no one can make any changes on any\nnon-temporary
tables. This is useful on replicas when one wants to ensure that\nthe
replica is kept identical to the primary.\n\nRELOAD\n------\n\nExecute
FLUSH statements or equivalent mariadb-admin/mysqladmin
commands.\n\nREPLICATION CLIENT\n------------------\n\nExecute SHOW MASTER
STATUS and SHOW BINARY LOGS informative statements.\nRenamed to BINLOG
MONITOR in MariaDB 10.5.2 (but still supported as an alias\nfor
compatibility reasons). SHOW SLAVE STATUS was part of REPLICATION
CLIENT\nprior to MariaDB 10.5.\n\nREPLICATION MASTER
ADMIN\n------------------------\n\nPermits administration of primary
servers, including the SHOW REPLICA HOSTS\nstatement, and setting the
gtid_binlog_state, gtid_domain_id,\nmaster_verify_checksum and server_id
system variables. Added in MariaDB 10.5.2.\n\nREPLICA
MONITOR\n---------------\n\nPermit SHOW REPLICA STATUS and SHOW RELAYLOG
EVENTS. From MariaDB 10.5.9.\n\nWhen a user would upgrade from an older
major release to a MariaDB 10.5 minor\nrelease prior to MariaDB 10.5.9,
certain user accounts would lose\ncapabilities. For example, a user account
that had the REPLICATION CLIENT\nprivilege in older major releases could
run SHOW REPLICA STATUS, but after\nupgrading to a MariaDB 10.5 minor
release prior to MariaDB 10.5.9, they could\nno longer run SHOW REPLICA
STATUS, because that statement was changed to\nrequire the REPLICATION
REPLICA ADMIN privilege.\n\nThis issue is fixed in MariaDB 10.5.9 with this
new privilege, which now\ngrants the user the ability to execute SHOW [ALL]
(SLAVE | REPLICA) STATUS.\n\nWhen a database is upgraded from an older
major release to MariaDB Server\n10.5.9 or later, any user accounts with
the REPLICATION CLIENT or REPLICATION\nSLAVE privileges will automatically
be granted the new REPLICA MONITOR\nprivilege. The privilege fix occurs
when the server is started up, not when\nmariadb-upgrade is
performed.\n\nHowever, when a database is upgraded from an early 10.5 minor
release to\n10.5.9 and later, the user will have to fix any user account
privileges\nmanually.\n\nREPLICATION
REPLICA\n-------------------\n\nSynonym for REPLICATION SLAVE. From MariaDB
10.5.1.\n\nREPLICATION SLAVE\n-----------------\n\nAccounts used by replica
servers on the primary need this privilege. This is\nneeded to get the
updates made on the master. From MariaDB 10.5.1, REPLICATION\nREPLICA is an
alias for REPLICATION SLAVE.\n\nREPLICATION SLAVE
ADMIN\n-----------------------\n\nPermits administering replica servers,
including START REPLICA/SLAVE, STOP\nREPLICA/SLAVE, CHANGE MASTER, SHOW
REPLICA/SLAVE STATUS, SHOW RELAYLOG EVENTS\nstatements, replaying the
binary log with the BINLOG statement (generated by\nmariadb-binlog), and
setting the system variables:\n\n* gtid_cleanup_batch_size\n*
gtid_ignore_duplicates\n* gtid_pos_auto_engines\n* gtid_slave_pos\n*
gtid_strict_mode\n* init_slave\n* read_binlog_speed_limit\n*
relay_log_purge\n* relay_log_recovery\n* replicate_do_db\n*
replicate_do_table\n* replicate_events_marked_for_skip\n*
replicate_ignore_db\n* replicate_ignore_table\n* replicate_wild_do_table\n*
replicate_wild_ignore_table\n* slave_compressed_protocol\n*
slave_ddl_exec_mode\n* slave_domain_parallel_threads\n* slave_exec_mode\n*
slave_max_allowed_packet\n* slave_net_timeout\n*
slave_parallel_max_queued\n* slave_parallel_mode\n*
slave_parallel_threads\n* slave_parallel_workers\n*
slave_run_triggers_for_rbr\n* slave_sql_verify_checksum\n*
slave_transaction_retry_interval\n* slave_type_conversions\n*
sync_master_info\n* sync_relay_log, and\n* sync_relay_log_info.\n\nAdded in
MariaDB 10.5.2.\n\nSET
USER\n--------\n','','https://mariadb.com/kb/en/grant/');
update help_topic set description = CONCAT(description, '\nEnables
setting the DEFINER when creating triggers, views, stored functions\nand
stored procedures. Added in MariaDB 10.5.2.\n\nSHOW
DATABASES\n--------------\n\nList all databases using the SHOW DATABASES
statement. Without the SHOW\nDATABASES privilege, you can still issue the
SHOW DATABASES statement, but it\nwill only list databases containing
tables on which you have privileges.\n\nSHUTDOWN\n--------\n\nShut down the
server using SHUTDOWN or the mysqladmin shutdown
command.\n\nSUPER\n-----\n\nExecute superuser statements: CHANGE MASTER TO,
KILL (users who do not have\nthis privilege can only KILL their own
threads), PURGE LOGS, SET global system\nvariables, or the mysqladmin debug
command. Also, this permission allows the\nuser to write data even if the
read_only startup option is set, enable or\ndisable logging, enable or
disable replication on replica, specify a DEFINER\nfor statements that
support that clause, connect once reaching the\nMAX_CONNECTIONS. If a
statement has been specified for the init-connect mysqld\noption, that
command will not be executed when a user with SUPER privileges\nconnects to
the server.\n\nThe SUPER privilege has been split into multiple smaller
privileges from\nMariaDB 10.5.2 to allow for more fine-grained privileges,
although it remains\nan alias for these smaller privileges.\n\nFrom MariaDB
10.11.0, the READ_ONLY ADMIN privilege has been removed from\nSUPER. The
benefit of this is that one can remove the READ_ONLY ADMIN\nprivilege from
all users and ensure that no one can make any changes on any\nnon-temporary
tables. This is useful on replicas when one wants to ensure that\nthe
replica is kept identical to the primary.\n\nDatabase
Privileges\n-------------------\n\nThe following table lists the privileges
that can be granted at the database\nlevel. You can also grant all table
and function privileges at the database\nlevel. Table and function
privileges on a database apply to all tables or\nfunctions in that
database, including those created later.\n\nTo set a privilege for a
database, specify the database using db_name.* for\npriv_level, or just use
* to specify the default
database.\n\n+----------------------------------+-----------------------------------------+\n|
Privilege | Description
|\n+----------------------------------+-----------------------------------------+\n|
CREATE | Create a database using the CREATE
|\n| | DATABASE statement, when the
privilege |\n| | is granted for a
database. You can |\n| | grant the
CREATE privilege on |\n| |
databases that do not yet exist. This |\n|
| also grants the CREATE privilege on |\n|
| all tables in the database.
|\n+----------------------------------+-----------------------------------------+\n|
CREATE ROUTINE | Create Stored Programs using the
|\n| | CREATE PROCEDURE and CREATE
FUNCTION |\n| | statements.
|\n+----------------------------------+-----------------------------------------+\n|
CREATE TEMPORARY TABLES | Create temporary tables with the
|\n| | CREATE TEMPORARY TABLE statement.
This |\n| | privilege enable writing and
dropping |\n| | those temporary tables
|\n+----------------------------------+-----------------------------------------+\n|
DROP | Drop a database using the DROP
|\n| | DATABASE statement, when the
privilege |\n| | is granted for a
database. This also |\n| | grants the
DROP privilege on all |\n| | tables
in the database.
|\n+----------------------------------+-----------------------------------------+\n|
EVENT | Create, drop and alter EVENTs.
|\n+----------------------------------+-----------------------------------------+\n|
GRANT OPTION | Grant database privileges. You can
|\n| | only grant privileges that you
have.
|\n+----------------------------------+-----------------------------------------+\n|
LOCK TABLES | Acquire explicit locks using the LOCK
|\n| | TABLES statement; you also need to
|\n| | have the SELECT privilege on a
table, |\n| | in order to lock it.
|\n+----------------------------------+-----------------------------------------+\n\nTable
Privileges\n----------------\n\n+----------------------------------+-----------------------------------------+\n|
Privilege | Description
|\n+----------------------------------+-----------------------------------------+\n|
ALTER | Change the structure of an existing
|\n| | table using the ALTER TABLE
statement.
|\n+----------------------------------+-----------------------------------------+\n|
CREATE | Create a table using the CREATE TABLE
|\n| | statement. You can grant the
CREATE |\n| | privilege on tables that
do not yet |\n| | exist.
|\n+----------------------------------+-----------------------------------------+\n|
CREATE VIEW | Create a view using the CREATE_VIEW
|\n| | statement.
|\n+----------------------------------+-----------------------------------------+\n|
DELETE | Remove rows from a table using the
|\n| | DELETE statement.
|\n+----------------------------------+-----------------------------------------+\n|
DELETE HISTORY | Remove historical rows from a table
|\n| | using the DELETE HISTORY statement.
|\n| | Displays as DELETE VERSIONING
ROWS |\n| | when running SHOW GRANTS
until MariaDB |\n| | 10.3.15 and until
MariaDB 10.4.5 |\n| | (MDEV-17655),
or when running SHOW |\n| |
PRIVILEGES until MariaDB 10.5.2, |\n|
| MariaDB 10.4.13 and MariaDB 10.3.23 |\n|
| (MDEV-20382). From MariaDB 10.3.4. |\n|
| From MariaDB 10.3.5, if a user has the |\n|
| SUPER privilege but not this |\n|
| privilege, running mysql_upgrade will |\n|
| grant this privilege as well.
|\n+----------------------------------+-----------------------------------------+\n|
DROP | Drop a table using the DROP TABLE
|\n| | statement or a view using the DROP
|\n| | VIEW statement. Also required
to |\n| | execute the TRUNCATE
TABLE statement.
|\n+----------------------------------+-----------------------------------------+\n|
GRANT OPTION | Grant table privileges. You can only
|\n| | grant privileges that you have.
|\n+----------------------------------+-----------------------------------------+\n|
INDEX | Create an index on a table using the
|\n| | CREATE INDEX statement. Without the
|\n| | INDEX privilege, you can still
create |\n| | indexes when creating a
table using |\n| | the CREATE TABLE
statement if the you |\n| | have the
CREATE privilege, and you can |\n| |
create indexes using the ALTER TABLE |\n|
| statement if you have the ALTER |\n|
| privilege.
|\n+----------------------------------+-----------------------------------------+\n|
INSERT | Add rows to a table using the INSERT
|\n| | statement. The INSERT privilege
can |\n| | also be set on individual
columns; see |\n| | Column Privileges
below for details.
|\n+----------------------------------+-----------------------------------------+\n|
REFERENCES | Unused.
|\n+----------------------------------+-----------------------------------------+\n|
SELECT | Read data from a table using the
|\n| | SELECT statement. The SELECT
privilege |\n| | can also be set on
individual columns; |\n| | see Column
Privileges below for |\n| |
details.
|\n+----------------------------------+-----------------------------------------+\n|
SHOW VIEW | Show the CREATE VIEW statement to
|\n| | create a view using the SHOW CREATE
|\n| | VIEW statement.
|\n+----------------------------------+-----------------------------------------+\n|
TRIGGER | Execute triggers associated to tables
|\n| | you update, execute the CREATE
TRIGGER |\n| | and DROP TRIGGER
statements. You will |\n| | still be
able to see triggers.
|\n+----------------------------------+-----------------------------------------+\n|
UPDATE | Update existing rows in a table using
|\n| | the UPDATE statement. UPDATE
|\n| | statements usually include a
WHERE |\n| | clause to update only
certain rows. |\n| | You must have
SELECT privileges on the |\n| | table or
the appropriate columns for |\n| | the
WHERE clause. The UPDATE privilege |\n| |
can also be set on individual columns; |\n|
| see Column Privileges below for |\n|
| details.
|\n+----------------------------------+-----------------------------------------+\n\nColumn
Privileges\n-----------------\n\nSome table privileges can be set for
individual columns of a table. To use\ncolumn privileges, specify the table
explicitly and provide a list of column\nnames after the privilege type.
For example, the following statement would\nallow the user to read the
names and positions of employees, but not other\ninformation from the same
table, such as salaries.\n\nGRANT SELECT (name, position) on Employee to
\'jeffrey\'@\'localhost\';\n\n+----------------------------------+-----------------------------------------+\n|
Privilege | Description
|\n+----------------------------------+-----------------------------------------+\n|
INSERT (column_list) | Add rows specifying values in columns
|\n| | using the INSERT statement. If you
|\n| | only have column-level INSERT
|\n| | privileges, you must
specify the |\n| | columns you are
setting in the INSERT |\n| | statement.
All other columns will be |\n| | set to
their default values, or NULL.
|\n+----------------------------------+-----------------------------------------+\n|
REFERENCES (column_list) | Unused.
|\n+----------------------------------+-----------------------------------------+\n|
SELECT (column_list) | Read values in columns using the
|\n| | SELECT statement. You cannot access
or |\n| | query any columns for which you
do not |\n| | have SELECT privileges,
including in |\n| | WHERE, ON, GROUP
BY, and ORDER BY |\n| | clauses.
|\n+----------------------------------+-----------------------------------------+\n|
UPDATE (column_list) | Update values in columns of existing
|\n| | rows using the UPDATE statement.
|\n| | UPDATE statements usually
include a |\n| | WHERE clause to
update only certain |\n| | rows. You
must have SELECT privileges |\n| | on
the table or the appropriate |\n|
| columns for the WHERE clause.
|\n+----------------------------------+-----------------------------------------+\n\nFunction
Privileges\n-------------------\n\n+----------------------------------+-----------------------------------------+\n|
Privilege | Description
|') WHERE help_topic_id = 107;
update help_topic set description = CONCAT(description,
'\n+----------------------------------+-----------------------------------------+\n|
ALTER ROUTINE | Change the characteristics of a stored
|\n| | function using the ALTER FUNCTION
|\n| | statement.
|\n+----------------------------------+-----------------------------------------+\n|
EXECUTE | Use a stored function. You need SELECT
|\n| | privileges for any tables or
columns |\n| | accessed by the
function.
|\n+----------------------------------+-----------------------------------------+\n|
GRANT OPTION | Grant function privileges. You can
|\n| | only grant privileges that you
have.
|\n+----------------------------------+-----------------------------------------+\n\nProcedure
Privileges\n--------------------\n\n+----------------------------------+-----------------------------------------+\n|
Privilege | Description
|\n+----------------------------------+-----------------------------------------+\n|
ALTER ROUTINE | Change the characteristics of a stored
|\n| | procedure using the ALTER PROCEDURE
|\n| | statement.
|\n+----------------------------------+-----------------------------------------+\n|
EXECUTE | Execute a stored procedure using the
|\n| | CALL statement. The privilege to
call |\n| | a procedure may allow you to
perform |\n| | actions you
wouldn\'t otherwise be able |\n| |
to do, such as insert rows into a |\n|
| table.
|\n+----------------------------------+-----------------------------------------+\n|
GRANT OPTION | Grant procedure privileges. You can
|\n| | only grant privileges that you
have.
|\n+----------------------------------+-----------------------------------------+\n\nGRANT
EXECUTE ON PROCEDURE mysql.create_db TO maintainer;\n\nProxy
Privileges\n----------------\n\n+----------------------------------+-----------------------------------------+\n|
Privilege | Description
|\n+----------------------------------+-----------------------------------------+\n|
PROXY | Permits one user to be a proxy for
|\n| | another.
|\n+----------------------------------+-----------------------------------------+\n\nThe
PROXY privilege allows one user to proxy as another user, which
means\ntheir privileges change to that of the proxy user, and the
CURRENT_USER()\nfunction returns the user name of the proxy user.\n\nThe
PROXY privilege only works with authentication plugins that support
it.\nThe default mysql_native_password authentication plugin does not
support proxy\nusers.\n\nThe pam authentication plugin is the only plugin
included with MariaDB that\ncurrently supports proxy users. The PROXY
privilege is commonly used with the\npam authentication plugin to enable
user and group mapping with PAM.\n\nFor example, to grant the PROXY
privilege to an anonymous account that\nauthenticates with the pam
authentication plugin, you could execute the\nfollowing:\n\nCREATE USER
\'dba\'@\'%\' IDENTIFIED BY
\'strongpassword\';\nGRANT ALL PRIVILEGES ON *.* TO
\'dba\'@\'%\' ;\n\nCREATE USER
\'\'@\'%\' IDENTIFIED VIA pam USING
\'mariadb\';\nGRANT PROXY ON \'dba\'@\'%\' TO
\'\'@\'%\';\n\nA user account can only grant the PROXY
privilege for a specific user account\nif the granter also has the PROXY
privilege for that specific user account,\nand if that privilege is defined
WITH GRANT OPTION. For example, the following\nexample fails because the
granter does not have the PROXY privilege for that\nspecific user account
at all:\n\nSELECT USER(),
CURRENT_USER();\n+-----------------+-----------------+\n| USER() |
CURRENT_USER() |\n+-----------------+-----------------+\n| alice@localhost
| alice@localhost |\n+-----------------+-----------------+\n\nSHOW
GRANTS;\n+------------------------------------------------------------------------------\n----------------------------------------+\n|
Grants for alice@localhost
\n
|\n+------------------------------------------------------------------------------\n----------------------------------------+\n|
GRANT ALL PRIVILEGES ON *.* TO \'alice\'@\'localhost\'
IDENTIFIED BY
PASSWORD\n\'*2470C0C06DEE42FD1618BB99005ADCA2EC9D1E19\'
|\n+------------------------------------------------------------------------------\n----------------------------------------+\n\nGRANT
PROXY ON \'dba\'@\'localhost\' TO
\'bob\'@\'localhost\';\nERROR 1698 (28000): Access
denied for user \'alice\'@\'localhost\'\n\nAnd the
following example fails because the granter does have the PROXY\nprivilege
for that specific user account, but it is not defined WITH
GRANT\nOPTION:\n\nSELECT USER(),
CURRENT_USER();\n+-----------------+-----------------+\n| USER() |
CURRENT_USER() |\n+-----------------+-----------------+\n| alice@localhost
| alice@localhost |\n+-----------------+-----------------+\n\nSHOW
GRANTS;\n+------------------------------------------------------------------------------\n----------------------------------------+\n|
Grants for alice@localhost
\n
|\n+------------------------------------------------------------------------------\n----------------------------------------+\n|
GRANT ALL PRIVILEGES ON *.* TO \'alice\'@\'localhost\'
IDENTIFIED BY
PASSWORD\n\'*2470C0C06DEE42FD1618BB99005ADCA2EC9D1E19\' |\n|
GRANT PROXY ON \'dba\'@\'localhost\' TO
\'alice\'@\'localhost\' \n
|\n+------------------------------------------------------------------------------\n----------------------------------------+\n\nGRANT
PROXY ON \'dba\'@\'localhost\' TO
\'bob\'@\'localhost\';\nERROR 1698 (28000): Access
denied for user \'alice\'@\'localhost\'\n\nBut the
following example succeeds because the granter does have the
PROXY\nprivilege for that specific user account, and it is defined WITH
GRANT OPTION:\n\nSELECT USER(),
CURRENT_USER();\n+-----------------+-----------------+\n| USER() |
CURRENT_USER() |\n+-----------------+-----------------+\n| alice@localhost
| alice@localhost |\n+-----------------+-----------------+\n\nSHOW
GRANTS;\n+------------------------------------------------------------------------------\n----------------------------------------------------------+\n|
Grants for alice@localhost
\n
|\n+------------------------------------------------------------------------------\n----------------------------------------------------------+\n|
GRANT ALL PRIVILEGES ON *.* TO \'alice\'@\'localhost\'
IDENTIFIED BY
PASSWORD\n\'*2470C0C06DEE42FD1618BB99005ADCA2EC9D1E19\' WITH
GRANT OPTION |\n| GRANT PROXY ON \'dba\'@\'localhost\'
TO \'alice\'@\'localhost\' WITH GRANT OPTION \n
|\n+------------------------------------------------------------------------------\n----------------------------------------------------------+\n\nGRANT
PROXY ON \'dba\'@\'localhost\' TO
\'bob\'@\'localhost\';\n\nA user account can grant the
PROXY privilege for any other user account if the\ngranter has the PROXY
privilege for the \'\'@\'%\' anonymous user account,
like\nthis:\n\nGRANT PROXY ON \'\'@\'%\' TO
\'dba\'@\'localhost\' WITH GRANT OPTION;\n\nFor
example, the following example succeeds because the user can grant
the\nPROXY privilege for any other user account:\n\nSELECT USER(),
CURRENT_USER();\n+-----------------+-----------------+\n| USER() |
CURRENT_USER() |\n+-----------------+-----------------+\n| alice@localhost
| alice@localhost |\n+-----------------+-----------------+\n\nSHOW
GRANTS;\n+------------------------------------------------------------------------------\n----------------------------------------------------------+\n|
Grants for alice@localhost
\n
|\n+------------------------------------------------------------------------------\n----------------------------------------------------------+\n|
GRANT ALL PRIVILEGES ON *.* TO \'alice\'@\'localhost\'
IDENTIFIED BY
PASSWORD\n\'*2470C0C06DEE42FD1618BB99005ADCA2EC9D1E19\' WITH
GRANT OPTION |\n| GRANT PROXY ON \'\'@\'%\' TO
\'alice\'@\'localhost\' WITH GRANT OPTION
\n
|\n+------------------------------------------------------------------------------\n----------------------------------------------------------+\n\nGRANT
PROXY ON \'app1_dba\'@\'localhost\' TO
\'bob\'@\'localhost\';\nQuery OK, 0 rows affected
(0.004 sec)\n\nGRANT PROXY ON
\'app2_dba\'@\'localhost\' TO
\'carol\'@\'localhost\';\nQuery OK, 0 rows affected
(0.004 sec)\n\nThe default root user accounts created by mysql_install_db
have this\nprivilege. For example:\n\nGRANT ALL PRIVILEGES ON *.* TO
\'root\'@\'localhost\' WITH GRANT OPTION;\nGRANT PROXY
ON \'\'@\'%\' TO
\'root\'@\'localhost\' WITH GRANT OPTION;\n\nThis
allows the default root user accounts to grant the PROXY privilege for\nany
other user account, and it also allows the default root user accounts
to\ngrant others the privilege to do the same.\n\nAuthentication
Options\n----------------------\n\nThe authentication options for the GRANT
statement are the same as those for\nthe CREATE USER
statement.\n\nIDENTIFIED BY
\'password\'\n------------------------\n\nThe optional IDENTIFIED
BY clause can be used to provide an account with a\npassword. The password
should be specified in plain text. It will be hashed by\nthe PASSWORD
function prior to being stored.\n\nFor example, if our password is mariadb,
then we can create the user with:\n\nGRANT USAGE ON *.* TO foo2@test
IDENTIFIED BY \'mariadb\';\n\nIf you do not specify a password
with the IDENTIFIED BY clause, the user will\nbe able to connect without a
password. A blank password is not a wildcard to\nmatch any password. The
user must connect without providing a password if no\npassword is
set.\n\nIf the user account already exists and if you provide the
IDENTIFIED BY\nclause, then the user\'s password will be changed. You
must have the privileges\nneeded for the SET PASSWORD statement to change a
user\'s password with GRANT.\n\nThe only authentication plugins that
this clause supports are\nmysql_native_password and
mysql_old_password.\n\nIDENTIFIED BY PASSWORD
\'password_hash\'\n--------------------------------------\n\nThe
optional IDENTIFIED BY PASSWORD clause can be used to provide an
account\nwith a password that has already been hashed. The password should
be specified\nas a hash that was provided by the PASSWORD function. It will
be stored as-is.\n\nFor example, if our password is mariadb, then we can
find the hash with:\n\nSELECT
PASSWORD(\'mariadb\');\n+-------------------------------------------+\n|
PASSWORD(\'mariadb\')
|\n+-------------------------------------------+\n|
*54958E764CE10E50764C2EECBB71D01F08549980
|\n+-------------------------------------------+\n1 row in set (0.00
sec)\n\nAnd then we can create a user with the hash:\n\nGRANT USAGE ON *.*
TO foo2@test IDENTIFIED BY \n PASSWORD
\'*54958E764CE10E50764C2EECBB71D01F08549980\';\n\nIf you do not
specify a password with the IDENTIFIED BY clause, the user will\nbe able to
connect without a password. A blank password is not a wildcard to\nmatch
any password. The user must connect without providing a password if
no\npassword is set.\n\nIf the user account already exists and if you
provide the IDENTIFIED BY\nclause, then the user\'s password will be
changed. You must have the privileges\nneeded for the SET PASSWORD
statement to change a user\'s password with GRANT.\n\nThe only
authentication plugins that this clause supports are\nmysql_native_password
and mysql_old_password.\n\nIDENTIFIED {VIA|WITH}
authentication_plugin\n-------------------------------------------\n\nThe
optional IDENTIFIED VIA authentication_plugin allows you to specify
that\nthe account should be authenticated by a specific authentication
plugin. The\nplugin name must be an active authentication plugin as per
SHOW PLUGINS. If it\ndoesn\'t show up in that output, then you will
need to install it with INSTALL\nPLUGIN or INSTALL SONAME.\n\nFor example,
this could be used with the PAM authentication plugin:\n\nGRANT USAGE ON
*.* TO foo2@test IDENTIFIED VIA pam;\n\nSome authentication plugins allow
additional arguments to be specified after a\nUSING or AS keyword. For
example, the PAM authentication plugin accepts a\nservice name:\n\nGRANT
USAGE ON *.* TO foo2@test IDENTIFIED VIA pam USING
\'mariadb\';\n\nThe exact meaning of the additional argument
would depend on the specific\nauthentication plugin.\n\nMariaDB starting
with 10.4.0\n----------------------------\nThe USING or AS keyword can also
be used to provide a plain-text password to a\nplugin if it\'s
provided as an argument to the PASSWORD() function. This is\nonly valid for
authentication plugins that have implemented a hook for the\nPASSWORD()
function. For example, the ed25519 authentication plugin
supports\nthis:\n\nCREATE USER safe@\'%\' IDENTIFIED VIA ed25519
\n USING PASSWORD(\'secret\');\n\nMariaDB starting with
10.4.3\n----------------------------\nOne can specify many authentication
plugins, they all work as alternatives\nways of authenticating a
user:\n\nCREATE USER safe@\'%\' IDENTIFIED VIA ed25519 \n USING
PASSWORD(\'secret\') OR unix_socket;\n\nBy default, when you
create a user without specifying an authentication\nplugin, MariaDB uses
the mysql_native_password plugin.\n\nResource Limit
Options\n----------------------\n\nIt is possible to set per-account limits
for certain server resources. The\nfollowing table shows the values that
can be set per
account:\n\n+--------------------------------------+--------------------------------------+')
WHERE help_topic_id = 107;
update help_topic set description = CONCAT(description, '\n| Limit
Type | Decription
|\n+--------------------------------------+--------------------------------------+\n|
MAX_QUERIES_PER_HOUR | Number of statements that the
|\n| | account can issue per hour
|\n| | (including updates)
|\n+--------------------------------------+--------------------------------------+\n|
MAX_UPDATES_PER_HOUR | Number of updates (not queries)
|\n| | that the account can issue per
hour
|\n+--------------------------------------+--------------------------------------+\n|
MAX_CONNECTIONS_PER_HOUR | Number of connections that the
|\n| | account can start per hour
|\n+--------------------------------------+--------------------------------------+\n|
MAX_USER_CONNECTIONS | Number of simultaneous connections
|\n| | that can be accepted from the
same |\n| | account; if it is 0,
|\n| | max_connections
will be used |\n| | instead;
if max_connections is 0, |\n| |
there is no limit for this |\n|
| account\'s simultaneous connections.
|\n+--------------------------------------+--------------------------------------+\n|
MAX_STATEMENT_TIME | Timeout, in seconds, for statements
|\n| | executed by the user. See also
|\n| | Aborting Statements that
Exceed a |\n| | Certain Time to
Execute.
|\n+--------------------------------------+--------------------------------------+\n\nIf
any of these limits are set to 0, then there is no limit for that
resource\nfor that user.\n\nTo set resource limits for an account, if you
do not want to change that\naccount\'s privileges, you can issue a
GRANT statement with the USAGE\nprivilege, which has no meaning. The
statement can name some or all limit\ntypes, in any order.\n\nHere is an
example showing how to set resource limits:\n\nGRANT USAGE ON *.* TO
\'someone\'@\'localhost\' WITH\n MAX_USER_CONNECTIONS
0\n MAX_QUERIES_PER_HOUR 200;\n\nThe resources are tracked per account,
which means \'user\'@\'server\'; not per\nuser name or
per connection.\n\nThe count can be reset for all users using FLUSH
USER_RESOURCES, FLUSH\nPRIVILEGES or mysqladmin reload.\n\nUsers with the
CONNECTION ADMIN privilege (in MariaDB 10.5.2 and later) or the\nSUPER
privilege are not restricted by max_user_connections, max_connections,\nor
max_password_errors.\n\nPer account resource limits are stored in the user
table, in the mysql\ndatabase. Columns used for resources limits are named
max_questions,\nmax_updates, max_connections (for
MAX_CONNECTIONS_PER_HOUR), and\nmax_user_connections (for
MAX_USER_CONNECTIONS).\n\nTLS Options\n-----------\n\nBy default, MariaDB
transmits data between the server and clients without\nencrypting it. This
is generally acceptable when the server and client run on\nthe same host or
in networks where security is guaranteed through other means.\nHowever, in
cases where the server and client exist on separate networks or\nthey are
in a high-risk network, the lack of encryption does introduce\nsecurity
concerns as a malicious actor could potentially eavesdrop on the\ntraffic
as it is sent over the network between them.\n\nTo mitigate this concern,
MariaDB allows you to encrypt data in transit\nbetween the server and
clients using the Transport Layer Security (TLS)\nprotocol. TLS was
formerly known as Secure Socket Layer (SSL), but strictly\nspeaking the SSL
protocol is a predecessor to TLS and, that version of the\nprotocol is now
considered insecure. The documentation still uses the term SSL\noften and
for compatibility reasons TLS-related server system and status\nvariables
still use the prefix ssl_, but internally, MariaDB only supports
its\nsecure successors.\n\nSee Secure Connections Overview for more
information about how to determine\nwhether your MariaDB server has TLS
support.\n\nYou can set certain TLS-related restrictions for specific user
accounts. For\ninstance, you might use this with user accounts that require
access to\nsensitive data while sending it across networks that you do not
control. These\nrestrictions can be enabled for a user account with the
CREATE USER, ALTER\nUSER, or GRANT statements. The following options are
available:\n\n+---------------------------+------------------------------------------------+\n|
Option | Description
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE NONE | TLS is not required for this account, but can
|\n| | still be used.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE SSL | The account must use TLS, but no valid X509
|\n| | certificate is required. This option
cannot |\n| | be combined with other TLS
options.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE X509 | The account must use TLS and must have a
|\n| | valid X509 certificate. This option
implies |\n| | REQUIRE SSL. This option cannot
be combined |\n| | with other TLS options.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE ISSUER \'issuer\' | The account must use TLS and must
have a |\n| | valid X509 certificate. Also,
the Certificate |\n| | Authority must be the one
specified via the |\n| | string issuer. This
option implies REQUIRE |\n| | X509. This
option can be combined with the |\n| |
SUBJECT, and CIPHER options in any order.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE SUBJECT \'subject\' | The account must use TLS and must
have a |\n| | valid X509 certificate. Also,
the |\n| | certificate\'s
Subject must be the one |\n| | specified
via the string subject. This option |\n| |
implies REQUIRE X509. This option can be |\n|
| combined with the ISSUER, and CIPHER options |\n|
| in any order.
|\n+---------------------------+------------------------------------------------+\n|
REQUIRE CIPHER \'cipher\' | The account must use TLS, but no
valid X509 |\n| | certificate is required.
Also, the encryption |\n| | used for the
connection must use a specific |\n| | cipher
method specified in the string cipher. |\n| |
This option implies REQUIRE SSL. This option |\n|
| can be combined with the ISSUER, and SUBJECT |\n|
| options in any order.
|\n+---------------------------+------------------------------------------------+\n\nThe
REQUIRE keyword must be used only once for all specified options, and
the\nAND keyword can be used to separate individual options, but it is not
required.\n\nFor example, you can create a user account that requires these
TLS options\nwith the following:\n\nGRANT USAGE ON *.* TO
\'alice\'@\'%\'\n REQUIRE SUBJECT \'/CN=alice/O=My
Dom, Inc./C=US/ST=Oregon/L=Portland\'\n AND ISSUER
\'/C=FI/ST=Somewhere/L=City/ O=Some
Company/CN=Peter\nParker/emailAddress=p.parker@marvel.com\'\n AND
CIPHER \'SHA-DES-CBC3-EDH-RSA\';\n\nIf any of these options are
set for a specific user account, then any client\nwho tries to connect with
that user account will have to be configured to\nconnect with TLS.\n\nSee
Securing Connections for Client and Server for information on how
to\nenable TLS on the client and
server.\n\nRoles\n-----\n\nSyntax\n------\n\nGRANT role TO grantee [,
grantee ... ]\n[ WITH ADMIN OPTION ]\n\ngrantee:\n rolename\n username
[authentication_option]\n\nThe GRANT statement is also used to grant the
use of a role to one or more\nusers or other roles. In order to be able to
grant a role, the grantor doing\nso must have permission to do so (see WITH
ADMIN in the CREATE ROLE article).\n\nSpecifying the WITH ADMIN OPTION
permits the grantee to in turn grant the role\nto another.\n\nFor example,
the following commands show how to grant the same role to a\ncouple
different users.\n\nGRANT journalist TO hulda;\n\nGRANT journalist TO
berengar WITH ADMIN OPTION;\n\nIf a user has been granted a role, they do
not automatically obtain all\npermissions associated with that role. These
permissions are only in use when\nthe user activates the role with the SET
ROLE statement.\n\nTO PUBLIC\n---------\n\nMariaDB starting with
10.11\n---------------------------\n\nSyntax\n------\n\nGRANT
<privilege> ON <database>.<object> TO PUBLIC;\nREVOKE
<privilege> ON <database>.<object> FROM PUBLIC;\n\nGRANT
... TO PUBLIC grants privileges to all users with access to the
server.\nThe privileges also apply to users created after the privileges
are granted.\nThis can be useful when one only wants to state once that all
users need to\nhave a certain set of privileges.\n\nWhen running SHOW
GRANTS, a user will also see all privileges inherited from\nPUBLIC. SHOW
GRANTS FOR PUBLIC will only show TO PUBLIC grants.\n\nGrant
Examples\n--------------\n\nGranting Root-like
Privileges\n-----------------------------\n\nYou can create a user that has
privileges similar to the default root accounts\nby executing the
following:\n\nCREATE USER
\'alexander\'@\'localhost\';\nGRANT ALL PRIVILEGES ON
*.* to \'alexander\'@\'localhost\' WITH GRANT
OPTION;\n\nURL: https://mariadb.com/kb/en/grant/') WHERE help_topic_id
= 107;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(108,10,'RENAME USER','Syntax\n------\n\nRENAME USER
old_user TO new_user\n [, old_user TO new_user]
...\n\nDescription\n-----------\n\nThe RENAME USER statement renames
existing MariaDB accounts. To use it, you\nmust have the global CREATE USER
privilege or the UPDATE privilege for the\nmysql database. Each account is
named using the same format as for the CREATE\nUSER statement; for example,
\'jeffrey\'@\'localhost\'. If you specify only
the\nuser name part of the account name, a host name part of
\'%\' is used.\n\nIf any of the old user accounts do not exist or
any of the new user accounts\nalready exist, ERROR 1396 (HY000) results. If
an error occurs, RENAME USER\nwill still rename the accounts that do not
result in an error.\n\nExamples\n--------\n\nCREATE USER
\'donald\', \'mickey\';\nRENAME USER
\'donald\' TO \'duck\'@\'localhost\',
\'mickey\' TO
\'mouse\'@\'localhost\';\n\nURL:
https://mariadb.com/kb/en/rename-user/','','https://mariadb.com/kb/en/rename-user/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(109,10,'REVOKE','Privileges\n----------\n\nSyntax\n------\n\nREVOKE
\n priv_type [(column_list)]\n [, priv_type [(column_list)]] ...\n ON
[object_type] priv_level\n FROM user [, user] ...\n\nREVOKE ALL
PRIVILEGES, GRANT OPTION\n FROM user [, user]
...\n\nDescription\n-----------\n\nThe REVOKE statement enables system
administrators to revoke privileges (or\nroles - see section below) from
MariaDB accounts. Each account is named using\nthe same format as for the
GRANT statement; for
example,\n\'jeffrey\'@\'localhost\'. If you specify
only the user name part of the account\nname, a host name part of
\'%\' is used. For details on the levels at which\nprivileges
exist, the allowable priv_type and priv_level values, and the\nsyntax for
specifying users and passwords, see GRANT.\n\nTo use the first REVOKE
syntax, you must have the GRANT OPTION privilege, and\nyou must have the
privileges that you are revoking.\n\nTo revoke all privileges, use the
second syntax, which drops all global,\ndatabase, table, column, and
routine privileges for the named user or users:\n\nREVOKE ALL PRIVILEGES,
GRANT OPTION FROM user [, user] ...\n\nTo use this REVOKE syntax, you must
have the global CREATE USER privilege or\nthe UPDATE privilege for the
mysql database. See GRANT.\n\nExamples\n--------\n\nREVOKE SUPER ON *.*
FROM
\'alexander\'@\'localhost\';\n\nRoles\n-----\n\nSyntax\n------\n\nREVOKE
role [, role ...]\n FROM grantee [, grantee2 ... ]\n\nREVOKE ADMIN OPTION
FOR role FROM grantee [, grantee2]\n\nDescription\n-----------\n\nREVOKE is
also used to remove a role from a user or another role that
it\'s\npreviously been assigned to. If a role has previously been set
as a default\nrole, REVOKE does not remove the record of the default role
from the\nmysql.user table. If the role is subsequently granted again, it
will again be\nthe user\'s default. Use SET DEFAULT ROLE NONE to
explicitly remove this.\n\nBefore MariaDB 10.1.13, the REVOKE role
statement was not permitted in\nprepared
statements.\n\nExample\n-------\n\nREVOKE journalist FROM hulda\n\nURL:
https://mariadb.com/kb/en/revoke/','','https://mariadb.com/kb/en/revoke/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(110,10,'SET PASSWORD','Syntax\n------\n\nSET PASSWORD [FOR
user] =\n {\n PASSWORD(\'some password\')\n |
OLD_PASSWORD(\'some password\')\n | \'encrypted
password\'\n }\n\nDescription\n-----------\n\nThe SET PASSWORD
statement assigns a password to an existing MariaDB user\naccount.\n\nIf
the password is specified using the PASSWORD() or OLD_PASSWORD()
function,\nthe literal text of the password should be given. If the
password is specified\nwithout using either function, the password should
be the already-encrypted\npassword value as returned by
PASSWORD().\n\nOLD_PASSWORD() should only be used if your MariaDB/MySQL
clients are very old\n(< 4.0.0).\n\nWith no FOR clause, this statement
sets the password for the current user. Any\nclient that has connected to
the server using a non-anonymous account can\nchange the password for that
account.\n\nWith a FOR clause, this statement sets the password for a
specific account on\nthe current server host. Only clients that have the
UPDATE privilege for the\nmysql database can do this. The user value should
be given in\nuser_name@host_name format, where user_name and host_name are
exactly as they\nare listed in the User and Host columns of the mysql.user
table (or view in\nMariaDB-10.4 onwards) entry.\n\nThe argument to
PASSWORD() and the password given to MariaDB clients can be of\narbitrary
length.\n\nAuthentication Plugin
Support\n-----------------------------\n\nMariaDB starting with
10.4\n--------------------------\nIn MariaDB 10.4 and later, SET PASSWORD
(with or without PASSWORD()) works for\naccounts authenticated via any
authentication plugin that supports passwords\nstored in the
mysql.global_priv table.\n\nThe ed25519, mysql_native_password, and
mysql_old_password authentication\nplugins store passwords in the
mysql.global_priv table.\n\nIf you run SET PASSWORD on an account that
authenticates with one of these\nauthentication plugins that stores
passwords in the mysql.global_priv table,\nthen the PASSWORD() function is
evaluated by the specific authentication\nplugin used by the account. The
authentication plugin hashes the password with\na method that is compatible
with that specific authentication plugin.\n\nThe unix_socket, named_pipe,
gssapi, and pam authentication plugins do not\nstore passwords in the
mysql.global_priv table. These authentication plugins\nrely on other
methods to authenticate the user.\n\nIf you attempt to run SET PASSWORD on
an account that authenticates with one\nof these authentication plugins
that doesn\'t store a password in the\nmysql.global_priv table, then
MariaDB Server will raise a warning like the\nfollowing:\n\nSET PASSWORD is
ignored for users authenticating via unix_socket plugin\n\nSee
Authentication from MariaDB 10.4 for an overview of authentication
changes\nin MariaDB 10.4.\n\nMariaDB until 10.3\n------------------\nIn
MariaDB 10.3 and before, SET PASSWORD (with or without PASSWORD())
only\nworks for accounts authenticated via mysql_native_password
or\nmysql_old_password authentication plugins\n\nPasswordless User
Accounts\n--------------------------\n\nUser accounts do not always require
passwords to login.\n\nThe unix_socket , named_pipe and gssapi
authentication plugins do not require\na password to authenticate the
user.\n\nThe pam authentication plugin may or may not require a password
to\nauthenticate the user, depending on the specific configuration.\n\nThe
mysql_native_password and mysql_old_password authentication
plugins\nrequire passwords for authentication, but the password can be
blank. In that\ncase, no password is required.\n\nIf you provide a password
while attempting to log into the server as an\naccount that doesn\'t
require a password, then MariaDB server will simply\nignore the
password.\n\nMariaDB starting with 10.4\n--------------------------\nIn
MariaDB 10.4 and later, a user account can be defined to use
multiple\nauthentication plugins in a specific order of preference. This
specific\nscenario may be more noticeable in these versions, since an
account could be\nassociated with some authentication plugins that require
a password, and some\nthat do not.\n\nExample\n-------\n\nFor example, if
you had an entry with User and Host column values of \'bob\'
and\n\'%.loc.gov\', you would write the statement like
this:\n\nSET PASSWORD FOR \'bob\'@\'%.loc.gov\' =
PASSWORD(\'newpass\');\n\nIf you want to delete a password for a
user, you would do:\n\nSET PASSWORD FOR \'bob\'@localhost =
PASSWORD(\"\");\n\nURL:
https://mariadb.com/kb/en/set-password/','','https://mariadb.com/kb/en/set-password/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(111,10,'CREATE ROLE','Syntax\n------\n\nCREATE [OR REPLACE]
ROLE [IF NOT EXISTS] role \n [WITH ADMIN\n {CURRENT_USER | CURRENT_ROLE |
user | role}]\n\nDescription\n-----------\n\nThe CREATE ROLE statement
creates one or more MariaDB roles. To use it, you\nmust have the global
CREATE USER privilege or the INSERT privilege for the\nmysql database. For
each account, CREATE ROLE creates a new row in the\nmysql.user table that
has no privileges, and with the corresponding is_role\nfield set to Y. It
also creates a record in the mysql.roles_mapping table.\n\nIf any of the
specified roles already exist, ERROR 1396 (HY000) results. If an\nerror
occurs, CREATE ROLE will still create the roles that do not result in
an\nerror. The maximum length for a role is 128 characters. Role names can
be\nquoted, as explained in the Identifier names page. Only one error is
produced\nfor all roles which have not been created:\n\nERROR 1396 (HY000):
Operation CREATE ROLE failed for
\'a\',\'b\',\'c\'\n\nFailed CREATE or DROP
operations, for both users and roles, produce the same\nerror
code.\n\nPUBLIC and NONE are reserved, and cannot be used as role names.
NONE is used\nto unset a role and PUBLIC has a special use in other
systems, such as Oracle,\nso is reserved for compatibility purposes.\n\nFor
valid identifiers to use as role names, see Identifier Names.\n\nWITH
ADMIN\n----------\n\nThe optional WITH ADMIN clause determines whether the
current user, the\ncurrent role or another user or role has use of the
newly created role. If the\nclause is omitted, WITH ADMIN CURRENT_USER is
treated as the default, which\nmeans that the current user will be able to
GRANT this role to users.\n\nOR REPLACE\n----------\n\nIf the optional OR
REPLACE clause is used, it acts as a shortcut for:\n\nDROP ROLE IF EXISTS
name;\nCREATE ROLE name ...;\n\nIF NOT EXISTS\n-------------\n\nWhen the IF
NOT EXISTS clause is used, MariaDB will return a warning instead\nof an
error if the specified role already exists. Cannot be used together
with\nthe OR REPLACE clause.\n\nExamples\n--------\n\nCREATE ROLE
journalist;\n\nCREATE ROLE developer WITH ADMIN
lorinda@localhost;\n\nGranting the role to another user. Only user
lorinda@localhost has permission\nto grant the developer role:\n\nSELECT
USER();\n+-------------------+\n| USER()
|\n+-------------------+\n| henning@localhost
|\n+-------------------+\n...\nGRANT developer TO ian@localhost;\nAccess
denied for user \'henning\'@\'localhost\'\n\nSELECT
USER();\n+-------------------+\n| USER()
|\n+-------------------+\n| lorinda@localhost
|\n+-------------------+\n\nGRANT m_role TO ian@localhost;\n\nThe OR
REPLACE and IF NOT EXISTS clauses. The journalist role already
exists:\n\nCREATE ROLE journalist;\nERROR 1396 (HY000): Operation CREATE
ROLE failed for \'journalist\'\n\nCREATE OR REPLACE ROLE
journalist;\nQuery OK, 0 rows affected (0.00 sec)\n\nCREATE ROLE IF NOT
EXISTS journalist;\nQuery OK, 0 rows affected, 1 warning (0.00 sec)\n\nSHOW
WARNINGS;\n+-------+------+---------------------------------------------------+\n|
Level | Code | Message
|\n+-------+------+---------------------------------------------------+\n|
Note | 1975 | Can\'t create role \'journalist\'; it already
exists
|\n+-------+------+---------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/create-role/','','https://mariadb.com/kb/en/create-role/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(112,10,'DROP ROLE','Syntax\n------\n\nDROP ROLE [IF EXISTS]
role_name [,role_name ...]\n\nDescription\n-----------\n\nThe DROP ROLE
statement removes one or more MariaDB roles. To use this\nstatement, you
must have the global CREATE USER privilege or the DELETE\nprivilege for the
mysql database.\n\nDROP ROLE does not disable roles for connections which
selected them with SET\nROLE. If a role has previously been set as a
default role, DROP ROLE does not\nremove the record of the default role
from the mysql.user table. If the role\nis subsequently recreated and
granted, it will again be the user\'s default.\nUse SET DEFAULT ROLE
NONE to explicitly remove this.\n\nIf any of the specified user accounts do
not exist, ERROR 1396 (HY000)\nresults. If an error occurs, DROP ROLE will
still drop the roles that do not\nresult in an error. Only one error is
produced for all roles which have not\nbeen dropped:\n\nERROR 1396 (HY000):
Operation DROP ROLE failed for
\'a\',\'b\',\'c\'\n\nFailed CREATE or DROP
operations, for both users and roles, produce the same\nerror code.\n\nIF
EXISTS\n---------\n\nIf the IF EXISTS clause is used, MariaDB will return a
warning instead of an\nerror if the role does not
exist.\n\nExamples\n--------\n\nDROP ROLE journalist;\n\nThe same thing
using the optional IF EXISTS clause:\n\nDROP ROLE journalist;\nERROR 1396
(HY000): Operation DROP ROLE failed for \'journalist\'\n\nDROP
ROLE IF EXISTS journalist;\nQuery OK, 0 rows affected, 1 warning (0.00
sec)\n\nNote (Code 1975): Can\'t drop role \'journalist\';
it doesn\'t exist\n\nURL:
https://mariadb.com/kb/en/drop-role/','','https://mariadb.com/kb/en/drop-role/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(113,10,'SET ROLE','Syntax\n------\n\nSET ROLE { role | NONE
}\n\nDescription\n-----------\n\nThe SET ROLE statement enables a role,
along with all of its associated\npermissions, for the current session. To
unset a role, use NONE .\n\nIf a role that doesn\'t exist, or to which
the user has not been assigned, is\nspecified, an ERROR 1959 (OP000):
Invalid role specification error occurs.\n\nAn automatic SET ROLE is
implicitly performed when a user connects if that\nuser has been assigned a
default role. See SET DEFAULT ROLE.\n\nExample\n-------\n\nSELECT
CURRENT_ROLE;\n+--------------+\n| CURRENT_ROLE |\n+--------------+\n| NULL
|\n+--------------+\n\nSET ROLE staff;\n\nSELECT
CURRENT_ROLE;\n+--------------+\n| CURRENT_ROLE |\n+--------------+\n|
staff |\n+--------------+\n\nSET ROLE NONE;\n\nSELECT
CURRENT_ROLE();\n+----------------+\n| CURRENT_ROLE()
|\n+----------------+\n| NULL |\n+----------------+\n\nURL:
https://mariadb.com/kb/en/set-role/','','https://mariadb.com/kb/en/set-role/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(114,10,'SET DEFAULT ROLE','Syntax\n------\n\nSET DEFAULT
ROLE { role | NONE } [ FOR user@host ]\n\nDescription\n-----------\n\nThe
SET DEFAULT ROLE statement sets a default role for a specified
(or\ncurrent) user. A default role is automatically enabled when a user
connects\n(an implicit SET ROLE statement is executed immediately after a
connection is\nestablished).\n\nTo be able to set a role as a default, the
role must already have been granted\nto that user, and one needs the
privileges to enable this role (if you cannot\ndo SET ROLE X, you
won\'t be able to do SET DEFAULT ROLE X). To set a default\nrole for
another user one needs to have write access to the mysql database.\n\nTo
remove a user\'s default role, use SET DEFAULT ROLE NONE [ FOR
user@host ].\nThe record of the default role is not removed if the role is
dropped or\nrevoked, so if the role is subsequently re-created or granted,
it will again\nbe the user\'s default role.\n\nThe default role is
stored in the default_role column in the mysql.user\ntable/view, as well as
in the Information Schema APPLICABLE_ROLES table, so\nthese can be viewed
to see which role has been assigned to a user as
the\ndefault.\n\nExamples\n--------\n\nSetting a default role for the
current user:\n\nSET DEFAULT ROLE journalist;\n\nRemoving a default role
from the current user:\n\nSET DEFAULT ROLE NONE;\n\nSetting a default role
for another user. The role has to have been granted to\nthe user before it
can be set as default:\n\nCREATE ROLE journalist;\nCREATE USER
taniel;\n\nSET DEFAULT ROLE journalist FOR taniel;\nERROR 1959 (OP000):
Invalid role specification `journalist`\n\nGRANT journalist TO taniel;\nSET
DEFAULT ROLE journalist FOR taniel;\n\nViewing mysql.user:\n\nselect * from
mysql.user where user=\'taniel\'\\G\n***************************
1. row ***************************\n Host: %\n User:
taniel\n...\n is_role: N\n default_role:
journalist\n...\n\nRemoving a default role for another user\n\nSET DEFAULT
ROLE NONE FOR taniel;\n\nURL:
https://mariadb.com/kb/en/set-default-role/','','https://mariadb.com/kb/en/set-default-role/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(115,10,'Roles Overview','Description\n-----------\n\nA role
bundles a number of privileges together. It assists larger\norganizations
where, typically, a number of users would have the same\nprivileges, and,
previously, the only way to change the privileges for a group\nof users was
by changing each user\'s privileges individually.\n\nAlternatively,
multiple external users could have been assigned the same user,\nand there
would have been no way to see which actual user was responsible for\nwhich
action.\n\nWith roles, managing this is easy. For example, there could be a
number of\nusers assigned to a journalist role, with identical privileges.
Changing the\nprivileges for all the journalists is a matter of simply
changing the role\'s\nprivileges, while the individual user is still
linked with any changes that\ntake place.\n\nRoles are created with the
CREATE ROLE statement, and dropped with the DROP\nROLE statement. Roles are
then assigned to a user with an extension to the\nGRANT statement, while
privileges are assigned to a role in the regular way\nwith GRANT.
Similarly, the REVOKE statement can be used to both revoke a role\nfrom a
user, or revoke a privilege from a role.\n\nOnce a user has connected, he
can obtain all privileges associated with a role\nby setting a role with
the SET ROLE statement. The CURRENT_ROLE function\nreturns the currently
set role for the session, if any.\n\nOnly roles granted directly to a user
can be set, roles granted to other roles\ncannot. Instead the privileges
granted to a role, which is, in turn, granted\nto another role (grantee),
will be immediately available to any user who sets\nthis second grantee
role.\n\nThe SET DEFAULT ROLE statement allows one to set a default role
for a user. A\ndefault role is automatically enabled when a user connects
(an implicit SET\nROLE statement is executed immediately after a connection
is established).\n\nRoles were implemented as a GSoC 2013 project by
Vicentiu Ciorbaru.\n\nSystem Tables\n-------------\n\nInformation about
roles and who they\'ve been granted to can be found in
the\nInformation Schema APPLICABLE_ROLES table as well as the
mysql.ROLES_MAPPING\ntable.\n\nThe Information Schema ENABLED_ROLES table
shows the enabled roles for the\ncurrent
session.\n\nExamples\n--------\n\nCreating a role and granting a
privilege:\n\nCREATE ROLE journalist;\n\nGRANT SHOW DATABASES ON *.* TO
journalist;\n\nGRANT journalist to hulda;\n\nNote, that hulda has no SHOW
DATABASES privilege, even though she was granted\nthe journalist role. She
needs to set the role first:\n\nSHOW DATABASES;\n+--------------------+\n|
Database |\n+--------------------+\n| information_schema
|\n+--------------------+\n\nSELECT CURRENT_ROLE;\n+--------------+\n|
CURRENT_ROLE |\n+--------------+\n| NULL |\n+--------------+\n\nSET
ROLE journalist;\n\nSELECT CURRENT_ROLE;\n+--------------+\n| CURRENT_ROLE
|\n+--------------+\n| journalist |\n+--------------+\n\nSHOW
DATABASES;\n+--------------------+\n| Database
|\n+--------------------+\n| ... |\n| information_schema
|\n| mysql |\n| performance_schema |\n| test
|\n| ... |\n+--------------------+\n\nSET ROLE
NONE;\n\nRoles can be granted to roles:\n\nCREATE ROLE writer;\n\nGRANT
SELECT ON data.* TO writer;\n\nGRANT writer TO journalist;\n\nBut one does
not need to set a role granted to a role. For example, hulda
will\nautomatically get all writer privileges when she sets the journalist
role:\n\nSELECT CURRENT_ROLE;\n+--------------+\n| CURRENT_ROLE
|\n+--------------+\n| NULL |\n+--------------+\n\nSHOW TABLES FROM
data;\nEmpty set (0.01 sec)\n\nSET ROLE journalist;\n\nSELECT
CURRENT_ROLE;\n+--------------+\n| CURRENT_ROLE |\n+--------------+\n|
journalist |\n+--------------+\n\nSHOW TABLES FROM
data;\n+------------------------------+\n| Tables_in_data
|\n+------------------------------+\n| set1 |\n|
... |\n+------------------------------+\n\nRoles
and Views (and Stored
Routines)\n-------------------------------------\n\nWhen a user sets a
role, he, in a sense, has two identities with two\nassociated sets of
privileges. But a view (or a stored routine) can have only\none definer.
So, when a view (or a stored routine) is created with the SQL\nSECURITY
DEFINER, one can specify whether the definer should be CURRENT_USER\n(and
the view will have none of the privileges of the user\'s role)
or\nCURRENT_ROLE (in this case, the view will use role\'s privileges,
but none of\nthe user\'s privileges). As a result, sometimes one can
create a view that is\nimpossible to use.\n\nCREATE ROLE r1;\n\nGRANT ALL
ON db1.* TO r1;\n\nGRANT r1 TO foo@localhost;\n\nGRANT ALL ON db.* TO
foo@localhost;\n\nSELECT CURRENT_USER\n+---------------+\n| current_user
|\n+---------------+\n| foo@localhost |\n+---------------+\n\nSET ROLE
r1;\n\nCREATE TABLE db1.t1 (i int);\n\nCREATE VIEW db.v1 AS SELECT * FROM
db1.t1;\n\nSHOW CREATE VIEW
db.v1;\n+------+-----------------------------------------------------------------------\n------------------------------------------------------------------+------------\n---------+----------------------+\n|
View | Create View
\n |\ncharacter_set_client |
collation_connection
|\n+------+-----------------------------------------------------------------------\n------------------------------------------------------------------+------------\n---------+----------------------+\n|
v1 | CREATE ALGORITHM=UNDEFINED DEFINER=`foo`@`localhost` SQL
SECURITY\nDEFINER VIEW `db`.`v1` AS SELECT `db1`.`t1`.`i` AS `i` from
`db1`.`t1` | utf8 \n | utf8_general_ci
|\n+------+-----------------------------------------------------------------------\n------------------------------------------------------------------+------------\n---------+----------------------+\n\nCREATE
DEFINER=CURRENT_ROLE VIEW db.v2 AS SELECT * FROM db1.t1;\n\nSHOW CREATE
VIEW
db.b2;\n+------+-----------------------------------------------------------------------\n-----------------------------------------------------+----------------------+--\n-------------------+\n|
View | Create View
\n | character_set_client |\ncollation_connection
|\n+------+-----------------------------------------------------------------------\n-----------------------------------------------------+----------------------+--\n-------------------+\n|
v2 | CREATE ALGORITHM=UNDEFINED DEFINER=`r1` SQL SECURITY DEFINER
VIEW\n`db`.`v2` AS select `db1`.`t1`.`a` AS `a` from `db1`.`t1` | utf8
\n | utf8_general_ci
|\n+------+-----------------------------------------------------------------------\n-----------------------------------------------------+----------------------+--\n-------------------+\n\nOther
Resources\n---------------\n\n* Roles Review by Peter Gulutzan\n\nURL:
https://mariadb.com/kb/en/roles_overview/','','https://mariadb.com/kb/en/roles_overview/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(116,10,'Account Locking','MariaDB starting with
10.4.2\n----------------------------\nAccount locking was introduced in
MariaDB 10.4.2.\n\nDescription\n-----------\n\nAccount locking permits
privileged administrators to lock/unlock user\naccounts. No new client
connections will be permitted if an account is locked\n(existing
connections are not affected).\n\nUser accounts can be locked at creation,
with the CREATE USER statement, or\nmodified after creation with the ALTER
USER statement. For example:\n\nCREATE USER
\'lorin\'@\'localhost\' ACCOUNT LOCK;\n\nor\n\nALTER
USER \'marijn\'@\'localhost\' ACCOUNT LOCK;\n\nThe
server will return an ER_ACCOUNT_HAS_BEEN_LOCKED error when locked
users\nattempt to connect:\n\nmysql -ulorin\n ERROR 4151 (HY000): Access
denied, this account is locked\n\nThe ALTER USER statement is also used to
unlock a user:\n\nALTER USER \'lorin\'@\'localhost\'
ACCOUNT UNLOCK;\n\nThe SHOW CREATE USER statement will show whether the
account is locked:\n\nSHOW CREATE USER
\'marijn\'@\'localhost\';\n+-----------------------------------------------+\n|
CREATE USER for marijn@localhost
|\n+-----------------------------------------------+\n| CREATE USER
\'marijn\'@\'localhost\' ACCOUNT LOCK
|\n+-----------------------------------------------+\n\nas well as querying
the mysql.global_priv table:\n\nSELECT CONCAT(user, \'@\', host,
\' => \', JSON_DETAILED(priv)) FROM\nmysql.global_priv \n
WHERE
user=\'marijn\';\n+------------------------------------------------------------------------------\n-------+\n|
CONCAT(user, \'@\', host, \' => \',
JSON_DETAILED(priv)) \n
|\n+------------------------------------------------------------------------------\n-------+\n|
marijn@localhost => {\n \"access\": 0,\n
\"plugin\": \"mysql_native_password\",\n
\"authentication_string\": \"\",\n
\"account_locked\": true,\n \"password_last_changed\":
1558017158\n}
|\n+------------------------------------------------------------------------------\n-------+\n\nURL:
https://mariadb.com/kb/en/account-locking/','','https://mariadb.com/kb/en/account-locking/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(117,10,'Authentication from MariaDB 10.4','MariaDB starting
with 10.4\n--------------------------\nMariaDB 10.4 introduced a number of
changes to the authentication process,\nintended to make things easier and
more intuitive.\n\nOverview\n--------\n\nThere are four new main features
in 10.4 relating to authentication:\n\n* It is possible to use more than
one authentication plugin for each user\naccount. For example, this can be
useful to slowly migrate users to the more\nsecure ed25519 authentication
plugin over time, while allowing the old\nmysql_native_password
authentication plugin as an alternative for the\ntransitional period.\n*
The root@localhost user account created by mysql_install_db is created
with\nthe ability to use two authentication plugins.\nFirst, it is
configured to try to use the unix_socket authentication plugin.\nThis
allows the root@localhost user to login without a password via the
local\nUnix socket file defined by the socket system variable, as long as
the login\nis attempted from a process owned by the operating system root
user account.\nSecond, if authentication fails with the unix_socket
authentication plugin,\nthen it is configured to try to use the
mysql_native_password authentication\nplugin. However, an invalid password
is initially set, so in order to\nauthenticate this way, a password must be
set with SET PASSWORD.\nHowever, just using the unix_socket authentication
plugin may be fine for many\nusers, and it is very secure. You may want to
try going without password\nauthentication to see how well it works for
you. Remember, the best way to\nkeep your password safe is not to have
one!\n\n* All user accounts, passwords, and global privileges are now
stored in the\nmysql.global_priv table. The mysql.user table still exists
and has exactly the\nsame set of columns as before, but it’s now a view
that references the\nmysql.global_priv table. Tools that analyze the
mysql.user table should\ncontinue to work as before. From MariaDB 10.4.13,
the dedicated mariadb.sys\nuser is created as the definer of this view.
Previously root was the definer,\nwhich resulted in privilege problems when
this username was changed.\n* MariaDB 10.4 adds supports for User Password
Expiry, which is not active by\ndefault.\n\nDescription\n-----------\n\nAs
a result of the above changes, the open-for-everyone all-powerful
root\naccount is finally gone. And installation scripts will no longer
demand that\nyou \"PLEASE REMEMBER TO SET A PASSWORD FOR THE MariaDB
root USER !\", because\nthe root account is securely created
automatically.\n\nTwo all-powerful accounts are created by default — root
and the OS user that\nowns the data directory, typically mysql. They are
created as:\n\nCREATE USER root@localhost IDENTIFIED VIA unix_socket OR
mysql_native_password\nUSING \'invalid\'\nCREATE USER
mysql@localhost IDENTIFIED VIA unix_socket OR\nmysql_native_password USING
\'invalid\'\n\nUsing unix_socket means that if you are the system
root user, you can login as\nroot@locahost without a password. This
technique was pioneered by Otto\nKekäläinen in Debian MariaDB packages
and has been successfully used in Debian\nsince as early as MariaDB
10.0.\n\nIt is based on a simple fact that asking the system root for a
password adds\nno extra security — root has full access to all the data
files and all process\nmemory anyway. But not asking for a password means,
there is no root password\nto forget (no need for the numerous tutorials on
\"how to reset MariaDB root\npassword\"). And if you want to
script some tedious database work, there is no\nneed to store the root
password in plain text for the script to use (no need\nfor debian-sys-maint
user).\n\nStill, some users may wish to log in as MariaDB root without
using sudo. Hence\nthe old authentication method — conventional MariaDB
password — is still\navailable. By default it is disabled
(\"invalid\" is not a valid password hash),\nbut one can set the
password with a usual SET PASSWORD statement. And still\nretain the
password-less access via sudo.\n\nIf you install MariaDB locally (say from
a tarball), you would not want to use\nsudo to be able to login. This is
why MariaDB creates a second all-powerful\nuser with the same name as a
system user that owns the data directory. In\nlocal (not system-wide)
installations, this will be the user who installed\nMariaDB — they
automatically get convenient password-less root-like access,\nbecause they
can access all the data files anyway.\n\nEven if MariaDB is installed
system-wide, you may not want to run your\ndatabase maintenance scripts as
system root — now you can run them as system\nmysql user. And you will
know that they will never destroy your entire system,\neven if you make a
typo in a shell script.\n\nHowever, seasoned MariaDB DBAs who are used to
the old ways do need to make\nsome changes. See the examples below for
common tasks.\n\nCookbook\n--------\n\nAfter installing MariaDB system-wide
the first thing you’ve got used to doing\nis logging in into the
unprotected root account and protecting it, that is,\nsetting the root
password:\n\n$ sudo dnf install MariaDB-server\n$ mysql
-uroot\n...\nMariaDB> set password =
password(\"XH4VmT3_jt\");\n\nThis is not only unnecessary now, it
will simply not work — there is no\nunprotected root account. To login as
root use\n\n$ sudo dnf install MariaDB-server\n$ sudo mysql\n\nNote that it
implies you are connecting via the unix socket, not tcp. If you\nhappen to
have protocol=tcp in a system-wide /etc/my.cnf file, use sudo
mysql\n--protocol=socket.\n\nAfter installing MariaDB locally you’ve also
used to connect to the\nunprotected root account using mysql -uroot. This
will not work either, simply\nuse mysql without specifying a
username.\n\nIf you\'ve forgotten your root password, no problem —
you can still connect\nusing sudo and change the password. And if
you\'ve also removed unix_socket\nauthentication, to restore access do
as follows:\n\n* restart MariaDB with --skip-grant-tables\n* login into the
unprotected server\n* run FLUSH PRIVILEGES (note, before 10.4 this
would’ve been the last step,\nnot anymore). This disables
--skip-grant-tables and allows you to change the\nstored authentication
method\n* run SET PASSWORD FOR root@localhost to change the root
password.\n\nTo view inside privilege tables, the old mysql.user table
still exists. You\ncan select from it as before, although you cannot update
it anymore. It\ndoesn’t show alternative authentication plugins and this
was one of the\nreasons for switching to the mysql.global_priv table —
complex authentication\nrules did not fit into rigid structure of a
relational table. You can select\nfrom the new table, for
example:\n\nselect concat(user, \'@\', host, \' =>
\', json_detailed(priv)) from\nmysql.global_priv;\n\nReverting to the
Previous Authentication Method for
root@localhost\n------------------------------------------------------------------\n\nIf
you don\'t want the root@localhost user account created by
mysql_install_db\nto use unix_socket authentication by default, then there
are a few ways to\nrevert to the previous mysql_native_password
authentication method for this\nuser account.\n\nConfiguring
mysql_install_db to Revert to the Previous Authentication
Method\n----------------------------------------------------------------------------\n\nOne
way to revert to the previous mysql_native_password authentication
method\nfor the root@localhost user account is to execute mysql_install_db
with a\nspecial option. If mysql_install_db is executed
while\n--auth-root-authentication-method=normal is specified, then it will
create the\ndefault user accounts using the default behavior of MariaDB
10.3 and before.\n\nThis means that the root@localhost user account will
use mysql_native_password\nauthentication by default. There are some other
differences as well. See\nmysql_install_db: User Accounts Created by
Default for more information.\n\nFor example, the option can be set on the
command-line while running\nmysql_install_db:\n\nmysql_install_db
--user=mysql
--datadir=/var/lib/mysql\n--auth-root-authentication-method=normal\n\nThe
option can also be set in an option file in an option group supported
by\nmysql_install_db. For
example:\n\n[mysql_install_db]\nauth_root_authentication_method=normal\n\nIf
the option is set in an option file and if mysql_install_db is
executed,\nthen mysql_install_db will read this option from the option
file, and it will\nautomatically set this option.\n\nAltering the User
Account to Revert to the Previous Authentication
Method\n-------------------------------------------------------------------------\n\nIf
you have already installed MariaDB, and if the root@localhost user
account\nis already using unix_socket authentication, then you can revert
to the old\nmysql_native_password authentication method for the user
account by executing\nthe following:\n\nALTER USER root@localhost
IDENTIFIED VIA mysql_native_password
USING\nPASSWORD(\"verysecret\")\n\nURL:
https://mariadb.com/kb/en/authentication-from-mariadb-104/','','https://mariadb.com/kb/en/authentication-from-mariadb-104/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(118,10,'User Password Expiry','MariaDB starting with
10.4.3\n----------------------------\nUser password expiry was introduced
in MariaDB 10.4.3.\n\nPassword expiry permits administrators to expire user
passwords, either\nmanually or automatically.\n\nSystem
Variables\n----------------\n\nThere are two system variables which affect
password expiry:\ndefault_password_lifetime, which determines the amount of
time between\nrequiring the user to change their password. 0, the default,
means automatic\npassword expiry is not active.\n\nThe second variable,
disconnect_on_expired_password determines whether a\nclient is permitted to
connect if their password has expired, or whether they\nare permitted to
connect in sandbox mode, able to perform a limited subset of\nqueries
related to resetting the password, in particular SET PASSWORD and
SET.\n\nSetting a Password Expiry Limit for a
User\n------------------------------------------\n\nBesides automatic
password expiry, as determined by default_password_lifetime,\npassword
expiry times can be set on an individual user basis, overriding the\nglobal
using the CREATE USER or ALTER USER statements, for example:\n\nCREATE USER
\'monty\'@\'localhost\' PASSWORD EXPIRE INTERVAL 120
DAY;\n\nALTER USER \'monty\'@\'localhost\' PASSWORD
EXPIRE INTERVAL 120 DAY;\n\nLimits can be disabled by use of the NEVER
keyword, for example:\n\nCREATE USER
\'monty\'@\'localhost\' PASSWORD EXPIRE NEVER;\n\nALTER
USER \'monty\'@\'localhost\' PASSWORD EXPIRE
NEVER;\n\nA manually set limit can be restored the system default by use of
DEFAULT, for\nexample:\n\nCREATE USER
\'monty\'@\'localhost\' PASSWORD EXPIRE
DEFAULT;\n\nALTER USER \'monty\'@\'localhost\' PASSWORD
EXPIRE DEFAULT;\n\nSHOW CREATE USER\n----------------\n\nThe SHOW CREATE
USER statement will display information about the password\nexpiry status
of the user. Unlike MySQL, it will not display if the user is\nunlocked, or
if the password expiry is set to default.\n\nCREATE USER
\'monty\'@\'localhost\' PASSWORD EXPIRE INTERVAL 120
DAY;\nCREATE USER \'konstantin\'@\'localhost\' PASSWORD
EXPIRE NEVER;\nCREATE USER \'amse\'@\'localhost\'
PASSWORD EXPIRE DEFAULT;\n\nSHOW CREATE USER
\'monty\'@\'localhost\';\n+------------------------------------------------------------------+\n|
CREATE USER for monty@localhost
|\n+------------------------------------------------------------------+\n|
CREATE USER \'monty\'@\'localhost\' PASSWORD EXPIRE
INTERVAL 120 DAY
|\n+------------------------------------------------------------------+\n\nSHOW
CREATE USER
\'konstantin\'@\'localhost\';\n+------------------------------------------------------------+\n|
CREATE USER for konstantin@localhost
|\n+------------------------------------------------------------+\n| CREATE
USER \'konstantin\'@\'localhost\' PASSWORD EXPIRE NEVER
|\n+------------------------------------------------------------+\n\nSHOW
CREATE USER
\'amse\'@\'localhost\';\n+--------------------------------+\n|
CREATE USER for amse@localhost |\n+--------------------------------+\n|
CREATE USER \'amse\'@\'localhost\'
|\n+--------------------------------+\n\nChecking When Passwords
Expire\n------------------------------\n\nThe following query can be used
to check when the current passwords expire for\nall users:\n\nWITH
password_expiration_info AS (\n SELECT User, Host,\n IF(\n
IFNULL(JSON_EXTRACT(Priv, \'$.password_lifetime\'), -1) = -1,\n
@@global.default_password_lifetime,\n JSON_EXTRACT(Priv,
\'$.password_lifetime\')\n ) AS password_lifetime,\n
JSON_EXTRACT(Priv, \'$.password_last_changed\') AS
password_last_changed\n FROM mysql.global_priv\n)\nSELECT pei.User,
pei.Host,\n pei.password_lifetime,\n
FROM_UNIXTIME(pei.password_last_changed) AS
password_last_changed_datetime,\n FROM_UNIXTIME(\n
pei.password_last_changed +\n (pei.password_lifetime * 60 * 60 * 24)\n ) AS
password_expiration_datetime\n FROM password_expiration_info pei\n WHERE
pei.password_lifetime != 0\n AND pei.password_last_changed IS NOT
NULL\nUNION\nSELECT pei.User, pei.Host,\n pei.password_lifetime,\n
FROM_UNIXTIME(pei.password_last_changed) AS
password_last_changed_datetime,\n 0 AS password_expiration_datetime\n FROM
password_expiration_info pei\n WHERE pei.password_lifetime = 0\n OR
pei.password_last_changed IS NULL;\n\n--connect-expired-password Client
Option\n----------------------------------------\n\nThe mysql client
--connect-expired-password option notifies the server that\nthe client is
prepared to handle expired password sandbox mode (even if the\n--batch
option was specified).\n\nURL:
https://mariadb.com/kb/en/user-password-expiry/','','https://mariadb.com/kb/en/user-password-expiry/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(119,11,'ST_X','Syntax\n------\n\nST_X(p)\nX(p)\n\nDescription\n-----------\n\nReturns
the X-coordinate value for the point p as a double-precision
number.\n\nST_X() and X() are synonyms.\n\nExamples\n--------\n\nSET @pt =
\'Point(56.7 53.34)\';\n\nSELECT
X(GeomFromText(@pt));\n+----------------------+\n| X(GeomFromText(@pt))
|\n+----------------------+\n| 56.7
|\n+----------------------+\n\nURL:
https://mariadb.com/kb/en/st_x/','','https://mariadb.com/kb/en/st_x/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(120,11,'ST_Y','Syntax\n------\n\nST_Y(p)\nY(p)\n\nDescription\n-----------\n\nReturns
the Y-coordinate value for the point p as a double-precision
number.\n\nST_Y() and Y() are synonyms.\n\nExamples\n--------\n\nSET @pt =
\'Point(56.7 53.34)\';\n\nSELECT
Y(GeomFromText(@pt));\n+----------------------+\n| Y(GeomFromText(@pt))
|\n+----------------------+\n| 53.34
|\n+----------------------+\n\nURL:
https://mariadb.com/kb/en/st_y/','','https://mariadb.com/kb/en/st_y/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(121,11,'X','A synonym for ST_X.\n\nURL:
https://mariadb.com/kb/en/point-properties-x/','','https://mariadb.com/kb/en/point-properties-x/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(122,11,'Y','A synonym for ST_Y.\n\nURL:
https://mariadb.com/kb/en/point-properties-y/','','https://mariadb.com/kb/en/point-properties-y/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(123,12,'UNCOMPRESS','Syntax\n------\n\nUNCOMPRESS(string_to_uncompress)\n\nDescription\n-----------\n\nUncompresses
a string compressed by the COMPRESS() function. If the argument\nis not a
compressed value, the result is NULL. This function requires MariaDB\nto
have been compiled with a compression library such as zlib. Otherwise,
the\nreturn value is always NULL. The have_compress server system
variable\nindicates whether a compression library is
present.\n\nExamples\n--------\n\nSELECT UNCOMPRESS(COMPRESS(\'a
string\'));\n+----------------------------------+\n|
UNCOMPRESS(COMPRESS(\'a string\'))
|\n+----------------------------------+\n| a string
|\n+----------------------------------+\n\nSELECT UNCOMPRESS(\'a
string\');\n+------------------------+\n| UNCOMPRESS(\'a
string\') |\n+------------------------+\n| NULL
|\n+------------------------+\n\nURL:
https://mariadb.com/kb/en/uncompress/','','https://mariadb.com/kb/en/uncompress/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(124,12,'DECODE','Syntax\n------\n\nDECODE(crypt_str,pass_str)\n\nIn
Oracle mode from MariaDB 10.3.2:\n\nDECODE(expr, search_expr, result_expr
[, search_expr2, result_expr2 ...]\n[default_expr])\n\nIn all modes from
MariaDB 10.3.2:\n\nDECODE_ORACLE(expr, search_expr, result_expr [,
search_expr2, result_expr2\n...]
[default_expr])\n\nDescription\n-----------\n\nIn the default mode, DECODE
decrypts the encrypted string crypt_str using\npass_str as the password.
crypt_str should be a string returned from ENCODE().\nThe resulting string
will be the original string only if pass_str is the same.\n\nIn Oracle mode
from MariaDB 10.3.2, DECODE compares expr to the search\nexpressions, in
order. If it finds a match, the corresponding result\nexpression is
returned. If no matches are found, the default expression is\nreturned, or
NULL if no default is provided.\n\nNULLs are treated as
equivalent.\n\nDECODE_ORACLE is a synonym for the Oracle-mode version of
the function, and is\navailable in all modes.\n\nExamples\n--------\n\nFrom
MariaDB 10.3.2:\n\nSELECT
DECODE_ORACLE(2+1,3*1,\'found1\',3*2,\'found2\',\'default\');\n+--------------------------------------------------------+\n|
DECODE_ORACLE(2+1,3*1,\'found1\',3*2,\'found2\',\'default\')
|\n+--------------------------------------------------------+\n| found1
|\n+--------------------------------------------------------+\n\nSELECT
DECODE_ORACLE(2+4,3*1,\'found1\',3*2,\'found2\',\'default\');\n+--------------------------------------------------------+\n|
DECODE_ORACLE(2+4,3*1,\'found1\',3*2,\'found2\',\'default\')
|\n+--------------------------------------------------------+\n| found2
|\n+--------------------------------------------------------+\n\nSELECT
DECODE_ORACLE(2+2,3*1,\'found1\',3*2,\'found2\',\'default\');\n+--------------------------------------------------------+\n|
DECODE_ORACLE(2+2,3*1,\'found1\',3*2,\'found2\',\'default\')
|\n+--------------------------------------------------------+\n| default
|\n+--------------------------------------------------------+\n\nNulls are
treated as equivalent:\n\nSELECT DECODE_ORACLE(NULL,NULL,\'Nulls are
equivalent\',\'Nulls are
not\nequivalent\');\n+----------------------------------------------------------------------------+\n|
DECODE_ORACLE(NULL,NULL,\'Nulls are equivalent\',\'Nulls are
not equivalent\')
|\n+----------------------------------------------------------------------------+\n|
Nulls are equivalent
|\n+----------------------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/decode/','','https://mariadb.com/kb/en/decode/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(125,12,'DECODE_ORACLE','MariaDB starting with
10.3.2\n----------------------------\nDECODE_ORACLE is a synonym for the
Oracle mode version of the DECODE function,\nand is available in all
modes.\n\nURL:
https://mariadb.com/kb/en/decode_oracle/','','https://mariadb.com/kb/en/decode_oracle/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(126,12,'AES_DECRYPT','Syntax\n------\n\nAES_DECRYPT(crypt_str,key_str)\n\nDescription\n-----------\n\nThis
function allows decryption of data using the official AES
(Advanced\nEncryption Standard) algorithm. For more information, see the
description of\nAES_ENCRYPT().\n\nURL:
https://mariadb.com/kb/en/aes_decrypt/','','https://mariadb.com/kb/en/aes_decrypt/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(127,12,'AES_ENCRYPT','Syntax\n------\n\nAES_ENCRYPT(str,key_str)\n\nDescription\n-----------\n\nAES_ENCRYPT()
and AES_DECRYPT() allow encryption and decryption of data using\nthe
official AES (Advanced Encryption Standard) algorithm, previously known
as\n\"Rijndael.\" Encoding with a 128-bit key length is used, but
you can extend it\nup to 256 bits by modifying the source. We chose 128
bits because it is much\nfaster and it is secure enough for most
purposes.\n\nAES_ENCRYPT() encrypts a string str using the key key_str, and
returns a\nbinary string.\n\nAES_DECRYPT() decrypts the encrypted string
and returns the original string.\n\nThe input arguments may be any length.
If either argument is NULL, the result\nof this function is also
NULL.\n\nBecause AES is a block-level algorithm, padding is used to encode
uneven\nlength strings and so the result string length may be calculated
using this\nformula:\n\n16 x (trunc(string_length / 16) + 1)\n\nIf
AES_DECRYPT() detects invalid data or incorrect padding, it returns
NULL.\nHowever, it is possible for AES_DECRYPT() to return a non-NULL value
(possibly\ngarbage) if the input data or the key is
invalid.\n\nExamples\n--------\n\nINSERT INTO t VALUES
(AES_ENCRYPT(\'text\',SHA2(\'password\',512)));\n\nURL:
https://mariadb.com/kb/en/aes_encrypt/','','https://mariadb.com/kb/en/aes_encrypt/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(128,12,'COMPRESS','Syntax\n------\n\nCOMPRESS(string_to_compress)\n\nDescription\n-----------\n\nCompresses
a string and returns the result as a binary string. This function\nrequires
MariaDB to have been compiled with a compression library such as\nzlib.
Otherwise, the return value is always NULL. The compressed string can
be\nuncompressed with UNCOMPRESS().\n\nThe have_compress server system
variable indicates whether a compression\nlibrary is
present.\n\nExamples\n--------\n\nSELECT
LENGTH(COMPRESS(REPEAT(\'a\',1000)));\n+------------------------------------+\n|
LENGTH(COMPRESS(REPEAT(\'a\',1000)))
|\n+------------------------------------+\n|
21 |\n+------------------------------------+\n\nSELECT
LENGTH(COMPRESS(\'\'));\n+----------------------+\n|
LENGTH(COMPRESS(\'\')) |\n+----------------------+\n|
0 |\n+----------------------+\n\nSELECT
LENGTH(COMPRESS(\'a\'));\n+-----------------------+\n|
LENGTH(COMPRESS(\'a\')) |\n+-----------------------+\n|
13 |\n+-----------------------+\n\nSELECT
LENGTH(COMPRESS(REPEAT(\'a\',16)));\n+----------------------------------+\n|
LENGTH(COMPRESS(REPEAT(\'a\',16)))
|\n+----------------------------------+\n| 15
|\n+----------------------------------+\n\nURL:
https://mariadb.com/kb/en/compress/','','https://mariadb.com/kb/en/compress/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(129,12,'DES_DECRYPT','DES_DECRYPT has been deprecated from
MariaDB 10.10.0, and will be removed in a\nfuture
release.\n\nSyntax\n------\n\nDES_DECRYPT(crypt_str[,key_str])\n\nDescription\n-----------\n\nDecrypts
a string encrypted with DES_ENCRYPT(). If an error occurs, this\nfunction
returns NULL.\n\nThis function works only if MariaDB has been configured
with TLS support.\n\nIf no key_str argument is given, DES_DECRYPT()
examines the first byte of the\nencrypted string to determine the DES key
number that was used to encrypt the\noriginal string, and then reads the
key from the DES key file to decrypt the\nmessage. For this to work, the
user must have the SUPER privilege. The key\nfile can be specified with the
--des-key-file server option.\n\nIf you pass this function a key_str
argument, that string is used as the key\nfor decrypting the message.\n\nIf
the crypt_str argument does not appear to be an encrypted string,
MariaDB\nreturns the given crypt_str.\n\nURL:
https://mariadb.com/kb/en/des_decrypt/','','https://mariadb.com/kb/en/des_decrypt/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(130,12,'DES_ENCRYPT','DES_ENCRYPT has been deprecated from
MariaDB 10.10.0, and will be removed in a\nfuture
release.\n\nSyntax\n------\n\nDES_ENCRYPT(str[,{key_num|key_str}])\n\nDescription\n-----------\n\nEncrypts
the string with the given key using the Triple-DES algorithm.\n\nThis
function works only if MariaDB has been configured with TLS support.\n\nThe
encryption key to use is chosen based on the second argument
to\nDES_ENCRYPT(), if one was given. With no argument, the first key from
the DES\nkey file is used. With a key_num argument, the given key number
(0-9) from the\nDES key file is used. With a key_str argument, the given
key string is used to\nencrypt str.\n\nThe key file can be specified with
the --des-key-file server option.\n\nThe return string is a binary string
where the first character is CHAR(128 |\nkey_num). If an error occurs,
DES_ENCRYPT() returns NULL.\n\nThe 128 is added to make it easier to
recognize an encrypted key. If you use a\nstring key, key_num is
127.\n\nThe string length for the result is given by this
formula:\n\nnew_len = orig_len + (8 - (orig_len % 8)) + 1\n\nEach line in
the DES key file has the following format:\n\nkey_num des_key_str\n\nEach
key_num value must be a number in the range from 0 to 9. Lines in the\nfile
may be in any order. des_key_str is the string that is used to encrypt\nthe
message. There should be at least one space between the number and
the\nkey. The first key is the default key that is used if you do not
specify any\nkey argument to DES_ENCRYPT().\n\nYou can tell MariaDB to read
new key values from the key file with the FLUSH\nDES_KEY_FILE statement.
This requires the RELOAD privilege.\n\nOne benefit of having a set of
default keys is that it gives applications a\nway to check for the
existence of encrypted column values, without giving the\nend user the
right to decrypt those values.\n\nExamples\n--------\n\nSELECT
customer_address FROM customer_table \n WHERE crypted_credit_card =
DES_ENCRYPT(\'credit_card_number\');\n\nURL:
https://mariadb.com/kb/en/des_encrypt/','','https://mariadb.com/kb/en/des_encrypt/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(131,12,'ENCODE','Syntax\n------\n\nENCODE(str,pass_str)\n\nDescription\n-----------\n\nENCODE
is not considered cryptographically secure, and should not be used
for\npassword encryption.\n\nEncrypt str using pass_str as the password. To
decrypt the result, use\nDECODE().\n\nThe result is a binary string of the
same length as str.\n\nThe strength of the encryption is based on how good
the random generator is.\n\nIt is not recommended to rely on the encryption
performed by the ENCODE\nfunction. Using a salt value (changed when a
password is updated) will improve\nmatters somewhat, but for storing
passwords, consider a more cryptographically\nsecure function, such as
SHA2().\n\nExamples\n--------\n\nENCODE(\'not so secret text\',
CONCAT(\'random_salt\',\'password\'))\n\nURL:
https://mariadb.com/kb/en/encode/','','https://mariadb.com/kb/en/encode/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(132,12,'ENCRYPT','Syntax\n------\n\nENCRYPT(str[,salt])\n\nDescription\n-----------\n\nEncrypts
a string using the Unix crypt() system call, returning an encrypted\nbinary
string. The salt argument should be a string with at least two\ncharacters
or the returned result will be NULL. If no salt argument is given,\na
random value of sufficient length is used.\n\nIt is not recommended to use
ENCRYPT() with utf16, utf32 or ucs2 multi-byte\ncharacter sets because the
crypt() system call expects a string terminated\nwith a zero byte.\n\nNote
that the underlying crypt() system call may have some limitations, such\nas
ignoring all but the first eight characters.\n\nIf the have_crypt system
variable is set to NO (because the crypt() system\ncall is not available),
the ENCRYPT function will always return
NULL.\n\nExamples\n--------\n\nSELECT ENCRYPT(\'encrypt
me\');\n+-----------------------+\n| ENCRYPT(\'encrypt me\')
|\n+-----------------------+\n| 4I5BsEx0lqTDk
|\n+-----------------------+\n\nURL:
https://mariadb.com/kb/en/encrypt/','','https://mariadb.com/kb/en/encrypt/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(133,12,'MD5','Syntax\n------\n\nMD5(str)\n\nDescription\n-----------\n\nCalculates
an MD5 128-bit checksum for the string.\n\nThe return value is a 32-hex
digit string, and as of MariaDB 5.5, is a\nnonbinary string in the
connection character set and collation, determined by\nthe values of the
character_set_connection and collation_connection system\nvariables. Before
5.5, the return value was a binary string.\n\nNULL is returned if the
argument was NULL.\n\nExamples\n--------\n\nSELECT
MD5(\'testing\');\n+----------------------------------+\n|
MD5(\'testing\')
|\n+----------------------------------+\n| ae2b1fca515949e5d54fb22b8ed95575
|\n+----------------------------------+\n\nURL:
https://mariadb.com/kb/en/md5/','','https://mariadb.com/kb/en/md5/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(134,12,'OLD_PASSWORD','Syntax\n------\n\nOLD_PASSWORD(str)\n\nDescription\n-----------\n\nOLD_PASSWORD()
was added to MySQL when the implementation of PASSWORD() was\nchanged to
improve security. OLD_PASSWORD() returns the value of the old\n(pre-MySQL
4.1) implementation of PASSWORD() as a string, and is intended to\npermit
you to reset passwords for any pre-4.1 clients that need to connect to\na
more recent MySQL server version, or any version of MariaDB, without
locking\nthem out.\n\nAs of MariaDB 5.5, the return value is a nonbinary
string in the connection\ncharacter set and collation, determined by the
values of the\ncharacter_set_connection and collation_connection system
variables. Before\n5.5, the return value was a binary string.\n\nThe return
value is 16 bytes in length, or NULL if the argument was NULL.\n\nURL:
https://mariadb.com/kb/en/old_password/','','https://mariadb.com/kb/en/old_password/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(135,12,'PASSWORD','Syntax\n------\n\nPASSWORD(str)\n\nDescription\n-----------\n\nThe
PASSWORD() function is used for hashing passwords for use
in\nauthentication by the MariaDB server. It is not intended for use in
other\napplications.\n\nCalculates and returns a hashed password string
from the plaintext password\nstr. Returns an empty string (>= MariaDB
10.0.4) if the argument was NULL.\n\nThe return value is a nonbinary string
in the connection character set and\ncollation, determined by the values of
the character_set_connection and\ncollation_connection system
variables.\n\nThis is the function that is used for hashing MariaDB
passwords for storage in\nthe Password column of the user table (see
privileges), usually used with the\nSET PASSWORD statement. It is not
intended for use in other applications.\n\nUntil MariaDB 10.3, the return
value is 41-bytes in length, and the first\ncharacter is always
\'*\'. From MariaDB 10.4, the function takes into account\nthe
authentication plugin where applicable (A CREATE USER or SET
PASSWORD\nstatement). For example, when used in conjunction with a user
authenticated by\nthe ed25519 plugin, the statement will create a longer
hash:\n\nCREATE USER edtest@localhost IDENTIFIED VIA ed25519 USING
PASSWORD(\'secret\');\n\nCREATE USER edtest2@localhost IDENTIFIED
BY \'secret\';\n\nSELECT CONCAT(user, \'@\', host,
\' => \', JSON_DETAILED(priv)) FROM\nmysql.global_priv\n WHERE
user LIKE \'edtest%\'\\G\n*************************** 1. row
***************************\nCONCAT(user, \'@\', host, \'
=> \', JSON_DETAILED(priv)): edtest@localhost => {\n...\n
\"plugin\": \"ed25519\",\n
\"authentication_string\":
\"ZIgUREUg5PVgQ6LskhXmO+eZLS0nC8be6HPjYWR4YJY\",\n...\n}\n***************************
2. row ***************************\nCONCAT(user, \'@\', host,
\' => \', JSON_DETAILED(priv)): edtest2@localhost =>
{\n...\n \"plugin\": \"mysql_native_password\",\n
\"authentication_string\":
\"*14E65567ABDB5135D0CFD9A70B3032C179A49EE7\",\n...\n}\n\nThe
behavior of this function is affected by the value of the
old_passwords\nsystem variable. If this is set to 1 (0 is default), MariaDB
reverts to using\nthe mysql_old_password authentication plugin by default
for newly created\nusers and passwords.\n\nExamples\n--------\n\nSELECT
PASSWORD(\'notagoodpwd\');\n+-------------------------------------------+\n|
PASSWORD(\'notagoodpwd\')
|\n+-------------------------------------------+\n|
*3A70EE9FC6594F88CE9E959CD51C5A1C002DC937
|\n+-------------------------------------------+\n\nSET PASSWORD FOR
\'bob\'@\'%.loc.gov\' =
PASSWORD(\'newpass\');\n\nURL:
https://mariadb.com/kb/en/password/','','https://mariadb.com/kb/en/password/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(136,12,'SHA1','Syntax\n------\n\nSHA1(str),
SHA(str)\n\nDescription\n-----------\n\nCalculates an SHA-1 160-bit
checksum for the string str, as described in RFC\n3174 (Secure Hash
Algorithm).\n\nThe value is returned as a string of 40 hex digits, or NULL
if the argument\nwas NULL. As of MariaDB 5.5, the return value is a
nonbinary string in the\nconnection character set and collation, determined
by the values of the\ncharacter_set_connection and collation_connection
system variables. Before\n5.5, the return value was a binary
string.\n\nExamples\n--------\n\nSELECT SHA1(\'some boring
text\');\n+------------------------------------------+\n|
SHA1(\'some boring text\')
|\n+------------------------------------------+\n|
af969fc2085b1bb6d31e517d5c456def5cdd7093
|\n+------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/sha1/','','https://mariadb.com/kb/en/sha1/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(137,12,'SHA2','Syntax\n------\n\nSHA2(str,hash_len)\n\nDescription\n-----------\n\nGiven
a string str, calculates an SHA-2 checksum, which is considered
more\ncryptographically secure than its SHA-1 equivalent. The SHA-2 family
includes\nSHA-224, SHA-256, SHA-384, and SHA-512, and the hash_len must
correspond to\none of these, i.e. 224, 256, 384 or 512. 0 is equivalent to
256.\n\nThe return value is a nonbinary string in the connection character
set and\ncollation, determined by the values of the
character_set_connection and\ncollation_connection system
variables.\n\nNULL is returned if the hash length is not valid, or the
string str is NULL.\n\nSHA2 will only work if MariaDB was has been
configured with TLS support.\n\nExamples\n--------\n\nSELECT
SHA2(\'Maria\',224);\n+----------------------------------------------------------+\n|
SHA2(\'Maria\',224)
|\n+----------------------------------------------------------+\n|
6cc67add32286412efcab9d0e1675a43a5c2ef3cec8879f81516ff83
|\n+----------------------------------------------------------+\n\nSELECT
SHA2(\'Maria\',256);\n+------------------------------------------------------------------+\n|
SHA2(\'Maria\',256)
|\n+------------------------------------------------------------------+\n|
9ff18ebe7449349f358e3af0b57cf7a032c1c6b2272cb2656ff85eb112232f16
|\n+------------------------------------------------------------------+\n\nSELECT
SHA2(\'Maria\',0);\n+------------------------------------------------------------------+\n|
SHA2(\'Maria\',0)
|\n+------------------------------------------------------------------+\n|
9ff18ebe7449349f358e3af0b57cf7a032c1c6b2272cb2656ff85eb112232f16
|\n+------------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/sha2/','','https://mariadb.com/kb/en/sha2/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(138,13,'ENDPOINT','A synonym for ST_ENDPOINT.\n\nURL:
https://mariadb.com/kb/en/linestring-properties-endpoint/','','https://mariadb.com/kb/en/linestring-properties-endpoint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(139,13,'GLENGTH','Syntax\n------\n\nGLength(ls)\n\nDescription\n-----------\n\nReturns
as a double-precision number the length of the LineString value ls in\nits
associated spatial reference.\n\nExamples\n--------\n\nSET @ls =
\'LineString(1 1,2 2,3 3)\';\n\nSELECT
GLength(GeomFromText(@ls));\n+----------------------------+\n|
GLength(GeomFromText(@ls)) |\n+----------------------------+\n|
2.82842712474619 |\n+----------------------------+\n\nURL:
https://mariadb.com/kb/en/glength/','','https://mariadb.com/kb/en/glength/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(140,13,'NumPoints','A synonym for ST_NumPoints.\n\nURL:
https://mariadb.com/kb/en/linestring-properties-numpoints/','','https://mariadb.com/kb/en/linestring-properties-numpoints/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(141,13,'PointN','A synonym for ST_PointN.\n\nURL:
https://mariadb.com/kb/en/linestring-properties-pointn/','','https://mariadb.com/kb/en/linestring-properties-pointn/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(142,13,'STARTPOINT','A synonym for ST_STARTPOINT.\n\nURL:
https://mariadb.com/kb/en/linestring-properties-startpoint/','','https://mariadb.com/kb/en/linestring-properties-startpoint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(143,13,'ST_ENDPOINT','Syntax\n------\n\nST_EndPoint(ls)\nEndPoint(ls)\n\nDescription\n-----------\n\nReturns
the Point that is the endpoint of the LineString value ls.\n\nST_EndPoint()
and EndPoint() are synonyms.\n\nExamples\n--------\n\nSET @ls =
\'LineString(1 1,2 2,3 3)\';\n\nSELECT
AsText(EndPoint(GeomFromText(@ls)));\n+-------------------------------------+\n|
AsText(EndPoint(GeomFromText(@ls)))
|\n+-------------------------------------+\n| POINT(3 3)
|\n+-------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_endpoint/','','https://mariadb.com/kb/en/st_endpoint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(144,13,'ST_NUMPOINTS','Syntax\n------\n\nST_NumPoints(ls)\nNumPoints(ls)\n\nDescription\n-----------\n\nReturns
the number of Point objects in the LineString value ls.\n\nST_NumPoints()
and NumPoints() are synonyms.\n\nExamples\n--------\n\nSET @ls =
\'LineString(1 1,2 2,3 3)\';\n\nSELECT
NumPoints(GeomFromText(@ls));\n+------------------------------+\n|
NumPoints(GeomFromText(@ls)) |\n+------------------------------+\n|
3 |\n+------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_numpoints/','','https://mariadb.com/kb/en/st_numpoints/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(145,13,'ST_POINTN','Syntax\n------\n\nST_PointN(ls,N)\nPointN(ls,N)\n\nDescription\n-----------\n\nReturns
the N-th Point in the LineString value ls. Points are numbered\nbeginning
with 1.\n\nST_PointN() and PointN() are
synonyms.\n\nExamples\n--------\n\nSET @ls = \'LineString(1 1,2 2,3
3)\';\n\nSELECT
AsText(PointN(GeomFromText(@ls),2));\n+-------------------------------------+\n|
AsText(PointN(GeomFromText(@ls),2))
|\n+-------------------------------------+\n| POINT(2 2)
|\n+-------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_pointn/','','https://mariadb.com/kb/en/st_pointn/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(146,13,'ST_STARTPOINT','Syntax\n------\n\nST_StartPoint(ls)\nStartPoint(ls)\n\nDescription\n-----------\n\nReturns
the Point that is the start point of the LineString value
ls.\n\nST_StartPoint() and StartPoint() are
synonyms.\n\nExamples\n--------\n\nSET @ls = \'LineString(1 1,2 2,3
3)\';\n\nSELECT
AsText(StartPoint(GeomFromText(@ls)));\n+---------------------------------------+\n|
AsText(StartPoint(GeomFromText(@ls)))
|\n+---------------------------------------+\n| POINT(1 1)
|\n+---------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_startpoint/','','https://mariadb.com/kb/en/st_startpoint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(147,14,'GET_LOCK','Syntax\n------\n\nGET_LOCK(str,timeout)\n\nDescription\n-----------\n\nTries
to obtain a lock with a name given by the string str, using a timeout
of\ntimeout seconds. Returns 1 if the lock was obtained successfully, 0 if
the\nattempt timed out (for example, because another client has previously
locked\nthe name), or NULL if an error occurred (such as running out of
memory or the\nthread was killed with mysqladmin kill).\n\nA lock is
released with RELEASE_LOCK(), when the connection terminates
(either\nnormally or abnormally). A connection can hold multiple locks at
the same\ntime, so a lock that is no longer needed needs to be explicitly
released.\n\nThe IS_FREE_LOCK function returns whether a specified lock a
free or not, and\nthe IS_USED_LOCK whether the function is in use or
not.\n\nLocks obtained with GET_LOCK() do not interact with transactions.
That is,\ncommitting a transaction does not release any such locks obtained
during the\ntransaction.\n\nIt is also possible to recursively set the same
lock. If a lock with the same\nname is set n times, it needs to be released
n times as well.\n\nstr is case insensitive for GET_LOCK() and related
functions. If str is an\nempty string or NULL, GET_LOCK() returns NULL and
does nothing. From MariaDB\n10.2.2, timeout supports microseconds. Before
then, it was rounded to the\nclosest integer.\n\nIf the metadata_lock_info
plugin is installed, locks acquired with this\nfunction are visible in the
Information Schema METADATA_LOCK_INFO table.\n\nThis function can be used
to implement application locks or to simulate record\nlocks. Names are
locked on a server-wide basis. If a name has been locked by\none client,
GET_LOCK() blocks any request by another client for a lock with\nthe same
name. This allows clients that agree on a given lock name to use the\nname
to perform cooperative advisory locking. But be aware that it also
allows\na client that is not among the set of cooperating clients to lock a
name,\neither inadvertently or deliberately, and thus prevent any of the
cooperating\nclients from locking that name. One way to reduce the
likelihood of this is to\nuse lock names that are database-specific or
application-specific. For\nexample, use lock names of the form db_name.str
or app_name.str.\n\nStatements using the GET_LOCK function are not safe for
statement-based\nreplication.\n\nThe patch to permit multiple locks was
contributed by Konstantin \"Kostja\"\nOsipov
(MDEV-3917).\n\nExamples\n--------\n\nSELECT
GET_LOCK(\'lock1\',10);\n+----------------------+\n|
GET_LOCK(\'lock1\',10) |\n+----------------------+\n|
1 |\n+----------------------+\n\nSELECT
IS_FREE_LOCK(\'lock1\'),
IS_USED_LOCK(\'lock1\');\n+-----------------------+-----------------------+\n|
IS_FREE_LOCK(\'lock1\') | IS_USED_LOCK(\'lock1\')
|\n+-----------------------+-----------------------+\n|
0 | 46
|\n+-----------------------+-----------------------+\n\nSELECT
IS_FREE_LOCK(\'lock2\'),
IS_USED_LOCK(\'lock2\');\n+-----------------------+-----------------------+\n|
IS_FREE_LOCK(\'lock2\') | IS_USED_LOCK(\'lock2\')
|\n+-----------------------+-----------------------+\n|
1 | NULL
|\n+-----------------------+-----------------------+\n\nMultiple locks can
be held:\n\nSELECT
GET_LOCK(\'lock2\',10);\n+----------------------+\n|
GET_LOCK(\'lock2\',10) |\n+----------------------+\n|
1 |\n+----------------------+\n\nSELECT
IS_FREE_LOCK(\'lock1\'),
IS_FREE_LOCK(\'lock2\');\n+-----------------------+-----------------------+\n|
IS_FREE_LOCK(\'lock1\') | IS_FREE_LOCK(\'lock2\')
|\n+-----------------------+-----------------------+\n|
0 | 0
|\n+-----------------------+-----------------------+\n\nSELECT
RELEASE_LOCK(\'lock1\'),
RELEASE_LOCK(\'lock2\');\n+-----------------------+-----------------------+\n|
RELEASE_LOCK(\'lock1\') | RELEASE_LOCK(\'lock2\')
|\n+-----------------------+-----------------------+\n|
1 | 1
|\n+-----------------------+-----------------------+\n\nIt is possible to
hold the same lock recursively. This example is viewed using\nthe
metadata_lock_info plugin:\n\nSELECT
GET_LOCK(\'lock3\',10);\n+----------------------+\n|
GET_LOCK(\'lock3\',10) |\n+----------------------+\n|
1 |\n+----------------------+\n\nSELECT
GET_LOCK(\'lock3\',10);\n+----------------------+\n|
GET_LOCK(\'lock3\',10) |\n+----------------------+\n|
1 |\n+----------------------+\n\nSELECT * FROM
INFORMATION_SCHEMA.METADATA_LOCK_INFO;\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n|
THREAD_ID | LOCK_MODE | LOCK_DURATION | LOCK_TYPE | TABLE_SCHEMA
|\nTABLE_NAME
|\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n|
46 | MDL_SHARED_NO_WRITE | NULL | User lock | lock3
|\n
|\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n\nSELECT
RELEASE_LOCK(\'lock3\');\n+-----------------------+\n|
RELEASE_LOCK(\'lock3\') |\n+-----------------------+\n|
1 |\n+-----------------------+\n\nSELECT * FROM
INFORMATION_SCHEMA.METADATA_LOCK_INFO;\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n|
THREAD_ID | LOCK_MODE | LOCK_DURATION | LOCK_TYPE | TABLE_SCHEMA
|\nTABLE_NAME
|\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n|
46 | MDL_SHARED_NO_WRITE | NULL | User lock | lock3
|\n
|\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n\nSELECT
RELEASE_LOCK(\'lock3\');\n+-----------------------+\n|
RELEASE_LOCK(\'lock3\') |\n+-----------------------+\n|
1 |\n+-----------------------+\n\nSELECT * FROM
INFORMATION_SCHEMA.METADATA_LOCK_INFO;\nEmpty set (0.000 sec)\n\nTimeout
example: Connection 1:\n\nSELECT
GET_LOCK(\'lock4\',10);\n+----------------------+\n|
GET_LOCK(\'lock4\',10) |\n+----------------------+\n|
1 |\n+----------------------+\n\nConnection 2:\n\nSELECT
GET_LOCK(\'lock4\',10);\n\nAfter 10
seconds...\n\n+----------------------+\n| GET_LOCK(\'lock4\',10)
|\n+----------------------+\n| 0
|\n+----------------------+\n\nDeadlocks are automatically detected and
resolved. Connection 1:\n\nSELECT GET_LOCK(\'lock5\',10);
\n+----------------------+\n| GET_LOCK(\'lock5\',10)
|\n+----------------------+\n| 1
|\n+----------------------+\n\nConnection 2:\n\nSELECT
GET_LOCK(\'lock6\',10);\n+----------------------+\n|
GET_LOCK(\'lock6\',10) |\n+----------------------+\n|
1 |\n+----------------------+\n\nConnection 1:\n\nSELECT
GET_LOCK(\'lock6\',10); \n+----------------------+\n|
GET_LOCK(\'lock6\',10) |\n+----------------------+\n|
0 |\n+----------------------+\n\nConnection 2:\n\nSELECT
GET_LOCK(\'lock5\',10);\nERROR 1213 (40001): Deadlock found when
trying to get lock; try restarting\ntransaction\n\nURL:
https://mariadb.com/kb/en/get_lock/','','https://mariadb.com/kb/en/get_lock/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(148,14,'INET6_ATON','Syntax\n------\n\nINET6_ATON(expr)\n\nDescription\n-----------\n\nGiven
an IPv6 or IPv4 network address as a string, returns a binary string\nthat
represents the numeric value of the address.\n\nNo trailing zone ID\'s
or traling network masks are permitted. For IPv4\naddresses, or IPv6
addresses with IPv4 address parts, no classful addresses or\ntrailing port
numbers are permitted and octal numbers are not supported.\n\nThe returned
binary string will be VARBINARY(16) or VARBINARY(4) for IPv6 and\nIPv4
addresses respectively.\n\nReturns NULL if the argument is not
understood.\n\nMariaDB starting with
10.5.0\n----------------------------\nFrom MariaDB 10.5.0, INET6_ATON can
take INET6 as an argument.\n\nExamples\n--------\n\nSELECT
HEX(INET6_ATON(\'10.0.1.1\'));\n+-----------------------------+\n|
HEX(INET6_ATON(\'10.0.1.1\'))
|\n+-----------------------------+\n| 0A000101
|\n+-----------------------------+\n\nSELECT
HEX(INET6_ATON(\'48f3::d432:1431:ba23:846f\'));\n+----------------------------------------------+\n|
HEX(INET6_ATON(\'48f3::d432:1431:ba23:846f\'))
|\n+----------------------------------------------+\n|
48F3000000000000D4321431BA23846F
|\n+----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/inet6_aton/','','https://mariadb.com/kb/en/inet6_aton/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(149,14,'INET6_NTOA','Syntax\n------\n\nINET6_NTOA(expr)\n\nDescription\n-----------\n\nGiven
an IPv6 or IPv4 network address as a numeric binary string, returns
the\naddress as a nonbinary string in the connection character set.\n\nThe
return string is lowercase, and is platform independent, since it does
not\nuse functions specific to the operating system. It has a maximum
length of 39\ncharacters.\n\nReturns NULL if the argument is not
understood.\n\nExamples\n--------\n\nSELECT
INET6_NTOA(UNHEX(\'0A000101\'));\n+-------------------------------+\n|
INET6_NTOA(UNHEX(\'0A000101\'))
|\n+-------------------------------+\n| 10.0.1.1
|\n+-------------------------------+\n\nSELECT
INET6_NTOA(UNHEX(\'48F3000000000000D4321431BA23846F\'));\n+-------------------------------------------------------+\n|
INET6_NTOA(UNHEX(\'48F3000000000000D4321431BA23846F\'))
|\n+-------------------------------------------------------+\n|
48f3::d432:1431:ba23:846f
|\n+-------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/inet6_ntoa/','','https://mariadb.com/kb/en/inet6_ntoa/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(150,14,'INET_ATON','Syntax\n------\n\nINET_ATON(expr)\n\nDescription\n-----------\n\nGiven
the dotted-quad representation of an IPv4 network address as a
string,\nreturns an integer that represents the numeric value of the
address. Addresses\nmay be 4- or 8-byte addresses.\n\nReturns NULL if the
argument is not understood.\n\nExamples\n--------\n\nSELECT
INET_ATON(\'192.168.1.1\');\n+--------------------------+\n|
INET_ATON(\'192.168.1.1\') |\n+--------------------------+\n|
3232235777 |\n+--------------------------+\n\nThis is calculated
as follows: 192 x 2563 + 168 x 256 2 + 1 x 256 + 1\n\nURL:
https://mariadb.com/kb/en/inet_aton/','','https://mariadb.com/kb/en/inet_aton/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(151,14,'INET_NTOA','Syntax\n------\n\nINET_NTOA(expr)\n\nDescription\n-----------\n\nGiven
a numeric IPv4 network address in network byte order (4 or 8
byte),\nreturns the dotted-quad representation of the address as a
string.\n\nExamples\n--------\n\nSELECT
INET_NTOA(3232235777);\n+-----------------------+\n| INET_NTOA(3232235777)
|\n+-----------------------+\n| 192.168.1.1
|\n+-----------------------+\n\n192.168.1.1 corresponds to 3232235777 since
192 x 2563 + 168 x 256 2 + 1 x 256\n+ 1 = 3232235777\n\nURL:
https://mariadb.com/kb/en/inet_ntoa/','','https://mariadb.com/kb/en/inet_ntoa/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(152,14,'IS_FREE_LOCK','Syntax\n------\n\nIS_FREE_LOCK(str)\n\nDescription\n-----------\n\nChecks
whether the lock named str is free to use (that is, not locked).\nReturns 1
if the lock is free (no one is using the lock), 0 if the lock is in\nuse,
and NULL if an error occurs (such as an incorrect argument, like an
empty\nstring or NULL). str is case insensitive.\n\nIf the
metadata_lock_info plugin is installed, the Information
Schema\nmetadata_lock_info table contains information about locks of this
kind (as\nwell as metadata locks).\n\nStatements using the IS_FREE_LOCK
function are not safe for statement-based\nreplication.\n\nURL:
https://mariadb.com/kb/en/is_free_lock/','','https://mariadb.com/kb/en/is_free_lock/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(153,14,'IS_IPV4','Syntax\n------\n\nIS_IPV4(expr)\n\nDescription\n-----------\n\nIf
the expression is a valid IPv4 address, returns 1, otherwise returns
0.\n\nIS_IPV4() is stricter than INET_ATON(), but as strict as
INET6_ATON(), in\ndetermining the validity of an IPv4 address. This implies
that if IS_IPV4\nreturns 1, the same expression will always return a
non-NULL result when\npassed to INET_ATON(), but that the reverse may not
apply.\n\nExamples\n--------\n\nSELECT
IS_IPV4(\'1110.0.1.1\');\n+-----------------------+\n|
IS_IPV4(\'1110.0.1.1\') |\n+-----------------------+\n|
0 |\n+-----------------------+\n\nSELECT
IS_IPV4(\'48f3::d432:1431:ba23:846f\');\n+--------------------------------------+\n|
IS_IPV4(\'48f3::d432:1431:ba23:846f\')
|\n+--------------------------------------+\n|
0 |\n+--------------------------------------+\n\nURL:
https://mariadb.com/kb/en/is_ipv4/','','https://mariadb.com/kb/en/is_ipv4/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(154,14,'IS_IPV4_COMPAT','Syntax\n------\n\nIS_IPV4_COMPAT(expr)\n\nDescription\n-----------\n\nReturns
1 if a given numeric binary string IPv6 address, such as returned
by\nINET6_ATON(), is IPv4-compatible, otherwise returns 0.\n\nMariaDB
starting with 10.5.0\n----------------------------\nFrom MariaDB 10.5.0,
when the argument is not INET6, automatic implicit CAST\nto INET6 is
applied. As a consequence, IS_IPV4_COMPAT now understands\narguments in
both text representation and binary(16) representation. Before\nMariaDB
10.5.0, the function understood only binary(16)
representation.\n\nExamples\n--------\n\nSELECT
IS_IPV4_COMPAT(INET6_ATON(\'::10.0.1.1\'));\n+------------------------------------------+\n|
IS_IPV4_COMPAT(INET6_ATON(\'::10.0.1.1\'))
|\n+------------------------------------------+\n|
1 |\n+------------------------------------------+\n\nSELECT
IS_IPV4_COMPAT(INET6_ATON(\'::48f3::d432:1431:ba23:846f\'));\n+-----------------------------------------------------------+\n|
IS_IPV4_COMPAT(INET6_ATON(\'::48f3::d432:1431:ba23:846f\'))
|\n+-----------------------------------------------------------+\n|
0
|\n+-----------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/is_ipv4_compat/','','https://mariadb.com/kb/en/is_ipv4_compat/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(155,14,'IS_IPV4_MAPPED','Syntax\n------\n\nIS_IPV4_MAPPED(expr)\n\nDescription\n-----------\n\nReturns
1 if a given a numeric binary string IPv6 address, such as returned
by\nINET6_ATON(), is a valid IPv4-mapped address, otherwise returns
0.\n\nMariaDB starting with 10.5.0\n----------------------------\nFrom
MariaDB 10.5.0, when the argument is not INET6, automatic implicit CAST\nto
INET6 is applied. As a consequence, IS_IPV4_MAPPED now
understands\narguments in both text representation and binary(16)
representation. Before\nMariaDB 10.5.0, the function understood only
binary(16) representation.\n\nExamples\n--------\n\nSELECT
IS_IPV4_MAPPED(INET6_ATON(\'::10.0.1.1\'));\n+------------------------------------------+\n|
IS_IPV4_MAPPED(INET6_ATON(\'::10.0.1.1\'))
|\n+------------------------------------------+\n|
0 |\n+------------------------------------------+\n\nSELECT
IS_IPV4_MAPPED(INET6_ATON(\'::ffff:10.0.1.1\'));\n+-----------------------------------------------+\n|
IS_IPV4_MAPPED(INET6_ATON(\'::ffff:10.0.1.1\'))
|\n+-----------------------------------------------+\n|
1
|\n+-----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/is_ipv4_mapped/','','https://mariadb.com/kb/en/is_ipv4_mapped/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(156,14,'IS_IPV6','Syntax\n------\n\nIS_IPV6(expr)\n\nDescription\n-----------\n\nReturns
1 if the expression is a valid IPv6 address specified as a
string,\notherwise returns 0. Does not consider IPv4 addresses to be valid
IPv6\naddresses.\n\nExamples\n--------\n\nSELECT
IS_IPV6(\'48f3::d432:1431:ba23:846f\');\n+--------------------------------------+\n|
IS_IPV6(\'48f3::d432:1431:ba23:846f\')
|\n+--------------------------------------+\n|
1 |\n+--------------------------------------+\n1 row in set (0.02
sec)\n\nSELECT IS_IPV6(\'10.0.1.1\');\n+---------------------+\n|
IS_IPV6(\'10.0.1.1\') |\n+---------------------+\n|
0 |\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/is_ipv6/','','https://mariadb.com/kb/en/is_ipv6/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(157,14,'IS_USED_LOCK','Syntax\n------\n\nIS_USED_LOCK(str)\n\nDescription\n-----------\n\nChecks
whether the lock named str is in use (that is, locked). If so, it\nreturns
the connection identifier of the client that holds the lock.\nOtherwise, it
returns NULL. str is case insensitive.\n\nIf the metadata_lock_info plugin
is installed, the Information Schema\nmetadata_lock_info table contains
information about locks of this kind (as\nwell as metadata
locks).\n\nStatements using the IS_USED_LOCK function are not safe for
statement-based\nreplication.\n\nURL:
https://mariadb.com/kb/en/is_used_lock/','','https://mariadb.com/kb/en/is_used_lock/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(158,14,'MASTER_GTID_WAIT','Syntax\n------\n\nMASTER_GTID_WAIT(gtid-list[,
timeout)\n\nDescription\n-----------\n\nThis function takes a string
containing a comma-separated list of global\ntransaction id\'s
(similar to the value of, for example, gtid_binlog_pos). It\nwaits until
the value of gtid_slave_pos has the same or higher seq_no within\nall
replication domains specified in the gtid-list; in other words, it
waits\nuntil the slave has reached the specified GTID position.\n\nAn
optional second argument gives a timeout in seconds. If the timeout
expires\nbefore the specified GTID position is reached, then the function
returns -1.\nPassing NULL or a negative number for the timeout means no
timeout, and the\nfunction will wait indefinitely.\n\nIf the wait completes
without a timeout, 0 is returned. Passing NULL for the\ngtid-list makes the
function return NULL immediately, without waiting.\n\nThe gtid-list may be
the empty string, in which case MASTER_GTID_WAIT()\nreturns immediately. If
the gtid-list contains fewer domains than\ngtid_slave_pos, then only those
domains are waited upon. If gtid-list contains\na domain that is not
present in @@gtid_slave_pos, then MASTER_GTID_WAIT() will\nwait until an
event containing such domain_id arrives on the slave (or until\ntimed out
or killed).\n\nMASTER_GTID_WAIT() can be useful to ensure that a slave has
caught up to a\nmaster. Simply take the value of gtid_binlog_pos on the
master, and use it in\na MASTER_GTID_WAIT() call on the slave; when the
call completes, the slave\nwill have caught up with that master
position.\n\nMASTER_GTID_WAIT() can also be used in client applications
together with the\nlast_gtid session variable. This is useful in a
read-scaleout replication\nsetup, where the application writes to a single
master but divides the reads\nout to a number of slaves to distribute the
load. In such a setup, there is a\nrisk that an application could first do
an update on the master, and then a\nbit later do a read on a slave, and if
the slave is not fast enough, the data\nread from the slave might not
include the update just made, possibly confusing\nthe application and/or
the end-user. One way to avoid this is to request the\nvalue of last_gtid
on the master just after the update. Then before doing the\nread on the
slave, do a MASTER_GTID_WAIT() on the value obtained from the\nmaster; this
will ensure that the read is not performed until the slave has\nreplicated
sufficiently far for the update to have become visible.\n\nNote that
MASTER_GTID_WAIT() can be used even if the slave is configured not\nto use
GTID for connections (CHANGE MASTER TO master_use_gtid=no). This
is\nbecause from MariaDB 10, GTIDs are always logged on the master server,
and\nalways recorded on the slave servers.\n\nDifferences to
MASTER_POS_WAIT()\n--------------------------------\n\n* MASTER_GTID_WAIT()
is global; it waits for any master connection to reach\n the specified GTID
position. MASTER_POS_WAIT() works only against a\n specific connection.
This also means that while MASTER_POS_WAIT() aborts if\n its master
connection is terminated with STOP SLAVE or due to an error,\n
MASTER_GTID_WAIT() continues to wait while slaves are stopped.\n\n*
MASTER_GTID_WAIT() can take its timeout as a floating-point value, so a\n
timeout in fractional seconds is supported, eg.
MASTER_GTID_WAIT(\"0-1-100\",\n 0.5). (The minimum wait is one
microsecond, 0.000001 seconds).\n\n* MASTER_GTID_WAIT() allows one to
specify a timeout of zero in order to do a\n non-blocking check to see if
the slaves have progressed to a specific GTID\nposition\n
(MASTER_POS_WAIT() takes a zero timeout as meaning an infinite wait). To
do\n an infinite MASTER_GTID_WAIT(), specify a negative timeout, or omit
the\n timeout argument.\n\n* MASTER_GTID_WAIT() does not return the number
of events executed since the\n wait started, nor does it return NULL if a
slave thread is stopped. It\n always returns either 0 for successful wait
completed, or -1 for timeout\n reached (or NULL if the specified gtid-pos
is NULL).\n\nSince MASTER_GTID_WAIT() looks only at the seq_no part of the
GTIDs, not the\nserver_id, care is needed if a slave becomes diverged from
another server so\nthat two different GTIDs with the same seq_no (in the
same domain) arrive at\nthe same server. This situation is in any case best
avoided; setting\ngtid_strict_mode is recommended, as this will prevent any
such out-of-order\nsequence numbers from ever being replicated on a
slave.\n\nURL:
https://mariadb.com/kb/en/master_gtid_wait/','','https://mariadb.com/kb/en/master_gtid_wait/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(159,14,'MASTER_POS_WAIT','Syntax\n------\n\nMASTER_POS_WAIT(log_name,log_pos[,timeout,[\"connection_name\"]])\n\nDescription\n-----------\n\nThis
function is useful in replication for controlling
primary/replica\nsynchronization. It blocks until the replica has read and
applied all updates\nup to the specified position (log_name,log_pos) in the
primary log. The return\nvalue is the number of log events the replica had
to wait for to advance to\nthe specified position. The function returns
NULL if the replica SQL thread is\nnot started, the replica\'s primary
information is not initialized, the\narguments are incorrect, or an error
occurs. It returns -1 if the timeout has\nbeen exceeded. If the replica SQL
thread stops while MASTER_POS_WAIT() is\nwaiting, the function returns
NULL. If the replica is past the specified\nposition, the function returns
immediately.\n\nIf a timeout value is specified, MASTER_POS_WAIT() stops
waiting when timeout\nseconds have elapsed. timeout must be greater than 0;
a zero or negative\ntimeout means no timeout.\n\nThe connection_name is
used when you are using multi-source-replication. If\nyou don\'t
specify it, it\'s set to the value of the
default_master_connection\nsystem variable.\n\nStatements using the
MASTER_POS_WAIT() function are not safe for replication.\n\nURL:
https://mariadb.com/kb/en/master_pos_wait/','','https://mariadb.com/kb/en/master_pos_wait/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(160,14,'NAME_CONST','Syntax\n------\n\nNAME_CONST(name,value)\n\nDescription\n-----------\n\nReturns
the given value. When used to produce a result set column,\nNAME_CONST()
causes the column to have the given name. The arguments should
be\nconstants.\n\nThis function is used internally when replicating stored
procedures. It makes\nlittle sense to use it explicitly in SQL statements,
and it was not supposed\nto be used like that.\n\nSELECT
NAME_CONST(\'myname\', 14);\n+--------+\n| myname
|\n+--------+\n| 14 |\n+--------+\n\nURL:
https://mariadb.com/kb/en/name_const/','','https://mariadb.com/kb/en/name_const/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(161,14,'RELEASE_ALL_LOCKS','MariaDB until
10.5.2\n--------------------\nRELEASE_ALL_LOCKS was added in MariaDB
10.5.2.\n\nSyntax\n------\n\nRELEASE_ALL_LOCKS()\n\nDescription\n-----------\n\nReleases
all named locks held by the current session. Returns the number of\nlocks
released, or 0 if none were held.\n\nStatements using the RELEASE_ALL_LOCKS
function are not safe for\nstatement-based
replication.\n\nExamples\n--------\n\nSELECT
RELEASE_ALL_LOCKS();\n+---------------------+\n| RELEASE_ALL_LOCKS() |
\n+---------------------+\n| 0
|\n+---------------------+\n\nSELECT
GET_LOCK(\'lock1\',10);\n+----------------------+\n|
GET_LOCK(\'lock1\',10) |\n+----------------------+\n|
1 |\n+----------------------+\n\nSELECT
RELEASE_ALL_LOCKS();\n+---------------------+\n| RELEASE_ALL_LOCKS() |
\n+---------------------+\n| 1
|\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/release_all_locks/','','https://mariadb.com/kb/en/release_all_locks/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(162,14,'RELEASE_LOCK','Syntax\n------\n\nRELEASE_LOCK(str)\n\nDescription\n-----------\n\nReleases
the lock named by the string str that was obtained with
GET_LOCK().\nReturns 1 if the lock was released, 0 if the lock was not
established by this\nthread (in which case the lock is not released), and
NULL if the named lock\ndid not exist. The lock does not exist if it was
never obtained by a call to\nGET_LOCK() or if it has previously been
released.\n\nstr is case insensitive. If str is an empty string or NULL,
RELEASE_LOCK()\nreturns NULL and does nothing.\n\nStatements using the
RELEASE_LOCK() function are not safe for replication.\n\nThe DO statement
is convenient to use with
RELEASE_LOCK().\n\nExamples\n--------\n\nConnection1:\n\nSELECT
GET_LOCK(\'lock1\',10);\n+----------------------+\n|
GET_LOCK(\'lock1\',10) |\n+----------------------+\n|
1 |\n+----------------------+\n\nConnection 2:\n\nSELECT
GET_LOCK(\'lock2\',10);\n+----------------------+\n|
GET_LOCK(\'lock2\',10) |\n+----------------------+\n|
1 |\n+----------------------+\n\nConnection 1:\n\nSELECT
RELEASE_LOCK(\'lock1\'), RELEASE_LOCK(\'lock2\'),
RELEASE_LOCK(\'lock3\');\n+-----------------------+-----------------------+-----------------------+\n|
RELEASE_LOCK(\'lock1\') | RELEASE_LOCK(\'lock2\') |
RELEASE_LOCK(\'lock3\')
|\n+-----------------------+-----------------------+-----------------------+\n|
1 | 0 | NULL
|\n+-----------------------+-----------------------+-----------------------+\n\nFrom
MariaDB 10.0.2, it is possible to hold the same lock recursively.
This\nexample is viewed using the metadata_lock_info plugin:\n\nSELECT
GET_LOCK(\'lock3\',10);\n+----------------------+\n|
GET_LOCK(\'lock3\',10) |\n+----------------------+\n|
1 |\n+----------------------+\n\nSELECT
GET_LOCK(\'lock3\',10);\n+----------------------+\n|
GET_LOCK(\'lock3\',10) |\n+----------------------+\n|
1 |\n+----------------------+\n\nSELECT * FROM
INFORMATION_SCHEMA.METADATA_LOCK_INFO;\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n|
THREAD_ID | LOCK_MODE | LOCK_DURATION | LOCK_TYPE | TABLE_SCHEMA
|\nTABLE_NAME
|\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n|
46 | MDL_SHARED_NO_WRITE | NULL | User lock | lock3
|\n
|\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n\nSELECT
RELEASE_LOCK(\'lock3\');\n+-----------------------+\n|
RELEASE_LOCK(\'lock3\') |\n+-----------------------+\n|
1 |\n+-----------------------+\n\nSELECT * FROM
INFORMATION_SCHEMA.METADATA_LOCK_INFO;\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n|
THREAD_ID | LOCK_MODE | LOCK_DURATION | LOCK_TYPE | TABLE_SCHEMA
|\nTABLE_NAME
|\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n|
46 | MDL_SHARED_NO_WRITE | NULL | User lock | lock3
|\n
|\n+-----------+---------------------+---------------+-----------+--------------+-\n----------+\n\nSELECT
RELEASE_LOCK(\'lock3\');\n+-----------------------+\n|
RELEASE_LOCK(\'lock3\') |\n+-----------------------+\n|
1 |\n+-----------------------+\n\nSELECT * FROM
INFORMATION_SCHEMA.METADATA_LOCK_INFO;\nEmpty set (0.000 sec)\n\nURL:
https://mariadb.com/kb/en/release_lock/','','https://mariadb.com/kb/en/release_lock/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(163,14,'SLEEP','Syntax\n------\n\nSLEEP(duration)\n\nDescription\n-----------\n\nSleeps
(pauses) for the number of seconds given by the duration argument,
then\nreturns 0. If SLEEP() is interrupted, it returns 1. The duration may
have a\nfractional part given in microseconds.\n\nStatements using the
SLEEP() function are not safe for
replication.\n\nExample\n-------\n\nSELECT SLEEP(5.5);\n+------------+\n|
SLEEP(5.5) |\n+------------+\n| 0 |\n+------------+\n1 row in set
(5.50 sec)\n\nURL:
https://mariadb.com/kb/en/sleep/','','https://mariadb.com/kb/en/sleep/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(164,14,'SYS_GUID','MariaDB starting with
10.6.1\n----------------------------\nThe SYS_GUID function was introduced
in MariaDB 10.6.1 to enhance Oracle\ncompatibility. Similar functionality
can be achieved with the UUID
function.\n\nSyntax\n------\n\nSYS_GUID()\n\nDescription\n-----------\n\nReturns
a 16-byte globally unique identifier (GUID), similar to the UUID\nfunction,
but without the - character.\n\nExample\n-------\n\nSELECT
SYS_GUID();\n+----------------------------------+\n| SYS_GUID()
|\n+----------------------------------+\n|
2C574E45BA2811EBB265F859713E4BE4
|\n+----------------------------------+\n\nURL:
https://mariadb.com/kb/en/sys_guid/','','https://mariadb.com/kb/en/sys_guid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(165,14,'UUID','Syntax\n------\n\nUUID()\n\nDescription\n-----------\n\nReturns
a Universally Unique Identifier (UUID).\n\nA UUID is designed as a number
that is globally unique in space and time. Two\ncalls to UUID() are
expected to generate two different values, even if these\ncalls are
performed on two separate computers that are not connected to
each\nother.\n\nUUID() results are intended to be unique, but cannot always
be relied upon to\nunpredictable and unguessable, so should not be relied
upon for these purposes.\n\nA UUID is a 128-bit number represented by a
utf8 string of five hexadecimal\nnumbers in
aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee format:\n\n* The first three numbers
are generated from a timestamp.\n* The fourth number preserves temporal
uniqueness in case the timestamp value\n loses monotonicity (for example,
due to daylight saving time).\n* The fifth number is an IEEE 802 node
number that provides spatial uniqueness.\n A random number is substituted
if the latter is not available (for example,\n because the host computer
has no Ethernet card, or we do not know how to find\n the hardware address
of an interface on your operating system). In this case,\n spatial
uniqueness cannot be guaranteed. Nevertheless, a collision should\n have
very low probability.\n\nCurrently, the MAC address of an interface is
taken into account only on\nFreeBSD and Linux. On other operating systems,
MariaDB uses a randomly\ngenerated 48-bit number.\n\nStatements using the
UUID() function are not safe for replication.\n\nThe results are generated
according to the \"DCE 1.1:Remote Procedure Call\"\n(Appendix A)
CAE (Common Applications Environment) Specifications published by\nThe Open
Group in October 1997 (Document Number
C706).\n\nExamples\n--------\n\nSELECT
UUID();\n+--------------------------------------+\n| UUID()
|\n+--------------------------------------+\n|
cd41294a-afb0-11df-bc9b-00241dd75637
|\n+--------------------------------------+\n\nURL:
https://mariadb.com/kb/en/uuid/','','https://mariadb.com/kb/en/uuid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(166,14,'UUID_SHORT','Syntax\n------\n\nUUID_SHORT()\n\nDescription\n-----------\n\nReturns
a \"short\" universally unique identifier as a 64-bit unsigned
integer\n(rather than a string-form 128-bit identifier as returned by the
UUID()\nfunction).\n\nThe value of UUID_SHORT() is guaranteed to be unique
if the following\nconditions hold:\n\n* The server_id of the current host
is unique among your set of master and\n slave servers\n* server_id is
between 0 and 255\n* You don\'t set back your system time for your
server between mysqld restarts\n* You do not invoke UUID_SHORT() on average
more than 16\n million times per second between mysqld restarts\n\nThe
UUID_SHORT() return value is constructed this way:\n\n(server_id & 255)
<< 56\n+ (server_startup_time_in_seconds << 24)\n+
incremented_variable++;\n\nStatements using the UUID_SHORT() function are
not safe for statement-based\nreplication.\n\nExamples\n--------\n\nSELECT
UUID_SHORT();\n+-------------------+\n| UUID_SHORT()
|\n+-------------------+\n| 21517162376069120
|\n+-------------------+\n\ncreate table t1 (a bigint unsigned
default(uuid_short()) primary key);\ninsert into t1 values(),();\nselect *
from t1;\n+-------------------+\n| a
|\n+-------------------+\n| 98113699159474176 |\n| 98113699159474177
|\n+-------------------+\n\nURL:
https://mariadb.com/kb/en/uuid_short/','','https://mariadb.com/kb/en/uuid_short/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(167,14,'VALUES / VALUE','Syntax\n------\n\nMariaDB starting
with 10.3.3\n----------------------------\n\nVALUE(col_name)\n\nMariaDB
until
10.3.2\n--------------------\n\nVALUES(col_name)\n\nDescription\n-----------\n\nIn
an INSERT ... ON DUPLICATE KEY UPDATE statement, you can use
the\nVALUES(col_name) function in the UPDATE clause to refer to column
values from\nthe INSERT portion of the statement. In other words,
VALUES(col_name) in the\nUPDATE clause refers to the value of col_name that
would be inserted, had no\nduplicate-key conflict occurred. This function
is especially useful in\nmultiple-row inserts.\n\nThe VALUES() function is
meaningful only in INSERT ... ON DUPLICATE KEY UPDATE\nstatements and
returns NULL otherwise.\n\nIn MariaDB 10.3.3 this function was renamed to
VALUE(), because it\'s\nincompatible with the standard Table Value
Constructors syntax, implemented in\nMariaDB 10.3.3.\n\nThe VALUES()
function can still be used even from MariaDB 10.3.3, but only in\nINSERT
... ON DUPLICATE KEY UPDATE statements; it\'s a syntax error
otherwise.\n\nExamples\n--------\n\nMariaDB starting with
10.3.3\n----------------------------\n\nINSERT INTO t (a,b,c) VALUES
(1,2,3),(4,5,6)\n ON DUPLICATE KEY UPDATE c=VALUE(a)+VALUE(b);\n\nMariaDB
until 10.3.2\n--------------------\n\nINSERT INTO t (a,b,c) VALUES
(1,2,3),(4,5,6)\n ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b);\n\nURL:
https://mariadb.com/kb/en/values-value/','','https://mariadb.com/kb/en/values-value/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(168,15,'!','Syntax\n------\n\nNOT,
!\n\nDescription\n-----------\n\nLogical NOT. Evaluates to 1 if the operand
is 0, to 0 if the operand is\nnon-zero, and NOT NULL returns NULL.\n\nBy
default, the ! operator has a higher precedence. If the
HIGH_NOT_PRECEDENCE\nSQL_MODE flag is set, NOT and ! have the same
precedence.\n\nExamples\n--------\n\nSELECT NOT 10;\n+--------+\n| NOT 10
|\n+--------+\n| 0 |\n+--------+\n\nSELECT NOT 0;\n+-------+\n| NOT 0
|\n+-------+\n| 1 |\n+-------+\n\nSELECT NOT NULL;\n+----------+\n| NOT
NULL |\n+----------+\n| NULL |\n+----------+\n\nSELECT !
(1+1);\n+---------+\n| ! (1+1) |\n+---------+\n| 0
|\n+---------+\n\nSELECT ! 1+1;\n+-------+\n| ! 1+1 |\n+-------+\n| 1
|\n+-------+\n\nURL:
https://mariadb.com/kb/en/not/','','https://mariadb.com/kb/en/not/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(169,15,'&&','Syntax\n------\n\nAND,
&&\n\nDescription\n-----------\n\nLogical AND. Evaluates to 1 if
all operands are non-zero and not NULL, to 0 if\none or more operands are
0, otherwise NULL is returned.\n\nFor this operator, short-circuit
evaluation can be used.\n\nExamples\n--------\n\nSELECT 1 &&
1;\n+--------+\n| 1 && 1 |\n+--------+\n| 1
|\n+--------+\n\nSELECT 1 && 0;\n+--------+\n| 1 && 0
|\n+--------+\n| 0 |\n+--------+\n\nSELECT 1 &&
NULL;\n+-----------+\n| 1 && NULL |\n+-----------+\n| NULL
|\n+-----------+\n\nSELECT 0 && NULL;\n+-----------+\n| 0
&& NULL |\n+-----------+\n| 0 |\n+-----------+\n\nSELECT
NULL && 0;\n+-----------+\n| NULL && 0 |\n+-----------+\n|
0 |\n+-----------+\n\nURL:
https://mariadb.com/kb/en/and/','','https://mariadb.com/kb/en/and/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(170,15,'XOR','Syntax\n------\n\nXOR\n\nDescription\n-----------\n\nXOR
stands for eXclusive OR. Returns NULL if either operand is NULL.
For\nnon-NULL operands, evaluates to 1 if an odd number of operands is
non-zero,\notherwise 0 is returned.\n\nExamples\n--------\n\nSELECT 1 XOR
1;\n+---------+\n| 1 XOR 1 |\n+---------+\n| 0
|\n+---------+\n\nSELECT 1 XOR 0;\n+---------+\n| 1 XOR 0 |\n+---------+\n|
1 |\n+---------+\n\nSELECT 1 XOR NULL;\n+------------+\n| 1 XOR NULL
|\n+------------+\n| NULL |\n+------------+\n\nIn the following
example, the right 1 XOR 1 is evaluated first, and returns 0.\nThen, 1 XOR
0 is evaluated, and 1 is returned.\n\nSELECT 1 XOR 1 XOR
1;\n+---------------+\n| 1 XOR 1 XOR 1 |\n+---------------+\n|
1 |\n+---------------+\n\nURL:
https://mariadb.com/kb/en/xor/','','https://mariadb.com/kb/en/xor/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(171,15,'||','Syntax\n------\n\nOR,
||\n\nDescription\n-----------\n\nLogical OR. When both operands are
non-NULL, the result is 1 if any operand is\nnon-zero, and 0 otherwise.
With a NULL operand, the result is 1 if the other\noperand is non-zero, and
NULL otherwise. If both operands are NULL, the result\nis NULL.\n\nFor this
operator, short-circuit evaluation can be used.\n\nNote that, if the
PIPES_AS_CONCAT SQL_MODE is set, || is used as a string\nconcatenation
operator. This means that a || b is the same as CONCAT(a,b). See\nCONCAT()
for details.\n\nOracle Mode\n-----------\n\nMariaDB starting with
10.3\n--------------------------\nIn Oracle mode from MariaDB 10.3, ||
ignores NULL.\n\nExamples\n--------\n\nSELECT 1 || 1;\n+--------+\n| 1 || 1
|\n+--------+\n| 1 |\n+--------+\n\nSELECT 1 || 0;\n+--------+\n| 1 ||
0 |\n+--------+\n| 1 |\n+--------+\n\nSELECT 0 || 0;\n+--------+\n| 0
|| 0 |\n+--------+\n| 0 |\n+--------+\n\nSELECT 0 ||
NULL;\n+-----------+\n| 0 || NULL |\n+-----------+\n| NULL
|\n+-----------+\n\nSELECT 1 || NULL;\n+-----------+\n| 1 || NULL
|\n+-----------+\n| 1 |\n+-----------+\n\nIn Oracle mode, from
MariaDB 10.3:\n\nSELECT 0 || NULL;\n+-----------+\n| 0 || NULL
|\n+-----------+\n| 0 |\n+-----------+\n\nURL:
https://mariadb.com/kb/en/or/','','https://mariadb.com/kb/en/or/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(172,16,'Stored Aggregate Functions','MariaDB starting with
10.3.3\n----------------------------\nThe ability to create stored
aggregate functions was added in MariaDB 10.3.3.\n\nAggregate functions are
functions that are computed over a sequence of rows\nand return one result
for the sequence of rows.\n\nCreating a custom aggregate function is done
using the CREATE FUNCTION\nstatement with two main differences:\n\n* The
addition of the AGGREGATE keyword, so CREATE AGGREGATE FUNCTION\n* The
FETCH GROUP NEXT ROW instruction inside the loop\n* Oracle PL/SQL
compatibility using SQL/PL is provided\n\nStandard
Syntax\n---------------\n\nCREATE AGGREGATE FUNCTION function_name
(parameters) RETURNS return_type\nBEGIN\n All types of declarations\n
DECLARE CONTINUE HANDLER FOR NOT FOUND RETURN return_val;\n LOOP\n
FETCH GROUP NEXT ROW; // fetches next row from table\n other
instructions\n END LOOP;\nEND\n\nStored aggregate functions were a 2016
Google Summer of Code project by Varun\nGupta.\n\nUsing
SQL/PL\n------------\n\nSET sql_mode=Oracle;\nDELIMITER //\n\nCREATE
AGGREGATE FUNCTION function_name (parameters) RETURN return_type\n
declarations\nBEGIN\n LOOP\n FETCH GROUP NEXT ROW; -- fetches next row
from table\n -- other instructions\n\nEND LOOP;\nEXCEPTION\n WHEN
NO_DATA_FOUND THEN\n RETURN return_val;\nEND //\n\nDELIMITER
;\n\nExamples\n--------\n\nFirst a simplified example:\n\nCREATE TABLE
marks(stud_id INT, grade_count INT);\n\nINSERT INTO marks VALUES (1,6),
(2,4), (3,7), (4,5), (5,8);\n\nSELECT * FROM
marks;\n+---------+-------------+\n| stud_id | grade_count
|\n+---------+-------------+\n| 1 | 6 |\n| 2 |
4 |\n| 3 | 7 |\n| 4 | 5 |\n| 5 |
8 |\n+---------+-------------+\n\nDELIMITER //\nCREATE AGGREGATE
FUNCTION IF NOT EXISTS aggregate_count(x INT) RETURNS INT\nBEGIN\n DECLARE
count_students INT DEFAULT 0;\n DECLARE CONTINUE HANDLER FOR NOT FOUND\n
RETURN count_students;\n LOOP\n FETCH GROUP NEXT ROW;\n IF x
THEN\n SET count_students = count_students+1;\n END IF;\n END
LOOP;\nEND //\nDELIMITER ;\n\nA non-trivial example that cannot easily be
rewritten using existing functions:\n\nDELIMITER //\nCREATE AGGREGATE
FUNCTION medi_int(x INT) RETURNS DOUBLE\nBEGIN\n DECLARE CONTINUE HANDLER
FOR NOT FOUND\n BEGIN\n DECLARE res DOUBLE;\n DECLARE cnt INT DEFAULT
(SELECT COUNT(*) FROM tt);\n DECLARE lim INT DEFAULT (cnt-1) DIV 2;\n
IF cnt % 2 = 0 THEN\n SET res = (SELECT AVG(a) FROM (SELECT a FROM tt
ORDER BY a LIMIT\nlim,2) ttt);\n ELSE\n SET res = (SELECT a FROM tt
ORDER BY a LIMIT lim,1);\n END IF;\n DROP TEMPORARY TABLE tt;\n
RETURN res;\n END;\n CREATE TEMPORARY TABLE tt (a INT);\n LOOP\n FETCH
GROUP NEXT ROW;\n INSERT INTO tt VALUES (x);\n END LOOP;\nEND
//\nDELIMITER ;\n\nSQL/PL Example\n--------------\n\nThis uses the same
marks table as created above.\n\nSET sql_mode=Oracle;\nDELIMITER
//\n\nCREATE AGGREGATE FUNCTION aggregate_count(x INT) RETURN INT AS
count_students\nINT DEFAULT 0;\nBEGIN\n LOOP\n FETCH GROUP NEXT ROW;\n
IF x THEN\n SET count_students := count_students+1;\n END IF;\n END
LOOP;\nEXCEPTION\n WHEN NO_DATA_FOUND THEN\n RETURN count_students;\nEND
aggregate_count //\nDELIMITER ;\n\nSELECT aggregate_count(stud_id) FROM
marks;\n\nURL:
https://mariadb.com/kb/en/stored-aggregate-functions/','','https://mariadb.com/kb/en/stored-aggregate-functions/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(173,16,'AVG','Syntax\n------\n\nAVG([DISTINCT]
expr)\n\nDescription\n-----------\n\nReturns the average value of expr. The
DISTINCT option can be used to return\nthe average of the distinct values
of expr. NULL values are ignored. It is an\naggregate function, and so can
be used with the GROUP BY clause.\n\nAVG() returns NULL if there were no
matching rows.\n\nAVG() can be used as a window
function.\n\nExamples\n--------\n\nCREATE TABLE sales (sales_value
INT);\n\nINSERT INTO sales VALUES(10),(20),(20),(40);\n\nSELECT
AVG(sales_value) FROM sales;\n+------------------+\n| AVG(sales_value)
|\n+------------------+\n| 22.5000
|\n+------------------+\n\nSELECT AVG(DISTINCT(sales_value)) FROM
sales;\n+----------------------------+\n| AVG(DISTINCT(sales_value))
|\n+----------------------------+\n| 23.3333
|\n+----------------------------+\n\nCommonly, AVG() is used with a GROUP
BY clause:\n\nCREATE TABLE student (name CHAR(10), test CHAR(10), score
TINYINT);\n\nINSERT INTO student VALUES \n (\'Chun\',
\'SQL\', 75), (\'Chun\', \'Tuning\', 73),\n
(\'Esben\', \'SQL\', 43), (\'Esben\',
\'Tuning\', 31),\n (\'Kaolin\', \'SQL\', 56),
(\'Kaolin\', \'Tuning\', 88),\n (\'Tatiana\',
\'SQL\', 87), (\'Tatiana\', \'Tuning\',
83);\n\nSELECT name, AVG(score) FROM student GROUP BY
name;\n+---------+------------+\n| name | AVG(score)
|\n+---------+------------+\n| Chun | 74.0000 |\n| Esben |
37.0000 |\n| Kaolin | 72.0000 |\n| Tatiana | 85.0000
|\n+---------+------------+\n\nBe careful to avoid this common mistake, not
grouping correctly and returning\nmismatched data:\n\nSELECT
name,test,AVG(score) FROM student;\n+------+------+------------+\n| name |
test | MIN(score) |\n+------+------+------------+\n| Chun | SQL |
31 |\n+------+------+------------+\n\nAs a window function:\n\nCREATE TABLE
student_test (name CHAR(10), test CHAR(10), score TINYINT);\n\nINSERT INTO
student_test VALUES \n (\'Chun\', \'SQL\', 75),
(\'Chun\', \'Tuning\', 73),\n (\'Esben\',
\'SQL\', 43), (\'Esben\', \'Tuning\', 31),\n
(\'Kaolin\', \'SQL\', 56), (\'Kaolin\',
\'Tuning\', 88),\n (\'Tatiana\', \'SQL\',
87), (\'Tatiana\', \'Tuning\', 83);\n\nSELECT name,
test, score, AVG(score) OVER (PARTITION BY test) \n AS average_by_test
FROM student_test;\n+---------+--------+-------+-----------------+\n| name
| test | score | average_by_test
|\n+---------+--------+-------+-----------------+\n| Chun | SQL |
75 | 65.2500 |\n| Chun | Tuning | 73 | 68.7500 |\n|
Esben | SQL | 43 | 65.2500 |\n| Esben | Tuning | 31 |
68.7500 |\n| Kaolin | SQL | 56 | 65.2500 |\n| Kaolin
| Tuning | 88 | 68.7500 |\n| Tatiana | SQL | 87 |
65.2500 |\n| Tatiana | Tuning | 83 | 68.7500
|\n+---------+--------+-------+-----------------+\n\nURL:
https://mariadb.com/kb/en/avg/','','https://mariadb.com/kb/en/avg/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(174,16,'BIT_AND','Syntax\n------\n\nBIT_AND(expr)
[over_clause]\n\nDescription\n-----------\n\nReturns the bitwise AND of all
bits in expr. The calculation is performed with\n64-bit (BIGINT) precision.
It is an aggregate function, and so can be used\nwith the GROUP BY
clause.\n\nIf no rows match, BIT_AND will return a value with all bits set
to 1. NULL\nvalues have no effect on the result unless all results are
NULL, which is\ntreated as no match.\n\nBIT_AND can be used as a window
function with the addition of the
over_clause.\n\nExamples\n--------\n\nCREATE TABLE vals (x INT);\n\nINSERT
INTO vals VALUES(111),(110),(100);\n\nSELECT BIT_AND(x), BIT_OR(x),
BIT_XOR(x) FROM vals;\n+------------+-----------+------------+\n|
BIT_AND(x) | BIT_OR(x) | BIT_XOR(x)
|\n+------------+-----------+------------+\n| 100 | 111 |
101 |\n+------------+-----------+------------+\n\nAs an aggregate
function:\n\nCREATE TABLE vals2 (category VARCHAR(1), x INT);\n\nINSERT
INTO vals2 VALUES\n
(\'a\',111),(\'a\',110),(\'a\',100),\n
(\'b\',\'000\'),(\'b\',001),(\'b\',011);\n\nSELECT
category, BIT_AND(x), BIT_OR(x), BIT_XOR(x) \n FROM vals GROUP BY
category;\n+----------+------------+-----------+------------+\n| category |
BIT_AND(x) | BIT_OR(x) | BIT_XOR(x)
|\n+----------+------------+-----------+------------+\n| a |
100 | 111 | 101 |\n| b | 0 | 11 |
10 |\n+----------+------------+-----------+------------+\n\nNo
match:\n\nSELECT BIT_AND(NULL);\n+----------------------+\n| BIT_AND(NULL)
|\n+----------------------+\n| 18446744073709551615
|\n+----------------------+\n\nURL:
https://mariadb.com/kb/en/bit_and/','','https://mariadb.com/kb/en/bit_and/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(175,16,'BIT_OR','Syntax\n------\n\nBIT_OR(expr)
[over_clause]\n\nDescription\n-----------\n\nReturns the bitwise OR of all
bits in expr. The calculation is performed with\n64-bit (BIGINT) precision.
It is an aggregate function, and so can be used\nwith the GROUP BY
clause.\n\nIf no rows match, BIT_OR will return a value with all bits set
to 0. NULL\nvalues have no effect on the result unless all results are
NULL, which is\ntreated as no match.\n\nBIT_OR can be used as a window
function with the addition of the
over_clause.\n\nExamples\n--------\n\nCREATE TABLE vals (x INT);\n\nINSERT
INTO vals VALUES(111),(110),(100);\n\nSELECT BIT_AND(x), BIT_OR(x),
BIT_XOR(x) FROM vals;\n+------------+-----------+------------+\n|
BIT_AND(x) | BIT_OR(x) | BIT_XOR(x)
|\n+------------+-----------+------------+\n| 100 | 111 |
101 |\n+------------+-----------+------------+\n\nAs an aggregate
function:\n\nCREATE TABLE vals2 (category VARCHAR(1), x INT);\n\nINSERT
INTO vals2 VALUES\n
(\'a\',111),(\'a\',110),(\'a\',100),\n
(\'b\',\'000\'),(\'b\',001),(\'b\',011);\n\nSELECT
category, BIT_AND(x), BIT_OR(x), BIT_XOR(x) \n FROM vals GROUP BY
category;\n+----------+------------+-----------+------------+\n| category |
BIT_AND(x) | BIT_OR(x) | BIT_XOR(x)
|\n+----------+------------+-----------+------------+\n| a |
100 | 111 | 101 |\n| b | 0 | 11 |
10 |\n+----------+------------+-----------+------------+\n\nNo
match:\n\nSELECT BIT_OR(NULL);\n+--------------+\n| BIT_OR(NULL)
|\n+--------------+\n| 0 |\n+--------------+\n\nURL:
https://mariadb.com/kb/en/bit_or/','','https://mariadb.com/kb/en/bit_or/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(176,16,'BIT_XOR','Syntax\n------\n\nBIT_XOR(expr)
[over_clause]\n\nDescription\n-----------\n\nReturns the bitwise XOR of all
bits in expr. The calculation is performed with\n64-bit (BIGINT) precision.
It is an aggregate function, and so can be used\nwith the GROUP BY
clause.\n\nIf no rows match, BIT_XOR will return a value with all bits set
to 0. NULL\nvalues have no effect on the result unless all results are
NULL, which is\ntreated as no match.\n\nBIT_XOR can be used as a window
function with the addition of the
over_clause.\n\nExamples\n--------\n\nCREATE TABLE vals (x INT);\n\nINSERT
INTO vals VALUES(111),(110),(100);\n\nSELECT BIT_AND(x), BIT_OR(x),
BIT_XOR(x) FROM vals;\n+------------+-----------+------------+\n|
BIT_AND(x) | BIT_OR(x) | BIT_XOR(x)
|\n+------------+-----------+------------+\n| 100 | 111 |
101 |\n+------------+-----------+------------+\n\nAs an aggregate
function:\n\nCREATE TABLE vals2 (category VARCHAR(1), x INT);\n\nINSERT
INTO vals2 VALUES\n
(\'a\',111),(\'a\',110),(\'a\',100),\n
(\'b\',\'000\'),(\'b\',001),(\'b\',011);\n\nSELECT
category, BIT_AND(x), BIT_OR(x), BIT_XOR(x) \n FROM vals GROUP BY
category;\n+----------+------------+-----------+------------+\n| category |
BIT_AND(x) | BIT_OR(x) | BIT_XOR(x)
|\n+----------+------------+-----------+------------+\n| a |
100 | 111 | 101 |\n| b | 0 | 11 |
10 |\n+----------+------------+-----------+------------+\n\nNo
match:\n\nSELECT BIT_XOR(NULL);\n+---------------+\n| BIT_XOR(NULL)
|\n+---------------+\n| 0 |\n+---------------+\n\nURL:
https://mariadb.com/kb/en/bit_xor/','','https://mariadb.com/kb/en/bit_xor/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(177,16,'COUNT','Syntax\n------\n\nCOUNT(expr)\n\nDescription\n-----------\n\nReturns
a count of the number of non-NULL values of expr in the rows retrieved\nby
a SELECT statement. The result is a BIGINT value. It is an
aggregate\nfunction, and so can be used with the GROUP BY
clause.\n\nCOUNT(*) counts the total number of rows in a table.\n\nCOUNT()
returns 0 if there were no matching rows.\n\nCOUNT() can be used as a
window function.\n\nExamples\n--------\n\nCREATE TABLE student (name
CHAR(10), test CHAR(10), score TINYINT);\n\nINSERT INTO student VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87), (\'Tatiana\',
\'Tuning\', 83);\n\nSELECT COUNT(*) FROM
student;\n+----------+\n| COUNT(*) |\n+----------+\n| 8
|\n+----------+\n\nCOUNT(DISTINCT) example:\n\nSELECT COUNT(DISTINCT
(name)) FROM student;\n+------------------------+\n| COUNT(DISTINCT (name))
|\n+------------------------+\n| 4
|\n+------------------------+\n\nAs a window function\n\nCREATE OR REPLACE
TABLE student_test (name CHAR(10), test CHAR(10),
score\nTINYINT);\n\nINSERT INTO student_test VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87);\n\nSELECT name, test,
score, COUNT(score) OVER (PARTITION BY name) \n AS tests_written FROM
student_test;\n+---------+--------+-------+---------------+\n| name |
test | score | tests_written
|\n+---------+--------+-------+---------------+\n| Chun | SQL | 75
| 2 |\n| Chun | Tuning | 73 | 2 |\n| Esben
| SQL | 43 | 2 |\n| Esben | Tuning | 31 |
2 |\n| Kaolin | SQL | 56 | 2 |\n| Kaolin | Tuning |
88 | 2 |\n| Tatiana | SQL | 87 | 1
|\n+---------+--------+-------+---------------+\n\nURL:
https://mariadb.com/kb/en/count/','','https://mariadb.com/kb/en/count/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(178,16,'COUNT DISTINCT','Syntax\n------\n\nCOUNT(DISTINCT
expr,[expr...])\n\nDescription\n-----------\n\nReturns a count of the
number of different non-NULL values.\n\nCOUNT(DISTINCT) returns 0 if there
were no matching rows.\n\nAlthough, from MariaDB 10.2.0, COUNT can be used
as a window function, COUNT\nDISTINCT cannot
be.\n\nExamples\n--------\n\nCREATE TABLE student (name CHAR(10), test
CHAR(10), score TINYINT);\n\nINSERT INTO student VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87), (\'Tatiana\',
\'Tuning\', 83);\n\nSELECT COUNT(*) FROM
student;\n+----------+\n| COUNT(*) |\n+----------+\n| 8
|\n+----------+\n\nSELECT COUNT(DISTINCT (name)) FROM
student;\n+------------------------+\n| COUNT(DISTINCT (name))
|\n+------------------------+\n| 4
|\n+------------------------+\n\nURL:
https://mariadb.com/kb/en/count-distinct/','','https://mariadb.com/kb/en/count-distinct/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(179,16,'GROUP_CONCAT','Syntax\n------\n\nGROUP_CONCAT(expr)\n\nDescription\n-----------\n\nThis
function returns a string result with the concatenated non-NULL
values\nfrom a group. It returns NULL if there are no non-NULL
values.\n\nThe maximum returned length in bytes is determined by the
group_concat_max_len\nserver system variable, which defaults to 1M (>=
MariaDB 10.2.4) or 1K (<=\nMariaDB 10.2.3).\n\nIf group_concat_max_len
<= 512, the return type is VARBINARY or VARCHAR;\notherwise, the return
type is BLOB or TEXT. The choice between binary or\nnon-binary types
depends from the input.\n\nThe full syntax is as
follows:\n\nGROUP_CONCAT([DISTINCT] expr [,expr ...]\n [ORDER BY
{unsigned_integer | col_name | expr}\n [ASC | DESC] [,col_name
...]]\n [SEPARATOR str_val]\n [LIMIT {[offset,] row_count |
row_count OFFSET offset}])\n\nDISTINCT eliminates duplicate values from the
output string.\n\nORDER BY determines the order of returned
values.\n\nSEPARATOR specifies a separator between the values. The default
separator is a\ncomma (,). It is possible to avoid using a separator by
specifying an empty\nstring.\n\nLIMIT\n-----\n\nMariaDB starting with
10.3.3\n----------------------------\nUntil MariaDB 10.3.2, it was not
possible to use the LIMIT clause with\nGROUP_CONCAT. This restriction was
lifted in MariaDB 10.3.3.\n\nExamples\n--------\n\nSELECT student_name,\n
GROUP_CONCAT(test_score)\n FROM student\n GROUP BY student_name;\n\nGet
a readable list of MariaDB users from the mysql.user table:\n\nSELECT
GROUP_CONCAT(DISTINCT User ORDER BY User SEPARATOR \'\\n\')\n
FROM mysql.user;\n\nIn the former example, DISTINCT is used because the
same user may occur more\nthan once. The new line (\\n) used as a SEPARATOR
makes the results easier to\nread.\n\nGet a readable list of hosts from
which each user can connect:\n\nSELECT User, GROUP_CONCAT(Host ORDER BY
Host SEPARATOR \', \') \n FROM mysql.user GROUP BY User ORDER BY
User;\n\nThe former example shows the difference between the
GROUP_CONCAT\'s ORDER BY\n(which sorts the concatenated hosts), and
the SELECT\'s ORDER BY (which sorts\nthe rows).\n\nFrom MariaDB
10.3.3, LIMIT can be used with GROUP_CONCAT, so, for example,\ngiven the
following table:\n\nCREATE TABLE d (dd DATE, cc INT);\n\nINSERT INTO d
VALUES (\'2017-01-01\',1);\nINSERT INTO d VALUES
(\'2017-01-02\',2);\nINSERT INTO d VALUES
(\'2017-01-04\',3);\n\nthe following query:\n\nSELECT
SUBSTRING_INDEX(GROUP_CONCAT(CONCAT_WS(\":\",dd,cc) ORDER BY
cc\nDESC),\",\",1) FROM
d;\n+----------------------------------------------------------------------------+\n|
SUBSTRING_INDEX(GROUP_CONCAT(CONCAT_WS(\":\",dd,cc) ORDER BY cc
DESC),\",\",1)
|\n+----------------------------------------------------------------------------+\n|
2017-01-04:3
|\n+----------------------------------------------------------------------------+\n\ncan
be more simply rewritten as:\n\nSELECT
GROUP_CONCAT(CONCAT_WS(\":\",dd,cc) ORDER BY cc DESC LIMIT 1)
FROM d;\n+-------------------------------------------------------------+\n|
GROUP_CONCAT(CONCAT_WS(\":\",dd,cc) ORDER BY cc DESC LIMIT 1)
|\n+-------------------------------------------------------------+\n|
2017-01-04:3
|\n+-------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/group_concat/','','https://mariadb.com/kb/en/group_concat/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(180,16,'MAX','Syntax\n------\n\nMAX([DISTINCT]
expr)\n\nDescription\n-----------\n\nReturns the largest, or maximum, value
of expr. MAX() can also take a string\nargument in which case it returns
the maximum string value. The DISTINCT\nkeyword can be used to find the
maximum of the distinct values of expr,\nhowever, this produces the same
result as omitting DISTINCT.\n\nNote that SET and ENUM fields are currently
compared by their string value\nrather than their relative position in the
set, so MAX() may produce a\ndifferent highest result than ORDER BY
DESC.\n\nIt is an aggregate function, and so can be used with the GROUP BY
clause.\n\nMAX() can be used as a window function.\n\nMAX() returns NULL if
there were no matching rows.\n\nExamples\n--------\n\nCREATE TABLE student
(name CHAR(10), test CHAR(10), score TINYINT);\n\nINSERT INTO student
VALUES \n (\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87), (\'Tatiana\',
\'Tuning\', 83);\n\nSELECT name, MAX(score) FROM student GROUP BY
name;\n+---------+------------+\n| name | MAX(score)
|\n+---------+------------+\n| Chun | 75 |\n| Esben |
43 |\n| Kaolin | 88 |\n| Tatiana | 87
|\n+---------+------------+\n\nMAX string:\n\nSELECT MAX(name) FROM
student;\n+-----------+\n| MAX(name) |\n+-----------+\n| Tatiana
|\n+-----------+\n\nBe careful to avoid this common mistake, not grouping
correctly and returning\nmismatched data:\n\nSELECT name,test,MAX(SCORE)
FROM student;\n+------+------+------------+\n| name | test | MAX(SCORE)
|\n+------+------+------------+\n| Chun | SQL | 88
|\n+------+------+------------+\n\nDifference between ORDER BY DESC and
MAX():\n\nCREATE TABLE student2(name CHAR(10),grade
ENUM(\'b\',\'c\',\'a\'));\n\nINSERT INTO
student2
VALUES(\'Chun\',\'b\'),(\'Esben\',\'c\'),(\'Kaolin\',\'a\');\n\nSELECT
MAX(grade) FROM student2;\n+------------+\n| MAX(grade)
|\n+------------+\n| c |\n+------------+\n\nSELECT grade FROM
student2 ORDER BY grade DESC LIMIT 1;\n+-------+\n| grade |\n+-------+\n| a
|\n+-------+\n\nAs a window function:\n\nCREATE OR REPLACE TABLE
student_test (name CHAR(10), test CHAR(10), score\nTINYINT);\nINSERT INTO
student_test VALUES \n (\'Chun\', \'SQL\', 75),
(\'Chun\', \'Tuning\', 73),\n (\'Esben\',
\'SQL\', 43), (\'Esben\', \'Tuning\', 31),\n
(\'Kaolin\', \'SQL\', 56), (\'Kaolin\',
\'Tuning\', 88),\n (\'Tatiana\', \'SQL\',
87);\n\nSELECT name, test, score, MAX(score) \n OVER (PARTITION BY name) AS
highest_score FROM
student_test;\n+---------+--------+-------+---------------+\n| name |
test | score | highest_score
|\n+---------+--------+-------+---------------+\n| Chun | SQL | 75
| 75 |\n| Chun | Tuning | 73 | 75 |\n| Esben
| SQL | 43 | 43 |\n| Esben | Tuning | 31 |
43 |\n| Kaolin | SQL | 56 | 88 |\n| Kaolin | Tuning |
88 | 88 |\n| Tatiana | SQL | 87 | 87
|\n+---------+--------+-------+---------------+\n\nURL:
https://mariadb.com/kb/en/max/','','https://mariadb.com/kb/en/max/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(181,16,'MIN','Syntax\n------\n\nMIN([DISTINCT]
expr)\n\nDescription\n-----------\n\nReturns the minimum value of expr.
MIN() may take a string argument, in which\ncase it returns the minimum
string value. The DISTINCT keyword can be used to\nfind the minimum of the
distinct values of expr, however, this produces the\nsame result as
omitting DISTINCT.\n\nNote that SET and ENUM fields are currently compared
by their string value\nrather than their relative position in the set, so
MIN() may produce a\ndifferent lowest result than ORDER BY ASC.\n\nIt is an
aggregate function, and so can be used with the GROUP BY clause.\n\nMIN()
can be used as a window function.\n\nMIN() returns NULL if there were no
matching rows.\n\nExamples\n--------\n\nCREATE TABLE student (name
CHAR(10), test CHAR(10), score TINYINT);\n\nINSERT INTO student VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87), (\'Tatiana\',
\'Tuning\', 83);\n\nSELECT name, MIN(score) FROM student GROUP BY
name;\n+---------+------------+\n| name | MIN(score)
|\n+---------+------------+\n| Chun | 73 |\n| Esben |
31 |\n| Kaolin | 56 |\n| Tatiana | 83
|\n+---------+------------+\n\nMIN() with a string:\n\nSELECT MIN(name)
FROM student;\n+-----------+\n| MIN(name) |\n+-----------+\n| Chun
|\n+-----------+\n\nBe careful to avoid this common mistake, not grouping
correctly and returning\nmismatched data:\n\nSELECT name,test,MIN(score)
FROM student;\n+------+------+------------+\n| name | test | MIN(score)
|\n+------+------+------------+\n| Chun | SQL | 31
|\n+------+------+------------+\n\nDifference between ORDER BY ASC and
MIN():\n\nCREATE TABLE student2(name CHAR(10),grade
ENUM(\'b\',\'c\',\'a\'));\n\nINSERT INTO
student2
VALUES(\'Chun\',\'b\'),(\'Esben\',\'c\'),(\'Kaolin\',\'a\');\n\nSELECT
MIN(grade) FROM student2;\n+------------+\n| MIN(grade)
|\n+------------+\n| a |\n+------------+\n\nSELECT grade FROM
student2 ORDER BY grade ASC LIMIT 1;\n+-------+\n| grade |\n+-------+\n| b
|\n+-------+\n\nAs a window function:\n\nCREATE OR REPLACE TABLE
student_test (name CHAR(10), test CHAR(10), score\nTINYINT);\nINSERT INTO
student_test VALUES \n (\'Chun\', \'SQL\', 75),
(\'Chun\', \'Tuning\', 73),\n (\'Esben\',
\'SQL\', 43), (\'Esben\', \'Tuning\', 31),\n
(\'Kaolin\', \'SQL\', 56), (\'Kaolin\',
\'Tuning\', 88),\n (\'Tatiana\', \'SQL\',
87);\n\nSELECT name, test, score, MIN(score) \n OVER (PARTITION BY name) AS
lowest_score FROM
student_test;\n+---------+--------+-------+--------------+\n| name |
test | score | lowest_score
|\n+---------+--------+-------+--------------+\n| Chun | SQL | 75
| 73 |\n| Chun | Tuning | 73 | 73 |\n| Esben |
SQL | 43 | 31 |\n| Esben | Tuning | 31 | 31
|\n| Kaolin | SQL | 56 | 56 |\n| Kaolin | Tuning | 88
| 56 |\n| Tatiana | SQL | 87 | 87
|\n+---------+--------+-------+--------------+\n\nURL:
https://mariadb.com/kb/en/min/','','https://mariadb.com/kb/en/min/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(182,16,'STD','Syntax\n------\n\nSTD(expr)\n\nDescription\n-----------\n\nReturns
the population standard deviation of expr. This is an extension
to\nstandard SQL. The standard SQL function STDDEV_POP() can be used
instead.\n\nIt is an aggregate function, and so can be used with the GROUP
BY clause.\n\nSTD() can be used as a window function.\n\nThis function
returns NULL if there were no matching rows.\n\nExamples\n--------\n\nAs an
aggregate function:\n\nCREATE OR REPLACE TABLE stats (category VARCHAR(2),
x INT);\n\nINSERT INTO stats VALUES \n
(\'a\',1),(\'a\',2),(\'a\',3),\n
(\'b\',11),(\'b\',12),(\'b\',20),(\'b\',30),(\'b\',60);\n\nSELECT
category, STDDEV_POP(x), STDDEV_SAMP(x), VAR_POP(x) \n FROM stats GROUP BY
category;\n+----------+---------------+----------------+------------+\n|
category | STDDEV_POP(x) | STDDEV_SAMP(x) | VAR_POP(x)
|\n+----------+---------------+----------------+------------+\n| a |
0.8165 | 1.0000 | 0.6667 |\n| b | 18.0400 |
20.1693 | 325.4400
|\n+----------+---------------+----------------+------------+\n\nAs a
window function:\n\nCREATE OR REPLACE TABLE student_test (name CHAR(10),
test CHAR(10), score\nTINYINT);\n\nINSERT INTO student_test VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87);\n\nSELECT name, test,
score, STDDEV_POP(score) \n OVER (PARTITION BY test) AS stddev_results FROM
student_test;\n+---------+--------+-------+----------------+\n| name |
test | score | stddev_results
|\n+---------+--------+-------+----------------+\n| Chun | SQL |
75 | 16.9466 |\n| Chun | Tuning | 73 | 24.1247 |\n|
Esben | SQL | 43 | 16.9466 |\n| Esben | Tuning | 31 |
24.1247 |\n| Kaolin | SQL | 56 | 16.9466 |\n| Kaolin |
Tuning | 88 | 24.1247 |\n| Tatiana | SQL | 87 |
16.9466 |\n+---------+--------+-------+----------------+\n\nURL:
https://mariadb.com/kb/en/std/','','https://mariadb.com/kb/en/std/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(183,16,'STDDEV','Syntax\n------\n\nSTDDEV(expr)\n\nDescription\n-----------\n\nReturns
the population standard deviation of expr. This function is provided\nfor
compatibility with Oracle. The standard SQL function STDDEV_POP() can
be\nused instead.\n\nIt is an aggregate function, and so can be used with
the GROUP BY clause.\n\nSTDDEV() can be used as a window function.\n\nThis
function returns NULL if there were no matching
rows.\n\nExamples\n--------\n\nAs an aggregate function:\n\nCREATE OR
REPLACE TABLE stats (category VARCHAR(2), x INT);\n\nINSERT INTO stats
VALUES \n (\'a\',1),(\'a\',2),(\'a\',3),\n
(\'b\',11),(\'b\',12),(\'b\',20),(\'b\',30),(\'b\',60);\n\nSELECT
category, STDDEV_POP(x), STDDEV_SAMP(x), VAR_POP(x) \n FROM stats GROUP BY
category;\n+----------+---------------+----------------+------------+\n|
category | STDDEV_POP(x) | STDDEV_SAMP(x) | VAR_POP(x)
|\n+----------+---------------+----------------+------------+\n| a |
0.8165 | 1.0000 | 0.6667 |\n| b | 18.0400 |
20.1693 | 325.4400
|\n+----------+---------------+----------------+------------+\n\nAs a
window function:\n\nCREATE OR REPLACE TABLE student_test (name CHAR(10),
test CHAR(10), score\nTINYINT);\n\nINSERT INTO student_test VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87);\n\nSELECT name, test,
score, STDDEV_POP(score) \n OVER (PARTITION BY test) AS stddev_results FROM
student_test;\n+---------+--------+-------+----------------+\n| name |
test | score | stddev_results
|\n+---------+--------+-------+----------------+\n| Chun | SQL |
75 | 16.9466 |\n| Chun | Tuning | 73 | 24.1247 |\n|
Esben | SQL | 43 | 16.9466 |\n| Esben | Tuning | 31 |
24.1247 |\n| Kaolin | SQL | 56 | 16.9466 |\n| Kaolin |
Tuning | 88 | 24.1247 |\n| Tatiana | SQL | 87 |
16.9466 |\n+---------+--------+-------+----------------+\n\nURL:
https://mariadb.com/kb/en/stddev/','','https://mariadb.com/kb/en/stddev/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(184,16,'STDDEV_POP','Syntax\n------\n\nSTDDEV_POP(expr)\n\nDescription\n-----------\n\nReturns
the population standard deviation of expr (the square root of\nVAR_POP()).
You can also use STD() or STDDEV(), which are equivalent but not\nstandard
SQL.\n\nIt is an aggregate function, and so can be used with the GROUP BY
clause.\n\nSTDDEV_POP() can be used as a window function.\n\nSTDDEV_POP()
returns NULL if there were no matching rows.\n\nExamples\n--------\n\nAs an
aggregate function:\n\nCREATE OR REPLACE TABLE stats (category VARCHAR(2),
x INT);\n\nINSERT INTO stats VALUES \n
(\'a\',1),(\'a\',2),(\'a\',3),\n
(\'b\',11),(\'b\',12),(\'b\',20),(\'b\',30),(\'b\',60);\n\nSELECT
category, STDDEV_POP(x), STDDEV_SAMP(x), VAR_POP(x) \n FROM stats GROUP BY
category;\n+----------+---------------+----------------+------------+\n|
category | STDDEV_POP(x) | STDDEV_SAMP(x) | VAR_POP(x)
|\n+----------+---------------+----------------+------------+\n| a |
0.8165 | 1.0000 | 0.6667 |\n| b | 18.0400 |
20.1693 | 325.4400
|\n+----------+---------------+----------------+------------+\n\nAs a
window function:\n\nCREATE OR REPLACE TABLE student_test (name CHAR(10),
test CHAR(10), score\nTINYINT);\n\nINSERT INTO student_test VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87);\n\nSELECT name, test,
score, STDDEV_POP(score) \n OVER (PARTITION BY test) AS stddev_results FROM
student_test;\n+---------+--------+-------+----------------+\n| name |
test | score | stddev_results
|\n+---------+--------+-------+----------------+\n| Chun | SQL |
75 | 16.9466 |\n| Chun | Tuning | 73 | 24.1247 |\n|
Esben | SQL | 43 | 16.9466 |\n| Esben | Tuning | 31 |
24.1247 |\n| Kaolin | SQL | 56 | 16.9466 |\n| Kaolin |
Tuning | 88 | 24.1247 |\n| Tatiana | SQL | 87 |
16.9466 |\n+---------+--------+-------+----------------+\n\nURL:
https://mariadb.com/kb/en/stddev_pop/','','https://mariadb.com/kb/en/stddev_pop/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(185,16,'STDDEV_SAMP','Syntax\n------\n\nSTDDEV_SAMP(expr)\n\nDescription\n-----------\n\nReturns
the sample standard deviation of expr (the square root of
VAR_SAMP()).\n\nIt is an aggregate function, and so can be used with the
GROUP BY clause.\n\nSTDDEV_SAMP() can be used as a window
function.\n\nSTDDEV_SAMP() returns NULL if there were no matching
rows.\n\nURL:
https://mariadb.com/kb/en/stddev_samp/','','https://mariadb.com/kb/en/stddev_samp/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(186,16,'SUM','Syntax\n------\n\nSUM([DISTINCT]
expr)\n\nDescription\n-----------\n\nReturns the sum of expr. If the return
set has no rows, SUM() returns NULL.\nThe DISTINCT keyword can be used to
sum only the distinct values of expr.\n\nSUM() can be used as a window
function, although not with the
DISTINCT\nspecifier.\n\nExamples\n--------\n\nCREATE TABLE sales
(sales_value INT);\nINSERT INTO sales VALUES(10),(20),(20),(40);\n\nSELECT
SUM(sales_value) FROM sales;\n+------------------+\n| SUM(sales_value)
|\n+------------------+\n| 90
|\n+------------------+\n\nSELECT SUM(DISTINCT(sales_value)) FROM
sales;\n+----------------------------+\n| SUM(DISTINCT(sales_value))
|\n+----------------------------+\n| 70
|\n+----------------------------+\n\nCommonly, SUM is used with a GROUP BY
clause:\n\nCREATE TABLE sales (name CHAR(10), month CHAR(10), units
INT);\n\nINSERT INTO sales VALUES \n (\'Chun\',
\'Jan\', 75), (\'Chun\', \'Feb\', 73),\n
(\'Esben\', \'Jan\', 43), (\'Esben\',
\'Feb\', 31),\n (\'Kaolin\', \'Jan\', 56),
(\'Kaolin\', \'Feb\', 88),\n (\'Tatiana\',
\'Jan\', 87), (\'Tatiana\', \'Feb\',
83);\n\nSELECT name, SUM(units) FROM sales GROUP BY
name;\n+---------+------------+\n| name | SUM(units)
|\n+---------+------------+\n| Chun | 148 |\n| Esben |
74 |\n| Kaolin | 144 |\n| Tatiana | 170
|\n+---------+------------+\n\nThe GROUP BY clause is required when using
an aggregate function along with\nregular column data, otherwise the result
will be a mismatch, as in the\nfollowing common type of mistake:\n\nSELECT
name,SUM(units) FROM sales\n;+------+------------+\n| name | SUM(units)
|\n+------+------------+\n| Chun | 536
|\n+------+------------+\n\nAs a window function:\n\nCREATE OR REPLACE
TABLE student_test (name CHAR(10), test CHAR(10), score\nTINYINT);\nINSERT
INTO student_test VALUES \n (\'Chun\', \'SQL\', 75),
(\'Chun\', \'Tuning\', 73),\n (\'Esben\',
\'SQL\', 43), (\'Esben\', \'Tuning\', 31),\n
(\'Kaolin\', \'SQL\', 56), (\'Kaolin\',
\'Tuning\', 88),\n (\'Tatiana\', \'SQL\',
87);\n\nSELECT name, test, score, SUM(score) OVER (PARTITION BY name) AS
total_score\nFROM
student_test;\n+---------+--------+-------+-------------+\n| name | test
| score | total_score |\n+---------+--------+-------+-------------+\n|
Chun | SQL | 75 | 148 |\n| Chun | Tuning | 73 |
148 |\n| Esben | SQL | 43 | 74 |\n| Esben | Tuning |
31 | 74 |\n| Kaolin | SQL | 56 | 144 |\n| Kaolin
| Tuning | 88 | 144 |\n| Tatiana | SQL | 87 | 87
|\n+---------+--------+-------+-------------+\n\nURL:
https://mariadb.com/kb/en/sum/','','https://mariadb.com/kb/en/sum/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(187,16,'VARIANCE','Syntax\n------\n\nVARIANCE(expr)\n\nDescription\n-----------\n\nReturns
the population standard variance of expr. This is an extension to\nstandard
SQL. The standard SQL function VAR_POP() can be used instead.\n\nVariance
is calculated by\n\n* working out the mean for the set\n* for each number,
subtracting the mean and squaring the result\n* calculate the average of
the resulting differences\n\nIt is an aggregate function, and so can be
used with the GROUP BY clause.\n\nVARIANCE() can be used as a window
function.\n\nVARIANCE() returns NULL if there were no matching
rows.\n\nExamples\n--------\n\nCREATE TABLE v(i tinyint);\n\nINSERT INTO v
VALUES(101),(99);\n\nSELECT VARIANCE(i) FROM v;\n+-------------+\n|
VARIANCE(i) |\n+-------------+\n| 1.0000 |\n+-------------+\n\nINSERT
INTO v VALUES(120),(80);\n\nSELECT VARIANCE(i) FROM v;\n+-------------+\n|
VARIANCE(i) |\n+-------------+\n| 200.5000 |\n+-------------+\n\nAs an
aggregate function:\n\nCREATE OR REPLACE TABLE stats (category VARCHAR(2),
x INT);\n\nINSERT INTO stats VALUES \n
(\'a\',1),(\'a\',2),(\'a\',3),\n
(\'b\',11),(\'b\',12),(\'b\',20),(\'b\',30),(\'b\',60);\n\nSELECT
category, STDDEV_POP(x), STDDEV_SAMP(x), VAR_POP(x) \n FROM stats GROUP BY
category;\n+----------+---------------+----------------+------------+\n|
category | STDDEV_POP(x) | STDDEV_SAMP(x) | VAR_POP(x)
|\n+----------+---------------+----------------+------------+\n| a |
0.8165 | 1.0000 | 0.6667 |\n| b | 18.0400 |
20.1693 | 325.4400
|\n+----------+---------------+----------------+------------+\n\nAs a
window function:\n\nCREATE OR REPLACE TABLE student_test (name CHAR(10),
test CHAR(10), score\nTINYINT);\n\nINSERT INTO student_test VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87);\n\nSELECT name, test,
score, VAR_POP(score) \n OVER (PARTITION BY test) AS variance_results FROM
student_test;\n+---------+--------+-------+------------------+\n| name |
test | score | variance_results
|\n+---------+--------+-------+------------------+\n| Chun | SQL |
75 | 287.1875 |\n| Chun | Tuning | 73 | 582.0000 |\n|
Esben | SQL | 43 | 287.1875 |\n| Esben | Tuning | 31 |
582.0000 |\n| Kaolin | SQL | 56 | 287.1875 |\n|
Kaolin | Tuning | 88 | 582.0000 |\n| Tatiana | SQL | 87 |
287.1875 |\n+---------+--------+-------+------------------+\n\nURL:
https://mariadb.com/kb/en/variance/','','https://mariadb.com/kb/en/variance/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(188,16,'VAR_POP','Syntax\n------\n\nVAR_POP(expr)\n\nDescription\n-----------\n\nReturns
the population standard variance of expr. It considers rows as the\nwhole
population, not as a sample, so it has the number of rows as
the\ndenominator. You can also use VARIANCE(), which is equivalent but is
not\nstandard SQL.\n\nVariance is calculated by\n\n* working out the mean
for the set\n* for each number, subtracting the mean and squaring the
result\n* calculate the average of the resulting differences\n\nIt is an
aggregate function, and so can be used with the GROUP BY
clause.\n\nVAR_POP() can be used as a window function.\n\nVAR_POP() returns
NULL if there were no matching rows.\n\nExamples\n--------\n\nCREATE TABLE
v(i tinyint);\n\nINSERT INTO v VALUES(101),(99);\n\nSELECT VAR_POP(i) FROM
v;\n+------------+\n| VAR_POP(i) |\n+------------+\n| 1.0000
|\n+------------+\n\nINSERT INTO v VALUES(120),(80);\n\nSELECT VAR_POP(i)
FROM v;\n+------------+\n| VAR_POP(i) |\n+------------+\n| 200.5000
|\n+------------+\n\nAs an aggregate function:\n\nCREATE OR REPLACE TABLE
stats (category VARCHAR(2), x INT);\n\nINSERT INTO stats VALUES \n
(\'a\',1),(\'a\',2),(\'a\',3),\n
(\'b\',11),(\'b\',12),(\'b\',20),(\'b\',30),(\'b\',60);\n\nSELECT
category, STDDEV_POP(x), STDDEV_SAMP(x), VAR_POP(x) \n FROM stats GROUP BY
category;\n+----------+---------------+----------------+------------+\n|
category | STDDEV_POP(x) | STDDEV_SAMP(x) | VAR_POP(x)
|\n+----------+---------------+----------------+------------+\n| a |
0.8165 | 1.0000 | 0.6667 |\n| b | 18.0400 |
20.1693 | 325.4400
|\n+----------+---------------+----------------+------------+\n\nAs a
window function:\n\nCREATE OR REPLACE TABLE student_test (name CHAR(10),
test CHAR(10), score\nTINYINT);\n\nINSERT INTO student_test VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87);\n\nSELECT name, test,
score, VAR_POP(score) \n OVER (PARTITION BY test) AS variance_results FROM
student_test;\n+---------+--------+-------+------------------+\n| name |
test | score | variance_results
|\n+---------+--------+-------+------------------+\n| Chun | SQL |
75 | 287.1875 |\n| Esben | SQL | 43 | 287.1875 |\n|
Kaolin | SQL | 56 | 287.1875 |\n| Tatiana | SQL | 87 |
287.1875 |\n| Chun | Tuning | 73 | 582.0000 |\n|
Esben | Tuning | 31 | 582.0000 |\n| Kaolin | Tuning | 88 |
582.0000 |\n+---------+--------+-------+------------------+\n\nURL:
https://mariadb.com/kb/en/var_pop/','','https://mariadb.com/kb/en/var_pop/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(189,16,'VAR_SAMP','Syntax\n------\n\nVAR_SAMP(expr)\n\nDescription\n-----------\n\nReturns
the sample variance of expr. That is, the denominator is the number
of\nrows minus one.\n\nIt is an aggregate function, and so can be used with
the GROUP BY clause.\n\nVAR_SAMP() can be used as a window
function.\n\nVAR_SAMP() returns NULL if there were no matching
rows.\n\nExamples\n--------\n\nAs an aggregate function:\n\nCREATE OR
REPLACE TABLE stats (category VARCHAR(2), x INT);\n\nINSERT INTO stats
VALUES \n (\'a\',1),(\'a\',2),(\'a\',3),\n
(\'b\',11),(\'b\',12),(\'b\',20),(\'b\',30),(\'b\',60);\n\nSELECT
category, STDDEV_POP(x), STDDEV_SAMP(x), VAR_POP(x) \n FROM stats GROUP BY
category;\n+----------+---------------+----------------+------------+\n|
category | STDDEV_POP(x) | STDDEV_SAMP(x) | VAR_POP(x)
|\n+----------+---------------+----------------+------------+\n| a |
0.8165 | 1.0000 | 0.6667 |\n| b | 18.0400 |
20.1693 | 325.4400
|\n+----------+---------------+----------------+------------+\n\nAs a
window function:\n\nCREATE OR REPLACE TABLE student_test (name CHAR(10),
test CHAR(10), score\nTINYINT);\n\nINSERT INTO student_test VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87);\n\nSELECT name, test,
score, VAR_SAMP(score) \n OVER (PARTITION BY test) AS variance_results FROM
student_test;\n+---------+--------+-------+------------------+\n| name |
test | score | variance_results
|\n+---------+--------+-------+------------------+\n| Chun | SQL |
75 | 382.9167 |\n| Chun | Tuning | 73 | 873.0000 |\n|
Esben | SQL | 43 | 382.9167 |\n| Esben | Tuning | 31 |
873.0000 |\n| Kaolin | SQL | 56 | 382.9167 |\n|
Kaolin | Tuning | 88 | 873.0000 |\n| Tatiana | SQL | 87 |
382.9167 |\n+---------+--------+-------+------------------+\n\nURL:
https://mariadb.com/kb/en/var_samp/','','https://mariadb.com/kb/en/var_samp/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(190,17,'BENCHMARK','Syntax\n------\n\nBENCHMARK(count,expr)\n\nDescription\n-----------\n\nThe
BENCHMARK() function executes the expression expr repeatedly count
times.\nIt may be used to time how quickly MariaDB processes the
expression. The\nresult value is always 0. The intended use is from within
the mysql client,\nwhich reports query execution
times.\n\nExamples\n--------\n\nSELECT
BENCHMARK(1000000,ENCODE(\'hello\',\'goodbye\'));\n+----------------------------------------------+\n|
BENCHMARK(1000000,ENCODE(\'hello\',\'goodbye\'))
|\n+----------------------------------------------+\n|
0
|\n+----------------------------------------------+\n1 row in set (0.21
sec)\n\nURL:
https://mariadb.com/kb/en/benchmark/','','https://mariadb.com/kb/en/benchmark/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(191,17,'BINLOG_GTID_POS','Syntax\n------\n\nBINLOG_GTID_POS(binlog_filename,binlog_offset)\n\nDescription\n-----------\n\nThe
BINLOG_GTID_POS() function takes as input an old-style binary log
position\nin the form of a file name and a file offset. It looks up the
position in the\ncurrent binlog, and returns a string representation of the
corresponding GTID\nposition. If the position is not found in the current
binlog, NULL is returned.\n\nExamples\n--------\n\nSELECT
BINLOG_GTID_POS(\"master-bin.000001\", 600);\n\nURL:
https://mariadb.com/kb/en/binlog_gtid_pos/','','https://mariadb.com/kb/en/binlog_gtid_pos/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(192,17,'CHARSET','Syntax\n------\n\nCHARSET(str)\n\nDescription\n-----------\n\nReturns
the character set of the string argument. If str is not a string, it\nis
considered as a binary string (so the function returns
\'binary\'). This\napplies to NULL, too. The return value is a
string in the utf8 character set.\n\nExamples\n--------\n\nSELECT
CHARSET(\'abc\');\n+----------------+\n|
CHARSET(\'abc\') |\n+----------------+\n| latin1
|\n+----------------+\n\nSELECT CHARSET(CONVERT(\'abc\' USING
utf8));\n+------------------------------------+\n|
CHARSET(CONVERT(\'abc\' USING utf8))
|\n+------------------------------------+\n| utf8
|\n+------------------------------------+\n\nSELECT
CHARSET(USER());\n+-----------------+\n| CHARSET(USER())
|\n+-----------------+\n| utf8 |\n+-----------------+\n\nURL:
https://mariadb.com/kb/en/charset/','','https://mariadb.com/kb/en/charset/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(193,17,'COERCIBILITY','Syntax\n------\n\nCOERCIBILITY(str)\n\nDescription\n-----------\n\nReturns
the collation coercibility value of the string argument.
Coercibility\ndefines what will be converted to what in case of collation
conflict, with an\nexpression with higher coercibility being converted to
the collation of an\nexpression with lower
coercibility.\n\n+-----------------------------+---------------------------+------------------+\n|
Coercibility | Description | Example
|\n+-----------------------------+---------------------------+------------------+\n|
0 | Explicit | Value using a
|\n| | | COLLATE
clause
|\n+-----------------------------+---------------------------+------------------+\n|
1 | No collation | Concatenated
|\n| | | strings
using |\n| | |
different |\n| |
| collations
|\n+-----------------------------+---------------------------+------------------+\n|
2 | Implicit | Column value
|\n+-----------------------------+---------------------------+------------------+\n|
3 | Constant | USER() return
|\n| | | value
|\n+-----------------------------+---------------------------+------------------+\n|
4 | Coercible | Literal string
|\n+-----------------------------+---------------------------+------------------+\n|
5 | Ignorable | NULL or derived
|\n| | | from NULL
|\n+-----------------------------+---------------------------+------------------+\n\nExamples\n--------\n\nSELECT
COERCIBILITY(\'abc\' COLLATE
latin1_swedish_ci);\n+-----------------------------------------------+\n|
COERCIBILITY(\'abc\' COLLATE latin1_swedish_ci)
|\n+-----------------------------------------------+\n|
0
|\n+-----------------------------------------------+\n\nSELECT
COERCIBILITY(USER());\n+----------------------+\n| COERCIBILITY(USER())
|\n+----------------------+\n| 3
|\n+----------------------+\n\nSELECT
COERCIBILITY(\'abc\');\n+---------------------+\n|
COERCIBILITY(\'abc\') |\n+---------------------+\n|
4 |\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/coercibility/','','https://mariadb.com/kb/en/coercibility/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(194,17,'COLLATION','Syntax\n------\n\nCOLLATION(str)\n\nDescription\n-----------\n\nReturns
the collation of the string argument. If str is not a string, it
is\nconsidered as a binary string (so the function returns
\'binary\'). This applies\nto NULL, too. The return value is a
string in the utf8 character set.\n\nSee Character Sets and
Collations.\n\nExamples\n--------\n\nSELECT
COLLATION(\'abc\');\n+-------------------+\n|
COLLATION(\'abc\') |\n+-------------------+\n| latin1_swedish_ci
|\n+-------------------+\n\nSELECT
COLLATION(_utf8\'abc\');\n+-----------------------+\n|
COLLATION(_utf8\'abc\') |\n+-----------------------+\n|
utf8_general_ci |\n+-----------------------+\n\nURL:
https://mariadb.com/kb/en/collation/','','https://mariadb.com/kb/en/collation/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(195,17,'CONNECTION_ID','Syntax\n------\n\nCONNECTION_ID()\n\nDescription\n-----------\n\nReturns
the connection ID for the connection. Every connection (including\nevents)
has an ID that is unique among the set of currently connected
clients.\n\nUntil MariaDB 10.3.1, returns MYSQL_TYPE_LONGLONG, or
bigint(10), in all\ncases. From MariaDB 10.3.1, returns MYSQL_TYPE_LONG, or
int(10), when the\nresult would fit within
32-bits.\n\nExamples\n--------\n\nSELECT
CONNECTION_ID();\n+-----------------+\n| CONNECTION_ID()
|\n+-----------------+\n| 3 |\n+-----------------+\n\nURL:
https://mariadb.com/kb/en/connection_id/','','https://mariadb.com/kb/en/connection_id/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(196,17,'CURRENT_ROLE','Syntax\n------\n\nCURRENT_ROLE,
CURRENT_ROLE()\n\nDescription\n-----------\n\nReturns the current role
name. This determines your access privileges. The\nreturn value is a string
in the utf8 character set.\n\nIf there is no current role, NULL is
returned.\n\nThe output of SELECT CURRENT_ROLE is equivalent to the
contents of the\nENABLED_ROLES Information Schema table.\n\nUSER() returns
the combination of user and host used to login. CURRENT_USER()\nreturns the
account used to determine current connection\'s
privileges.\n\nExamples\n--------\n\nSELECT
CURRENT_ROLE;\n+--------------+\n| CURRENT_ROLE |\n+--------------+\n| NULL
|\n+--------------+\n\nSET ROLE staff;\n\nSELECT
CURRENT_ROLE;\n+--------------+\n| CURRENT_ROLE |\n+--------------+\n|
staff |\n+--------------+\n\nURL:
https://mariadb.com/kb/en/current_role/','','https://mariadb.com/kb/en/current_role/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(197,17,'CURRENT_USER','Syntax\n------\n\nCURRENT_USER,
CURRENT_USER()\n\nDescription\n-----------\n\nReturns the user name and
host name combination for the MariaDB account that\nthe server used to
authenticate the current client. This account determines\nyour access
privileges. The return value is a string in the utf8 character set.\n\nThe
value of CURRENT_USER() can differ from the value of
USER().\nCURRENT_ROLE() returns the current active
role.\n\nExamples\n--------\n\nshell> mysql
--user=\"anonymous\"\n\nselect
user(),current_user();\n+---------------------+----------------+\n| user()
| current_user() |\n+---------------------+----------------+\n|
anonymous@localhost | @localhost
|\n+---------------------+----------------+\n\nWhen calling CURRENT_USER()
in a stored procedure, it returns the owner of the\nstored procedure, as
defined with DEFINER.\n\nURL:
https://mariadb.com/kb/en/current_user/','','https://mariadb.com/kb/en/current_user/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(198,17,'DATABASE','Syntax\n------\n\nDATABASE()\n\nDescription\n-----------\n\nReturns
the default (current) database name as a string in the utf8 character\nset.
If there is no default database, DATABASE() returns NULL. Within a
stored\nroutine, the default database is the database that the routine is
associated\nwith, which is not necessarily the same as the database that is
the default in\nthe calling context.\n\nSCHEMA() is a synonym for
DATABASE().\n\nTo select a default database, the USE statement can be run.
Another way to set\nthe default database is specifying its name at mysql
command line client\nstartup.\n\nExamples\n--------\n\nSELECT
DATABASE();\n+------------+\n| DATABASE() |\n+------------+\n| NULL
|\n+------------+\n\nUSE test;\nDatabase changed\n\nSELECT
DATABASE();\n+------------+\n| DATABASE() |\n+------------+\n| test
|\n+------------+\n\nURL:
https://mariadb.com/kb/en/database/','','https://mariadb.com/kb/en/database/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(199,17,'DECODE_HISTOGRAM','Syntax\n------\n\nDECODE_HISTOGRAM(hist_type,histogram)\n\nDescription\n-----------\n\nReturns
a string of comma separated numeric values corresponding to a\nprobability
distribution represented by the histogram of type
hist_type\n(SINGLE_PREC_HB or DOUBLE_PREC_HB). The hist_type and histogram
would be\ncommonly used from the mysql.column_stats table.\n\nSee Histogram
Based Statistics for details.\n\nExamples\n--------\n\nCREATE TABLE origin
(\n i INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,\n v INT UNSIGNED
NOT NULL\n);\n\nINSERT INTO origin(v) VALUES \n
(1),(2),(3),(4),(5),(10),(20),\n (30),(40),(50),(60),(70),(80),\n
(90),(100),(200),(400),(800);\n\nSET
histogram_size=10,histogram_type=SINGLE_PREC_HB;\n\nANALYZE TABLE origin
PERSISTENT FOR
ALL;\n+-------------+---------+----------+-----------------------------------------+\n|
Table | Op | Msg_type | Msg_text
|\n+-------------+---------+----------+-----------------------------------------+\n|
test.origin | analyze | status | Engine-independent statistics collected
|\n| test.origin | analyze | status | OK
|\n+-------------+---------+----------+-----------------------------------------+\n\nSELECT
db_name,table_name,column_name,hist_type,\n
hex(histogram),decode_histogram(hist_type,histogram)\n FROM
mysql.column_stats WHERE db_name=\'test\' and
table_name=\'origin\';\n+---------+------------+-------------+----------------+----------------------+-\n-----------------------------------------------------------------+\n|
db_name | table_name | column_name | hist_type | hex(histogram)
|\ndecode_histogram(hist_type,histogram)
|\n+---------+------------+-------------+----------------+----------------------+-\n-----------------------------------------------------------------+\n|
test | origin | i | SINGLE_PREC_HB | 0F2D3C5A7887A5C3D2F0
|\n0.059,0.118,0.059,0.118,0.118,0.059,0.118,0.118,0.059,0.118,0.059 |\n|
test | origin | v | SINGLE_PREC_HB | 000001060C0F161C1F7F
|\n0.000,0.000,0.004,0.020,0.024,0.012,0.027,0.024,0.012,0.376,0.502
|\n+---------+------------+-------------+----------------+----------------------+-\n-----------------------------------------------------------------+\n\nSET
histogram_size=20,histogram_type=DOUBLE_PREC_HB;\n\nANALYZE TABLE origin
PERSISTENT FOR
ALL;\n+-------------+---------+----------+-----------------------------------------+\n|
Table | Op | Msg_type | Msg_text
|\n+-------------+---------+----------+-----------------------------------------+\n|
test.origin | analyze | status | Engine-independent statistics collected
|\n| test.origin | analyze | status | OK
|\n+-------------+---------+----------+-----------------------------------------+\n\nSELECT
db_name,table_name,column_name,\n
hist_type,hex(histogram),decode_histogram(hist_type,histogram)\n FROM
mysql.column_stats WHERE db_name=\'test\' and
table_name=\'origin\';\n+---------+------------+-------------+----------------+------------------------\n-----------------+-------------------------------------------------------------\n---------------------------+\n|
db_name | table_name | column_name | hist_type | hex(histogram)
\n | decode_histogram(hist_type,histogram)\n
|\n+---------+------------+-------------+----------------+------------------------\n-----------------+-------------------------------------------------------------\n---------------------------+\n|
test | origin | i | DOUBLE_PREC_HB
|\n0F0F2D2D3C3C5A5A78788787A5A5C3C3D2D2F0F0
|\n0.05882,0.11765,0.05882,0.11765,0.11765,0.05882,0.11765,0.11765,0.05882,0.11765\n0.05882
|\n| test | origin | v | DOUBLE_PREC_HB
|\n5200F600480116067E0CB30F1B16831CB81FD67F
|\n0.00125,0.00250,0.00125,0.01877,0.02502,0.01253,0.02502,0.02502,0.01253,0.37546\n0.50063
|\n\nURL:
https://mariadb.com/kb/en/decode_histogram/','','https://mariadb.com/kb/en/decode_histogram/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(200,17,'DEFAULT','Syntax\n------\n\nDEFAULT(col_name)\n\nDescription\n-----------\n\nReturns
the default value for a table column. If the column has no default\nvalue
(and is not NULLABLE - NULLABLE fields have a NULL default), an error
is\nreturned.\n\nFor integer columns using AUTO_INCREMENT, 0 is
returned.\n\nWhen using DEFAULT as a value to set in an INSERT or UPDATE
statement, you can\nuse the bare keyword DEFAULT without the parentheses
and argument to refer to\nthe column in context. You can only use DEFAULT
as a bare keyword if you are\nusing it alone without a surrounding
expression or function.\n\nExamples\n--------\n\nSelect only non-default
values for a column:\n\nSELECT i FROM t WHERE i != DEFAULT(i);\n\nUpdate
values to be one greater than the default value:\n\nUPDATE t SET i =
DEFAULT(i)+1 WHERE i < 100;\n\nWhen referring to the default value
exactly in UPDATE or INSERT, you can omit\nthe argument:\n\nINSERT INTO t
(i) VALUES (DEFAULT);\nUPDATE t SET i = DEFAULT WHERE i < 100;\n\nCREATE
OR REPLACE TABLE t (\n i INT NOT NULL AUTO_INCREMENT,\n j INT NOT NULL,\n k
INT DEFAULT 3,\n l INT NOT NULL DEFAULT 4,\n m INT,\n PRIMARY KEY
(i)\n);\n\nDESC
t;\n+-------+---------+------+-----+---------+----------------+\n| Field |
Type | Null | Key | Default | Extra
|\n+-------+---------+------+-----+---------+----------------+\n| i |
int(11) | NO | PRI | NULL | auto_increment |\n| j | int(11) | NO
| | NULL | |\n| k | int(11) | YES | | 3
| |\n| l | int(11) | NO | | 4 |
|\n| m | int(11) | YES | | NULL |
|\n+-------+---------+------+-----+---------+----------------+\n\nINSERT
INTO t (j) VALUES (1);\nINSERT INTO t (j,m) VALUES (2,2);\nINSERT INTO t
(j,l,m) VALUES (3,3,3);\n\nSELECT * FROM t;\n+---+---+------+---+------+\n|
i | j | k | l | m |\n+---+---+------+---+------+\n| 1 | 1 | 3 | 4
| NULL |\n| 2 | 2 | 3 | 4 | 2 |\n| 3 | 3 | 3 | 3 | 3
|\n+---+---+------+---+------+\n\nSELECT DEFAULT(i), DEFAULT(k), DEFAULT
(l), DEFAULT(m) FROM
t;\n+------------+------------+-------------+------------+\n| DEFAULT(i) |
DEFAULT(k) | DEFAULT (l) | DEFAULT(m)
|\n+------------+------------+-------------+------------+\n| 0 |
3 | 4 | NULL |\n| 0 | 3 |
4 | NULL |\n| 0 | 3 | 4 | NULL
|\n+------------+------------+-------------+------------+\n\nSELECT
DEFAULT(i), DEFAULT(k), DEFAULT (l), DEFAULT(m), DEFAULT(j) FROM t;\nERROR
1364 (HY000): Field \'j\' doesn\'t have a default
value\n\nSELECT * FROM t WHERE i = DEFAULT(i);\nEmpty set (0.001
sec)\n\nSELECT * FROM t WHERE j = DEFAULT(j);\nERROR 1364 (HY000): Field
\'j\' doesn\'t have a default value\n\nSELECT * FROM t WHERE
k = DEFAULT(k);\n+---+---+------+---+------+\n| i | j | k | l | m
|\n+---+---+------+---+------+\n| 1 | 1 | 3 | 4 | NULL |\n| 2 | 2 | 3
| 4 | 2 |\n| 3 | 3 | 3 | 3 | 3
|\n+---+---+------+---+------+\n\nSELECT * FROM t WHERE l =
DEFAULT(l);\n+---+---+------+---+------+\n| i | j | k | l | m
|\n+---+---+------+---+------+\n| 1 | 1 | 3 | 4 | NULL |\n| 2 | 2 | 3
| 4 | 2 |\n+---+---+------+---+------+\n\nSELECT * FROM t WHERE m =
DEFAULT(m);\nEmpty set (0.001 sec)\n\nSELECT * FROM t WHERE m <=>
DEFAULT(m);\n+---+---+------+---+------+\n| i | j | k | l | m
|\n+---+---+------+---+------+\n| 1 | 1 | 3 | 4 | NULL
|\n+---+---+------+---+------+\n\nURL:
https://mariadb.com/kb/en/default/','','https://mariadb.com/kb/en/default/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(201,17,'FOUND_ROWS','Syntax\n------\n\nFOUND_ROWS()\n\nDescription\n-----------\n\nA
SELECT statement may include a LIMIT clause to restrict the number of
rows\nthe server returns to the client. In some cases, it is desirable to
know how\nmany rows the statement would have returned without the LIMIT,
but without\nrunning the statement again. To obtain this row count, include
a\nSQL_CALC_FOUND_ROWS option in the SELECT statement, and then
invoke\nFOUND_ROWS() afterwards.\n\nYou can also use FOUND_ROWS() to obtain
the number of rows returned by a\nSELECT which does not contain a LIMIT
clause. In this case you don\'t need to\nuse the SQL_CALC_FOUND_ROWS
option. This can be useful for example in a stored\nprocedure.\n\nAlso,
this function works with some other statements which return a
resultset,\nincluding SHOW, DESC and HELP. For DELETE ... RETURNING you
should use\nROW_COUNT(). It also works as a prepared statement, or after
executing a\nprepared statement.\n\nStatements which don\'t return any
results don\'t affect FOUND_ROWS() - the\nprevious value will still be
returned.\n\nWarning: When used after a CALL statement, this function
returns the number of\nrows selected by the last query in the procedure,
not by the whole procedure.\n\nStatements using the FOUND_ROWS() function
are not safe for replication.\n\nExamples\n--------\n\nSHOW
ENGINES\\G\n*************************** 1. row
***************************\n Engine: CSV\n Support: YES\n Comment:
Stores tables as CSV files\nTransactions: NO\n XA: NO\n Savepoints:
NO\n*************************** 2. row ***************************\n
Engine: MRG_MyISAM\n Support: YES\n Comment: Collection of identical
MyISAM tables\nTransactions: NO\n XA: NO\n Savepoints:
NO\n\n...\n\n*************************** 8. row
***************************\n Engine: PERFORMANCE_SCHEMA\n Support:
YES\n Comment: Performance Schema\nTransactions: NO\n XA: NO\n
Savepoints: NO\n8 rows in set (0.000 sec)\n\nSELECT
FOUND_ROWS();\n+--------------+\n| FOUND_ROWS() |\n+--------------+\n|
8 |\n+--------------+\n\nSELECT SQL_CALC_FOUND_ROWS * FROM tbl_name
WHERE id > 100 LIMIT 10;\n\nSELECT FOUND_ROWS();\n+--------------+\n|
FOUND_ROWS() |\n+--------------+\n| 23
|\n+--------------+\n\nURL:
https://mariadb.com/kb/en/found_rows/','','https://mariadb.com/kb/en/found_rows/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(202,17,'LAST_INSERT_ID','Syntax\n------\n\nLAST_INSERT_ID(),
LAST_INSERT_ID(expr)\n\nDescription\n-----------\n\nLAST_INSERT_ID() (no
arguments) returns the first automatically generated\nvalue successfully
inserted for an AUTO_INCREMENT column as a result of the\nmost recently
executed INSERT statement. The value of LAST_INSERT_ID() remains\nunchanged
if no rows are successfully inserted.\n\nIf one gives an argument to
LAST_INSERT_ID(), then it will return the value of\nthe expression and the
next call to LAST_INSERT_ID() will return the same\nvalue. The value will
also be sent to the client and can be accessed by the\nmysql_insert_id
function.\n\nFor example, after inserting a row that generates an
AUTO_INCREMENT value, you\ncan get the value like this:\n\nSELECT
LAST_INSERT_ID();\n+------------------+\n| LAST_INSERT_ID()
|\n+------------------+\n| 9 |\n+------------------+\n\nYou
can also use LAST_INSERT_ID() to delete the last inserted row:\n\nDELETE
FROM product WHERE id = LAST_INSERT_ID();\n\nIf no rows were successfully
inserted, LAST_INSERT_ID() returns 0.\n\nThe value of LAST_INSERT_ID() will
be consistent across all versions if all\nrows in the INSERT or UPDATE
statement were successful.\n\nThe currently executing statement does not
affect the value of\nLAST_INSERT_ID(). Suppose that you generate an
AUTO_INCREMENT value with one\nstatement, and then refer to
LAST_INSERT_ID() in a multiple-row INSERT\nstatement that inserts rows into
a table with its own AUTO_INCREMENT column.\nThe value of LAST_INSERT_ID()
will remain stable in the second statement; its\nvalue for the second and
later rows is not affected by the earlier row\ninsertions. (However, if you
mix references to LAST_INSERT_ID() and\nLAST_INSERT_ID(expr), the effect is
undefined.)\n\nIf the previous statement returned an error, the value of
LAST_INSERT_ID() is\nundefined. For transactional tables, if the statement
is rolled back due to an\nerror, the value of LAST_INSERT_ID() is left
undefined. For manual ROLLBACK,\nthe value of LAST_INSERT_ID() is not
restored to that before the transaction;\nit remains as it was at the point
of the ROLLBACK.\n\nWithin the body of a stored routine (procedure or
function) or a trigger, the\nvalue of LAST_INSERT_ID() changes the same way
as for statements executed\noutside the body of these kinds of objects. The
effect of a stored routine or\ntrigger upon the value of LAST_INSERT_ID()
that is seen by following\nstatements depends on the kind of routine:\n\n*
If a stored procedure executes statements that change the value
of\nLAST_INSERT_ID(), the new value will be seen by statements that follow
the\nprocedure call.\n\n* For stored functions and triggers that change the
value, the value is\nrestored when the function or trigger ends, so
following statements will not\nsee a changed
value.\n\nExamples\n--------\n\nCREATE TABLE t (\n id INTEGER UNSIGNED
AUTO_INCREMENT PRIMARY KEY,\n f VARCHAR(1))\nENGINE = InnoDB;\n\nINSERT
INTO t(f) VALUES(\'a\');\n\nSELECT
LAST_INSERT_ID();\n+------------------+\n| LAST_INSERT_ID()
|\n+------------------+\n| 1
|\n+------------------+\n\nINSERT INTO t(f)
VALUES(\'b\');\n\nINSERT INTO t(f)
VALUES(\'c\');\n\nSELECT
LAST_INSERT_ID();\n+------------------+\n| LAST_INSERT_ID()
|\n+------------------+\n| 3
|\n+------------------+\n\nINSERT INTO t(f)
VALUES(\'d\'),(\'e\');\n\nSELECT
LAST_INSERT_ID();\n+------------------+\n| LAST_INSERT_ID()
|\n+------------------+\n| 4
|\n+------------------+\n\nSELECT * FROM t;\n+----+------+\n| id | f
|\n+----+------+\n| 1 | a |\n| 2 | b |\n| 3 | c |\n| 4 | d
|\n| 5 | e |\n+----+------+\n\nSELECT
LAST_INSERT_ID(12);\n+--------------------+\n| LAST_INSERT_ID(12)
|\n+--------------------+\n| 12
|\n+--------------------+\n\nSELECT
LAST_INSERT_ID();\n+------------------+\n| LAST_INSERT_ID()
|\n+------------------+\n| 12
|\n+------------------+\n\nINSERT INTO t(f)
VALUES(\'f\');\n\nSELECT
LAST_INSERT_ID();\n+------------------+\n| LAST_INSERT_ID()
|\n+------------------+\n| 6
|\n+------------------+\n\nSELECT * FROM t;\n+----+------+\n| id | f
|\n+----+------+\n| 1 | a |\n| 2 | b |\n| 3 | c |\n| 4 | d
|\n| 5 | e |\n| 6 | f |\n+----+------+\n\nSELECT
LAST_INSERT_ID(12);\n+--------------------+\n| LAST_INSERT_ID(12)
|\n+--------------------+\n| 12
|\n+--------------------+\n\nINSERT INTO t(f)
VALUES(\'g\');\n\nSELECT * FROM t;\n+----+------+\n| id | f
|\n+----+------+\n| 1 | a |\n| 2 | b |\n| 3 | c |\n| 4 | d
|\n| 5 | e |\n| 6 | f |\n| 7 | g |\n+----+------+\n\nURL:
https://mariadb.com/kb/en/last_insert_id/','','https://mariadb.com/kb/en/last_insert_id/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(203,17,'LAST_VALUE','Syntax\n------\n\nLAST_VALUE(expr,[expr,...])\n\nLAST_VALUE(expr)
OVER (\n [ PARTITION BY partition_expression ]\n [ ORDER BY order_list
]\n)\n\nDescription\n-----------\n\nLAST_VALUE() evaluates all expressions
and returns the last.\n\nThis is useful together with setting user
variables to a value with\n@var:=expr, for example when you want to get
data of rows updated/deleted\nwithout having to do two queries against the
table.\n\nLAST_VALUE can be used as a window function.\n\nReturns NULL if
no last value exists.\n\nExamples\n--------\n\nCREATE TABLE t1 (a int, b
int);\nINSERT INTO t1 VALUES(1,10),(2,20);\nDELETE FROM t1 WHERE a=1 AND
last_value(@a:=a,@b:=b,1);\nSELECT @a,@b;\n+------+------+\n| @a | @b
|\n+------+------+\n| 1 | 10 |\n+------+------+\n\nAs a window
function:\n\nCREATE TABLE t1 (\n pk int primary key,\n a int,\n b int,\n c
char(10),\n d decimal(10, 3),\n e real\n);\n\nINSERT INTO t1 VALUES\n( 1,
0, 1, \'one\', 0.1, 0.001),\n( 2, 0, 2,
\'two\', 0.2, 0.002),\n( 3, 0, 3, \'three\',
0.3, 0.003),\n( 4, 1, 2, \'three\', 0.4, 0.004),\n( 5, 1,
1, \'two\', 0.5, 0.005),\n( 6, 1, 1, \'one\',
0.6, 0.006),\n( 7, 2, NULL, \'n_one\', 0.5, 0.007),\n( 8,
2, 1, \'n_two\', NULL, 0.008),\n( 9, 2, 2, NULL, 0.7,
0.009),\n(10, 2, 0, \'n_four\', 0.8, 0.010),\n(11, 2, 10,
NULL, 0.9, NULL);\n\nSELECT pk, FIRST_VALUE(pk) OVER (ORDER BY pk) AS
first_asc,\n LAST_VALUE(pk) OVER (ORDER BY pk) AS last_asc,\n
FIRST_VALUE(pk) OVER (ORDER BY pk DESC) AS first_desc,\n LAST_VALUE(pk)
OVER (ORDER BY pk DESC) AS last_desc\nFROM t1\nORDER BY pk
DESC;\n\n+----+-----------+----------+------------+-----------+\n| pk |
first_asc | last_asc | first_desc | last_desc
|\n+----+-----------+----------+------------+-----------+\n| 11 | 1
| 11 | 11 | 11 |\n| 10 | 1 | 10 |
11 | 10 |\n| 9 | 1 | 9 | 11 | 9
|\n| 8 | 1 | 8 | 11 | 8 |\n| 7 | 1
| 7 | 11 | 7 |\n| 6 | 1 | 6 |
11 | 6 |\n| 5 | 1 | 5 | 11 | 5
|\n| 4 | 1 | 4 | 11 | 4 |\n| 3 | 1
| 3 | 11 | 3 |\n| 2 | 1 | 2 |
11 | 2 |\n| 1 | 1 | 1 | 11 | 1
|\n+----+-----------+----------+------------+-----------+\n\nCREATE OR
REPLACE TABLE t1 (i int);\nINSERT INTO t1 VALUES
(1),(2),(3),(4),(5),(6),(7),(8),(9),(10);\n\nSELECT i,\n FIRST_VALUE(i)
OVER (ORDER BY i ROWS BETWEEN CURRENT ROW and 1 FOLLOWING) AS\nf_1f,\n
LAST_VALUE(i) OVER (ORDER BY i ROWS BETWEEN CURRENT ROW and 1 FOLLOWING)
AS\nl_1f,\n FIRST_VALUE(i) OVER (ORDER BY i ROWS BETWEEN 1 PRECEDING AND 1
FOLLOWING) AS\nf_1p1f,\n LAST_VALUE(i) OVER (ORDER BY i ROWS BETWEEN 1
PRECEDING AND 1 FOLLOWING) AS\nf_1p1f,\n FIRST_VALUE(i) OVER (ORDER BY i
ROWS BETWEEN 2 PRECEDING AND 1 PRECEDING) AS\nf_2p1p,\n LAST_VALUE(i) OVER
(ORDER BY i ROWS BETWEEN 2 PRECEDING AND 1 PRECEDING) AS\nf_2p1p,\n
FIRST_VALUE(i) OVER (ORDER BY i ROWS BETWEEN 1 FOLLOWING AND 2 FOLLOWING)
AS\nf_1f2f,\n LAST_VALUE(i) OVER (ORDER BY i ROWS BETWEEN 1 FOLLOWING AND 2
FOLLOWING) AS\nf_1f2f\nFROM
t1;\n\n+------+------+------+--------+--------+--------+--------+--------+--------+\n|
i | f_1f | l_1f | f_1p1f | f_1p1f | f_2p1p | f_2p1p | f_1f2f | f_1f2f
|\n+------+------+------+--------+--------+--------+--------+--------+--------+\n|
1 | 1 | 2 | 1 | 2 | NULL | NULL | 2 | 3
|\n| 2 | 2 | 3 | 1 | 3 | 1 | 1 | 3 |
4 |\n| 3 | 3 | 4 | 2 | 4 | 1 | 2 | 4 |
5 |\n| 4 | 4 | 5 | 3 | 5 | 2 | 3 | 5 |
6 |\n| 5 | 5 | 6 | 4 | 6 | 3 | 4 | 6
| 7 |\n| 6 | 6 | 7 | 5 | 7 | 4 | 5 |
7 | 8 |\n| 7 | 7 | 8 | 6 | 8 | 5 | 6 |
8 | 9 |\n| 8 | 8 | 9 | 7 | 9 | 6 | 7 |
9 | 10 |\n| 9 | 9 | 10 | 8 | 10 | 7 | 8
| 10 | 10 |\n| 10 | 10 | 10 | 9 | 10 | 8 |
9 | NULL | NULL
|\n+------+------+------+--------+--------+--------+--------+--------+--------+\n\nURL:
https://mariadb.com/kb/en/last_value/','','https://mariadb.com/kb/en/last_value/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(204,17,'PROCEDURE
ANALYSE','Syntax\n------\n\nanalyse([max_elements[,max_memory]])\n\nDescription\n-----------\n\nThis
procedure is defined in the sql/sql_analyse.cc file. It examines
the\nresult from a query and returns an analysis of the results that
suggests\noptimal data types for each column. To obtain this analysis,
append PROCEDURE\nANALYSE to the end of a SELECT statement:\n\nSELECT ...
FROM ... WHERE ... PROCEDURE ANALYSE([max_elements,[max_memory]])\n\nFor
example:\n\nSELECT col1, col2 FROM table1 PROCEDURE ANALYSE(10,
2000);\n\nThe results show some statistics for the values returned by the
query, and\npropose an optimal data type for the columns. This can be
helpful for checking\nyour existing tables, or after importing new data.
You may need to try\ndifferent settings for the arguments so that PROCEDURE
ANALYSE() does not\nsuggest the ENUM data type when it is not
appropriate.\n\nThe arguments are optional and are used as follows:\n\n*
max_elements (default 256) is the maximum number of distinct values
that\nanalyse notices per column. This is used by analyse to check whether
the\noptimal data type should be of type ENUM; if there are more than
max_elements\ndistinct values, then ENUM is not a suggested type.\n*
max_memory (default 8192) is the maximum amount of memory that
analyse\nshould allocate per column while trying to find all distinct
values.\n\nURL:
https://mariadb.com/kb/en/procedure-analyse/','','https://mariadb.com/kb/en/procedure-analyse/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(205,17,'ROWNUM','MariaDB starting with
10.6.1\n----------------------------\nFrom MariaDB 10.6.1, the ROWNUM()
function is supported.\n\nSyntax\n------\n\nROWNUM()\n\nIn Oracle mode one
can just use ROWNUM, without the
parentheses.\n\nDescription\n-----------\n\nROWNUM() returns the current
number of accepted rows in the current context.\nIt main purpose is to
emulate the ROWNUM pseudo column in Oracle. For MariaDB\nnative
applications, we recommend the usage of LIMIT, as it is easier to use\nand
gives more predictable results than the usage of ROWNUM().\n\nThe main
difference between using LIMIT and ROWNUM() to limit the rows in
the\nresult is that LIMIT works on the result set while ROWNUM works on the
number\nof accepted rows (before any ORDER or GROUP BY clauses).\n\nThe
following queries will return the same results:\n\nSELECT * from t1 LIMIT
10;\nSELECT * from t1 WHERE ROWNUM() <= 10;\n\nWhile the following may
return different results based on in which orders the\nrows are
found:\n\nSELECT * from t1 ORDER BY a LIMIT 10;\nSELECT * from t1 ORDER BY
a WHERE ROWNUM() <= 10;\n\nThe recommended way to use ROWNUM to limit
the number of returned rows and get\npredictable results is to have the
query in a subquery and test for ROWNUM()\nin the outer query:\n\nSELECT *
FROM (select * from t1 ORDER BY a) WHERE ROWNUM() <= 10;\n\nROWNUM() can
be used in the following contexts:\n\n* SELECT\n* INSERT\n* UPDATE\n*
DELETE\n* LOAD DATA INFILE\n\nUsed in other contexts, ROWNUM() will return
0.\n\nExamples\n--------\n\nINSERT INTO t1 VALUES
(1,ROWNUM()),(2,ROWNUM()),(3,ROWNUM());\n\nINSERT INTO t1 VALUES (1),(2)
returning a, ROWNUM();\n\nUPDATE t1 SET row_num_column=ROWNUM();\n\nDELETE
FROM t1 WHERE a < 10 AND ROWNUM() < 2;\n\nLOAD DATA INFILE
\'filename\' into table t1 fields terminated by \',\'
\n lines terminated by \"\\r\\n\" (a,b) set
c=ROWNUM();\n\nOptimizations\n-------------\n\nIn many cases where ROWNUM()
is used, MariaDB will use the same optimizations\nit uses with
LIMIT.\n\nLIMIT optimization is possible when using ROWNUM in the following
manner:\n\n* When one is in a top level WHERE clause comparing ROWNUM()
with a numerical\nconstant using any of the following
expressions:\nROWNUM() < number\nROWNUM() <= number\nROWNUM() =
1\nROWNUM() can be also be the right argument to the comparison
function.\n\nIn the above cases, LIMIT optimization can be done in the
following cases:\n\n* For the current sub query when the ROWNUM comparison
is done on the top\nlevel:\n\nSELECT * from t1 WHERE ROWNUM() <= 2 AND
t1.a > 0\n\n* For an inner sub query, when the upper level has only a
ROWNUM() comparison\nin the WHERE clause:\n\nSELECT * from (select * from
t1) as t WHERE ROWNUM() <= 2\n\nOther Changes Related to
ROWNUM\n-------------------------------\n\nWhen ROWNUM() is used anywhere
in a query, the optimization to ignore ORDER BY\nin subqueries are
disabled.\n\nThis was done to get the following common Oracle query to work
as expected:\n\nselect * from (select * from t1 order by a desc) as t where
rownum() <= 2;\n\nBy default MariaDB ignores any ORDER BY in subqueries
both because the SQL\nstandard defines results sets in subqueries to be
un-ordered and because of\nperformance reasons (especially when using views
in subqueries). See MDEV-3926\n\"Wrong result with GROUP BY ... WITH
ROLLUP\" for a discussion of this topic.\n\nOther
Considerations\n--------------------\n\nWhile MariaDB tries to emulate
Oracle\'s usage of ROWNUM() as closely as\npossible, there are cases
where the result is different:\n\n* When the optimizer finds rows in a
different order (because of different\nstorage methods or optimization).
This may also happen in Oracle if one adds\nor deletes an index, in which
case the rows may be found in a different order.\n\nNote that usage of
ROWNUM() in functions or stored procedures will use their\nown context, not
the caller\'s context.\n\nURL:
https://mariadb.com/kb/en/rownum/','','https://mariadb.com/kb/en/rownum/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(206,17,'ROW_COUNT','Syntax\n------\n\nROW_COUNT()\n\nDescription\n-----------\n\nROW_COUNT()
returns the number of rows updated, inserted or deleted by the\npreceding
statement. This is the same as the row count that the mysql
client\ndisplays and the value from the mysql_affected_rows() C API
function.\n\nGenerally:\n\n* For statements which return a result set (such
as SELECT, SHOW, DESC or\nHELP), returns -1, even when the result set is
empty. This is also true for\nadministrative statements, such as
OPTIMIZE.\n* For DML statements other than SELECT and for ALTER TABLE,
returns the number\nof affected rows.\n* For DDL statements (including
TRUNCATE) and for other statements which don\'t\nreturn any result set
(such as USE, DO, SIGNAL or DEALLOCATE PREPARE), returns\n0.\n\nFor UPDATE,
affected rows is by default the number of rows that were actually\nchanged.
If the CLIENT_FOUND_ROWS flag to mysql_real_connect() is specified\nwhen
connecting to mysqld, affected rows is instead the number of rows
matched\nby the WHERE clause.\n\nFor REPLACE, deleted rows are also
counted. So, if REPLACE deletes a row and\nadds a new row, ROW_COUNT()
returns 2.\n\nFor INSERT ... ON DUPLICATE KEY, updated rows are counted
twice. So, if INSERT\nadds a new rows and modifies another row, ROW_COUNT()
returns 3.\n\nROW_COUNT() does not take into account rows that are not
directly\ndeleted/updated by the last statement. This means that rows
deleted by foreign\nkeys or triggers are not counted.\n\nWarning: You can
use ROW_COUNT() with prepared statements, but you need to\ncall it after
EXECUTE, not after DEALLOCATE PREPARE, because the row count for\nallocate
prepare is always 0.\n\nWarning: When used after a CALL statement, this
function returns the number of\nrows affected by the last statement in the
procedure, not by the whole\nprocedure.\n\nWarning: After INSERT DELAYED,
ROW_COUNT() returns the number of the rows you\ntried to insert, not the
number of the successful writes.\n\nThis information can also be found in
the diagnostics area.\n\nStatements using the ROW_COUNT() function are not
safe for replication.\n\nExamples\n--------\n\nCREATE TABLE t (A
INT);\n\nINSERT INTO t VALUES(1),(2),(3);\n\nSELECT
ROW_COUNT();\n+-------------+\n| ROW_COUNT() |\n+-------------+\n|
3 |\n+-------------+\n\nDELETE FROM t WHERE A IN(1,2);\n\nSELECT
ROW_COUNT(); \n+-------------+\n| ROW_COUNT() |\n+-------------+\n|
2 |\n+-------------+\n\nExample with prepared statements:\n\nSET @q =
\'INSERT INTO t VALUES(1),(2),(3);\';\n\nPREPARE stmt FROM
@q;\n\nEXECUTE stmt;\nQuery OK, 3 rows affected (0.39 sec)\nRecords: 3
Duplicates: 0 Warnings: 0\n\nSELECT ROW_COUNT();\n+-------------+\n|
ROW_COUNT() |\n+-------------+\n| 3 |\n+-------------+\n\nURL:
https://mariadb.com/kb/en/row_count/','','https://mariadb.com/kb/en/row_count/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(207,17,'SCHEMA','Syntax\n------\n\nSCHEMA()\n\nDescription\n-----------\n\nThis
function is a synonym for DATABASE().\n\nURL:
https://mariadb.com/kb/en/schema/','','https://mariadb.com/kb/en/schema/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(208,17,'SESSION_USER','Syntax\n------\n\nSESSION_USER()\n\nDescription\n-----------\n\nSESSION_USER()
is a synonym for USER().\n\nURL:
https://mariadb.com/kb/en/session_user/','','https://mariadb.com/kb/en/session_user/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(209,17,'SYSTEM_USER','Syntax\n------\n\nSYSTEM_USER()\n\nDescription\n-----------\n\nSYSTEM_USER()
is a synonym for USER().\n\nURL:
https://mariadb.com/kb/en/system_user/','','https://mariadb.com/kb/en/system_user/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(210,17,'USER','Syntax\n------\n\nUSER()\n\nDescription\n-----------\n\nReturns
the current MariaDB user name and host name, given when authenticating\nto
MariaDB, as a string in the utf8 character set.\n\nNote that the value of
USER() may differ from the value of CURRENT_USER(),\nwhich is the user used
to authenticate the current client. CURRENT_ROLE()\nreturns the current
active role.\n\nSYSTEM_USER() and SESSION_USER are synonyms for
USER().\n\nStatements using the USER() function or one of its synonyms are
not safe for\nstatement level
replication.\n\nExamples\n--------\n\nshell> mysql
--user=\"anonymous\"\n\nSELECT
USER(),CURRENT_USER();\n+---------------------+----------------+\n| USER()
| CURRENT_USER() |\n+---------------------+----------------+\n|
anonymous@localhost | @localhost
|\n+---------------------+----------------+\n\nTo select only the IP
address, use SUBSTRING_INDEX(),\n\nSELECT SUBSTRING_INDEX(USER(),
\'@\', -1);\n+----------------------------------+\n|
SUBSTRING_INDEX(USER(), \'@\', -1)
|\n+----------------------------------+\n| 192.168.0.101
|\n+----------------------------------+\n\nURL:
https://mariadb.com/kb/en/user/','','https://mariadb.com/kb/en/user/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(211,17,'VERSION','Syntax\n------\n\nVERSION()\n\nDescription\n-----------\n\nReturns
a string that indicates the MariaDB server version. The string uses\nthe
utf8 character set.\n\nExamples\n--------\n\nSELECT
VERSION();\n+----------------+\n| VERSION() |\n+----------------+\n|
10.4.7-MariaDB |\n+----------------+\n\nThe VERSION() string may have one
or more of the following
suffixes:\n\n+---------------------------+------------------------------------------------+\n|
Suffix | Description
|\n+---------------------------+------------------------------------------------+\n|
-embedded | The server is an embedded server (libmysqld).
|\n+---------------------------+------------------------------------------------+\n|
-log | General logging, slow logging or binary
|\n| | (replication) logging is enabled.
|\n+---------------------------+------------------------------------------------+\n|
-debug | The server is compiled for debugging.
|\n+---------------------------+------------------------------------------------+\n|
-valgrind | The server is compiled to be instrumented
|\n| | with valgrind.
|\n+---------------------------+------------------------------------------------+\n\nChanging
the Version String\n---------------------------\n\nSome old legacy code may
break because they are parsing the VERSION string and\nexpecting a MySQL
string or a simple version string like Joomla til API17,
see\nMDEV-7780.\n\nFrom MariaDB 10.2, one can fool these applications by
setting the version\nstring from the command line or the my.cnf files with
--version=....\n\nURL:
https://mariadb.com/kb/en/version/','','https://mariadb.com/kb/en/version/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(212,18,'Assignment Operator
(:=)','Syntax\n------\n\nvar_name :=
expr\n\nDescription\n-----------\n\nAssignment operator for assigning a
value. The value on the right is assigned\nto the variable on
left.\n\nUnlike the = operator, := can always be used to assign a value to
a variable.\n\nThis operator works with both user-defined variables and
local variables.\n\nWhen assigning the same value to several variables,
LAST_VALUE() can be useful.\n\nExamples\n--------\n\nSELECT @x :=
10;\n+----------+\n| @x := 10 |\n+----------+\n| 10
|\n+----------+\n\nSELECT @x, @y := @x;\n+------+----------+\n| @x | @y
:= @x |\n+------+----------+\n| 10 | 10
|\n+------+----------+\n\nURL:
https://mariadb.com/kb/en/assignment-operator/','','https://mariadb.com/kb/en/assignment-operator/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(213,18,'Assignment Operator
(=)','Syntax\n------\n\nidentifier =
expr\n\nDescription\n-----------\n\nThe equal sign is used as both an
assignment operator in certain contexts, and\nas a comparison operator.
When used as assignment operator, the value on the\nright is assigned to
the variable (or column, in some contexts) on the left.\n\nSince its use
can be ambiguous, unlike the := assignment operator, the =\nassignment
operator cannot be used in all contexts, and is only valid as part\nof a
SET statement, or the SET clause of an UPDATE statement\n\nThis operator
works with both user-defined variables and local
variables.\n\nExamples\n--------\n\nUPDATE table_name SET x = 2 WHERE x
> 100;\n\nSET @x = 1, @y := 2;\n\nURL:
https://mariadb.com/kb/en/assignment-operators-assignment-operator/','','https://mariadb.com/kb/en/assignment-operators-assignment-operator/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(214,19,'Not Equal Operator','Syntax\n------\n\n<>,
!=\n\nDescription\n-----------\n\nNot equal operator. Evaluates both SQL
expressions and returns 1 if they are\nnot equal and 0 if they are equal,
or NULL if either expression is NULL. If\nthe expressions return different
data types, (for instance, a number and a\nstring), performs type
conversion.\n\nWhen used in row comparisons these two queries return the
same results:\n\nSELECT (t1.a, t1.b) != (t2.x, t2.y) \nFROM t1 INNER JOIN
t2;\n\nSELECT (t1.a != t2.x) OR (t1.b != t2.y)\nFROM t1 INNER JOIN
t2;\n\nExamples\n--------\n\nSELECT \'.01\' <>
\'0.01\';\n+-----------------+\n| \'.01\' <>
\'0.01\' |\n+-----------------+\n| 1
|\n+-----------------+\n\nSELECT .01 <>
\'0.01\';\n+---------------+\n| .01 <> \'0.01\'
|\n+---------------+\n| 0 |\n+---------------+\n\nSELECT
\'zapp\' <> \'zappp\';\n+-------------------+\n|
\'zapp\' <> \'zappp\' |\n+-------------------+\n|
1 |\n+-------------------+\n\nURL:
https://mariadb.com/kb/en/not-equal/','','https://mariadb.com/kb/en/not-equal/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(215,19,'<','Syntax\n------\n\n<\n\nDescription\n-----------\n\nLess
than operator. Evaluates both SQL expressions and returns 1 if the
left\nvalue is less than the right value and 0 if it is not, or NULL if
either\nexpression is NULL. If the expressions return different data types,
(for\ninstance, a number and a string), performs type conversion.\n\nWhen
used in row comparisons these two queries return the same
results:\n\nSELECT (t1.a, t1.b) < (t2.x, t2.y) \nFROM t1 INNER JOIN
t2;\n\nSELECT (t1.a < t2.x) OR ((t1.a = t2.x) AND (t1.b <
t2.y))\nFROM t1 INNER JOIN t2;\n\nExamples\n--------\n\nSELECT 2 <
2;\n+-------+\n| 2 < 2 |\n+-------+\n| 0 |\n+-------+\n\nType
conversion:\n\nSELECT 3<\'4\';\n+-------+\n|
3<\'4\' |\n+-------+\n| 1 |\n+-------+\n\nCase
insensitivity - see Character Sets and Collations:\n\nSELECT
\'a\'<\'A\';\n+---------+\n|
\'a\'<\'A\' |\n+---------+\n| 0
|\n+---------+\n\nURL:
https://mariadb.com/kb/en/less-than/','','https://mariadb.com/kb/en/less-than/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(216,19,'<=','Syntax\n------\n\n<=\n\nDescription\n-----------\n\nLess
than or equal operator. Evaluates both SQL expressions and returns 1
if\nthe left value is less than or equal to the right value and 0 if it is
not, or\nNULL if either expression is NULL. If the expressions return
different data\ntypes, (for instance, a number and a string), performs type
conversion.\n\nWhen used in row comparisons these two queries return the
same results:\n\nSELECT (t1.a, t1.b) <= (t2.x, t2.y) \nFROM t1 INNER
JOIN t2;\n\nSELECT (t1.a < t2.x) OR ((t1.a = t2.x) AND (t1.b <=
t2.y))\nFROM t1 INNER JOIN t2;\n\nExamples\n--------\n\nSELECT 0.1 <=
2;\n+----------+\n| 0.1 <= 2 |\n+----------+\n| 1
|\n+----------+\n\nSELECT
\'a\'<=\'A\';\n+----------+\n|
\'a\'<=\'A\' |\n+----------+\n| 1
|\n+----------+\n\nURL:
https://mariadb.com/kb/en/less-than-or-equal/','','https://mariadb.com/kb/en/less-than-or-equal/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(217,19,'<=>','Syntax\n------\n\n<=>\n\nDescription\n-----------\n\nNULL-safe
equal operator. It performs an equality comparison like the =\noperator,
but returns 1 rather than NULL if both operands are NULL, and 0\nrather
than NULL if one operand is NULL.\n\na <=> b is equivalent to a = b
OR (a IS NULL AND b IS NULL).\n\nWhen used in row comparisons these two
queries return the same results:\n\nSELECT (t1.a, t1.b) <=> (t2.x,
t2.y) \nFROM t1 INNER JOIN t2;\n\nSELECT (t1.a <=> t2.x) AND (t1.b
<=> t2.y)\nFROM t1 INNER JOIN t2;\n\nSee also NULL Values in
MariaDB.\n\nExamples\n--------\n\nSELECT 1 <=> 1, NULL <=>
NULL, 1 <=> NULL;\n+---------+---------------+------------+\n| 1
<=> 1 | NULL <=> NULL | 1 <=> NULL
|\n+---------+---------------+------------+\n| 1 | 1 |
0 |\n+---------+---------------+------------+\n\nSELECT 1 = 1, NULL =
NULL, 1 = NULL;\n+-------+-------------+----------+\n| 1 = 1 | NULL = NULL
| 1 = NULL |\n+-------+-------------+----------+\n| 1 | NULL |
NULL |\n+-------+-------------+----------+\n\nURL:
https://mariadb.com/kb/en/null-safe-equal/','','https://mariadb.com/kb/en/null-safe-equal/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(218,19,'=','Syntax\n------\n\nleft_expr =
right_expr\n\nDescription\n-----------\n\nEqual operator. Evaluates both
SQL expressions and returns 1 if they are\nequal, 0 if they are not equal,
or NULL if either expression is NULL. If the\nexpressions return different
data types (for example, a number and a string),\na type conversion is
performed.\n\nWhen used in row comparisons these two queries are synonymous
and return the\nsame results:\n\nSELECT (t1.a, t1.b) = (t2.x, t2.y) FROM t1
INNER JOIN t2;\n\nSELECT (t1.a = t2.x) AND (t1.b = t2.y) FROM t1 INNER JOIN
t2;\n\nTo perform a NULL-safe comparison, use the <=> operator.\n\n=
can also be used as an assignment operator.\n\nExamples\n--------\n\nSELECT
1 = 0;\n+-------+\n| 1 = 0 |\n+-------+\n| 0 |\n+-------+\n\nSELECT
\'0\' = 0;\n+---------+\n| \'0\' = 0 |\n+---------+\n|
1 |\n+---------+\n\nSELECT \'0.0\' = 0;\n+-----------+\n|
\'0.0\' = 0 |\n+-----------+\n| 1
|\n+-----------+\n\nSELECT \'0.01\' = 0;\n+------------+\n|
\'0.01\' = 0 |\n+------------+\n| 0
|\n+------------+\n\nSELECT \'.01\' = 0.01;\n+--------------+\n|
\'.01\' = 0.01 |\n+--------------+\n| 1
|\n+--------------+\n\nSELECT (5 * 2) = CONCAT(\'1\',
\'0\');\n+----------------------------+\n| (5 * 2) =
CONCAT(\'1\', \'0\')
|\n+----------------------------+\n| 1
|\n+----------------------------+\n\nSELECT 1 = NULL;\n+----------+\n| 1 =
NULL |\n+----------+\n| NULL |\n+----------+\n\nSELECT NULL =
NULL;\n+-------------+\n| NULL = NULL |\n+-------------+\n| NULL
|\n+-------------+\n\nURL:
https://mariadb.com/kb/en/equal/','','https://mariadb.com/kb/en/equal/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(219,19,'>','Syntax\n------\n\n>\n\nDescription\n-----------\n\nGreater
than operator. Evaluates both SQL expressions and returns 1 if the\nleft
value is greater than the right value and 0 if it is not, or NULL
if\neither expression is NULL. If the expressions return different data
types,\n(for instance, a number and a string), performs type
conversion.\n\nWhen used in row comparisons these two queries return the
same results:\n\nSELECT (t1.a, t1.b) > (t2.x, t2.y) \nFROM t1 INNER JOIN
t2;\n\nSELECT (t1.a > t2.x) OR ((t1.a = t2.x) AND (t1.b >
t2.y))\nFROM t1 INNER JOIN t2;\n\nExamples\n--------\n\nSELECT 2 >
2;\n+-------+\n| 2 > 2 |\n+-------+\n| 0 |\n+-------+\n\nSELECT
\'b\' > \'a\';\n+-----------+\n| \'b\'
> \'a\' |\n+-----------+\n| 1 |\n+-----------+\n\nURL:
https://mariadb.com/kb/en/greater-than/','','https://mariadb.com/kb/en/greater-than/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(220,19,'>=','Syntax\n------\n\n>=\n\nDescription\n-----------\n\nGreater
than or equal operator. Evaluates both SQL expressions and returns 1\nif
the left value is greater than or equal to the right value and 0 if it
is\nnot, or NULL if either expression is NULL. If the expressions return
different\ndata types, (for instance, a number and a string), performs type
conversion.\n\nWhen used in row comparisons these two queries return the
same results:\n\nSELECT (t1.a, t1.b) >= (t2.x, t2.y) \nFROM t1 INNER
JOIN t2;\n\nSELECT (t1.a > t2.x) OR ((t1.a = t2.x) AND (t1.b >=
t2.y))\nFROM t1 INNER JOIN t2;\n\nExamples\n--------\n\nSELECT 2 >=
2;\n+--------+\n| 2 >= 2 |\n+--------+\n| 1 |\n+--------+\n\nSELECT
\'A\' >= \'a\';\n+------------+\n| \'A\'
>= \'a\' |\n+------------+\n| 1
|\n+------------+\n\nURL:
https://mariadb.com/kb/en/greater-than-or-equal/','','https://mariadb.com/kb/en/greater-than-or-equal/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(221,19,'BETWEEN AND','Syntax\n------\n\nexpr BETWEEN min
AND max\n\nDescription\n-----------\n\nIf expr is greater than or equal to
min and expr is less than or equal to max,\nBETWEEN returns 1, otherwise it
returns 0. This is equivalent to the\nexpression (min <= expr AND expr
<= max) if all the arguments are of the same\ntype. Otherwise type
conversion takes place according to the rules described\nat Type
Conversion, but applied to all the three
arguments.\n\nExamples\n--------\n\nSELECT 1 BETWEEN 2 AND
3;\n+-------------------+\n| 1 BETWEEN 2 AND 3 |\n+-------------------+\n|
0 |\n+-------------------+\n\nSELECT \'b\' BETWEEN
\'a\' AND \'c\';\n+-------------------------+\n|
\'b\' BETWEEN \'a\' AND \'c\'
|\n+-------------------------+\n| 1
|\n+-------------------------+\n\nSELECT 2 BETWEEN 2 AND
\'3\';\n+---------------------+\n| 2 BETWEEN 2 AND
\'3\' |\n+---------------------+\n| 1
|\n+---------------------+\n\nSELECT 2 BETWEEN 2 AND
\'x-3\';\n+-----------------------+\n| 2 BETWEEN 2 AND
\'x-3\' |\n+-----------------------+\n| 0
|\n+-----------------------+\n1 row in set, 1 warning (0.00 sec)\n\nWarning
(Code 1292): Truncated incorrect DOUBLE value:
\'x-3\'\n\nNULL:\n\nSELECT 1 BETWEEN 1 AND
NULL;\n+----------------------+\n| 1 BETWEEN 1 AND NULL
|\n+----------------------+\n| NULL
|\n+----------------------+\n\nDATE, DATETIME and TIMESTAMP examples.
Omitting the time component compares\nagainst 00:00, so later times on the
same date are not returned:\n\nCREATE TABLE `x` (\n a date ,\n b
datetime,\n c timestamp\n)\n\nINSERT INTO x VALUES \n
(\'2018-11-11\', \'2018-11-11 05:15\',
\'2018-11-11 05:15\'), \n (\'2018-11-12\',
\'2018-11-12 05:15\', \'2018-11-12 05:15\');\n\nSELECT
* FROM x WHERE a BETWEEN \'2018-11-11\' AND
\'2018-11-12\';\n+------------+---------------------+---------------------+\n|
a | b | c
|\n+------------+---------------------+---------------------+\n| 2018-11-11
| 2018-11-11 05:15:00 | 2018-11-11 05:15:00 |\n| 2018-11-12 | 2018-11-12
05:15:00 | 2018-11-12 05:15:00
|\n+------------+---------------------+---------------------+\n\nSELECT *
FROM x WHERE b BETWEEN \'2018-11-11\' AND
\'2018-11-12\';\n+------------+---------------------+---------------------+\n|
a | b | c
|\n+------------+---------------------+---------------------+\n| 2018-11-11
| 2018-11-11 05:15:00 | 2018-11-11 05:15:00
|\n+------------+---------------------+---------------------+\n\nSELECT *
FROM x WHERE c BETWEEN \'2018-11-11\' AND
\'2018-11-12\';\n+------------+---------------------+---------------------+\n|
a | b | c
|\n+------------+---------------------+---------------------+\n| 2018-11-11
| 2018-11-11 05:15:00 | 2018-11-11 05:15:00
|\n+------------+---------------------+---------------------+\n\nURL:
https://mariadb.com/kb/en/between-and/','','https://mariadb.com/kb/en/between-and/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(222,19,'COALESCE','Syntax\n------\n\nCOALESCE(value,...)\n\nDescription\n-----------\n\nReturns
the first non-NULL value in the list, or NULL if there are no
non-NULL\nvalues. At least one parameter must be passed.\n\nThe function is
useful when substituting a default value for null values when\ndisplaying
data.\n\nSee also NULL Values in MariaDB.\n\nExamples\n--------\n\nSELECT
COALESCE(NULL,1);\n+------------------+\n| COALESCE(NULL,1)
|\n+------------------+\n| 1
|\n+------------------+\n\nSELECT
COALESCE(NULL,NULL,NULL);\n+--------------------------+\n|
COALESCE(NULL,NULL,NULL) |\n+--------------------------+\n|
NULL |\n+--------------------------+\n\nWhen two arguments are given,
COALESCE() is the same as IFNULL():\n\nSET @a=NULL, @b=1;\n\nSELECT
COALESCE(@a, @b), IFNULL(@a, @b);\n+------------------+----------------+\n|
COALESCE(@a, @b) | IFNULL(@a, @b)
|\n+------------------+----------------+\n| 1 |
1 |\n+------------------+----------------+\n\nHex type confusion:\n\nCREATE
TABLE t1 (a INT, b VARCHAR(10));\nINSERT INTO t1 VALUES (0x31,
0x61),(COALESCE(0x31), COALESCE(0x61));\n\nSELECT * FROM
t1;\n+------+------+\n| a | b |\n+------+------+\n| 49 | a |\n|
1 | a |\n+------+------+\n\nThe reason for the differing results above
is that when 0x31 is inserted\ndirectly to the column, it\'s treated
as a number (see Hexadecimal Literals),\nwhile when 0x31 is passed to
COALESCE(), it\'s treated as a string, because:\n\n* HEX values have a
string data type by default.\n* COALESCE() has the same data type as the
argument.\n\nSubstituting zero for NULL (in this case when the aggregate
function returns\nNULL after finding no rows):\n\nSELECT SUM(score) FROM
student;\n+------------+\n| SUM(score) |\n+------------+\n| NULL
|\n+------------+\n\nSELECT COALESCE(SUM(score),0) FROM
student;\n+------------------------+\n| COALESCE(SUM(score),0)
|\n+------------------------+\n| 0
|\n+------------------------+\n\nURL:
https://mariadb.com/kb/en/coalesce/','','https://mariadb.com/kb/en/coalesce/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(223,19,'GREATEST','Syntax\n------\n\nGREATEST(value1,value2,...)\n\nDescription\n-----------\n\nWith
two or more arguments, returns the largest (maximum-valued) argument.
The\narguments are compared using the same rules as for
LEAST().\n\nExamples\n--------\n\nSELECT
GREATEST(2,0);\n+---------------+\n| GREATEST(2,0) |\n+---------------+\n|
2 |\n+---------------+\n\nSELECT
GREATEST(34.0,3.0,5.0,767.0);\n+------------------------------+\n|
GREATEST(34.0,3.0,5.0,767.0) |\n+------------------------------+\n|
767.0 |\n+------------------------------+\n\nSELECT
GREATEST(\'B\',\'A\',\'C\');\n+-----------------------+\n|
GREATEST(\'B\',\'A\',\'C\')
|\n+-----------------------+\n| C
|\n+-----------------------+\n\nURL:
https://mariadb.com/kb/en/greatest/','','https://mariadb.com/kb/en/greatest/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(224,19,'IN','Syntax\n------\n\nexpr IN
(value,...)\n\nDescription\n-----------\n\nReturns 1 if expr is equal to
any of the values in the IN list, else returns\n0. If all values are
constants, they are evaluated according to the type of\nexpr and sorted.
The search for the item then is done using a binary search.\nThis means IN
is very quick if the IN value list consists entirely of\nconstants.
Otherwise, type conversion takes place according to the rules\ndescribed at
Type Conversion, but applied to all the arguments.\n\nIf expr is NULL, IN
always returns NULL. If at least one of the values in the\nlist is NULL,
and one of the comparisons is true, the result is 1. If at least\none of
the values in the list is NULL and none of the comparisons is true,
the\nresult is NULL.\n\nExamples\n--------\n\nSELECT 2 IN
(0,3,5,7);\n+----------------+\n| 2 IN (0,3,5,7) |\n+----------------+\n|
0 |\n+----------------+\n\nSELECT \'wefwf\' IN
(\'wee\',\'wefwf\',\'weg\');\n+----------------------------------+\n|
\'wefwf\' IN
(\'wee\',\'wefwf\',\'weg\')
|\n+----------------------------------+\n| 1
|\n+----------------------------------+\n\nType conversion:\n\nSELECT 1 IN
(\'1\', \'2\',
\'3\');\n+----------------------+\n| 1 IN (\'1\',
\'2\', \'3\') |\n+----------------------+\n|
1 |\n+----------------------+\n\nSELECT NULL IN (1, 2,
3);\n+-------------------+\n| NULL IN (1, 2, 3) |\n+-------------------+\n|
NULL |\n+-------------------+\n\nSELECT 1 IN (1, 2,
NULL);\n+-------------------+\n| 1 IN (1, 2, NULL)
|\n+-------------------+\n| 1
|\n+-------------------+\n\nSELECT 5 IN (1, 2,
NULL);\n+-------------------+\n| 5 IN (1, 2, NULL)
|\n+-------------------+\n| NULL
|\n+-------------------+\n\nURL:
https://mariadb.com/kb/en/in/','','https://mariadb.com/kb/en/in/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(225,19,'INTERVAL','Syntax\n------\n\nINTERVAL(N,N1,N2,N3,...)\n\nDescription\n-----------\n\nReturns
the index of the last argument that is less than the first argument or\nis
NULL.\n\nReturns 0 if N < N1, 1 if N < N2, 2 if N < N3 and so on
or -1 if N is NULL.\nAll arguments are treated as integers. It is required
that N1 < N2 < N3 < ...\n< Nn for this function to work
correctly. This is because a fast binary search\nis
used.\n\nExamples\n--------\n\nSELECT INTERVAL(23, 1, 15, 17, 30, 44,
200);\n+--------------------------------------+\n| INTERVAL(23, 1, 15, 17,
30, 44, 200) |\n+--------------------------------------+\n|
3 |\n+--------------------------------------+\n\nSELECT
INTERVAL(10, 1, 10, 100, 1000);\n+--------------------------------+\n|
INTERVAL(10, 1, 10, 100, 1000) |\n+--------------------------------+\n|
2 |\n+--------------------------------+\n\nSELECT
INTERVAL(22, 23, 30, 44, 200);\n+-------------------------------+\n|
INTERVAL(22, 23, 30, 44, 200) |\n+-------------------------------+\n|
0 |\n+-------------------------------+\n\nSELECT
INTERVAL(10, 2, NULL);\n+-----------------------+\n| INTERVAL(10, 2, NULL)
|\n+-----------------------+\n| 2
|\n+-----------------------+\n\nURL:
https://mariadb.com/kb/en/interval/','','https://mariadb.com/kb/en/interval/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(226,19,'IS','Syntax\n------\n\nIS
boolean_value\n\nDescription\n-----------\n\nTests a value against a
boolean value, where boolean_value can be TRUE, FALSE,\nor
UNKNOWN.\n\nThere is an important difference between using IS TRUE or
comparing a value\nwith TRUE using =. When using =, only 1 equals to TRUE.
But when using IS\nTRUE, all values which are logically true (like a number
> 1) return TRUE.\n\nExamples\n--------\n\nSELECT 1 IS TRUE, 0 IS FALSE,
NULL IS UNKNOWN;\n+-----------+------------+-----------------+\n| 1 IS TRUE
| 0 IS FALSE | NULL IS UNKNOWN
|\n+-----------+------------+-----------------+\n| 1 | 1 |
1
|\n+-----------+------------+-----------------+\n\nDifference between = and
IS TRUE:\n\nSELECT 2 = TRUE, 2 IS TRUE;\n+----------+-----------+\n| 2 =
TRUE | 2 IS TRUE |\n+----------+-----------+\n| 0 | 1
|\n+----------+-----------+\n\nURL:
https://mariadb.com/kb/en/is/','','https://mariadb.com/kb/en/is/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(227,19,'IS NOT','Syntax\n------\n\nIS NOT
boolean_value\n\nDescription\n-----------\n\nTests a value against a
boolean value, where boolean_value can be TRUE, FALSE,\nor
UNKNOWN.\n\nExamples\n--------\n\nSELECT 1 IS NOT UNKNOWN, 0 IS NOT
UNKNOWN, NULL IS NOT
UNKNOWN;\n+------------------+------------------+---------------------+\n|
1 IS NOT UNKNOWN | 0 IS NOT UNKNOWN | NULL IS NOT UNKNOWN
|\n+------------------+------------------+---------------------+\n|
1 | 1 | 0
|\n+------------------+------------------+---------------------+\n\nSELECT
NULL IS NOT TRUE, NULL IS NOT
FALSE;\n+------------------+-------------------+\n| NULL IS NOT TRUE | NULL
IS NOT FALSE |\n+------------------+-------------------+\n|
1 | 1 |\n+------------------+-------------------+\n\nURL:
https://mariadb.com/kb/en/is-not/','','https://mariadb.com/kb/en/is-not/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(228,19,'IS NOT NULL','Syntax\n------\n\nIS NOT
NULL\n\nDescription\n-----------\n\nTests whether a value is not NULL. See
also NULL Values in MariaDB.\n\nExamples\n--------\n\nSELECT 1 IS NOT NULL,
0 IS NOT NULL, NULL IS NOT
NULL;\n+---------------+---------------+------------------+\n| 1 IS NOT
NULL | 0 IS NOT NULL | NULL IS NOT NULL
|\n+---------------+---------------+------------------+\n| 1 |
1 | 0
|\n+---------------+---------------+------------------+\n\nURL:
https://mariadb.com/kb/en/is-not-null/','','https://mariadb.com/kb/en/is-not-null/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(229,19,'IS NULL','Syntax\n------\n\nIS
NULL\n\nDescription\n-----------\n\nTests whether a value is NULL. See also
NULL Values in MariaDB.\n\nExamples\n--------\n\nSELECT 1 IS NULL, 0 IS
NULL, NULL IS NULL;\n+-----------+-----------+--------------+\n| 1 IS NULL
| 0 IS NULL | NULL IS NULL |\n+-----------+-----------+--------------+\n|
0 | 0 | 1
|\n+-----------+-----------+--------------+\n\nCompatibility\n-------------\n\nSome
ODBC applications use the syntax auto_increment_field IS NOT NULL to
find\nthe latest row that was inserted with an autogenerated key value. If
your\napplications need this, you can set the sql_auto_is_null variable to
1.\n\nSET @@sql_auto_is_null=1;\nCREATE TABLE t1 (auto_increment_column INT
NOT NULL AUTO_INCREMENT PRIMARY\nKEY);\nINSERT INTO t1 VALUES
(NULL);\nSELECT * FROM t1 WHERE auto_increment_column IS
NULL;\n\n+-----------------------+\n| auto_increment_column
|\n+-----------------------+\n| 1
|\n+-----------------------+\n\nURL:
https://mariadb.com/kb/en/is-null/','','https://mariadb.com/kb/en/is-null/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(230,19,'ISNULL','Syntax\n------\n\nISNULL(expr)\n\nDescription\n-----------\n\nIf
expr is NULL, ISNULL() returns 1, otherwise it returns 0.\n\nSee also NULL
Values in MariaDB.\n\nExamples\n--------\n\nSELECT
ISNULL(1+1);\n+-------------+\n| ISNULL(1+1) |\n+-------------+\n|
0 |\n+-------------+\n\nSELECT ISNULL(1/0);\n+-------------+\n|
ISNULL(1/0) |\n+-------------+\n| 1 |\n+-------------+\n\nURL:
https://mariadb.com/kb/en/isnull/','','https://mariadb.com/kb/en/isnull/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(231,19,'LEAST','Syntax\n------\n\nLEAST(value1,value2,...)\n\nDescription\n-----------\n\nWith
two or more arguments, returns the smallest (minimum-valued) argument.\nThe
arguments are compared using the following rules:\n\n* If the return value
is used in an INTEGER context or all arguments are\ninteger-valued, they
are compared as integers.\n* If the return value is used in a REAL context
or all arguments are\nreal-valued, they are compared as reals.\n* If any
argument is a case-sensitive string, the arguments are compared
as\ncase-sensitive strings.\n* In all other cases, the arguments are
compared as case-insensitive strings.\n\nLEAST() returns NULL if any
argument is NULL.\n\nExamples\n--------\n\nSELECT
LEAST(2,0);\n+------------+\n| LEAST(2,0) |\n+------------+\n| 0
|\n+------------+\n\nSELECT
LEAST(34.0,3.0,5.0,767.0);\n+---------------------------+\n|
LEAST(34.0,3.0,5.0,767.0) |\n+---------------------------+\n|
3.0 |\n+---------------------------+\n\nSELECT
LEAST(\'B\',\'A\',\'C\');\n+--------------------+\n|
LEAST(\'B\',\'A\',\'C\')
|\n+--------------------+\n| A
|\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/least/','','https://mariadb.com/kb/en/least/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(232,19,'NOT BETWEEN','Syntax\n------\n\nexpr NOT BETWEEN
min AND max\n\nDescription\n-----------\n\nThis is the same as NOT (expr
BETWEEN min AND max).\n\nNote that the meaning of the alternative form NOT
expr BETWEEN min AND max is\naffected by the HIGH_NOT_PRECEDENCE SQL_MODE
flag.\n\nExamples\n--------\n\nSELECT 1 NOT BETWEEN 2 AND
3;\n+-----------------------+\n| 1 NOT BETWEEN 2 AND 3
|\n+-----------------------+\n| 1
|\n+-----------------------+\n\nSELECT \'b\' NOT BETWEEN
\'a\' AND \'c\';\n+-----------------------------+\n|
\'b\' NOT BETWEEN \'a\' AND \'c\'
|\n+-----------------------------+\n| 0
|\n+-----------------------------+\n\nNULL:\n\nSELECT 1 NOT BETWEEN 1 AND
NULL;\n+--------------------------+\n| 1 NOT BETWEEN 1 AND NULL
|\n+--------------------------+\n| NULL
|\n+--------------------------+\n\nURL:
https://mariadb.com/kb/en/not-between/','','https://mariadb.com/kb/en/not-between/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(233,19,'NOT IN','Syntax\n------\n\nexpr NOT IN
(value,...)\n\nDescription\n-----------\n\nThis is the same as NOT (expr IN
(value,...)).\n\nExamples\n--------\n\nSELECT 2 NOT IN
(0,3,5,7);\n+--------------------+\n| 2 NOT IN (0,3,5,7)
|\n+--------------------+\n| 1
|\n+--------------------+\n\nSELECT \'wefwf\' NOT IN
(\'wee\',\'wefwf\',\'weg\');\n+--------------------------------------+\n|
\'wefwf\' NOT IN
(\'wee\',\'wefwf\',\'weg\')
|\n+--------------------------------------+\n|
0 |\n+--------------------------------------+\n\nSELECT 1 NOT IN
(\'1\', \'2\',
\'3\');\n+--------------------------+\n| 1 NOT IN
(\'1\', \'2\', \'3\')
|\n+--------------------------+\n| 0
|\n+--------------------------+\n\nNULL:\n\nSELECT NULL NOT IN (1, 2,
3);\n+-----------------------+\n| NULL NOT IN (1, 2, 3)
|\n+-----------------------+\n| NULL
|\n+-----------------------+\n\nSELECT 1 NOT IN (1, 2,
NULL);\n+-----------------------+\n| 1 NOT IN (1, 2, NULL)
|\n+-----------------------+\n| 0
|\n+-----------------------+\n\nSELECT 5 NOT IN (1, 2,
NULL);\n+-----------------------+\n| 5 NOT IN (1, 2, NULL)
|\n+-----------------------+\n| NULL
|\n+-----------------------+\n\nURL:
https://mariadb.com/kb/en/not-in/','','https://mariadb.com/kb/en/not-in/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(234,20,'&','Syntax\n------\n\n&\n\nDescription\n-----------\n\nBitwise
AND. Converts the values to binary and compares bits. Only if both
the\ncorresponding bits are 1 is the resulting bit also 1.\n\nSee also
bitwise OR.\n\nExamples\n--------\n\nSELECT 2&1;\n+-----+\n| 2&1
|\n+-----+\n| 0 |\n+-----+\n\nSELECT 3&1;\n+-----+\n| 3&1
|\n+-----+\n| 1 |\n+-----+\n\nSELECT 29 & 15;\n+---------+\n| 29
& 15 |\n+---------+\n| 13 |\n+---------+\n\nURL:
https://mariadb.com/kb/en/bitwise_and/','','https://mariadb.com/kb/en/bitwise_and/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(235,20,'<<','Syntax\n------\n\nvalue1 <<
value2\n\nDescription\n-----------\n\nConverts a longlong (BIGINT) number
(value1) to binary and shifts value2 units\nto the
left.\n\nExamples\n--------\n\nSELECT 1 << 2;\n+--------+\n| 1
<< 2 |\n+--------+\n| 4 |\n+--------+\n\nURL:
https://mariadb.com/kb/en/shift-left/','','https://mariadb.com/kb/en/shift-left/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(236,20,'>>','Syntax\n------\n\nvalue1 >>
value2\n\nDescription\n-----------\n\nConverts a longlong (BIGINT) number
(value1) to binary and shifts value2 units\nto the
right.\n\nExamples\n--------\n\nSELECT 4 >> 2;\n+--------+\n| 4
>> 2 |\n+--------+\n| 1 |\n+--------+\n\nURL:
https://mariadb.com/kb/en/shift-right/','','https://mariadb.com/kb/en/shift-right/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(237,20,'BIT_COUNT','Syntax\n------\n\nBIT_COUNT(N)\n\nDescription\n-----------\n\nReturns
the number of bits that are set in the argument
N.\n\nExamples\n--------\n\nSELECT BIT_COUNT(29),
BIT_COUNT(b\'101010\');\n+---------------+----------------------+\n|
BIT_COUNT(29) | BIT_COUNT(b\'101010\')
|\n+---------------+----------------------+\n| 4 |
3 |\n+---------------+----------------------+\n\nURL:
https://mariadb.com/kb/en/bit_count/','','https://mariadb.com/kb/en/bit_count/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(238,20,'^','Syntax\n------\n\n^\n\nDescription\n-----------\n\nBitwise
XOR. Converts the values to binary and compares bits. If one (and
only\none) of the corresponding bits is 1 is the resulting bit also
1.\n\nExamples\n--------\n\nSELECT 1 ^ 1;\n+-------+\n| 1 ^ 1
|\n+-------+\n| 0 |\n+-------+\n\nSELECT 1 ^ 0;\n+-------+\n| 1 ^ 0
|\n+-------+\n| 1 |\n+-------+\n\nSELECT 11 ^ 3;\n+--------+\n| 11 ^ 3
|\n+--------+\n| 8 |\n+--------+\n\nURL:
https://mariadb.com/kb/en/bitwise-xor/','','https://mariadb.com/kb/en/bitwise-xor/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(239,20,'|','Syntax\n------\n\n|\n\nDescription\n-----------\n\nBitwise
OR. Converts the values to binary and compares bits. If either of
the\ncorresponding bits has a value of 1, the resulting bit is also
1.\n\nSee also bitwise AND.\n\nExamples\n--------\n\nSELECT
2|1;\n+-----+\n| 2|1 |\n+-----+\n| 3 |\n+-----+\n\nSELECT 29 |
15;\n+---------+\n| 29 | 15 |\n+---------+\n| 31
|\n+---------+\n\nURL:
https://mariadb.com/kb/en/bitwise-or/','','https://mariadb.com/kb/en/bitwise-or/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(240,20,'~','Syntax\n------\n\n~\n\nDescription\n-----------\n\nBitwise
NOT. Converts the value to 4 bytes binary and inverts all
bits.\n\nExamples\n--------\n\nSELECT 3 & ~1;\n+--------+\n| 3 & ~1
|\n+--------+\n| 2 |\n+--------+\n\nSELECT 5 & ~1;\n+--------+\n|
5 & ~1 |\n+--------+\n| 4 |\n+--------+\n\nURL:
https://mariadb.com/kb/en/bitwise-not/','','https://mariadb.com/kb/en/bitwise-not/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(241,20,'Parentheses','Parentheses are sometimes called
precedence operators - this means that they\ncan be used to change the
other operator\'s precedence in an expression. The\nexpressions that
are written between parentheses are computed before the\nexpressions that
are written outside. Parentheses must always contain an\nexpression (that
is, they cannot be empty), and can be nested.\n\nFor example, the following
expressions could return different results:\n\n* NOT a OR b\n* NOT (a OR
b)\n\nIn the first case, NOT applies to a, so if a is FALSE or b is TRUE,
the\nexpression returns TRUE. In the second case, NOT applies to the result
of a OR\nb, so if at least one of a or b is TRUE, the expression is
TRUE.\n\nWhen the precedence of operators is not intuitive, you can use
parentheses to\nmake it immediately clear for whoever reads the
statement.\n\nThe precedence of the NOT operator can also be affected by
the\nHIGH_NOT_PRECEDENCE SQL_MODE flag.\n\nOther
uses\n----------\n\nParentheses must always be used to enclose
subqueries.\n\nParentheses can also be used in a JOIN statement between
multiple tables to\ndetermine which tables must be joined first.\n\nAlso,
parentheses are used to enclose the list of parameters to be passed
to\nbuilt-in functions, user-defined functions and stored routines.
However, when\nno parameter is passed to a stored procedure, parentheses
are optional. For\nbuiltin functions and user-defined functions, spaces are
not allowed between\nthe function name and the open parenthesis, unless the
IGNORE_SPACE SQL_MODE\nis set. For stored routines (and for functions if
IGNORE_SPACE is set) spaces\nare allowed before the open parenthesis,
including tab characters and new line\ncharacters.\n\nSyntax
errors\n-------------\n\nIf there are more open parentheses than closed
parentheses, the error usually\nlooks like this:\n\nERROR 1064 (42000): You
have an error in your SQL syntax; check the manual that\ncorresponds to
your MariaDB server version for the right syntax to use near
\'\'\na\nt line 1\n\nNote the empty string.\n\nIf there are more
closed parentheses than open parentheses, the error usually\nlooks like
this:\n\nERROR 1064 (42000): You have an error in your SQL syntax; check
the manual that\ncorresponds to your MariaDB server version for the right
syntax to use near \')\'\nat line 1\n\nNote the quoted closed
parenthesis.\n\nURL:
https://mariadb.com/kb/en/parentheses/','','https://mariadb.com/kb/en/parentheses/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(242,20,'TRUE FALSE','Description\n-----------\n\nThe
constants TRUE and FALSE evaluate to 1 and 0, respectively. The
constant\nnames can be written in any
lettercase.\n\nExamples\n--------\n\nSELECT TRUE, true, FALSE,
false;\n+------+------+-------+-------+\n| TRUE | TRUE | FALSE | FALSE
|\n+------+------+-------+-------+\n| 1 | 1 | 0 | 0
|\n+------+------+-------+-------+\n\nURL:
https://mariadb.com/kb/en/true-false/','','https://mariadb.com/kb/en/true-false/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(243,21,'ANALYZE TABLE','Syntax\n------\n\nANALYZE
[NO_WRITE_TO_BINLOG | LOCAL] TABLE tbl_name [,tbl_name ...] \n [PERSISTENT
FOR [ALL|COLUMNS ([col_name [,col_name ...]])]\n [INDEXES ([index_name
[,index_name ...]])]]\n\nDescription\n-----------\n\nANALYZE TABLE analyzes
and stores the key distribution for a table (index\nstatistics). This
statement works with MyISAM, Aria and InnoDB tables. During\nthe analysis,
InnoDB will allow reads/writes, and MyISAM/Aria reads/inserts.\nFor MyISAM
tables, this statement is equivalent to using myisamchk --analyze.\n\nFor
more information on how the analysis works within InnoDB, see
InnoDB\nLimitations.\n\nMariaDB uses the stored key distribution to decide
the order in which tables\nshould be joined when you perform a join on
something other than a constant.\nIn addition, key distributions can be
used when deciding which indexes to use\nfor a specific table within a
query.\n\nThis statement requires SELECT and INSERT privileges for the
table.\n\nBy default, ANALYZE TABLE statements are written to the binary
log and will be\nreplicated. The NO_WRITE_TO_BINLOG keyword (LOCAL is an
alias) will ensure the\nstatement is not written to the binary log.\n\nFrom
MariaDB 10.3.19, ANALYZE TABLE statements are not logged to the binary\nlog
if read_only is set. See also Read-Only Replicas.\n\nANALYZE TABLE is also
supported for partitioned tables. You can use ALTER\nTABLE ... ANALYZE
PARTITION to analyze one or more partitions.\n\nThe Aria storage engine
supports progress reporting for the ANALYZE
TABLE\nstatement.\n\nEngine-Independent
Statistics\n-----------------------------\n\nANALYZE TABLE supports
engine-independent statistics. See Engine-Independent\nTable Statistics:
Collecting Statistics with the ANALYZE TABLE Statement for\nmore
information.\n\nUseful Variables\n----------------\n\nFor calculating the
number of duplicates, ANALYZE TABLE uses a buffer of\nsort_buffer_size
bytes per column. You can slightly increase the speed of\nANALYZE TABLE by
increasing this variable.\n\nURL:
https://mariadb.com/kb/en/analyze-table/','','https://mariadb.com/kb/en/analyze-table/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(244,21,'CHECK TABLE','Syntax\n------\n\nCHECK TABLE
tbl_name [, tbl_name] ... [option] ...\n\noption = {FOR UPGRADE | QUICK |
FAST | MEDIUM | EXTENDED | CHANGED}\n\nDescription\n-----------\n\nCHECK
TABLE checks a table or tables for errors. CHECK TABLE works for\nArchive,
Aria, CSV, InnoDB and MyISAM tables. For Aria and MyISAM tables, the\nkey
statistics are updated as well. For CSV, see also Checking and
Repairing\nCSV Tables.\n\nAs an alternative, myisamchk is a commandline
tool for checking MyISAM tables\nwhen the tables are not being accessed.
For Aria tables, there is a similar\ntool: aria_chk.\n\nFor checking
dynamic columns integrity, COLUMN_CHECK() can be used.\n\nCHECK TABLE can
also check views for problems, such as tables that are\nreferenced in the
view definition that no longer exist.\n\nCHECK TABLE is also supported for
partitioned tables. You can use ALTER TABLE\n... CHECK PARTITION to check
one or more partitions.\n\nThe meaning of the different options are as
follows - note that this can vary\na bit between storage
engines:\n\n+-----+----------------------------------------------------------------------+\n|
FOR | Do a very quick check if the storage format for the table has
|\n| UPG | changed so that one needs to do a REPAIR. This is only needed
when |\n| ADE | one upgrades between major versions of MariaDB or MySQL.
This is |\n| | usually done by running mysql_upgrade.
|\n+-----+----------------------------------------------------------------------+\n|
FAS | Only check tables that has not been closed properly or are marked
|\n| | as corrupt. Only supported by the MyISAM and Aria engines. For
|\n| | other engines the table is checked normally
|\n+-----+----------------------------------------------------------------------+\n|
CHA | Check only tables that has changed since last REPAIR / CHECK. Only
|\n| GED | supported by the MyISAM and Aria engines. For other engines the
|\n| | table is checked normally.
|\n+-----+----------------------------------------------------------------------+\n|
QUI | Do a fast check. For MyISAM and Aria, this means skipping the check
|\n| K | of the delete link chain, which may take some time.
|\n+-----+----------------------------------------------------------------------+\n|
MED | Scan also the data files. Checks integrity between data and index
|\n| UM | files with checksums. In most cases this should find all
possible |\n| | errors.
|\n+-----+----------------------------------------------------------------------+\n|
EXT | Does a full check to verify every possible error. For MyISAM and
|\n| NDE | Aria, verify for each row that all it keys exists and points to
the |\n| | row. This may take a long time on large tables. Ignored by
InnoDB |\n| | before MariaDB 10.6.11, MariaDB 10.7.7, MariaDB 10.8.6
and MariaDB |\n| | 10.9.4.
|\n+-----+----------------------------------------------------------------------+\n\nFor
most cases running CHECK TABLE without options or MEDIUM should be
good\nenough.\n\nThe Aria storage engine supports progress reporting for
this statement.\n\nIf you want to know if two tables are identical, take a
look at CHECKSUM TABLE.\n\nInnoDB\n------\n\nIf CHECK TABLE finds an error
in an InnoDB table, MariaDB might shutdown to\nprevent the error
propagation. In this case, the problem will be reported in\nthe error log.
Otherwise the table or an index might be marked as corrupted,\nto prevent
use. This does not happen with some minor problems, like a wrong\nnumber of
entries in a secondary index. Those problems are reported in the\noutput of
CHECK TABLE.\n\nEach tablespace contains a header with metadata. This
header is not checked by\nthis statement.\n\nDuring the execution of CHECK
TABLE, other threads may be blocked.\n\nURL:
https://mariadb.com/kb/en/check-table/','','https://mariadb.com/kb/en/check-table/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(245,21,'CHECK VIEW','Syntax\n------\n\nCHECK VIEW
view_name\n\nDescription\n-----------\n\nThe CHECK VIEW statement was
introduced in MariaDB 10.0.18 to assist with\nfixing MDEV-6916, an issue
introduced in MariaDB 5.2 where the view algorithms\nwere swapped. It
checks whether the view algorithm is correct. It is run as\npart of
mysql_upgrade, and should not normally be required in regular use.\n\nURL:
https://mariadb.com/kb/en/check-view/','','https://mariadb.com/kb/en/check-view/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(246,21,'CHECKSUM TABLE','Syntax\n------\n\nCHECKSUM TABLE
tbl_name [, tbl_name] ... [ QUICK | EXTENDED
]\n\nDescription\n-----------\n\nCHECKSUM TABLE reports a table checksum.
This is very useful if you want to\nknow if two tables are the same (for
example on a master and slave).\n\nWith QUICK, the live table checksum is
reported if it is available, or NULL\notherwise. This is very fast. A live
checksum is enabled by specifying the\nCHECKSUM=1 table option when you
create the table; currently, this is\nsupported only for Aria and MyISAM
tables.\n\nWith EXTENDED, the entire table is read row by row and the
checksum is\ncalculated. This can be very slow for large tables.\n\nIf
neither QUICK nor EXTENDED is specified, MariaDB returns a live checksum
if\nthe table storage engine supports it and scans the table
otherwise.\n\nCHECKSUM TABLE requires the SELECT privilege for the
table.\n\nFor a nonexistent table, CHECKSUM TABLE returns NULL and
generates a warning.\n\nThe table row format affects the checksum value. If
the row format changes,\nthe checksum will change. This means that when a
table created with a\nMariaDB/MySQL version is upgraded to another version,
the checksum value will\nprobably change.\n\nTwo identical tables should
always match to the same checksum value; however,\nalso for non-identical
tables there is a very slight chance that they will\nreturn the same value
as the hashing algorithm is not completely\ncollision-free.\n\nIdentical
Tables\n----------------\n\nIdentical tables mean that the CREATE statement
is identical and that the\nfollowing variable, which affects the storage
formats, was the same when the\ntables were created:\n\n*
mysql56-temporal-format\n\nDifferences Between MariaDB and
MySQL\n-------------------------------------\n\nCHECKSUM TABLE may give a
different result as MariaDB doesn\'t ignore NULLs in\nthe columns as
MySQL 5.1 does (Later MySQL versions should calculate checksums\nthe same
way as MariaDB). You can get the \'old style\' checksum in
MariaDB by\nstarting mysqld with the --old option. Note however that that
the MyISAM and\nAria storage engines in MariaDB are using the new checksum
internally, so if\nyou are using --old, the CHECKSUM command will be slower
as it needs to\ncalculate the checksum row by row. Starting from MariaDB
Server 10.9, --old is\ndeprecated and will be removed in a future release.
Set --old-mode or OLD_MODE\nto COMPAT_5_1_CHECKSUM to get \'old
style\' checksum.\n\nURL:
https://mariadb.com/kb/en/checksum-table/','','https://mariadb.com/kb/en/checksum-table/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(247,21,'OPTIMIZE TABLE','Syntax\n------\n\nOPTIMIZE
[NO_WRITE_TO_BINLOG | LOCAL] TABLE\n tbl_name [, tbl_name] ...\n [WAIT n
| NOWAIT]\n\nDescription\n-----------\n\nOPTIMIZE TABLE has two main
functions. It can either be used to defragment\ntables, or to update the
InnoDB fulltext index.\n\nMariaDB starting with
10.3.0\n----------------------------\n\nWAIT/NOWAIT\n-----------\n\nSet the
lock wait timeout. See WAIT and
NOWAIT.\n\nDefragmenting\n-------------\n\nOPTIMIZE TABLE works for InnoDB
(before MariaDB 10.1.1, only if the\ninnodb_file_per_table server system
variable is set), Aria, MyISAM and ARCHIVE\ntables, and should be used if
you have deleted a large part of a table or if\nyou have made many changes
to a table with variable-length rows (tables that\nhave VARCHAR, VARBINARY,
BLOB, or TEXT columns). Deleted rows are maintained\nin a linked list and
subsequent INSERT operations reuse old row positions.\n\nThis statement
requires SELECT and INSERT privileges for the table.\n\nBy default,
OPTIMIZE TABLE statements are written to the binary log and will\nbe
replicated. The NO_WRITE_TO_BINLOG keyword (LOCAL is an alias) will
ensure\nthe statement is not written to the binary log.\n\nFrom MariaDB
10.3.19, OPTIMIZE TABLE statements are not logged to the binary\nlog if
read_only is set. See also Read-Only Replicas.\n\nOPTIMIZE TABLE is also
supported for partitioned tables. You can use ALTER\nTABLE ... OPTIMIZE
PARTITION to optimize one or more partitions.\n\nYou can use OPTIMIZE TABLE
to reclaim the unused space and to defragment the\ndata file. With other
storage engines, OPTIMIZE TABLE does nothing by default,\nand returns this
message: \" The storage engine for the table doesn\'t
support\noptimize\". However, if the server has been started with the
--skip-new option,\nOPTIMIZE TABLE is linked to ALTER TABLE, and recreates
the table. This\noperation frees the unused space and updates index
statistics.\n\nThe Aria storage engine supports progress reporting for this
statement.\n\nIf a MyISAM table is fragmented, concurrent inserts will not
be performed\nuntil an OPTIMIZE TABLE statement is executed on that table,
unless the\nconcurrent_insert server system variable is set to
ALWAYS.\n\nUpdating an InnoDB fulltext
index\n---------------------------------\n\nWhen rows are added or deleted
to an InnoDB fulltext index, the index is not\nimmediately re-organized, as
this can be an expensive operation. Change\nstatistics are stored in a
separate location . The fulltext index is only\nfully re-organized when an
OPTIMIZE TABLE statement is run.\n\nBy default, an OPTIMIZE TABLE will
defragment a table. In order to use it to\nupdate fulltext index
statistics, the innodb_optimize_fulltext_only system\nvariable must be set
to 1. This is intended to be a temporary setting, and\nshould be reset to 0
once the fulltext index has been re-organized.\n\nSince fulltext
re-organization can take a long time, the\ninnodb_ft_num_word_optimize
variable limits the re-organization to a number of\nwords (2000 by
default). You can run multiple OPTIMIZE statements to fully\nre-organize
the index.\n\nDefragmenting InnoDB
tablespaces\n--------------------------------\n\nMariaDB 10.1.1 merged the
Facebook/Kakao defragmentation patch, allowing one\nto use OPTIMIZE TABLE
to defragment InnoDB tablespaces. For this functionality\nto be enabled,
the innodb_defragment system variable must be enabled. No new\ntables are
created and there is no need to copy data from old tables to new\ntables.
Instead, this feature loads n pages (determined
by\ninnodb-defragment-n-pages) and tries to move records so that pages
would be\nfull of records and then frees pages that are fully empty after
the operation.\nNote that tablespace files (including ibdata1) will not
shrink as the result\nof defragmentation, but one will get better memory
utilization in the InnoDB\nbuffer pool as there are fewer data pages in
use.\n\nSee Defragmenting InnoDB Tablespaces for more details.\n\nURL:
https://mariadb.com/kb/en/optimize-table/','','https://mariadb.com/kb/en/optimize-table/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(248,21,'REPAIR TABLE','Syntax\n------\n\nREPAIR
[NO_WRITE_TO_BINLOG | LOCAL] TABLE\n tbl_name [, tbl_name] ...\n [QUICK]
[EXTENDED] [USE_FRM]\n\nDescription\n-----------\n\nREPAIR TABLE repairs a
possibly corrupted table. By default, it has the same\neffect
as\n\nmyisamchk --recover tbl_name\n\nor\n\naria_chk --recover
tbl_name\n\nSee aria_chk and myisamchk for more.\n\nREPAIR TABLE works for
Archive, Aria, CSV and MyISAM tables. For InnoDB, see\nrecovery modes. For
CSV, see also Checking and Repairing CSV Tables. For\nArchive, this
statement also improves compression. If the storage engine does\nnot
support this statement, a warning is issued.\n\nThis statement requires
SELECT and INSERT privileges for the table.\n\nBy default, REPAIR TABLE
statements are written to the binary log and will be\nreplicated. The
NO_WRITE_TO_BINLOG keyword (LOCAL is an alias) will ensure the\nstatement
is not written to the binary log.\n\nFrom MariaDB 10.3.19, REPAIR TABLE
statements are not logged to the binary log\nif read_only is set. See also
Read-Only Replicas.\n\nWhen an index is recreated, the storage engine may
use a configurable buffer\nin the process. Incrementing the buffer speeds
up the index creation. Aria and\nMyISAM allocate a buffer whose size is
defined by aria_sort_buffer_size or\nmyisam_sort_buffer_size, also used for
ALTER TABLE.\n\nREPAIR TABLE is also supported for partitioned tables.
However, the USE_FRM\noption cannot be used with this statement on a
partitioned table.\n\nALTER TABLE ... REPAIR PARTITION can be used to
repair one or more partitions.\n\nThe Aria storage engine supports progress
reporting for this statement.\n\nURL:
https://mariadb.com/kb/en/repair-table/','','https://mariadb.com/kb/en/repair-table/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(249,21,'REPAIR VIEW','Syntax\n------\n\nREPAIR
[NO_WRITE_TO_BINLOG | LOCAL] VIEW view_name[, view_name] ...
[FROM\nMYSQL]\n\nDescription\n-----------\n\nThe REPAIR VIEW statement was
introduced to assist with fixing MDEV-6916, an\nissue introduced in MariaDB
5.2 where the view algorithms were swapped\ncompared to their MySQL on disk
representation. It checks whether the view\nalgorithm is correct. It is run
as part of mysql_upgrade, and should not\nnormally be required in regular
use.\n\nBy default it corrects the checksum and if necessary adds the
mariadb-version\nfield. If the optional FROM MYSQL clause is used, and no
mariadb-version field\nis present, the MERGE and TEMPTABLE algorithms are
toggled.\n\nBy default, REPAIR VIEW statements are written to the binary
log and will be\nreplicated. The NO_WRITE_TO_BINLOG keyword (LOCAL is an
alias) will ensure the\nstatement is not written to the binary log.\n\nURL:
https://mariadb.com/kb/en/repair-view/','','https://mariadb.com/kb/en/repair-view/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(250,22,'mysql.func Table','The mysql.func table stores
information about user-defined functions (UDFs)\ncreated with the CREATE
FUNCTION UDF statement.\n\nMariaDB starting with
10.4\n--------------------------\nIn MariaDB 10.4 and later, this table
uses the Aria storage engine.\n\nMariaDB until 10.3\n------------------\nIn
MariaDB 10.3 and before, this table uses the MyISAM storage engine.\n\nThe
mysql.func table contains the following
fields:\n\n+----------+---------+---------+-------+--------------+---------------------+\n|
Field | Type | Null | Key | Default | Description
|\n+----------+---------+---------+-------+--------------+---------------------+\n|
name | char(64 | NO | PRI | | UDF name
|\n| | | | | |
|\n+----------+---------+---------+-------+--------------+---------------------+\n|
ret | tinyint | NO | | 0 |
|\n| | 1) | | | |
|\n+----------+---------+---------+-------+--------------+---------------------+\n|
dl | char(12 | NO | | | Shared library name
|\n| | ) | | | |
|\n+----------+---------+---------+-------+--------------+---------------------+\n|
type | enum(\'f | NO | | NULL | Type, either
|\n| | nction\' | | | |
function or |\n| | \'aggreg | | |
| aggregate. |\n| | te\') | |
| | Aggregate |\n| | | |
| | functions are |\n| | |
| | | summary functions |\n| | |
| | | such as SUM() and |\n| | |
| | | AVG().
|\n+----------+---------+---------+-------+--------------+---------------------+\n\nExample\n-------\n\nSELECT
* FROM
mysql.func;\n+------------------------------+-----+--------------+-----------+\n|
name | ret | dl | type
|\n+------------------------------+-----+--------------+-----------+\n|
spider_direct_sql | 2 | ha_spider.so | function |\n|
spider_bg_direct_sql | 2 | ha_spider.so | aggregate |\n|
spider_ping_table | 2 | ha_spider.so | function |\n|
spider_copy_tables | 2 | ha_spider.so | function |\n|
spider_flush_table_mon_cache | 2 | ha_spider.so | function
|\n+------------------------------+-----+--------------+-----------+\n\nURL:
https://mariadb.com/kb/en/mysqlfunc-table/','','https://mariadb.com/kb/en/mysqlfunc-table/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(251,22,'CREATE FUNCTION UDF','Syntax\n------\n\nCREATE [OR
REPLACE] [AGGREGATE] FUNCTION [IF NOT EXISTS] function_name\n RETURNS
{STRING|INTEGER|REAL|DECIMAL}\n SONAME
shared_library_name\n\nDescription\n-----------\n\nA user-defined function
(UDF) is a way to extend MariaDB with a new function\nthat works like a
native (built-in) MariaDB function such as ABS() or
CONCAT().\n\nfunction_name is the name that should be used in SQL
statements to invoke the\nfunction.\n\nTo create a function, you must have
the INSERT privilege for the mysql\ndatabase. This is necessary
becauseCREATE FUNCTION adds a row to the\nmysql.func system table that
records the function\'s name, type, and shared\nlibrary name. If you
do not have this table, you should run the mysql_upgrade\ncommand to create
it.\n\nUDFs need to be written in C, C++ or another language that uses C
calling\nconventions, MariaDB needs to have been dynamically compiled, and
your\noperating system must support dynamic loading.\n\nFor an example, see
sql/udf_example.cc in the source tree. For a collection of\nexisting UDFs
see http://www.mysqludf.org/.\n\nStatements making use of user-defined
functions are not safe for replication.\n\nFor creating a stored function
as opposed to a user-defined function, see\nCREATE FUNCTION.\n\nFor valid
identifiers to use as function names, see Identifier
Names.\n\nRETURNS\n-------\n\nThe RETURNS clause indicates the type of the
function\'s return value, and can\nbe one of STRING, INTEGER, REAL or
DECIMAL. DECIMAL functions currently return\nstring values and should be
written like STRING
functions.\n\nshared_library_name\n-------------------\n\nshared_library_name
is the basename of the shared object file that contains\nthe code that
implements the function. The file must be located in the plugin\ndirectory.
This directory is given by the value of the plugin_dir system\nvariable.
Note that before MariaDB/MySQL 5.1, the shared object could be\nlocated in
any directory that was searched by your system\'s dynamic
linker.\n\nAGGREGATE\n---------\n\nAggregate functions are summary
functions such as SUM() and AVG().\n\nMariaDB starting with
10.4\n--------------------------\nAggregate UDF functions can be used as
window functions.\n\nOR REPLACE\n----------\n\nMariaDB starting with
10.1.3\n----------------------------\nThe OR REPLACE clause was added in
MariaDB 10.1.3\n\nIf the optional OR REPLACE clause is used, it acts as a
shortcut for:\n\nDROP FUNCTION IF EXISTS function_name;\nCREATE FUNCTION
name ...;\n\nIF NOT EXISTS\n-------------\n\nMariaDB starting with
10.1.3\n----------------------------\nThe IF NOT EXISTS clause was added in
MariaDB 10.1.3\n\nWhen the IF NOT EXISTS clause is used, MariaDB will
return a warning instead\nof an error if the specified function already
exists. Cannot be used together\nwith OR REPLACE.\n\nUpgrading a
UDF\n---------------\n\nTo upgrade the UDF\'s shared library, first
run a DROP FUNCTION statement, then\nupgrade the shared library and finally
run the CREATE FUNCTION statement. If\nyou upgrade without following this
process, you may crash the server.\n\nExamples\n--------\n\nCREATE FUNCTION
jsoncontains_path RETURNS integer SONAME
\'ha_connect.so\';\nQuery OK, 0 rows affected (0.00 sec)\n\nOR
REPLACE and IF NOT EXISTS:\n\nCREATE FUNCTION jsoncontains_path RETURNS
integer SONAME \'ha_connect.so\';\nERROR 1125 (HY000): Function
\'jsoncontains_path\' already exists\n\nCREATE OR REPLACE
FUNCTION jsoncontains_path RETURNS integer
SONAME\n\'ha_connect.so\';\nQuery OK, 0 rows affected (0.00
sec)\n\nCREATE FUNCTION IF NOT EXISTS jsoncontains_path RETURNS integer
SONAME\n\'ha_connect.so\';\nQuery OK, 0 rows affected, 1 warning
(0.00 sec)\n\nSHOW
WARNINGS;\n+-------+------+---------------------------------------------+\n|
Level | Code | Message
|\n+-------+------+---------------------------------------------+\n| Note
| 1125 | Function \'jsoncontains_path\' already exists
|\n+-------+------+---------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/create-function-udf/','','https://mariadb.com/kb/en/create-function-udf/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(252,22,'DROP FUNCTION UDF','Syntax\n------\n\nDROP FUNCTION
[IF EXISTS] function_name\n\nDescription\n-----------\n\nThis statement
drops the user-defined function (UDF) named function_name.\n\nTo drop a
function, you must have the DELETE privilege for the mysql database.\nThis
is because DROP FUNCTION removes the row from the mysql.func system
table\nthat records the function\'s name, type and shared library
name.\n\nFor dropping a stored function, see DROP FUNCTION.\n\nUpgrading a
UDF\n---------------\n\nTo upgrade the UDF\'s shared library, first
run a DROP FUNCTION statement, then\nupgrade the shared library and finally
run the CREATE FUNCTION statement. If\nyou upgrade without following this
process, you may crash the server.\n\nExamples\n--------\n\nDROP FUNCTION
jsoncontains_path;\n\nIF EXISTS:\n\nDROP FUNCTION jsoncontains_path;\nERROR
1305 (42000): FUNCTION test.jsoncontains_path does not exist\n\nDROP
FUNCTION IF EXISTS jsoncontains_path;\nQuery OK, 0 rows affected, 1 warning
(0.00 sec)\n\nSHOW
WARNINGS;\n+-------+------+------------------------------------------------+\n|
Level | Code | Message
|\n+-------+------+------------------------------------------------+\n|
Note | 1305 | FUNCTION test.jsoncontains_path does not exist
|\n+-------+------+------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/drop-function-udf/','','https://mariadb.com/kb/en/drop-function-udf/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(253,22,'Creating User-Defined Functions','User-defined
functions allow MariaDB to be extended with a new function that\nworks like
a native (built-in) MariaDB function such as ABS() or CONCAT().\nThere are
alternative ways to add a new function: writing a native function\n(which
requires modifying and compiling the server source code), or writing
a\nstored function.\n\nStatements making use of user-defined functions are
not safe for replication.\n\nFunctions are written in C or C++, and to make
use of them, the operating\nsystem must support dynamic loading.\n\nEach
new SQL function requires corresponding functions written in C/C++. In\nthe
list below, at least the main function - x() - and one other,
are\nrequired. x should be replaced by the name of the function you are
creating.\n\nAll functions need to be thread-safe, so not global or static
variables that\nchange can be allocated. Memory is allocated in x_init()/
and freed in\nx_deinit().\n\nSimple
Functions\n----------------\n\nx()\n---\n\nRequired for all UDFs; this is
where the results are
calculated.\n\n+------------------------------------------+----------------------------------+\n|
C/C++ type | SQL type
|\n+------------------------------------------+----------------------------------+\n|
char * | STRING
|\n+------------------------------------------+----------------------------------+\n|
long long | INTEGER
|\n+------------------------------------------+----------------------------------+\n|
double | REAL
|\n+------------------------------------------+----------------------------------+\n\nDECIMAL
functions return string values, and so should be written accordingly.\nIt
is not possible to create ROW
functions.\n\nx_init()\n--------\n\nInitialization function for x(). Can be
used for the following:\n\n* Check the number of arguments to X() (the SQL
equivalent).\n* Verify the argument types, or to force arguments to be of a
particular type\nafter the function is called.\n* Specify whether the
result can be NULL.\n* Specify the maximum result length.\n* For REAL
functions, specify the maximum number of decimals for the result.\n*
Allocate any required
memory.\n\nx_deinit()\n----------\n\nDe-initialization function for x().
Used to de-allocate memory that was\nallocated in
x_init().\n\nDescription\n-----------\n\nEach time the SQL function X() is
called:\n\n* MariaDB will first call the C/C++ initialization function,
x_init(),\nassuming it exists. All setup will be performed, and if it
returns an error,\nthe SQL statement is aborted and no further functions
are called.\n* If there is no x_init() function, or it has been called and
did not return\nan error, x() is then called once per row.\n* After all
rows have finished processing, x_deinit() is called, if present,\nto clean
up by de-allocating any memory that was allocated in x_init().\n* See
User-defined Functions Calling Sequences for more details on
the\nfunctions.\n\nAggregate Functions\n-------------------\n\nThe
following functions are required for aggregate functions, such as
AVG()\nand SUM(). When using CREATE FUNCTION, the AGGREGATE keyword is
required.\n\nx_clear()\n---------\n\nUsed to reset the current aggregate,
but without inserting the argument as the\ninitial aggregate value for the
new group.\n\nx_add()\n-------\n\nUsed to add the argument to the current
aggregate.\n\nx_remove()\n----------\n\nStarting from MariaDB 10.4,
improves the support of window functions (so it is\nnot obligatory to add
it) and should remove the argument from the
current\naggregate.\n\nDescription\n-----------\n\nEach time the aggregate
SQL function X() is called:\n\n* MariaDB will first call the C/C++
initialization function, x_init(),\nassuming it exists. All setup will be
performed, and if it returns an error,\nthe SQL statement is aborted and no
further functions are called.\n* If there is no x_init() function, or it
has been called and did not return\nan error, x() is then called once per
row.\n* After all rows have finished processing, x_deinit() is called, if
present,\nto clean up by de-allocating any memory that was allocated in
x_init().\n\n* MariaDB will first call the C/C++ initialization function,
x_init(),\nassuming it exists. All setup will be performed, and if it
returns an error,\nthe SQL statement is aborted and no further functions
are called.\n* The table is sorted according to the GROUP BY expression.\n*
x_clear() is called for the first row of each new group.\n* x_add() is
called once per row for each row in the same group.\n* x() is called when
the group changes, or after the last row, to get the\naggregate result. \n*
The latter three steps are repeated until all rows have been processed.\n*
After all rows have finished processing, x_deinit() is called, if
present,\nto clean up by de-allocating any memory that was allocated in
x_init().\n\nExamples\n--------\n\nFor an example, see sql/udf_example.cc
in the source tree. For a collection of\nexisting UDFs see
https://github.com/mysqludf.\n\nURL:
https://mariadb.com/kb/en/creating-user-defined-functions/','','https://mariadb.com/kb/en/creating-user-defined-functions/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(254,22,'User-Defined Functions Calling Sequences','The
functions described in Creating User-defined Functions are expanded
on\nthis page. They are declared as follows:\n\nSimple
Functions\n----------------\n\nx()\n---\n\nIf x() returns an integer, it is
declared as follows:\n\nlong long x(UDF_INIT *initid, UDF_ARGS *args,\n
char *is_null, char *error);\n\nIf x() returns a string (DECIMAL
functions also return string values), it is\ndeclared as follows:\n\nchar
*x(UDF_INIT *initid, UDF_ARGS *args,\n char *result, unsigned long
*length,\n char *is_null, char *error);\n\nIf x() returns a real, it is
declared as follows:\n\ndouble x(UDF_INIT *initid, UDF_ARGS *args,\n
char *is_null, char *error);\n\nx_init()\n--------\n\nmy_bool
x_init(UDF_INIT *initid, UDF_ARGS *args, char
*message);\n\nx_deinit()\n----------\n\nvoid x_deinit(UDF_INIT
*initid);\n\nDescription\n-----------\n\ninitid is a parameter passed to
all three functions that points to a UDF_INIT\nstructure, used for
communicating information between the functions. Its\nstructure members
are:\n\n* my_bool maybe_null\nmaybe_null should be set to 1 if x_init can
return a NULL value, Defaults to 1\nif any arguments are declared
maybe_null.\n\n* unsigned int decimals\nNumber of decimals after the
decimal point. The default, if an explicit number\nof decimals is passed in
the arguments to the main function, is the maximum\nnumber of decimals, so
if 9.5, 9.55 and 9.555 are passed to the function, the\ndefault would be
three (based on 9.555, the maximum). If there are no\nexplicit number of
decimals, the default is set to 31, or one more than the\nmaximum for the
DOUBLE, FLOAT and DECIMAL types. This default can be changed\nin the
function to suit the actual calculation.\n\n* unsigned int
max_length\nMaximum length of the result. For integers, the default is 21.
For strings,\nthe length of the longest argument. For reals, the default is
13 plus the\nnumber of decimals indicated by initid->decimals. The
length includes any\nsigns or decimal points. Can also be set to 65KB or
16MB in order to return a\nBLOB. The memory remains unallocated, but this
is used to decide on the data\ntype to use if the data needs to be
temporarily stored.\n\n* char *ptr\nA pointer for use as required by the
function. Commonly, initid->ptr is used\nto communicate allocated
memory, with x_init() allocating the memory and\nassigning it to this
pointer, x() using it, and x_deinit() de-allocating it.\n\n* my_bool
const_item\nShould be set to 1 in x_init() if x() always returns the same
value, otherwise\n0.\n\nAggregate
Functions\n-------------------\n\nx_clear()\n---------\n\nx_clear() is a
required function for aggregate functions, and is declared
as\nfollows:\n\nvoid x_clear(UDF_INIT *initid, char *is_null, char
*error);\n\nIt is called when the summary results need to be reset, that is
at the\nbeginning of each new group. but also to reset the values when
there were no\nmatching rows.\n\nis_null is set to point to CHAR(0) before
calling x_clear().\n\nIn the case of an error, you can store the value to
which the error argument\npoints (a single-byte variable, not a string
string buffer) in the variable.\n\nx_reset()\n---------\n\nx_reset() is
declared as follows:\n\nvoid x_reset(UDF_INIT *initid, UDF_ARGS *args,\n
char *is_null, char *error);\n\nIt is called on finding the first row in
a new group. Should reset the summary\nvariables, and then use UDF_ARGS as
the first value in the group\'s internal\nsummary value. The function
is not required if the UDF interface
uses\nx_clear().\n\nx_add()\n-------\n\nx_add() is declared as
follows:\n\nvoid x_add(UDF_INIT *initid, UDF_ARGS *args,\n char
*is_null, char *error);\n\nIt is called for all rows belonging to the same
group, and should be used to\nadd the value in UDF_ARGS to the internal
summary variable.\n\nx_remove()\n----------\n\nx_remove() was added in
MariaDB 10.4 and is declared as follows (same as\nx_add()):\n\nvoid
x_remove(UDF_INIT* initid, UDF_ARGS* args,\n char* is_null, char
*error );\n\nIt adds more efficient support of aggregate UDFs as window
functions.\nx_remove() should \"subtract\" the row (reverse
x_add()). In MariaDB 10.4\naggregate UDFs will work as WINDOW functions
without x_remove() but it will\nnot be so efficient.\n\nIf x_remove()
supported (defined) detected automatically.\n\nURL:
https://mariadb.com/kb/en/user-defined-functions-calling-sequences/','','https://mariadb.com/kb/en/user-defined-functions-calling-sequences/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(255,22,'User-Defined Functions Security','The MariaDB
server imposes a number of limitations on user-defined functions\nfor
security purposes.\n\n* The INSERT privilege for the mysql database is
required to run CREATE\nFUNCTION, as a record will be added to the
mysql.func-table.\n* The DELETE privilege for the mysql database is
required to run DROP FUNCTION\nas the corresponding record will be removed
from the mysql.func-table.\n* UDF object files can only be placed in the
plugin directory, as specified by\nthe value of the plugin_dir system
variable.\n* At least one symbol, beyond the required x() - corresponding
to an SQL\nfunction X()) - is required. These can be x_init(), x_deinit(),
xxx_reset(),\nx_clear() and x_add() functions (see Creating User-defined
Functions). The\nallow-suspicious-udfs mysqld option (by default unset)
provides a workaround,\npermitting only one symbol to be used. This is not
recommended, as it opens\nthe possibility of loading shared objects that
are not legitimate user-defined\nfunctions.\n\nURL:
https://mariadb.com/kb/en/user-defined-functions-security/','','https://mariadb.com/kb/en/user-defined-functions-security/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(256,23,'Numeric Data Type Overview','There are a number of
numeric data types:\n\n* TINYINT\n* BOOLEAN - Synonym for TINYINT(1)\n*
INT1 - Synonym for TINYINT\n* SMALLINT\n* INT2 - Synonym for SMALLINT\n*
MEDIUMINT\n* INT3 - Synonym for MEDIUMINT\n* INT, INTEGER\n* INT4 - Synonym
for INT\n* BIGINT\n* INT8 - Synonym for BIGINT\n* DECIMAL, DEC, NUMERIC,
FIXED\n* FLOAT\n* DOUBLE, DOUBLE PRECISION, REAL\n* BIT\n\nSee the specific
articles for detailed information on each.\n\nSIGNED, UNSIGNED and
ZEROFILL\n-----------------------------\n\nMost numeric types can be
defined as SIGNED, UNSIGNED or ZEROFILL, for example:\n\nTINYINT[(M)]
[SIGNED | UNSIGNED | ZEROFILL]\n\nIf SIGNED, or no attribute, is specified,
a portion of the numeric type will\nbe reserved for the sign (plus or
minus). For example, a TINYINT SIGNED can\nrange from -128 to 127.\n\nIf
UNSIGNED is specified, no portion of the numeric type is reserved for
the\nsign, so for integer types range can be larger. For example, a
TINYINT\nUNSIGNED can range from 0 to 255. Floating point and fixed-point
types also\ncan be UNSIGNED, but this only prevents negative values from
being stored and\ndoesn\'t alter the range.\n\nIf ZEROFILL is
specified, the column will be set to UNSIGNED and the spaces\nused by
default to pad the field are replaced with zeros. ZEROFILL is ignored\nin
expressions or as part of a UNION. ZEROFILL is a non-standard MySQL
and\nMariaDB enhancement.\n\nNote that although the preferred syntax
indicates that the attributes are\nexclusive, more than one attribute can
be specified.\n\nUntil MariaDB 10.2.7 (MDEV-8659), any combination of the
attributes could be\nused in any order, with duplicates. In this case:\n\n*
the presence of ZEROFILL makes the column UNSIGNED ZEROFILL.\n* the
presence of UNSIGNED makes the column UNSIGNED.\n\nFrom MariaDB 10.2.8,
only the following combinations are supported:\n\n* SIGNED\n* UNSIGNED\n*
ZEROFILL\n* UNSIGNED ZEROFILL\n* ZEROFILL UNSIGNED\n\nThe latter two should
be replaced with simply ZEROFILL, but are still accepted\nby the
parser.\n\nExamples\n--------\n\nCREATE TABLE zf (\n i1 TINYINT SIGNED,\n
i2 TINYINT UNSIGNED,\n i3 TINYINT ZEROFILL\n);\n\nINSERT INTO zf VALUES
(2,2,2);\n\nSELECT * FROM zf;\n+------+------+------+\n| i1 | i2 | i3
|\n+------+------+------+\n| 2 | 2 | 002
|\n+------+------+------+\n\nRange\n-----\n\nWhen attempting to add a value
that is out of the valid range for the numeric\ntype, MariaDB will react
depending on the strict SQL_MODE setting.\n\nIf strict_mode has been set
(the default from MariaDB 10.2.4), MariaDB will\nreturn an error.\n\nIf
strict_mode has not been set (the default until MariaDB 10.2.3),
MariaDB\nwill adjust the number to fit in the field, returning a
warning.\n\nExamples\n--------\n\nWith strict_mode set:\n\nSHOW VARIABLES
LIKE
\'sql_mode\';\n+---------------+--------------------------------------------------------------\n----------------------------+\n|
Variable_name | Value
\n
|\n+---------------+--------------------------------------------------------------\n----------------------------+\n|
sql_mode
|\nSTRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SU\nSTITUTION
|\n+---------------+--------------------------------------------------------------\n----------------------------+\n\nCREATE
TABLE ranges (i1 TINYINT, i2 SMALLINT, i3 TINYINT UNSIGNED);\n\nINSERT INTO
ranges VALUES (257,257,257);\nERROR 1264 (22003): Out of range value for
column \'i1\' at row 1\n\nSELECT * FROM ranges;\nEmpty set (0.10
sec)\n\nWith strict_mode unset:\n\nSHOW VARIABLES LIKE
\'sql_mode%\';\n+---------------+-------+\n| Variable_name |
Value |\n+---------------+-------+\n| sql_mode |
|\n+---------------+-------+\n\nCREATE TABLE ranges (i1 TINYINT, i2
SMALLINT, i3 TINYINT UNSIGNED);\n\nINSERT INTO ranges VALUES
(257,257,257);\nQuery OK, 1 row affected, 2 warnings (0.00 sec)\n\nSHOW
WARNINGS;\n+---------+------+---------------------------------------------+\n|
Level | Code | Message
|\n+---------+------+---------------------------------------------+\n|
Warning | 1264 | Out of range value for column \'i1\' at row 1
|\n| Warning | 1264 | Out of range value for column \'i3\' at row
1 |\n+---------+------+---------------------------------------------+\n2
rows in set (0.00 sec)\n\nSELECT * FROM ranges;\n+------+------+------+\n|
i1 | i2 | i3 |\n+------+------+------+\n| 127 | 257 | 255
|\n+------+------+------+\n\nAuto_increment\n--------------\n\nThe
AUTO_INCREMENT attribute can be used to generate a unique identity for
new\nrows. For more details, see auto_increment.\n\nURL:
https://mariadb.com/kb/en/numeric-data-type-overview/','','https://mariadb.com/kb/en/numeric-data-type-overview/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(257,23,'TINYINT','Syntax\n------\n\nTINYINT[(M)] [SIGNED |
UNSIGNED | ZEROFILL]\n\nDescription\n-----------\n\nA very small integer.
The signed range is -128 to 127. The unsigned range is 0\nto 255. For
details on the attributes, see Numeric Data Type Overview.\n\nINT1 is a
synonym for TINYINT. BOOL and BOOLEAN are synonyms for
TINYINT(1).\n\nExamples\n--------\n\nCREATE TABLE tinyints (a TINYINT,b
TINYINT UNSIGNED,c TINYINT ZEROFILL);\n\nWith strict_mode set, the default
from MariaDB 10.2.4:\n\nINSERT INTO tinyints VALUES (-10,-10,-10);\nERROR
1264 (22003): Out of range value for column \'b\' at row
1\n\nINSERT INTO tinyints VALUES (-10,10,-10);\nERROR 1264 (22003): Out of
range value for column \'c\' at row 1\n\nINSERT INTO tinyints
VALUES (-10,10,10);\n\nSELECT * FROM tinyints;\n+------+------+------+\n| a
| b | c |\n+------+------+------+\n| -10 | 10 | 010
|\n+------+------+------+\n\nINSERT INTO tinyints VALUES
(128,128,128);\nERROR 1264 (22003): Out of range value for column
\'a\' at row 1\n\nINSERT INTO tinyints VALUES
(127,128,128);\n\nSELECT * FROM tinyints;\n+------+------+------+\n| a |
b | c |\n+------+------+------+\n| -10 | 10 | 010 |\n| 127 |
128 | 128 |\n+------+------+------+\n\nWith strict_mode unset, the default
until MariaDB 10.2.3:\n\nINSERT INTO tinyints VALUES (-10,-10,-10);\nQuery
OK, 1 row affected, 2 warnings (0.08 sec)\nWarning (Code 1264): Out of
range value for column \'b\' at row 1\nWarning (Code 1264): Out
of range value for column \'c\' at row 1\n\nINSERT INTO tinyints
VALUES (-10,10,-10);\nQuery OK, 1 row affected, 1 warning (0.11
sec)\nWarning (Code 1264): Out of range value for column \'c\' at
row 1\n\nINSERT INTO tinyints VALUES (-10,10,10);\n\nSELECT * FROM
tinyints;\n+------+------+------+\n| a | b | c
|\n+------+------+------+\n| -10 | 0 | 000 |\n| -10 | 10 | 000
|\n| -10 | 10 | 010 |\n+------+------+------+\n\nINSERT INTO tinyints
VALUES (128,128,128);\nQuery OK, 1 row affected, 1 warning (0.19
sec)\nWarning (Code 1264): Out of range value for column \'a\' at
row 1\n\nINSERT INTO tinyints VALUES (127,128,128);\n\nSELECT * FROM
tinyints;\n+------+------+------+\n| a | b | c
|\n+------+------+------+\n| -10 | 0 | 000 |\n| -10 | 10 | 000
|\n| -10 | 10 | 010 |\n| 127 | 128 | 128 |\n| 127 | 128 | 128
|\n+------+------+------+\n\nURL:
https://mariadb.com/kb/en/tinyint/','','https://mariadb.com/kb/en/tinyint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(258,23,'BOOLEAN','Syntax\n------\n\nBOOL,
BOOLEAN\n\nDescription\n-----------\n\nThese types are synonyms for
TINYINT(1). A value of zero is considered false.\nNon-zero values are
considered true.\n\nHowever, the values TRUE and FALSE are merely aliases
for 1 and 0. See Boolean\nLiterals, as well as the IS operator for testing
values against a boolean.\n\nExamples\n--------\n\nCREATE TABLE boo (i
BOOLEAN);\n\nDESC
boo;\n+-------+------------+------+-----+---------+-------+\n| Field | Type
| Null | Key | Default | Extra
|\n+-------+------------+------+-----+---------+-------+\n| i |
tinyint(1) | YES | | NULL |
|\n+-------+------------+------+-----+---------+-------+\n\nSELECT IF(0,
\'true\', \'false\');\n+------------------------+\n|
IF(0, \'true\', \'false\')
|\n+------------------------+\n| false
|\n+------------------------+\n\nSELECT IF(1, \'true\',
\'false\');\n+------------------------+\n| IF(1,
\'true\', \'false\') |\n+------------------------+\n|
true |\n+------------------------+\n\nSELECT IF(2,
\'true\', \'false\');\n+------------------------+\n|
IF(2, \'true\', \'false\')
|\n+------------------------+\n| true
|\n+------------------------+\n\nTRUE and FALSE as aliases for 1 and
0:\n\nSELECT IF(0 = FALSE, \'true\',
\'false\');\n\n+--------------------------------+\n| IF(0 =
FALSE, \'true\', \'false\')
|\n+--------------------------------+\n| true
|\n+--------------------------------+\n\nSELECT IF(1 = TRUE,
\'true\',
\'false\');\n+-------------------------------+\n| IF(1 = TRUE,
\'true\', \'false\')
|\n+-------------------------------+\n| true
|\n+-------------------------------+\n\nSELECT IF(2 = TRUE,
\'true\',
\'false\');\n+-------------------------------+\n| IF(2 = TRUE,
\'true\', \'false\')
|\n+-------------------------------+\n| false
|\n+-------------------------------+\n\nSELECT IF(2 = FALSE,
\'true\',
\'false\');\n+--------------------------------+\n| IF(2 = FALSE,
\'true\', \'false\')
|\n+--------------------------------+\n| false
|\n+--------------------------------+\n\nThe last two statements display
the results shown because 2 is equal to\nneither 1 nor 0.\n\nURL:
https://mariadb.com/kb/en/boolean/','','https://mariadb.com/kb/en/boolean/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(259,23,'SMALLINT','Syntax\n------\n\nSMALLINT[(M)] [SIGNED
| UNSIGNED | ZEROFILL]\n\nDescription\n-----------\n\nA small integer. The
signed range is -32768 to 32767. The unsigned range is 0\nto 65535.\n\nIf a
column has been set to ZEROFILL, all values will be prepended by zeros
so\nthat the SMALLINT value contains a number of M digits.\n\nNote: If the
ZEROFILL attribute has been specified, the column will\nautomatically
become UNSIGNED.\n\nINT2 is a synonym for SMALLINT.\n\nFor more details on
the attributes, see Numeric Data Type
Overview.\n\nExamples\n--------\n\nCREATE TABLE smallints (a SMALLINT,b
SMALLINT UNSIGNED,c SMALLINT ZEROFILL);\n\nWith strict_mode set, the
default from MariaDB 10.2.4:\n\nINSERT INTO smallints VALUES
(-10,-10,-10);\nERROR 1264 (22003): Out of range value for column
\'b\' at row 1\n\nINSERT INTO smallints VALUES
(-10,10,-10);\nERROR 1264 (22003): Out of range value for column
\'c\' at row 1\n\nINSERT INTO smallints VALUES
(-10,10,10);\n\nINSERT INTO smallints VALUES (32768,32768,32768);\nERROR
1264 (22003): Out of range value for column \'a\' at row
1\n\nINSERT INTO smallints VALUES (32767,32768,32768);\n\nSELECT * FROM
smallints;\n+-------+-------+-------+\n| a | b | c
|\n+-------+-------+-------+\n| -10 | 10 | 00010 |\n| 32767 | 32768 |
32768 |\n+-------+-------+-------+\n\nWith strict_mode unset, the default
until MariaDB 10.2.3:\n\nINSERT INTO smallints VALUES (-10,-10,-10);\nQuery
OK, 1 row affected, 2 warnings (0.09 sec)\nWarning (Code 1264): Out of
range value for column \'b\' at row 1\nWarning (Code 1264): Out
of range value for column \'c\' at row 1\n\nINSERT INTO smallints
VALUES (-10,10,-10);\nQuery OK, 1 row affected, 1 warning (0.08
sec)\nWarning (Code 1264): Out of range value for column \'c\' at
row 1\n\nINSERT INTO smallints VALUES (-10,10,10);\n\nINSERT INTO smallints
VALUES (32768,32768,32768);\nQuery OK, 1 row affected, 1 warning (0.04
sec)\nWarning (Code 1264): Out of range value for column \'a\' at
row 1\n\nINSERT INTO smallints VALUES (32767,32768,32768);\n\nSELECT * FROM
smallints;\n+-------+-------+-------+\n| a | b | c
|\n+-------+-------+-------+\n| -10 | 0 | 00000 |\n| -10 | 10 |
00000 |\n| -10 | 10 | 00010 |\n| 32767 | 32768 | 32768 |\n| 32767 |
32768 | 32768 |\n+-------+-------+-------+\n\nURL:
https://mariadb.com/kb/en/smallint/','','https://mariadb.com/kb/en/smallint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(260,23,'MEDIUMINT','Syntax\n------\n\nMEDIUMINT[(M)]
[SIGNED | UNSIGNED | ZEROFILL]\n\nDescription\n-----------\n\nA
medium-sized integer. The signed range is -8388608 to 8388607. The
unsigned\nrange is 0 to 16777215.\n\nZEROFILL pads the integer with zeroes
and assumes UNSIGNED (even if UNSIGNED\nis not specified).\n\nINT3 is a
synonym for MEDIUMINT.\n\nFor details on the attributes, see Numeric Data
Type Overview.\n\nExamples\n--------\n\nCREATE TABLE mediumints (a
MEDIUMINT,b MEDIUMINT UNSIGNED,c MEDIUMINT\nZEROFILL);\n\nDESCRIBE
mediumints;\n+-------+--------------------------------+------+-----+---------+-------+\n|
Field | Type | Null | Key | Default | Extra
|\n+-------+--------------------------------+------+-----+---------+-------+\n|
a | mediumint(9) | YES | | NULL | |\n|
b | mediumint(8) unsigned | YES | | NULL | |\n|
c | mediumint(8) unsigned zerofill | YES | | NULL |
|\n+-------+--------------------------------+------+-----+---------+-------+\n\nWith
strict_mode set, the default from MariaDB 10.2.4:\n\nINSERT INTO mediumints
VALUES (-10,-10,-10);\nERROR 1264 (22003): Out of range value for column
\'b\' at row 1\n\nINSERT INTO mediumints VALUES
(-10,10,-10);\nERROR 1264 (22003): Out of range value for column
\'c\' at row 1\n\nINSERT INTO mediumints VALUES
(-10,10,10);\n\nINSERT INTO mediumints VALUES
(8388608,8388608,8388608);\nERROR 1264 (22003): Out of range value for
column \'a\' at row 1\n\nINSERT INTO mediumints VALUES
(8388607,8388608,8388608);\n\nSELECT * FROM
mediumints;\n+---------+---------+----------+\n| a | b | c
|\n+---------+---------+----------+\n| -10 | 10 | 00000010 |\n|
8388607 | 8388608 | 08388608 |\n+---------+---------+----------+\n\nWith
strict_mode unset, the default until MariaDB 10.2.3:\n\nINSERT INTO
mediumints VALUES (-10,-10,-10);\nQuery OK, 1 row affected, 2 warnings
(0.05 sec)\nWarning (Code 1264): Out of range value for column
\'b\' at row 1\nWarning (Code 1264): Out of range value for
column \'c\' at row 1\n\nINSERT INTO mediumints VALUES
(-10,10,-10);\nQuery OK, 1 row affected, 1 warning (0.08 sec)\nWarning
(Code 1264): Out of range value for column \'c\' at row
1\n\nINSERT INTO mediumints VALUES (-10,10,10);\n\nINSERT INTO mediumints
VALUES (8388608,8388608,8388608);\nQuery OK, 1 row affected, 1 warning
(0.05 sec)\nWarning (Code 1264): Out of range value for column
\'a\' at row 1\n\nINSERT INTO mediumints VALUES
(8388607,8388608,8388608);\n\nSELECT * FROM
mediumints;\n+---------+---------+----------+\n| a | b | c
|\n+---------+---------+----------+\n| -10 | 0 | 00000000 |\n|
-10 | 0 | 00000000 |\n| -10 | 10 | 00000000 |\n| -10
| 10 | 00000010 |\n| 8388607 | 8388608 | 08388608 |\n| 8388607 |
8388608 | 08388608 |\n+---------+---------+----------+\n\nURL:
https://mariadb.com/kb/en/mediumint/','','https://mariadb.com/kb/en/mediumint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(261,23,'INT','Syntax\n------\n\nINT[(M)] [SIGNED | UNSIGNED
| ZEROFILL]\nINTEGER[(M)] [SIGNED | UNSIGNED |
ZEROFILL]\n\nDescription\n-----------\n\nA normal-size integer. When marked
UNSIGNED, it ranges from 0 to 4294967295,\notherwise its range is
-2147483648 to 2147483647 (SIGNED is the default). If a\ncolumn has been
set to ZEROFILL, all values will be prepended by zeros so that\nthe INT
value contains a number of M digits. INTEGER is a synonym for INT.\n\nNote:
If the ZEROFILL attribute has been specified, the column
will\nautomatically become UNSIGNED.\n\nINT4 is a synonym for INT.\n\nFor
details on the attributes, see Numeric Data Type
Overview.\n\nExamples\n--------\n\nCREATE TABLE ints (a INT,b INT
UNSIGNED,c INT ZEROFILL);\n\nWith strict_mode set, the default from MariaDB
10.2.4:\n\nINSERT INTO ints VALUES (-10,-10,-10);\nERROR 1264 (22003): Out
of range value for column \'b\' at row 1\n\nINSERT INTO ints
VALUES (-10,10,-10);\nERROR 1264 (22003): Out of range value for column
\'c\' at row 1\n\nINSERT INTO ints VALUES (-10,10,10);\n\nINSERT
INTO ints VALUES (2147483648,2147483648,2147483648);\nERROR 1264 (22003):
Out of range value for column \'a\' at row 1\n\nINSERT INTO ints
VALUES (2147483647,2147483648,2147483648);\n\nSELECT * FROM
ints;\n+------------+------------+------------+\n| a | b
| c |\n+------------+------------+------------+\n| -10 |
10 | 0000000010 |\n| 2147483647 | 2147483648 | 2147483648
|\n+------------+------------+------------+\n\nWith strict_mode unset, the
default until MariaDB 10.2.3:\n\nINSERT INTO ints VALUES
(-10,-10,-10);\nQuery OK, 1 row affected, 2 warnings (0.10 sec)\nWarning
(Code 1264): Out of range value for column \'b\' at row
1\nWarning (Code 1264): Out of range value for column \'c\' at
row 1\n\nINSERT INTO ints VALUES (-10,10,-10);\nQuery OK, 1 row affected, 1
warning (0.08 sec)\nWarning (Code 1264): Out of range value for column
\'c\' at row 1\n\nINSERT INTO ints VALUES (-10,10,10);\n\nINSERT
INTO ints VALUES (2147483648,2147483648,2147483648);\nQuery OK, 1 row
affected, 1 warning (0.07 sec)\nWarning (Code 1264): Out of range value for
column \'a\' at row 1\n\nINSERT INTO ints VALUES
(2147483647,2147483648,2147483648);\n\nSELECT * FROM
ints;\n+------------+------------+------------+\n| a | b
| c |\n+------------+------------+------------+\n| -10 |
0 | 0000000000 |\n| -10 | 10 | 0000000000 |\n|
-10 | 10 | 0000000010 |\n| 2147483647 | 2147483648 | 2147483648
|\n| 2147483647 | 2147483648 | 2147483648
|\n+------------+------------+------------+\n\nURL:
https://mariadb.com/kb/en/int/','','https://mariadb.com/kb/en/int/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(262,23,'BIGINT','Syntax\n------\n\nBIGINT[(M)] [SIGNED |
UNSIGNED | ZEROFILL]\n\nDescription\n-----------\n\nA large integer. The
signed range is -9223372036854775808 to\n9223372036854775807. The unsigned
range is 0 to 18446744073709551615.\n\nIf a column has been set to
ZEROFILL, all values will be prepended by zeros so\nthat the BIGINT value
contains a number of M digits.\n\nNote: If the ZEROFILL attribute has been
specified, the column will\nautomatically become UNSIGNED.\n\nFor more
details on the attributes, see Numeric Data Type Overview.\n\nSERIAL is an
alias for:\n\nBIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE\n\nINT8 is a
synonym for BIGINT.\n\nExamples\n--------\n\nCREATE TABLE bigints (a
BIGINT,b BIGINT UNSIGNED,c BIGINT ZEROFILL);\n\nWith strict_mode set, the
default from MariaDB 10.2.4:\n\nINSERT INTO bigints VALUES
(-10,-10,-10);\nERROR 1264 (22003): Out of range value for column
\'b\' at row 1\n\nINSERT INTO bigints VALUES (-10,10,-10);\nERROR
1264 (22003): Out of range value for column \'c\' at row
1\n\nINSERT INTO bigints VALUES (-10,10,10);\n\nINSERT INTO bigints
VALUES\n(9223372036854775808,9223372036854775808,9223372036854775808);\nERROR
1264 (22003): Out of range value for column \'a\' at row
1\n\nINSERT INTO bigints
VALUES\n(9223372036854775807,9223372036854775808,9223372036854775808);\n\nSELECT
* FROM
bigints;\n+---------------------+---------------------+----------------------+\n|
a | b | c
|\n+---------------------+---------------------+----------------------+\n|
-10 | 10 | 00000000000000000010 |\n|
9223372036854775807 | 9223372036854775808 | 09223372036854775808
|\n+---------------------+---------------------+----------------------+\n\nWith
strict_mode unset, the default until MariaDB 10.2.3:\n\nINSERT INTO bigints
VALUES (-10,-10,-10);\nQuery OK, 1 row affected, 2 warnings (0.08
sec)\nWarning (Code 1264): Out of range value for column \'b\' at
row 1\nWarning (Code 1264): Out of range value for column \'c\'
at row 1\n\nINSERT INTO bigints VALUES (-10,10,-10);\nQuery OK, 1 row
affected, 1 warning (0.08 sec)\nWarning (Code 1264): Out of range value for
column \'c\' at row 1\n\nINSERT INTO bigints VALUES
(-10,10,10);\n\nINSERT INTO bigints
VALUES\n(9223372036854775808,9223372036854775808,9223372036854775808);\nQuery
OK, 1 row affected, 1 warning (0.07 sec)\nWarning (Code 1264): Out of range
value for column \'a\' at row 1\n\nINSERT INTO bigints
VALUES\n(9223372036854775807,9223372036854775808,9223372036854775808);\n\nSELECT
* FROM
bigints;\n+---------------------+---------------------+----------------------+\n|
a | b | c
|\n+---------------------+---------------------+----------------------+\n|
-10 | 0 | 00000000000000000000 |\n|
-10 | 10 | 00000000000000000000 |\n|
-10 | 10 | 00000000000000000010 |\n|
9223372036854775807 | 9223372036854775808 | 09223372036854775808 |\n|
9223372036854775807 | 9223372036854775808 | 09223372036854775808
|\n+---------------------+---------------------+----------------------+\n\nURL:
https://mariadb.com/kb/en/bigint/','','https://mariadb.com/kb/en/bigint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(263,23,'DECIMAL','Syntax\n------\n\nDECIMAL[(M[,D])]
[SIGNED | UNSIGNED | ZEROFILL]\n\nDescription\n-----------\n\nA packed
\"exact\" fixed-point number. M is the total number of digits
(the\nprecision) and D is the number of digits after the decimal point (the
scale).\n\n* The decimal point and (for negative numbers) the
\"-\" sign are not\ncounted in M. \n* If D is 0, values have no
decimal point or fractional\npart and on INSERT the value will be rounded
to the nearest DECIMAL. \n* The maximum number of digits (M) for DECIMAL is
65. \n* The maximum number of supported decimals (D) is 30 before MariadB
10.2.1 and\n38 afterwards. \n* If D is omitted, the default is 0. If M is
omitted, the default is 10.\n\nUNSIGNED, if specified, disallows negative
values.\n\nZEROFILL, if specified, pads the number with zeros, up to the
total number of\ndigits specified by M.\n\nAll basic calculations (+, -, *,
/) with DECIMAL columns are done with a\nprecision of 65 digits.\n\nFor
more details on the attributes, see Numeric Data Type Overview.\n\nDEC,
NUMERIC and FIXED are synonyms, as well as NUMBER in Oracle mode
from\nMariaDB 10.3.\n\nExamples\n--------\n\nCREATE TABLE t1 (d DECIMAL
UNSIGNED ZEROFILL);\n\nINSERT INTO t1 VALUES
(1),(2),(3),(4.0),(5.2),(5.7);\nQuery OK, 6 rows affected, 2 warnings (0.16
sec)\nRecords: 6 Duplicates: 0 Warnings: 2\n\nNote (Code 1265): Data
truncated for column \'d\' at row 5\nNote (Code 1265): Data
truncated for column \'d\' at row 6\n\nSELECT * FROM
t1;\n+------------+\n| d |\n+------------+\n| 0000000001 |\n|
0000000002 |\n| 0000000003 |\n| 0000000004 |\n| 0000000005 |\n| 0000000006
|\n+------------+\n\nWith strict_mode set, the default from MariaDB
10.2.4:\n\nINSERT INTO t1 VALUES (-7);\nERROR 1264 (22003): Out of range
value for column \'d\' at row 1\n\nWith strict_mode unset, the
default until MariaDB 10.2.3:\n\nINSERT INTO t1 VALUES (-7);\nQuery OK, 1
row affected, 1 warning (0.02 sec)\nWarning (Code 1264): Out of range value
for column \'d\' at row 1\n\nSELECT * FROM t1;\n+------------+\n|
d |\n+------------+\n| 0000000001 |\n| 0000000002 |\n| 0000000003
|\n| 0000000004 |\n| 0000000005 |\n| 0000000006 |\n| 0000000000
|\n+------------+\n\nURL:
https://mariadb.com/kb/en/decimal/','','https://mariadb.com/kb/en/decimal/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(264,23,'FLOAT','Syntax\n------\n\nFLOAT[(M,D)] [SIGNED |
UNSIGNED | ZEROFILL]\n\nDescription\n-----------\n\nA small
(single-precision) floating-point number (see DOUBLE for a\nregular-size
floating point number). Allowable values are:\n\n* -3.402823466E+38 to
-1.175494351E-38\n* 0\n* 1.175494351E-38 to 3.402823466E+38.\n\nThese are
the theoretical limits, based on the IEEE standard. The actual range\nmight
be slightly smaller depending on your hardware or operating system.\n\nM is
the total number of digits and D is the number of digits following
the\ndecimal point. If M and D are omitted, values are stored to the limits
allowed\nby the hardware. A single-precision floating-point number is
accurate to\napproximately 7 decimal places.\n\nUNSIGNED, if specified,
disallows negative values.\n\nUsing FLOAT might give you some unexpected
problems because all calculations\nin MariaDB are done with double
precision. See Floating Point Accuracy.\n\nFor more details on the
attributes, see Numeric Data Type Overview.\n\nURL:
https://mariadb.com/kb/en/float/','','https://mariadb.com/kb/en/float/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(265,23,'DOUBLE','Syntax\n------\n\nDOUBLE[(M,D)] [SIGNED |
UNSIGNED | ZEROFILL]\nDOUBLE PRECISION[(M,D)] [SIGNED | UNSIGNED |
ZEROFILL]\nREAL[(M,D)] [SIGNED | UNSIGNED |
ZEROFILL]\n\nDescription\n-----------\n\nA normal-size (double-precision)
floating-point number (see FLOAT for a\nsingle-precision floating-point
number).\n\nAllowable values are:\n\n* -1.7976931348623157E+308 to
-2.2250738585072014E-308\n* 0\n* 2.2250738585072014E-308 to
1.7976931348623157E+308\n\nThese are the theoretical limits, based on the
IEEE standard. The actual range\nmight be slightly smaller depending on
your hardware or operating system.\n\nM is the total number of digits and D
is the number of digits following the\ndecimal point. If M and D are
omitted, values are stored to the limits allowed\nby the hardware. A
double-precision floating-point number is accurate to\napproximately 15
decimal places.\n\nUNSIGNED, if specified, disallows negative
values.\n\nZEROFILL, if specified, pads the number with zeros, up to the
total number of\ndigits specified by M.\n\nREAL and DOUBLE PRECISION are
synonyms, unless the REAL_AS_FLOAT SQL mode is\nenabled, in which case REAL
is a synonym for FLOAT rather than DOUBLE.\n\nSee Floating Point Accuracy
for issues when using floating-point numbers.\n\nFor more details on the
attributes, see Numeric Data Type Overview.\n\nExamples\n--------\n\nCREATE
TABLE t1 (d DOUBLE(5,0) zerofill);\n\nINSERT INTO t1 VALUES
(1),(2),(3),(4);\n\nSELECT * FROM t1;\n+-------+\n| d |\n+-------+\n|
00001 |\n| 00002 |\n| 00003 |\n| 00004 |\n+-------+\n\nURL:
https://mariadb.com/kb/en/double/','','https://mariadb.com/kb/en/double/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(266,23,'BIT','Syntax\n------\n\nBIT[(M)]\n\nDescription\n-----------\n\nA
bit-field type. M indicates the number of bits per value, from 1 to 64.
The\ndefault is 1 if M is omitted.\n\nBit values can be inserted with
b\'value\' notation, where value is the bit\nvalue in 0\'s
and 1\'s.\n\nBit fields are automatically zero-padded from the left to
the full length of\nthe bit, so for example in a BIT(4) field,
\'10\' is equivalent to \'0010\'.\n\nBits are returned
as binary, so to display them, either add 0, or use a\nfunction such as
HEX, OCT or BIN to convert them.\n\nExamples\n--------\n\nCREATE TABLE b (
b1 BIT(8) );\n\nWith strict_mode set, the default from MariaDB
10.2.4:\n\nINSERT INTO b VALUES (b\'11111111\');\n\nINSERT INTO b
VALUES (b\'01010101\');\n\nINSERT INTO b VALUES
(b\'1111111111111\');\nERROR 1406 (22001): Data too long for
column \'b1\' at row 1\n\nSELECT b1+0, HEX(b1), OCT(b1), BIN(b1)
FROM b;\n+------+---------+---------+----------+\n| b1+0 | HEX(b1) |
OCT(b1) | BIN(b1) |\n+------+---------+---------+----------+\n| 255 | FF
| 377 | 11111111 |\n| 85 | 55 | 125 | 1010101
|\n+------+---------+---------+----------+\n\nWith strict_mode unset, the
default until MariaDB 10.2.3:\n\nINSERT INTO b VALUES
(b\'11111111\'),(b\'01010101\'),(b\'1111111111111\');\nQuery
OK, 3 rows affected, 1 warning (0.10 sec)\nRecords: 3 Duplicates: 0
Warnings: 1\n\nSHOW
WARNINGS;\n+---------+------+---------------------------------------------+\n|
Level | Code | Message
|\n+---------+------+---------------------------------------------+\n|
Warning | 1264 | Out of range value for column \'b1\' at row 3
|\n+---------+------+---------------------------------------------+\n\nSELECT
b1+0, HEX(b1), OCT(b1), BIN(b1) FROM
b;\n+------+---------+---------+----------+\n| b1+0 | HEX(b1) | OCT(b1) |
BIN(b1) |\n+------+---------+---------+----------+\n| 255 | FF | 377
| 11111111 |\n| 85 | 55 | 125 | 1010101 |\n| 255 | FF
| 377 | 11111111 |\n+------+---------+---------+----------+\n\nURL:
https://mariadb.com/kb/en/bit/','','https://mariadb.com/kb/en/bit/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(267,23,'Floating-point Accuracy','Due to their nature, not
all floating-point numbers can be stored with exact\nprecision. Hardware
architecture, the CPU or even the compiler version and\noptimization level
may affect the precision.\n\nIf you are comparing DOUBLEs or FLOATs with
numeric decimals, it is not safe\nto use the equality
operator.\n\nSometimes, changing a floating-point number from
single-precision (FLOAT) to\ndouble-precision (DOUBLE) will fix the
problem.\n\nExample\n-------\n\nf1, f2 and f3 have seemingly identical
values across each row, but due to\nfloating point accuracy, the results
may be unexpected.\n\nCREATE TABLE fpn (id INT, f1 FLOAT, f2 DOUBLE, f3
DECIMAL (10,3));\nINSERT INTO fpn VALUES
(1,2,2,2),(2,0.1,0.1,0.1);\n\nSELECT * FROM fpn WHERE f1*f1 =
f2*f2;\n+------+------+------+-------+\n| id | f1 | f2 | f3
|\n+------+------+------+-------+\n| 1 | 2 | 2 | 2.000
|\n+------+------+------+-------+\n\nThe reason why only one instead of two
rows was returned becomes clear when we\nsee how the floating point squares
were evaluated.\n\nSELECT f1*f1, f2*f2, f3*f3 FROM
fpn;\n+----------------------+----------------------+----------+\n| f1*f1
| f2*f2 | f3*f3
|\n+----------------------+----------------------+----------+\n|
4 | 4 | 4.000000 |\n| 0.010000000298023226 |
0.010000000000000002 | 0.010000
|\n+----------------------+----------------------+----------+\n\nURL:
https://mariadb.com/kb/en/floating-point-accuracy/','','https://mariadb.com/kb/en/floating-point-accuracy/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(268,23,'BINARY','This page describes the BINARY data type.
For details about the operator, see\nBinary
Operator.\n\nSyntax\n------\n\nBINARY(M)\n\nDescription\n-----------\n\nThe
BINARY type is similar to the CHAR type, but stores binary byte
strings\nrather than non-binary character strings. M represents the column
length in\nbytes.\n\nIt contains no character set, and comparison and
sorting are based on the\nnumeric value of the bytes.\n\nIf the maximum
length is exceeded, and SQL strict mode is not enabled , the\nextra
characters will be dropped with a warning. If strict mode is enabled,
an\nerror will occur.\n\nBINARY values are right-padded with 0x00 (the zero
byte) to the specified\nlength when inserted. The padding is not removed on
select, so this needs to\nbe taken into account when sorting and comparing,
where all bytes are\nsignificant. The zero byte, 0x00 is less than a space
for comparison purposes.\n\nExamples\n--------\n\nInserting too many
characters, first with strict mode off, then with it on:\n\nCREATE TABLE
bins (a BINARY(10));\n\nINSERT INTO bins
VALUES(\'12345678901\');\nQuery OK, 1 row affected, 1 warning
(0.04 sec)\n\nSELECT * FROM bins;\n+------------+\n| a
|\n+------------+\n| 1234567890 |\n+------------+\n\nSET
sql_mode=\'STRICT_ALL_TABLES\';\n\nINSERT INTO bins
VALUES(\'12345678901\');\nERROR 1406 (22001): Data too long for
column \'a\' at row 1\n\nSorting is performed with the byte
value:\n\nTRUNCATE bins;\n\nINSERT INTO bins
VALUES(\'A\'),(\'B\'),(\'a\'),(\'b\');\n\nSELECT
* FROM bins ORDER BY a;\n+------+\n| a |\n+------+\n| A |\n| B
|\n| a |\n| b |\n+------+\n\nUsing CAST to sort as a CHAR
instead:\n\nSELECT * FROM bins ORDER BY CAST(a AS CHAR);\n+------+\n| a
|\n+------+\n| a |\n| A |\n| b |\n| B |\n+------+\n\nThe field
is a BINARY(10), so padding of two \'\\0\'s are inserted,
causing\ncomparisons that don\'t take this into account to
fail:\n\nTRUNCATE bins;\n\nINSERT INTO bins
VALUES(\'12345678\');\n\nSELECT a = \'12345678\', a =
\'12345678\\0\\0\' from
bins;\n+----------------+--------------------+\n| a =
\'12345678\' | a = \'12345678\\0\\0\'
|\n+----------------+--------------------+\n| 0 |
1 |\n+----------------+--------------------+\n\nURL:
https://mariadb.com/kb/en/binary/','','https://mariadb.com/kb/en/binary/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(269,23,'BLOB','Syntax\n------\n\nBLOB[(M)]\n\nDescription\n-----------\n\nA
BLOB column with a maximum length of 65,535 (216 - 1) bytes. Each BLOB
value\nis stored using a two-byte length prefix that indicates the number
of bytes in\nthe value.\n\nAn optional length M can be given for this type.
If this is done, MariaDB\ncreates the column as the smallest BLOB type
large enough to hold values M\nbytes long.\n\nBLOBS can also be used to
store dynamic columns.\n\nBefore MariaDB 10.2.1, BLOB and TEXT columns
could not be assigned a DEFAULT\nvalue. This restriction was lifted in
MariaDB 10.2.1.\n\nIndexing\n--------\n\nMariaDB starting with
10.4\n--------------------------\nFrom MariaDB 10.4, it is possible to set
a unique index on a column that uses\nthe BLOB data type. In previous
releases this was not possible, as the index\nwould only guarantee the
uniqueness of a fixed number of characters.\n\nOracle
Mode\n-----------\n\nMariaDB starting with
10.3\n--------------------------\nIn Oracle mode from MariaDB 10.3, BLOB is
a synonym for LONGBLOB.\n\nURL:
https://mariadb.com/kb/en/blob/','','https://mariadb.com/kb/en/blob/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(270,23,'BLOB and TEXT Data
Types','Description\n-----------\n\nA BLOB is a binary large
object that can hold a variable amount of data. The\nfour BLOB types
are\n\n* TINYBLOB,\n* BLOB, \n* MEDIUMBLOB, and\n* LONGBLOB.\n\nThese
differ only in the maximum length of the values they can hold.\n\nThe TEXT
types are\n\n* TINYTEXT,\n* TEXT,\n* MEDIUMTEXT, and\n* LONGTEXT.\n* JSON
(alias for LONGTEXT)\n\nThese correspond to the four BLOB types and have
the same maximum lengths and\nstorage requirements.\n\nMariaDB starting
with 10.2.1\n----------------------------\nStarting from MariaDB 10.2.1,
BLOB and TEXT columns can have a DEFAULT value.\n\nMariaDB starting with
10.4.3\n----------------------------\nFrom MariaDB 10.4, it is possible to
set a unique index on columns that use\nthe BLOB or TEXT data
types.\n\nURL:
https://mariadb.com/kb/en/blob-and-text-data-types/','','https://mariadb.com/kb/en/blob-and-text-data-types/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(271,23,'CHAR','This article covers the CHAR data type. See
CHAR Function for the function.\n\nSyntax\n------\n\n[NATIONAL] CHAR[(M)]
[CHARACTER SET charset_name] [COLLATE
collation_name]\n\nDescription\n-----------\n\nA fixed-length string that
is always right-padded with spaces to the specified\nlength when stored. M
represents the column length in characters. The range of\nM is 0 to 255. If
M is omitted, the length is 1.\n\nCHAR(0) columns can contain 2 values: an
empty string or NULL. Such columns\ncannot be part of an index. The CONNECT
storage engine does not support\nCHAR(0).\n\nNote: Trailing spaces are
removed when CHAR values are retrieved unless the\nPAD_CHAR_TO_FULL_LENGTH
SQL mode is enabled.\n\nBefore MariaDB 10.2, all collations were of type
PADSPACE, meaning that CHAR\n(as well as VARCHAR and TEXT) values are
compared without regard for trailing\nspaces. This does not apply to the
LIKE pattern-matching operator, which takes\ninto account trailing
spaces.\n\nIf a unique index consists of a column where trailing pad
characters are\nstripped or ignored, inserts into that column where values
differ only by the\nnumber of trailing pad characters will result in a
duplicate-key error.\n\nExamples\n--------\n\nTrailing spaces:\n\nCREATE
TABLE strtest (c CHAR(10));\nINSERT INTO strtest VALUES(\'Maria
\');\n\nSELECT c=\'Maria\',c=\'Maria \' FROM
strtest;\n+-----------+--------------+\n| c=\'Maria\' |
c=\'Maria \' |\n+-----------+--------------+\n| 1 |
1 |\n+-----------+--------------+\n\nSELECT c LIKE
\'Maria\',c LIKE \'Maria \' FROM
strtest;\n+----------------+-------------------+\n| c LIKE
\'Maria\' | c LIKE \'Maria \'
|\n+----------------+-------------------+\n| 1 |
0 |\n+----------------+-------------------+\n\nNO PAD
Collations\n-----------------\n\nNO PAD collations regard trailing spaces
as normal characters. You can get a\nlist of all NO PAD collations by
querying the Information Schema Collations\ntable, for example:\n\nSELECT
collation_name FROM information_schema.collations \n WHERE collation_name
LIKE \"%nopad%\";\n+------------------------------+\n|
collation_name |\n+------------------------------+\n|
big5_chinese_nopad_ci |\n| big5_nopad_bin
|\n...\n\nURL:
https://mariadb.com/kb/en/char/','','https://mariadb.com/kb/en/char/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(272,23,'CHAR BYTE','Description\n-----------\n\nThe CHAR
BYTE data type is an alias for the BINARY data type. This is
a\ncompatibility feature.\n\nURL:
https://mariadb.com/kb/en/char-byte/','','https://mariadb.com/kb/en/char-byte/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(273,23,'ENUM','Syntax\n------\n\nENUM(\'value1\',\'value2\',...)
[CHARACTER SET charset_name]
[COLLATE\ncollation_name]\n\nDescription\n-----------\n\nAn enumeration. A
string object that can have only one value, chosen from the\nlist of values
\'value1\', \'value2\', ..., NULL or the special
\'\' error value. In\ntheory, an ENUM column can have a maximum
of 65,535 distinct values; in\npractice, the real maximum depends on many
factors. ENUM values are\nrepresented internally as integers.\n\nTrailing
spaces are automatically stripped from ENUM values on table
creation.\n\nENUMs require relatively little storage space compared to
strings, either one\nor two bytes depending on the number of enumeration
values.\n\nNULL and empty values\n---------------------\n\nAn ENUM can also
contain NULL and empty values. If the ENUM column is declared\nto permit
NULL values, NULL becomes a valid value, as well as the default\nvalue (see
below). If strict SQL Mode is not enabled, and an invalid value
is\ninserted into an ENUM, a special empty string, with an index value of
zero\n(see Numeric index, below), is inserted, with a warning. This may
be\nconfusing, because the empty string is also a possible value, and the
only\ndifference if that is this case its index is not 0. Inserting will
fail with\nan error if strict mode is active.\n\nIf a DEFAULT clause is
missing, the default value will be:\n\n* NULL if the column is nullable;\n*
otherwise, the first value in the enumeration.\n\nNumeric
index\n-------------\n\nENUM values are indexed numerically in the order
they are defined, and sorting\nwill be performed in this numeric order. We
suggest not using ENUM to store\nnumerals, as there is little to no storage
space benefit, and it is easy to\nconfuse the enum integer with the enum
numeral value by leaving out the quotes.\n\nAn ENUM defined as
ENUM(\'apple\',\'orange\',\'pear\') would
have the following\nindex
values:\n\n+--------------------------------------+--------------------------------------+\n|
Index | Value
|\n+--------------------------------------+--------------------------------------+\n|
NULL | NULL
|\n+--------------------------------------+--------------------------------------+\n|
0 | \'\'
|\n+--------------------------------------+--------------------------------------+\n|
1 | \'apple\'
|\n+--------------------------------------+--------------------------------------+\n|
2 | \'orange\'
|\n+--------------------------------------+--------------------------------------+\n|
3 | \'pear\'
|\n+--------------------------------------+--------------------------------------+\n\nExamples\n--------\n\nCREATE
TABLE fruits (\n id INT NOT NULL auto_increment PRIMARY KEY,\n fruit
ENUM(\'apple\',\'orange\',\'pear\'),\n
bushels INT);\n\nDESCRIBE
fruits;\n+---------+-------------------------------+------+-----+---------+-------------\n--+\n|
Field | Type | Null | Key | Default | Extra
\n
|\n+---------+-------------------------------+------+-----+---------+-------------\n--+\n|
id | int(11) | NO | PRI | NULL
|\nauto_increment |\n| fruit |
enum(\'apple\',\'orange\',\'pear\') | YES |
| NULL | \n |\n| bushels | int(11) |
YES | | NULL | \n
|\n+---------+-------------------------------+------+-----+---------+-------------\n--+\n\nINSERT
INTO fruits\n (fruit,bushels) VALUES\n (\'pear\',20),\n
(\'apple\',100),\n (\'orange\',25);\n\nINSERT INTO
fruits\n (fruit,bushels) VALUES\n (\'avocado\',10);\nERROR 1265
(01000): Data truncated for column \'fruit\' at row 1\n\nSELECT *
FROM fruits;\n+----+--------+---------+\n| id | fruit | bushels
|\n+----+--------+---------+\n| 1 | pear | 20 |\n| 2 | apple |
100 |\n| 3 | orange | 25 |\n+----+--------+---------+\n\nSelecting
by numeric index:\n\nSELECT * FROM fruits WHERE
fruit=2;\n+----+--------+---------+\n| id | fruit | bushels
|\n+----+--------+---------+\n| 3 | orange | 25
|\n+----+--------+---------+\n\nSorting is according to the index
value:\n\nCREATE TABLE enums (a
ENUM(\'2\',\'1\'));\n\nINSERT INTO enums VALUES
(\'1\'),(\'2\');\n\nSELECT * FROM enums ORDER BY a
ASC;\n+------+\n| a |\n+------+\n| 2 |\n| 1
|\n+------+\n\nIt\'s easy to get confused between returning the enum
integer with the stored\nvalue, so we don\'t suggest using ENUM to
store numerals. The first example\nreturns the 1st indexed field
(\'2\' has an index value of 1, as it\'s defined\nfirst),
while the second example returns the string value
\'1\'.\n\nSELECT * FROM enums WHERE a=1;\n+------+\n| a
|\n+------+\n| 2 |\n+------+\n\nSELECT * FROM enums WHERE
a=\'1\';\n+------+\n| a |\n+------+\n| 1
|\n+------+\n\nURL:
https://mariadb.com/kb/en/enum/','','https://mariadb.com/kb/en/enum/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(274,23,'INET6','MariaDB starting with
10.5.0\n----------------------------\nThe INET6 data type was added in
MariaDB
10.5.0\n\nSyntax\n------\n\nINET6\n\nDescription\n-----------\n\nThe INET6
data type is intended for storage of IPv6 addresses, as well as
IPv4\naddresses assuming conventional mapping of IPv4 addresses into IPv6
addresses.\n\nBoth short and long IPv6 notation are permitted, according to
RFC-5952.\n\n* Values are stored as a 16-byte fixed length binary string,
with most\nsignificant byte first.\n* Storage engines see INET6 as
BINARY(16).\n* Clients see INET6 as CHAR(39) and get text representation on
retrieval.\n\nThe IPv4-compatible notation is considered as deprecated. It
is supported for\ncompatibility with the INET6_ATON function, which also
understands this\nformat. It\'s recommended to use the mapped format
to store IPv4 addresses in\nINET6.\n\nWhen an IPv4 mapped (or compatible)
value is stored in INET6, it still\noccupies 16
bytes:\n\nRetrieval\n---------\n\nOn retrieval, in the client-server text
protocol, INET6 values are converted\nto the short text representation,
according to RFC-5952, that is with all\nleading zeroes in each group
removed and with consequent zero groups\ncompressed.\n\nBesides creating
one\'s own stored function, there is no a way to retrieve an\nINET6
value using long text representation.\n\nCasting\n-------\n\n* CAST from a
character string to INET6 understands addresses in short or long\ntext
notation (including IPv4 mapped and compatible addresses). NULL
is\nreturned if the format is not understood.\n* CAST from a binary string
to INET6 requires a 16-byte string as an argument.\nNULL is returned if the
argument length is not equal to 16.\n* CAST from other data types to INET6
first converts data to a character\nstring, then CAST from character string
to INET6 is applied.\n* CAST from INET6 to CHAR returns short text address
notation.\n* CAST from INET6 to BINARY returns its 16-byte binary string
representation.\n* CAST from INET6 to data types other than CHAR (e.g.
SIGNED, UNSIGNED, TIME,\netc) returns an
error.\n\nComparisons\n-----------\n\nAn INET6 expression can be compared
to:\n\n* another INET6 expression\n* a character string expression with a
text (short or long) address\nrepresentation:\n* a 16-byte binary string
expression:\n\nAttempting to compare INET6 to an expression of any other
data type returns an\nerror.\n\nMixing INET6 Values for
Result\n------------------------------\n\nAn INET6 expression can be mixed
for result (i.e. UNION, CASE..THEN, COALESCE\netc) with:\n\n* another INET6
expression. The resulting data type is INET6.\n* a character string in text
(short or long) address representation. The\nresult data type is INET6. The
character string counterpart is automatically\nconverted to INET6. If the
string format is not understood, it\'s converted\nwith a warning to
either NULL or to \'::\', depending on the NULL-ability of
the\nresult.\n* a 16-byte binary string. The resulting data type is INET6.
The binary string\ncounterpart is automatically converted to INET6. If the
length of the binary\nstring is not equal to 16, it\'s converted with
a warning to NULL or to \'::\'\ndepending on the NULL-ability of
the result.\n\nAttempts to mix INET6 for result with other data types will
return an error.\n\nMixing INET6 with other data types for LEAST and
GREATEST, when mixing for\ncomparison and mixing for result are involved at
the same time, uses the same\nrules with mixing for result, described in
the previous paragraphs.\n\nFunctions and
Operators\n-----------------------\n\n* HEX() with an INET6 argument
returns a hexadecimal representation of the\nunderlying 16-byte binary
string\n* Arithmetic operators (+,-,*,/,MOD,DIV) are not supported for
INET6. This may\nchange in the future.\n* The INET6_ATON function now
understands INET6 values as an argument\n* The prototypes of the
IS_IPV4_COMPAT and IS_IPV4_MAPPED functions have\nchanged from a BINARY(16)
to a INET6,\n* When the argument for these two functions is not INET6,
automatic implicit\nCAST to INET6 is applied. As a consequence, both
functions now understand\narguments in both text representation and
binary(16) representation. Before\nMariaDB 10.5.0, these functions
understood only binary(16) representation.\n\nPrepared Statement
Parameters\n-----------------------------\n\nINET6 understands both text
and binary(16) address representation in prepared\nstatement parameters
(PREPARE..EXECUTE and EXECUTE IMMEDIATE statements).\n\nMigration between
BINARY(16) and INET6\n---------------------------------------\n\nBefore
MariaDB 10.5.0, you may have used BINARY(16) as a storage for
IPv6\ninternet addresses, in combination with INET6_ATON and INET6_NTOA
to\nrespectively insert and retrieve data.\n\nFrom 10.5, you can ALTER
BINARY(16) columns storing IPv6 addresses to INET6.\nAfter such an alter,
there is no a need to use INET6_ATON() and INET6_NTOA().\nAddresses can be
inserted and retrieved directly.\n\nIt is also possible to convert INET6
columns to BINARY(16) and continue using\nthe data in combination with
INET6_NTOA() and INET6_ATON().\n\nExamples\n--------\n\nCREATE TABLE t1 (a
INET6);\n\nInserting using short text address notation:\n\nINSERT INTO t1
VALUES (\'2001:db8::ff00:42:8329\');\n\nLong text address
notation:\n\nINSERT INTO t1 VALUES
(\'2001:0db8:0000:0000:0000:ff00:0042:8329\');\n\n16-byte binary
string notation:\n\nINSERT INTO t1 VALUES
(0x20010DB8000000000000FF0000428329);\nINSERT INTO t1 VALUES
(UNHEX(\'20010DB8000000000000FF0000428329\'));\n\nIPv4 addresses,
using IPv4-mapped and IPv4-compatible notations:\n\nINSERT INTO t1 VALUES
(\'::ffff:192.0.2.128\'); -- mapped\nINSERT INTO t1 VALUES
(\'::192.0.2.128\'); -- compatible\n\nSELECT * FROM
t1;\n+------------------------+\n| a
|\n+------------------------+\n| 2001:db8::ff00:42:8329 |\n|
2001:db8::ff00:42:8329 |\n| 2001:db8::ff00:42:8329 |\n|
2001:db8::ff00:42:8329 |\n| ::ffff:192.0.2.128 |\n| ::192.0.2.128
|\n+------------------------+\n\nIPv4 mapped (or compatible) values
still occupy 16 bytes:\n\nCREATE OR REPLACE TABLE t1 (a INET6);\n\nINSERT
INTO t1 VALUES (\'::ffff:192.0.2.128\');\n\nSELECT * FROM
t1;\n+--------------------+\n| a
|\n+--------------------+\n| ::ffff:192.0.2.128
|\n+--------------------+\n\nSELECT HEX(a) FROM
t1;\n+----------------------------------+\n| HEX(a)
|\n+----------------------------------+\n|
00000000000000000000FFFFC0000280
|\n+----------------------------------+\n\nCasting from INET6 to anything
other than CHAR returns an error:\n\nSELECT CAST(a AS DECIMAL) FROM
t1;\n\nERROR 4079 (HY000): Illegal parameter data type inet6 for
operation\n\'decimal_typecast\'\n\nComparison
Examples\n-------------------\n\nComparison with another INET6
expression:\n\nCREATE OR REPLACE TABLE t1 (a INET6);\n CREATE OR REPLACE
TABLE t2 (a INET6);\n\nINSERT INTO t1
VALUES\n(\'2001:db8::ff00:42:8328\'),(\'2001:db8::ff00:42:8329\');\n
INSERT INTO t2
VALUES\n(\'2001:db8::ff00:42:832a\'),(\'2001:db8::ff00:42:8329\');\n\nSELECT
t1.* FROM t1,t2 WHERE t1.a=t2.a;\n +------------------------+\n | a
|\n +------------------------+\n | 2001:db8::ff00:42:8329
|\n +------------------------+\n\nWith a character string expression with
a text (short or long) address\nrepresentation:\n\nCREATE OR REPLACE TABLE
t1 (a INET6);\n\nINSERT INTO t1 VALUES
(\'2001:db8::ff00:42:8329\');\n\nSELECT * FROM t1 WHERE
a=\'2001:db8::ff00:42:8329\';\n +------------------------+\n |
a |\n +------------------------+\n |
2001:db8::ff00:42:8329 |\n +------------------------+\n\nWith a 16-byte
binary string expression:\n\nCREATE OR REPLACE TABLE t1 (a
INET6);\n\nINSERT INTO t1 VALUES
(\'2001:db8::ff00:42:8329\');\n\nSELECT * FROM t1 WHERE
a=X\'20010DB8000000000000FF0000428329\';\n
+------------------------+\n | a |\n
+------------------------+\n | 2001:db8::ff00:42:8329 |\n
+------------------------+\n\nWith an expression of another data
type:\n\nSELECT * FROM t1 WHERE a=1;\nERROR 4078 (HY000): Illegal parameter
data types inet6 and int for operation\n\'=\'\n\nMixing for
Result Examples\n--------------------------\n\nMixed with another INET6
expression, returning an INET6 data type:\n\nCREATE OR REPLACE TABLE t1 (a
INET6, b INET6);\n\nINSERT INTO t1 VALUES
(NULL,\'2001:db8::ff00:42:8329\');\n\nSELECT a FROM t1 UNION
SELECT b FROM t1;\n +------------------------+\n | a
|\n +------------------------+\n | NULL |\n |
2001:db8::ff00:42:8329 |\n +------------------------+\n\nSELECT
COALESCE(a, b) FROM t1;\n +------------------------+\n | COALESCE(a, b)
|\n +------------------------+\n | 2001:db8::ff00:42:8329 |\n
+------------------------+\n\nMixed with a character string in text (short
or long) address representation:\n\nCREATE OR REPLACE TABLE t1 (a INET6, b
VARCHAR(64));\n\nINSERT INTO t1 VALUES
(NULL,\'2001:db8::ff00:42:8328\');\n\nINSERT INTO t1 VALUES
(NULL,\'2001:db8::ff00:42:832a garbage\');\n\nSELECT
COALESCE(a,b) FROM t1;\n +------------------------+\n | COALESCE(a,b)
|\n +------------------------+\n | 2001:db8::ff00:42:8328 |\n |
NULL |\n +------------------------+\n 2 rows in set, 1
warning (0.001 sec)\n\nSHOW
WARNINGS;\n\n+---------+------+---------------------------------------------------------+\n
| Level | Code |
Message\n|\n\n+---------+------+---------------------------------------------------------+\n
| Warning | 1292 | Incorrect inet6 value: \'2001:db8::ff00:42:832a
garbage\'\n|\n\n+---------+------+---------------------------------------------------------+\n\nMixed
with a 16-byte binary string:\n\nCREATE OR REPLACE TABLE t1 (a INET6, b
VARBINARY(16));\n\nINSERT INTO t1 VALUES
(NULL,CONCAT(0xFFFF,REPEAT(0x0000,6),0xFFFF));\n\nINSERT INTO t1 VALUES
(NULL,0x00/*garbage*/);\n\nSELECT COALESCE(a,b) FROM t1;\n
+---------------+\n | COALESCE(a,b) |\n +---------------+\n | ffff::ffff
|\n | NULL |\n +---------------+\n 2 rows in set, 1 warning
(0.001 sec)\n\nSHOW WARNINGS;\n
+---------+------+-------------------------------+\n | Level | Code |
Message |\n
+---------+------+-------------------------------+\n | Warning | 1292 |
Incorrect inet6 value: \'\\x00\' |\n
+---------+------+-------------------------------+\n\nMixing with other
data types:\n\nSELECT CAST(\'ffff::ffff\' AS INET6) UNION SELECT
1;\nERROR 4078 (HY000): Illegal parameter data types inet6 and int for
operation\n\'UNION\'\n\nFunctions and Operators
Examples\n--------------------------------\n\nHEX with an INET6 argument
returning a hexadecimal representation:\n\nSELECT
HEX(CAST(\'2001:db8::ff00:42:8329\' AS INET6));\n
+----------------------------------------------+\n |
HEX(CAST(\'2001:db8::ff00:42:8329\' AS INET6)) |\n
+----------------------------------------------+\n |
20010DB8000000000000FF0000428329 |\n
+----------------------------------------------+\n\nINET6_ATON now
understands INET6 values as an argument:\n\nCREATE OR REPLACE TABLE t1 (a
INET6);\n\nINSERT INTO t1 VALUES
(\'2001:db8::ff00:42:8329\');\n\nSELECT a, HEX(INET6_ATON(a))
FROM t1;\n +------------------------+----------------------------------+\n
| a | HEX(INET6_ATON(a)) |\n
+------------------------+----------------------------------+\n |
2001:db8::ff00:42:8329 | 20010DB8000000000000FF0000428329 |\n
+------------------------+----------------------------------+\n\nIS_IPV4_COMPAT
and IS_IPV4_MAPPED prototype now a BINARY(16)):\n\nCREATE OR REPLACE TABLE
t1 (a INET6);\n\nINSERT INTO t1 VALUES
(\'2001:db8::ff00:42:8329\');\n INSERT INTO t1 VALUES
(\'::ffff:192.168.0.1\');\n INSERT INTO t1 VALUES
(\'::192.168.0.1\');\n\nSELECT a, IS_IPV4_MAPPED(a),
IS_IPV4_COMPAT(a) FROM t1;\n
+------------------------+-------------------+-------------------+\n | a
| IS_IPV4_MAPPED(a) | IS_IPV4_COMPAT(a) |\n
+------------------------+-------------------+-------------------+\n |
2001:db8::ff00:42:8329 | 0 | 0 |\n |
::ffff:192.168.0.1 | 1 | 0 |\n |
::192.168.0.1 | 0 | 1 |\n
+------------------------+-------------------+-------------------+\n\nAutomatic
implicit CAST to INET6:\n\nCREATE OR REPLACE TABLE t1 (\n a INET6,\n b
VARCHAR(39) DEFAULT a\n );\n\nINSERT INTO t1 (a) VALUES
(\'ffff::ffff\'),(\'::ffff:192.168.0.1\');\n\nSELECT a,
IS_IPV4_MAPPED(a), b, IS_IPV4_MAPPED(b) FROM
t1;\n\n+--------------------+-------------------+--------------------+----------------\n--+\n
| a | IS_IPV4_MAPPED(a) | b
|\nIS_IPV4_MAPPED(b)
|\n\n+--------------------+-------------------+--------------------+----------------\n--+\n
| ffff::ffff | 0 | ffff::ffff |\n 0 |\n
| ::ffff:192.168.0.1 | 1 | ::ffff:192.168.0.1 |\n 1
|\n\n+--------------------+-------------------+--------------------+----------------\n--+\n\nCREATE
OR REPLACE TABLE t1 (\n a INET6,\n b BINARY(16) DEFAULT UNHEX(HEX(a))\n
);\n\nINSERT INTO t1 (a) VALUES
(\'ffff::ffff\'),(\'::ffff:192.168.0.1\');\n\nSELECT a,
IS_IPV4_MAPPED(a), HEX(b), IS_IPV4_MAPPED(b) FROM
t1;\n\n+--------------------+-------------------+----------------------------------+--\n----------------+\n
| a | IS_IPV4_MAPPED(a) | HEX(b)\n | IS_IPV4_MAPPED(b)
|\n\n+--------------------+-------------------+----------------------------------+--\n----------------+\n
| ffff::ffff | 0
|\nFFFF000000000000000000000000FFFF | 0 |\n |
::ffff:192.168.0.1 | 1 |\n00000000000000000000FFFFC0A80001
| 1
|\n\n+--------------------+-------------------+----------------------------------+--\n----------------+\n\nPrepared
Statement Parameters
Examples\n--------------------------------------\n\nCREATE OR REPLACE TABLE
t1 (a INET6);\n\nEXECUTE IMMEDIATE \'INSERT INTO t1 VALUES (?)\'
USING \'ffff::fffe\';\nEXECUTE IMMEDIATE \'INSERT INTO t1
VALUES (?)\'
USING\nX\'FFFF000000000000000000000000FFFF\';\n\nSELECT * FROM
t1;\n+------------+\n| a |\n+------------+\n| ffff::fffe |\n|
ffff::ffff |\n+------------+\n\nEXECUTE IMMEDIATE \'SELECT * FROM t1
WHERE a=?\' USING \'ffff::fffe\';\n+------------+\n| a
|\n+------------+\n| ffff::fffe |\n+------------+\n\nEXECUTE IMMEDIATE
\'SELECT * FROM t1 WHERE a=?\'
USING','','https://mariadb.com/kb/en/inet6/');
update help_topic set description = CONCAT(description,
'\nX\'FFFF000000000000000000000000FFFF\';\n+------------+\n|
a |\n+------------+\n| ffff::ffff |\n+------------+\n\nMigration
between BINARY(16) and INET6
Examples\n-----------------------------------------------\n\nBefore MariaDB
10.5:\n\nCREATE OR REPLACE TABLE t1 (a BINARY(16));\n\nINSERT INTO t1
VALUES (INET6_ATON(\'ffff::ffff\'));\n\nSELECT INET6_NTOA(a) FROM
t1;\n+---------------+\n| INET6_NTOA(a) |\n+---------------+\n| ffff::ffff
|\n+---------------+\n\nMigrating to INET6, from MariaDB 10.5:\n\nALTER
TABLE t1 MODIFY a INET6;\n\nINSERT INTO t1 VALUES
(\'ffff::fffe\');\n\nSELECT * FROM t1;\n+------------+\n| a
|\n+------------+\n| ffff::ffff |\n| ffff::fffe
|\n+------------+\n\nMigration from INET6 to BINARY(16):\n\nCREATE OR
REPLACE TABLE t1 (a INET6);\n\nINSERT INTO t1 VALUES
(\'2001:db8::ff00:42:8329\');\nINSERT INTO t1 VALUES
(\'::ffff:192.168.0.1\');\nINSERT INTO t1 VALUES
(\'::192.168.0.1\');\n\nALTER TABLE t1 MODIFY a
BINARY(16);\n\nSELECT INET6_NTOA(a) FROM t1;\n+------------------------+\n|
INET6_NTOA(a) |\n+------------------------+\n|
2001:db8::ff00:42:8329 |\n| ::ffff:192.168.0.1 |\n| ::192.168.0.1
|\n+------------------------+\n\nURL:
https://mariadb.com/kb/en/inet6/') WHERE help_topic_id = 274;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(275,23,'JSON Data Type','MariaDB starting with
10.2.7\n----------------------------\nThe JSON alias was added in MariaDB
10.2.7. This was done to make it possible\nto use JSON columns in statement
based replication from MySQL to MariaDB and\nto make it possible for
MariaDB to read mysqldumps from MySQL.\n\nJSON is an alias for LONGTEXT
introduced for compatibility reasons with\nMySQL\'s JSON data type.
MariaDB implements this as a LONGTEXT rather, as the\nJSON data type
contradicts the SQL standard, and MariaDB\'s benchmarks indicate\nthat
performance is at least equivalent.\n\nIn order to ensure that a a valid
json document is inserted, the JSON_VALID\nfunction can be used as a CHECK
constraint. This constraint is automatically\nincluded for types using the
JSON alias from MariaDB 10.4.3.\n\nExamples\n--------\n\nCREATE TABLE t (j
JSON);\n\nDESC t;\n+-------+----------+------+-----+---------+-------+\n|
Field | Type | Null | Key | Default | Extra
|\n+-------+----------+------+-----+---------+-------+\n| j | longtext
| YES | | NULL |
|\n+-------+----------+------+-----+---------+-------+\n\nWith
validation:\n\nCREATE TABLE t2 (\n j JSON\n CHECK
(JSON_VALID(j))\n);\n\nINSERT INTO t2 VALUES
(\'invalid\');\nERROR 4025 (23000): CONSTRAINT `j` failed for
`test`.`t2`\n\nINSERT INTO t2 VALUES (\'{\"id\": 1,
\"name\": \"Monty\"}\');\nQuery OK, 1 row affected
(0.13 sec)\n\nReplicating JSON Data Between MySQL and
MariaDB\n-----------------------------------------------\n\nThe JSON type
in MySQL stores the JSON object in a compact form, not as\nLONGTEXT as in
MariaDB. This means that row based replication will not work\nfor JSON
types from MySQL to MariaDB.\n\nThere are a a few different ways to solve
this:\n\n* Use statement based replication.\n* Change the JSON column to
type TEXT in MySQL\n* If you must use row-based replication and cannot
change the MySQL master\nfrom JSON to TEXT, you can try to introduce an
intermediate MySQL slave and\nchange the column type from JSON to TEXT on
it. Then you replicate from this\nintermediate slave to
MariaDB.\n\nConverting a MySQL TABLE with JSON Fields to
MariaDB\n----------------------------------------------------\n\nMariaDB
can\'t directly access MySQL\'s JSON format.\n\nThere are a a few
different ways to move the table to MariaDB:\n\n* From MariaDB 10.5.7, see
the you can use the mysql_json plugin. See Making\nMariaDB understand MySQL
JSON.\n* Change the JSON column to type TEXT in MySQL. After this, MariaDB
can\ndirectly use the table without any need for a dump and restore.\n* Use
mariadb-dump/mysqldump to copy the table.\n\nDifferences Between MySQL JSON
Strings and MariaDB JSON
Strings\n---------------------------------------------------------------\n\n*
In MySQL, JSON is an object and is compared according to json values.
In\nMariaDB JSON strings are normal strings and compared as strings. One
exception\nis when using JSON_EXTRACT() in which case strings are unescaped
before\ncomparison.\n\nURL:
https://mariadb.com/kb/en/json-data-type/','','https://mariadb.com/kb/en/json-data-type/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(276,23,'MEDIUMBLOB','Syntax\n------\n\nMEDIUMBLOB\n\nDescription\n-----------\n\nA
BLOB column with a maximum length of 16,777,215 (224 - 1) bytes.
Each\nMEDIUMBLOB value is stored using a three-byte length prefix that
indicates the\nnumber of bytes in the value.\n\nURL:
https://mariadb.com/kb/en/mediumblob/','','https://mariadb.com/kb/en/mediumblob/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(277,23,'MEDIUMTEXT','Syntax\n------\n\nMEDIUMTEXT
[CHARACTER SET charset_name] [COLLATE
collation_name]\n\nDescription\n-----------\n\nA TEXT column with a maximum
length of 16,777,215 (224 - 1) characters. The\neffective maximum length is
less if the value contains multi-byte characters.\nEach MEDIUMTEXT value is
stored using a three-byte length prefix that\nindicates the number of bytes
in the value.\n\nURL:
https://mariadb.com/kb/en/mediumtext/','','https://mariadb.com/kb/en/mediumtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(278,23,'LONGBLOB','Syntax\n------\n\nLONGBLOB\n\nDescription\n-----------\n\nA
BLOB column with a maximum length of 4,294,967,295 bytes or 4GB (232 -
1).\nThe effective maximum length of LONGBLOB columns depends on the
configured\nmaximum packet size in the client/server protocol and available
memory. Each\nLONGBLOB value is stored using a four-byte length prefix that
indicates the\nnumber of bytes in the value.\n\nOracle
Mode\n-----------\n\nMariaDB starting with
10.3\n--------------------------\nIn Oracle mode from MariaDB 10.3, BLOB is
a synonym for LONGBLOB.\n\nURL:
https://mariadb.com/kb/en/longblob/','','https://mariadb.com/kb/en/longblob/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(279,23,'LONGTEXT','Syntax\n------\n\nLONGTEXT [CHARACTER
SET charset_name] [COLLATE collation_name]\n\nDescription\n-----------\n\nA
TEXT column with a maximum length of 4,294,967,295 or 4GB (232 -
1)\ncharacters. The effective maximum length is less if the value
contains\nmulti-byte characters. The effective maximum length of LONGTEXT
columns also\ndepends on the configured maximum packet size in the
client/server protocol\nand available memory. Each LONGTEXT value is stored
using a four-byte length\nprefix that indicates the number of bytes in the
value.\n\nFrom MariaDB 10.2.7, JSON is an alias for LONGTEXT. See JSON Data
Type for\ndetails.\n\nOracle Mode\n-----------\n\nMariaDB starting with
10.3\n--------------------------\nIn Oracle mode from MariaDB 10.3, CLOB is
a synonym for LONGTEXT.\n\nURL:
https://mariadb.com/kb/en/longtext/','','https://mariadb.com/kb/en/longtext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(280,23,'ROW','MariaDB starting with
10.3.0\n----------------------------\nThe ROW data type was introduced in
MariaDB 10.3.0.\n\nSyntax\n------\n\nROW (<field name> <data
type> [{, <field name> <data type>}...
])\n\nDescription\n-----------\n\nROW is a data type for stored procedure
variables.\n\nFeatures\n--------\n\nROW fields as normal
variables\n------------------------------\n\nROW fields (members) act as
normal variables, and are able to appear in all\nquery parts where a stored
procedure variable is allowed:\n\n* Assignment is using the := operator and
the SET command:\n\na.x:= 10;\na.x:= b.x;\nSET a.x= 10, a.y=20, a.z=
b.z;\n\n* Passing to functions and operators:\n\nSELECT f1(rec.a),
rec.a<10;\n\n* Clauses (select list, WHERE, HAVING, LIMIT,
etc...,):\n\nSELECT var.a, t1.b FROM t1 WHERE t1.b=var.b LIMIT var.c;\n\n*
INSERT values:\n\nINSERT INTO t1 VALUES (rec.a, rec.b, rec.c);\n\n* SELECT
.. INTO targets\n\nSELECT a,b INTO rec.a, rec.b FROM t1 WHERE
t1.id=10;\n\n* Dynamic SQL out parameters (EXECUTE and EXECUTE
IMMEDIATE)\n\nEXECUTE IMMEDIATE \'CALL proc_with_out_param(?)\'
USING rec.a;\n\nROW type variables as FETCH
targets\n-----------------------------------\n\nROW type variables are
allowed as FETCH targets:\n\nFETCH cur INTO rec;\n\nwhere cur is a CURSOR
and rec is a ROW type stored procedure variable.\n\nNote, currently an
attempt to use FETCH for a ROW type variable returns this\nerror:\n\nERROR
1328 (HY000): Incorrect number of FETCH variables\n\nFETCH from a cursor
cur into a ROW variable rec works as follows:\n\n* The number of fields in
cur must match the number of fields in rec.\n Otherwise, an error is
reported.\n\n* Assignment is done from left to right. The first cursor
field is assigned to\n the first variable field, the second cursor field is
assigned to the second\n variable field, etc.\n\n* Field names in rec are
not important and can differ from field names\n in cur.\n\nSee FETCH
Examples (below) for examples of using this with sql_mode=ORACLE
and\nsql_mode=DEFAULT.\n\nROW type variables as SELECT...INTO
targets\n-------------------------------------------\n\nROW type variables
are allowed as SELECT..INTO targets with some differences\ndepending on
which sql_mode is in use.\n\n* When using sql_mode=ORACLE, table%ROWTYPE
and cursor%ROWTYPE\n variables can be used as SELECT...INTO targets.\n\n*
Using multiple ROW variables in the SELECT..INTO list will report an\n
error.\n\n* Using ROW variables with a different column count than in\n the
SELECT..INTO list will report an error.\n\nSee SELECT...INTO Examples
(below) for examples of using this with\nsql_mode=ORACLE and
sql_mode=DEFAULT.\n\nFeatures not
implemented\n------------------------\n\nThe following features are
planned, but not implemented yet:\n\n* Returning a ROW type expression from
a stored function (see MDEV-12252).\nThis will need some grammar change to
support field names after parentheses:\n\nSELECT f1().x FROM DUAL;\n\n*
Returning a ROW type expression from a built-in hybrid type function,
such\nas CASE, IF, etc. \n* ROW of ROWs\n\nExamples\n--------\n\nDeclaring
a ROW in a stored
procedure\n-------------------------------------\n\nDELIMITER $$\nCREATE
PROCEDURE p1()\nBEGIN\n DECLARE r ROW (c1 INT, c2 VARCHAR(10));\n SET r.c1=
10;\n SET r.c2= \'test\';\n INSERT INTO t1 VALUES (r.c1,
r.c2);\nEND;\n$$\nDELIMITER ;\nCALL p1();\n\nFETCH
Examples\n--------------\n\nA complete FETCH example for
sql_mode=ORACLE:\n\nDROP TABLE IF EXISTS t1;\nCREATE TABLE t1 (a INT, b
VARCHAR(32));\nINSERT INTO t1 VALUES (10,\'b10\');\nINSERT INTO
t1 VALUES (20,\'b20\');\nINSERT INTO t1 VALUES
(30,\'b30\');\n\nSET sql_mode=oracle;\nDROP PROCEDURE IF EXISTS
p1;\nDELIMITER $$\nCREATE PROCEDURE p1 AS\n rec ROW(a INT, b
VARCHAR(32));\n CURSOR c IS SELECT a,b FROM t1;\nBEGIN\n OPEN c;\n LOOP\n
FETCH c INTO rec;\n EXIT WHEN c%NOTFOUND;\n SELECT (\'rec=(\'
|| rec.a ||\',\'|| rec.b||\')\');\n END LOOP;\n CLOSE
c;\nEND;\n$$\nDELIMITER ;\nCALL p1();\n\nA complete FETCH example for
sql_mode=DEFAULT:\n\nDROP TABLE IF EXISTS t1;\nCREATE TABLE t1 (a INT, b
VARCHAR(32));\nINSERT INTO t1 VALUES (10,\'b10\');\nINSERT INTO
t1 VALUES (20,\'b20\');\nINSERT INTO t1 VALUES
(30,\'b30\');\n\nSET sql_mode=DEFAULT;\nDROP PROCEDURE IF EXISTS
p1;\nDELIMITER $$\nCREATE PROCEDURE p1()\nBEGIN\n DECLARE done INT DEFAULT
FALSE;\n DECLARE rec ROW(a INT, b VARCHAR(32));\n DECLARE c CURSOR FOR
SELECT a,b FROM t1;\n DECLARE CONTINUE HANDLER FOR NOT FOUND SET done =
TRUE;\n OPEN c;\nread_loop:\n LOOP\n FETCH c INTO rec;\n IF done THEN\n
LEAVE read_loop;\n END IF;\n SELECT
CONCAT(\'rec=(\',rec.a,\',\',rec.b,\')\');\n
END LOOP;\n CLOSE c;\nEND;\n$$\nDELIMITER ;\nCALL p1();\n\nSELECT...INTO
Examples\n----------------------\n\nA SELECT...INTO example for
sql_mode=DEFAULT:\n\nSET sql_mode=DEFAULT;\nDROP TABLE IF EXISTS t1;\nDROP
PROCEDURE IF EXISTS p1;\nCREATE TABLE t1 (a INT, b VARCHAR(32));\nINSERT
INTO t1 VALUES (10,\'b10\');\nDELIMITER $$\nCREATE PROCEDURE
p1()\nBEGIN\n DECLARE rec1 ROW(a INT, b VARCHAR(32));\n SELECT * FROM t1
INTO rec1;\n SELECT rec1.a, rec1.b;\nEND;\n$$\nDELIMITER ;\nCALL
p1();\n\nThe above example returns:\n\n+--------+--------+\n| rec1.a |
rec1.b |\n+--------+--------+\n| 10 | b10
|\n+--------+--------+\n\nA SELECT...INTO example for
sql_mode=ORACLE:\n\nSET sql_mode=ORACLE;\nDROP TABLE IF EXISTS t1;\nDROP
PROCEDURE IF EXISTS p1;\nCREATE TABLE t1 (a INT, b VARCHAR(32));\nINSERT
INTO t1 VALUES (10,\'b10\');\nDELIMITER $$\nCREATE PROCEDURE p1
AS\n rec1 ROW(a INT, b VARCHAR(32));\nBEGIN\n SELECT * FROM t1 INTO rec1;\n
SELECT rec1.a, rec1.b;\nEND;\n$$\nDELIMITER ;\nCALL p1();\n\nThe above
example returns:\n\n+--------+--------+\n| rec1.a | rec1.b
|\n+--------+--------+\n| 10 | b10 |\n+--------+--------+\n\nAn
example for sql_mode=ORACLE using table%ROWTYPE variables as
SELECT..INTO\ntargets:\n\nSET sql_mode=ORACLE;\nDROP TABLE IF EXISTS
t1;\nDROP PROCEDURE IF EXISTS p1;\nCREATE TABLE t1 (a INT, b
VARCHAR(32));\nINSERT INTO t1 VALUES (10,\'b10\');\nDELIMITER
$$\nCREATE PROCEDURE p1 AS\n rec1 t1%ROWTYPE;\nBEGIN\n SELECT * FROM t1
INTO rec1;\n SELECT rec1.a, rec1.b;\nEND;\n$$\nDELIMITER ;\nCALL
p1();\n\nThe above example returns:\n\n+--------+--------+\n| rec1.a |
rec1.b |\n+--------+--------+\n| 10 | b10
|\n+--------+--------+\n\nAn example for sql_mode=ORACLE using
cursor%ROWTYPE variables as SELECT..INTO\ntargets:\n\nSET
sql_mode=ORACLE;\nDROP TABLE IF EXISTS t1;\nDROP PROCEDURE IF EXISTS
p1;\nCREATE TABLE t1 (a INT, b VARCHAR(32));\nINSERT INTO t1 VALUES
(10,\'b10\');\nDELIMITER $$\nCREATE PROCEDURE p1 AS\n CURSOR cur1
IS SELECT * FROM t1;\n rec1 cur1%ROWTYPE;\nBEGIN\n SELECT * FROM t1 INTO
rec1;\n SELECT rec1.a, rec1.b;\nEND;\n$$\nDELIMITER ;\nCALL p1();\n\nThe
above example returns:\n\n+--------+--------+\n| rec1.a | rec1.b
|\n+--------+--------+\n| 10 | b10 |\n+--------+--------+\n\nURL:
https://mariadb.com/kb/en/row/','','https://mariadb.com/kb/en/row/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(281,23,'TEXT','Syntax\n------\n\nTEXT[(M)] [CHARACTER SET
charset_name] [COLLATE collation_name]\n\nDescription\n-----------\n\nA
TEXT column with a maximum length of 65,535 (216 - 1) characters.
The\neffective maximum length is less if the value contains multi-byte
characters.\nEach TEXT value is stored using a two-byte length prefix that
indicates the\nnumber of bytes in the value. If you need a bigger storage,
consider using\nMEDIUMTEXT instead.\n\nAn optional length M can be given
for this type. If this is done, MariaDB\ncreates the column as the smallest
TEXT type large enough to hold values M\ncharacters long.\n\nBefore MariaDB
10.2, all MariaDB collations were of type PADSPACE, meaning\nthat TEXT (as
well as VARCHAR and CHAR values) are compared without regard for\ntrailing
spaces. This does not apply to the LIKE pattern-matching operator,\nwhich
takes into account trailing spaces.\n\nBefore MariaDB 10.2.1, BLOB and TEXT
columns could not be assigned a DEFAULT\nvalue. This restriction was lifted
in MariaDB 10.2.1.\n\nExamples\n--------\n\nTrailing spaces:\n\nCREATE
TABLE strtest (d TEXT(10));\nINSERT INTO strtest VALUES(\'Maria
\');\n\nSELECT d=\'Maria\',d=\'Maria \' FROM
strtest;\n+-----------+--------------+\n| d=\'Maria\' |
d=\'Maria \' |\n+-----------+--------------+\n| 1 |
1 |\n+-----------+--------------+\n\nSELECT d LIKE
\'Maria\',d LIKE \'Maria \' FROM
strtest;\n+----------------+-------------------+\n| d LIKE
\'Maria\' | d LIKE \'Maria \'
|\n+----------------+-------------------+\n| 0 |
1 |\n+----------------+-------------------+\n\nIndexing\n--------\n\nTEXT
columns can only be indexed over a specified length. This means that
they\ncannot be used as the primary key of a table norm until MariaDB 10.4,
can a\nunique index be created on them.\n\nMariaDB starting with
10.4\n--------------------------\nStarting with MariaDB 10.4, a unique
index can be created on a TEXT column.\n\nInternally, this uses hash
indexing to quickly check the values and if a hash\ncollision is found, the
actual stored values are compared in order to retain\nthe
uniqueness.\n\nDifference between VARCHAR and
TEXT\n-----------------------------------\n\n* VARCHAR columns can be fully
indexed. TEXT columns can only be indexed over\na specified length.\n*
Using TEXT or BLOB in a SELECT query that uses temporary tables for
storing\nintermediate results will force the temporary table to be disk
based (using\nthe Aria storage engine instead of the memory storage engine,
which is a bit\nslower. This is not that bad as the Aria storage engine
caches the rows in\nmemory. To get the benefit of this, one should ensure
that the\naria_pagecache_buffer_size variable is big enough to hold most of
the row and\nindex data for temporary tables.\n\nFor Storage Engine
Developers\n-----------------------------\n\n* Internally the full length
of the VARCHAR column is allocated inside each\nTABLE objects record[]
structure. As there are three such buffers, each open\ntable will allocate
3 times max-length-to-store-varchar bytes of memory.\n* TEXT and BLOB
columns are stored with a pointer (4 or 8 bytes) + a 1-4 bytes\nlength.
The TEXT data is only stored once. This means that internally TEXT\nuses
less memory for each open table but instead has the additional
overhead\nthat each TEXT object needs to be allocated and freed for each
row access\n(with some caching in between).\n\nURL:
https://mariadb.com/kb/en/text/','','https://mariadb.com/kb/en/text/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(282,23,'TINYBLOB','Syntax\n------\n\nTINYBLOB\n\nDescription\n-----------\n\nA
BLOB column with a maximum length of 255 (28 - 1) bytes. Each TINYBLOB
value\nis stored using a one-byte length prefix that indicates the number
of bytes in\nthe value.\n\nURL:
https://mariadb.com/kb/en/tinyblob/','','https://mariadb.com/kb/en/tinyblob/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(283,23,'TINYTEXT','Syntax\n------\n\nTINYTEXT [CHARACTER
SET charset_name] [COLLATE collation_name]\n\nDescription\n-----------\n\nA
TEXT column with a maximum length of 255 (28 - 1) characters. The
effective\nmaximum length is less if the value contains multi-byte
characters. Each\nTINYTEXT value is stored using a one-byte length prefix
that indicates the\nnumber of bytes in the value.\n\nURL:
https://mariadb.com/kb/en/tinytext/','','https://mariadb.com/kb/en/tinytext/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(284,23,'VARBINARY','Syntax\n------\n\nVARBINARY(M)\n\nDescription\n-----------\n\nThe
VARBINARY type is similar to the VARCHAR type, but stores binary
byte\nstrings rather than non-binary character strings. M represents the
maximum\ncolumn length in bytes.\n\nIt contains no character set, and
comparison and sorting are based on the\nnumeric value of the bytes.\n\nIf
the maximum length is exceeded, and SQL strict mode is not enabled ,
the\nextra characters will be dropped with a warning. If strict mode is
enabled, an\nerror will occur.\n\nUnlike BINARY values, VARBINARYs are not
right-padded when inserting.\n\nOracle Mode\n-----------\n\nMariaDB
starting with 10.3\n--------------------------\nIn Oracle mode from MariaDB
10.3, RAW is a synonym for VARBINARY.\n\nExamples\n--------\n\nInserting
too many characters, first with strict mode off, then with it on:\n\nCREATE
TABLE varbins (a VARBINARY(10));\n\nINSERT INTO varbins
VALUES(\'12345678901\');\nQuery OK, 1 row affected, 1 warning
(0.04 sec)\n\nSELECT * FROM varbins;\n+------------+\n| a
|\n+------------+\n| 1234567890 |\n+------------+\n\nSET
sql_mode=\'STRICT_ALL_TABLES\';\n\nINSERT INTO varbins
VALUES(\'12345678901\');\nERROR 1406 (22001): Data too long for
column \'a\' at row 1\n\nSorting is performed with the byte
value:\n\nTRUNCATE varbins;\n\nINSERT INTO varbins
VALUES(\'A\'),(\'B\'),(\'a\'),(\'b\');\n\nSELECT
* FROM varbins ORDER BY a;\n+------+\n| a |\n+------+\n| A |\n| B
|\n| a |\n| b |\n+------+\n\nUsing CAST to sort as a CHAR
instead:\n\nSELECT * FROM varbins ORDER BY CAST(a AS CHAR);\n+------+\n| a
|\n+------+\n| a |\n| A |\n| b |\n| B |\n+------+\n\nURL:
https://mariadb.com/kb/en/varbinary/','','https://mariadb.com/kb/en/varbinary/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(285,23,'VARCHAR','Syntax\n------\n\n[NATIONAL] VARCHAR(M)
[CHARACTER SET charset_name] [COLLATE
collation_name]\n\nDescription\n-----------\n\nA variable-length string. M
represents the maximum column length in\ncharacters. The range of M is 0 to
65,532. The effective maximum length of a\nVARCHAR is subject to the
maximum row size and the character set used. For\nexample, utf8 characters
can require up to three bytes per character, so a\nVARCHAR column that uses
the utf8 character set can be declared to be a\nmaximum of 21,844
characters.\n\nNote: For the ColumnStore engine, M represents the maximum
column length in\nbytes.\n\nMariaDB stores VARCHAR values as a one-byte or
two-byte length prefix plus\ndata. The length prefix indicates the number
of bytes in the value. A VARCHAR\ncolumn uses one length byte if values
require no more than 255 bytes, two\nlength bytes if values may require
more than 255 bytes.\n\nMariaDB follows the standard SQL specification, and
does not remove trailing\nspaces from VARCHAR values.\n\nVARCHAR(0) columns
can contain 2 values: an empty string or NULL. Such columns\ncannot be part
of an index. The CONNECT storage engine does not
support\nVARCHAR(0).\n\nVARCHAR is shorthand for CHARACTER VARYING.
NATIONAL VARCHAR is the standard\nSQL way to define that a VARCHAR column
should use some predefined character\nset. MariaDB uses utf8 as this
predefined character set, as does MySQL 4.1 and\nup. NVARCHAR is shorthand
for NATIONAL VARCHAR.\n\nBefore MariaDB 10.2, all MariaDB collations were
of type PADSPACE, meaning\nthat VARCHAR (as well as CHAR and TEXT values)
are compared without regard for\ntrailing spaces. This does not apply to
the LIKE pattern-matching operator,\nwhich takes into account trailing
spaces. From MariaDB 10.2, a number of NO\nPAD collations are
available.\n\nIf a unique index consists of a column where trailing pad
characters are\nstripped or ignored, inserts into that column where values
differ only by the\nnumber of trailing pad characters will result in a
duplicate-key error.\n\nExamples\n--------\n\nThe following are
equivalent:\n\nVARCHAR(30) CHARACTER SET utf8\nNATIONAL
VARCHAR(30)\nNVARCHAR(30)\nNCHAR VARCHAR(30)\nNATIONAL CHARACTER
VARYING(30)\nNATIONAL CHAR VARYING(30)\n\nTrailing spaces:\n\nCREATE TABLE
strtest (v VARCHAR(10));\nINSERT INTO strtest VALUES(\'Maria
\');\n\nSELECT v=\'Maria\',v=\'Maria \' FROM
strtest;\n+-----------+--------------+\n| v=\'Maria\' |
v=\'Maria \' |\n+-----------+--------------+\n| 1 |
1 |\n+-----------+--------------+\n\nSELECT v LIKE
\'Maria\',v LIKE \'Maria \' FROM
strtest;\n+----------------+-------------------+\n| v LIKE
\'Maria\' | v LIKE \'Maria \'
|\n+----------------+-------------------+\n| 0 |
1
|\n+----------------+-------------------+\n\nTruncation\n----------\n\n*
Depending on whether or not strict sql mode is set, you will either get
a\nwarning or an error if you try to insert a string that is too long into
a\nVARCHAR column. If the extra characters are spaces, the spaces that
can\'t fit\nwill be removed and you will always get a warning,
regardless of the sql mode\nsetting.\n\nDifference Between VARCHAR and
TEXT\n-----------------------------------\n\n* VARCHAR columns can be fully
indexed. TEXT columns can only be indexed over\na specified length.\n*
Using TEXT or BLOB in a SELECT query that uses temporary tables for
storing\nintermediate results will force the temporary table to be disk
based (using\nthe Aria storage engine instead of the memory storage engine,
which is a bit\nslower. This is not that bad as the Aria storage engine
caches the rows in\nmemory. To get the benefit of this, one should ensure
that the\naria_pagecache_buffer_size variable is big enough to hold most of
the row and\nindex data for temporary tables.\n\nOracle
Mode\n-----------\n\nMariaDB starting with
10.3\n--------------------------\nIn Oracle mode from MariaDB 10.3,
VARCHAR2 is a synonym.\n\nFor Storage Engine
Developers\n-----------------------------\n\n* Internally the full length
of the VARCHAR column is allocated inside each\nTABLE objects record[]
structure. As there are three such buffers, each open\ntable will allocate
3 times max-length-to-store-varchar bytes of memory.\n* TEXT and BLOB
columns are stored with a pointer (4 or 8 bytes) + a 1-4 bytes\nlength.
The TEXT data is only stored once. This means that internally TEXT\nuses
less memory for each open table but instead has the additional
overhead\nthat each TEXT object needs to be allocated and freed for each
row access\n(with some caching in between).\n\nURL:
https://mariadb.com/kb/en/varchar/','','https://mariadb.com/kb/en/varchar/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(286,23,'SET Data
Type','Syntax\n------\n\nSET(\'value1\',\'value2\',...)
[CHARACTER SET charset_name]
[COLLATE\ncollation_name]\n\nDescription\n-----------\n\nA set. A string
object that can have zero or more values, each of which must\nbe chosen
from the list of values \'value1\', \'value2\', ... A
SET column can\nhave a maximum of 64 members. SET values are represented
internally as\nintegers.\n\nSET values cannot contain commas.\n\nIf a SET
contains duplicate values, an error will be returned if strict mode\nis
enabled, or a warning if strict mode is not enabled.\n\nURL:
https://mariadb.com/kb/en/set-data-type/','','https://mariadb.com/kb/en/set-data-type/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(287,23,'DATE','Syntax\n------\n\nDATE\n\nDescription\n-----------\n\nA
date. The supported range is \'1000-01-01\' to
\'9999-12-31\'. MariaDB displays\nDATE values in
\'YYYY-MM-DD\' format, but can be assigned dates in
looser\nformats, including strings or numbers, as long as they make sense.
These\ninclude a short year, YY-MM-DD, no delimiters, YYMMDD, or any other
acceptable\ndelimiter, for example YYYY/MM/DD. For details, see date and
time literals.\n\n\'0000-00-00\' is a permitted special value
(zero-date), unless the NO_ZERO_DATE\nSQL_MODE is used. Also, individual
components of a date can be set to 0 (for\nexample:
\'2015-00-12\'), unless the NO_ZERO_IN_DATE SQL_MODE is used. In
many\ncases, the result of en expression involving a zero-date, or a date
with\nzero-parts, is NULL. If the ALLOW_INVALID_DATES SQL_MODE is enabled,
if the\nday part is in the range between 1 and 31, the date does not
produce any\nerror, even for months that have less than 31 days.\n\nOracle
Mode\n-----------\n\nMariaDB starting with
10.3\n--------------------------\nIn Oracle mode from MariaDB 10.3, DATE
with a time portion is a synonym for\nDATETIME. See also
mariadb_schema.\n\nExamples\n--------\n\nCREATE TABLE t1 (d
DATE);\n\nINSERT INTO t1 VALUES (\"2010-01-12\"),
(\"2011-2-28\"),
(\'120314\'),(\'13*04*21\');\n\nSELECT * FROM
t1;\n+------------+\n| d |\n+------------+\n| 2010-01-12 |\n|
2011-02-28 |\n| 2012-03-14 |\n| 2013-04-21 |\n+------------+\n\nURL:
https://mariadb.com/kb/en/date/','','https://mariadb.com/kb/en/date/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(288,23,'TIME','Syntax\n------\n\nTIME [(<microsecond
precision>)]\n\nDescription\n-----------\n\nA time. The range is
\'-838:59:59.999999\' to \'838:59:59.999999\'.
Microsecond\nprecision can be from 0-6; if not specified 0 is used.
Microseconds have been\navailable since MariaDB 5.3.\n\nMariaDB displays
TIME values in \'HH:MM:SS.ssssss\' format, but allows\nassignment
of times in looser formats, including \'D HH:MM:SS\',
\'HH:MM:SS\',\n\'HH:MM\', \'D HH:MM\',
\'D HH\', \'SS\', or \'HHMMSS\', as well as
permitting dropping\nof any leading zeros when a delimiter is provided, for
example \'3:9:10\'. For\ndetails, see date and time
literals.\n\nMariaDB starting with
10.1.2\n----------------------------\nMariaDB 10.1.2 introduced the
--mysql56-temporal-format option, on by default,\nwhich allows MariaDB to
store TIMEs using the same low-level format MySQL 5.6\nuses.\n\nInternal
Format\n---------------\n\nIn MariaDB 10.1.2 a new temporal format was
introduced from MySQL 5.6 that\nalters how the TIME, DATETIME and TIMESTAMP
columns operate at lower levels.\nThese changes allow these temporal data
types to have fractional parts and\nnegative values. You can disable this
feature using the\nmysql56_temporal_format system variable.\n\nTables that
include TIMESTAMP values that were created on an older version of\nMariaDB
or that were created while the mysql56_temporal_format system variable\nwas
disabled continue to store data using the older data type format.\n\nIn
order to update table columns from the older format to the newer
format,\nexecute an ALTER TABLE... MODIFY COLUMN statement that changes the
column to\nthe *same* data type. This change may be needed if you want to
export the\ntable\'s tablespace and import it onto a server that
has\nmysql56_temporal_format=ON set (see MDEV-15225).\n\nFor instance, if
you have a TIME column in your table:\n\nSHOW VARIABLES LIKE
\'mysql56_temporal_format\';\n\n+-------------------------+-------+\n|
Variable_name | Value |\n+-------------------------+-------+\n|
mysql56_temporal_format | ON
|\n+-------------------------+-------+\n\nALTER TABLE example_table MODIFY
ts_col TIME;\n\nWhen MariaDB executes the ALTER TABLE statement, it
converts the data from the\nolder temporal format to the newer one.\n\nIn
the event that you have several tables and columns using temporal
data\ntypes that you want to switch over to the new format, make sure the
system\nvariable is enabled, then perform a dump and restore using
mysqldump. The\ncolumns using relevant temporal data types are restored
using the new temporal\nformat.\n\nStarting from MariaDB 10.5.1 columns
with old temporal formats are marked with\na /* mariadb-5.3 */ comment in
the output of SHOW CREATE TABLE, SHOW COLUMNS,\nDESCRIBE statements, as
well as in the COLUMN_TYPE column of the\nINFORMATION_SCHEMA.COLUMNS
Table.\n\nSHOW CREATE TABLE
mariadb5312_time\\G\n*************************** 1. row
***************************\n Table: mariadb5312_time\nCreate Table:
CREATE TABLE `mariadb5312_time` (\n `t0` time /* mariadb-5.3 */ DEFAULT
NULL,\n `t6` time(6) /* mariadb-5.3 */ DEFAULT NULL\n) ENGINE=MyISAM
DEFAULT CHARSET=latin1\n\nNote, columns with the current format are not
marked with a comment.\n\nExamples\n--------\n\nINSERT INTO time VALUES
(\'90:00:00\'), (\'800:00:00\'), (800), (22),
(151413),\n(\'9:6:3\'), (\'12 09\');\n\nSELECT * FROM
time;\n+-----------+\n| t |\n+-----------+\n| 90:00:00 |\n|
800:00:00 |\n| 00:08:00 |\n| 00:00:22 |\n| 15:14:13 |\n| 09:06:03 |\n|
297:00:00 |\n+-----------+\n\nURL:
https://mariadb.com/kb/en/time/','','https://mariadb.com/kb/en/time/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(289,23,'DATETIME','Syntax\n------\n\nDATETIME [(microsecond
precision)]\n\nDescription\n-----------\n\nA date and time
combination.\n\nMariaDB displays DATETIME values in \'YYYY-MM-DD
HH:MM:SS.ffffff\' format, but\nallows assignment of values to DATETIME
columns using either strings or\nnumbers. For details, see date and time
literals.\n\nDATETIME columns also accept CURRENT_TIMESTAMP as the default
value.\n\nMariaDB 10.1.2 introduced the --mysql56-temporal-format option,
on by default,\nwhich allows MariaDB to store DATETMEs using the same
low-level format MySQL\n5.6 uses. For more information, see Internal
Format, below.\n\nFor storage requirements, see Data Type Storage
Requirements.\n\nSupported Values\n----------------\n\nMariaDB stores
values that use the DATETIME data type in a format that\nsupports values
between 1000-01-01 00:00:00.000000 and
9999-12-31\n23:59:59.999999.\n\nMariaDB can also store microseconds with a
precision between 0 and 6. If no\nmicrosecond precision is specified, then
0 is used by default.\n\nMariaDB also supports \'0000-00-00\' as
a special zero-date value, unless\nNO_ZERO_DATE is specified in the
SQL_MODE. Similarly, individual components of\na date can be set to 0 (for
example: \'2015-00-12\'), unless NO_ZERO_IN_DATE is\nspecified in
the SQL_MODE. In many cases, the result of en expression\ninvolving a
zero-date, or a date with zero-parts, is NULL. If the\nALLOW_INVALID_DATES
SQL_MODE is enabled, if the day part is in the range\nbetween 1 and 31, the
date does not produce any error, even for months that\nhave less than 31
days.\n\nTime Zones\n----------\n\nIf a column uses the DATETIME data type,
then any inserted values are stored\nas-is, so no automatic time zone
conversions are performed.\n\nMariaDB also does not currently support time
zone literals that contain time\nzone identifiers. See MDEV-11829 for more
information.\n\nMariaDB validates DATETIME literals against the
session\'s time zone. For\nexample, if a specific time range never
occurred in a specific time zone due\nto daylight savings time, then
DATETIME values within that range would be\ninvalid for that time
zone.\n\nFor example, daylight savings time started on March 10, 2019 in
the US, so the\ntime range between 02:00:00 and 02:59:59 is invalid for
that day in US time\nzones:\n\nSET time_zone =
\'America/New_York\';\nQuery OK, 0 rows affected (0.000
sec)\n\nINSERT INTO timestamp_test VALUES (\'2019-03-10
02:55:05\');\nERROR 1292 (22007): Incorrect datetime value:
\'2019-03-10 02:55:05\' for
column\n`db1`.`timestamp_test`.`timestamp_test` at row 1\n\nBut that same
time range is fine in other time zones, such as Coordinated\nUniversal Time
(UTC). For example:\n\nSET time_zone = \'UTC\';\nQuery OK, 0 rows
affected (0.000 sec)\n\nINSERT INTO timestamp_test VALUES
(\'2019-03-10 02:55:05\');\nQuery OK, 1 row affected (0.002
sec)\n\nOracle Mode\n-----------\n\nMariaDB starting with
10.3\n--------------------------\nIn Oracle mode from MariaDB 10.3, DATE
with a time portion is a synonym for\nDATETIME. See also
mariadb_schema.\n\nInternal Format\n---------------\n\nIn MariaDB 10.1.2 a
new temporal format was introduced from MySQL 5.6 that\nalters how the
TIME, DATETIME and TIMESTAMP columns operate at lower levels.\nThese
changes allow these temporal data types to have fractional parts
and\nnegative values. You can disable this feature using
the\nmysql56_temporal_format system variable.\n\nTables that include
TIMESTAMP values that were created on an older version of\nMariaDB or that
were created while the mysql56_temporal_format system variable\nwas
disabled continue to store data using the older data type format.\n\nIn
order to update table columns from the older format to the newer
format,\nexecute an ALTER TABLE... MODIFY COLUMN statement that changes the
column to\nthe *same* data type. This change may be needed if you want to
export the\ntable\'s tablespace and import it onto a server that
has\nmysql56_temporal_format=ON set (see MDEV-15225).\n\nFor instance, if
you have a DATETIME column in your table:\n\nSHOW VARIABLES LIKE
\'mysql56_temporal_format\';\n\n+-------------------------+-------+\n|
Variable_name | Value |\n+-------------------------+-------+\n|
mysql56_temporal_format | ON
|\n+-------------------------+-------+\n\nALTER TABLE example_table MODIFY
ts_col DATETIME;\n\nWhen MariaDB executes the ALTER TABLE statement, it
converts the data from the\nolder temporal format to the newer one.\n\nIn
the event that you have several tables and columns using temporal
data\ntypes that you want to switch over to the new format, make sure the
system\nvariable is enabled, then perform a dump and restore using
mysqldump. The\ncolumns using relevant temporal data types are restored
using the new temporal\nformat.\n\nStarting from MariaDB 10.5.1 columns
with old temporal formats are marked with\na /* mariadb-5.3 */ comment in
the output of SHOW CREATE TABLE, SHOW COLUMNS,\nDESCRIBE statements, as
well as in the COLUMN_TYPE column of the\nINFORMATION_SCHEMA.COLUMNS
Table.\n\nSHOW CREATE TABLE
mariadb5312_datetime\\G\n*************************** 1. row
***************************\n Table: mariadb5312_datetime\nCreate Table:
CREATE TABLE `mariadb5312_datetime` (\n `dt0` datetime /* mariadb-5.3 */
DEFAULT NULL,\n `dt6` datetime(6) /* mariadb-5.3 */ DEFAULT NULL\n)
ENGINE=MyISAM DEFAULT CHARSET=latin1\n\nExamples\n--------\n\nCREATE TABLE
t1 (d DATETIME);\n\nINSERT INTO t1 VALUES (\"2011-03-11\"),
(\"2012-04-19 13:08:22\"),\n (\"2013-07-18
13:44:22.123456\");\n\nSELECT * FROM t1;\n+---------------------+\n| d
|\n+---------------------+\n| 2011-03-11 00:00:00 |\n|
2012-04-19 13:08:22 |\n| 2013-07-18 13:44:22
|\n+---------------------+\n\nCREATE TABLE t2 (d DATETIME(6));\n\nINSERT
INTO t2 VALUES (\"2011-03-11\"), (\"2012-04-19
13:08:22\"),\n (\"2013-07-18 13:44:22.123456\");\n\nSELECT *
FROM t2;\n+----------------------------+\n| d
|\n+----------------------------+\n| 2011-03-11 00:00:00.000000 |\n|
2012-04-19 13:08:22.000000 |\n| 2013-07-18 13:44:22.123456
|\n+----------------------------++\n\nStrings used in datetime context are
automatically converted to datetime(6).\nIf you want to have a datetime
without seconds, you should use\nCONVERT(..,datetime).\n\nSELECT
CONVERT(\'2007-11-30
10:30:19\',datetime);\n+-----------------------------------------+\n|
CONVERT(\'2007-11-30 10:30:19\',datetime)
|\n+-----------------------------------------+\n| 2007-11-30 10:30:19
|\n+-----------------------------------------+\n\nSELECT
CONVERT(\'2007-11-30
10:30:19\',datetime(6));\n+--------------------------------------------+\n|
CONVERT(\'2007-11-30 10:30:19\',datetime(6))
|\n+--------------------------------------------+\n| 2007-11-30
10:30:19.000000
|\n+--------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/datetime/','','https://mariadb.com/kb/en/datetime/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(290,23,'TIMESTAMP','Syntax\n------\n\nTIMESTAMP
[(<microsecond precision)]\n\nDescription\n-----------\n\nA timestamp in
the format YYYY-MM-DD HH:MM:SS.ffffff.\n\nThe timestamp field is generally
used to define at which moment in time a row\nwas added or updated and by
default will automatically be assigned the current\ndatetime when a record
is inserted or updated. The automatic properties only\napply to the first
TIMESTAMP in the record; subsequent TIMESTAMP columns will\nnot be
changed.\n\nMariaDB includes the --mysql56-temporal-format option, on by
default, which\nallows MariaDB to store TIMESTAMPs using the same low-level
format MySQL 5.6\nuses.\n\nFor more information, see Internal
Format.\n\nSupported Values\n----------------\n\nMariaDB stores values that
use the TIMESTAMP data type as the number of\nseconds since
\'1970-01-01 00:00:00\' (UTC). This means that the TIMESTAMP
data\ntype can hold values between \'1970-01-01 00:00:01\' (UTC)
and \'2038-01-19\n03:14:07\' (UTC).\n\nMariaDB can also store
microseconds with a precision between 0 and 6. If no\nmicrosecond precision
is specified, then 0 is used by default.\n\nAutomatic
Values\n----------------\n\nMariaDB has special behavior for the first
column that uses the TIMESTAMP data\ntype in a specific table. For the
first column that uses the TIMESTAMP data\ntype in a specific table,
MariaDB automatically assigns the following\nproperties to the column:\n\n*
DEFAULT CURRENT_TIMESTAMP\n* ON UPDATE CURRENT_TIMESTAMP\n\nThis means that
if the column is not explicitly assigned a value in an INSERT\nor UPDATE
query, then MariaDB will automatically initialize the column\'s
value\nwith the current date and time.\n\nThis automatic initialization for
INSERT and UPDATE queries can also be\nexplicitly enabled for a column that
uses the TIMESTAMP data type by\nspecifying the DEFAULT CURRENT_TIMESTAMP
and ON UPDATE CURRENT_TIMESTAMP\nclauses for the column. In these clauses,
any synonym of CURRENT_TIMESTAMP is\naccepted, including
CURRENT_TIMESTAMP(), NOW(), LOCALTIME, LOCALTIME(),\nLOCALTIMESTAMP, and
LOCALTIMESTAMP().\n\nThis automatic initialization for INSERT queries can
also be explicitly\ndisabled for a column that uses the TIMESTAMP data type
by specifying a\nconstant DEFAULT value. For example, DEFAULT 0.\n\nThis
automatic initialization for UPDATE queries can also be
explicitly\ndisabled for a column that uses the TIMESTAMP data type by
specifying a\nDEFAULT clause for the column, but no ON UPDATE clause. If a
DEFAULT clause is\nexplicitly specified for a column that uses the
TIMESTAMP data type, but an ON\nUPDATE clause is not specified for the
column, then the timestamp value will\nnot automatically change when an
UPDATE statement is executed.\n\nMariaDB also has special behavior if NULL
is assigned to column that uses the\nTIMESTAMP data type. If the column is
assigned the NULL value in an INSERT or\nUPDATE query, then MariaDB will
automatically initialize the column\'s value\nwith the current date
and time. For details, see NULL values in MariaDB.\n\nThis automatic
initialization for NULL values can also be explicitly disabled\nfor a
column that uses the TIMESTAMP data type by specifying the NULL\nattribute
for the column. In this case, if the column\'s value is set to
NULL,\nthen the column\'s value will actually be set to NULL.\n\nTime
Zones\n----------\n\nIf a column uses the TIMESTAMP data type, then any
inserted values are\nconverted from the session\'s time zone to
Coordinated Universal Time (UTC)\nwhen stored, and converted back to the
session\'s time zone when retrieved.\n\nMariaDB does not currently
store any time zone identifier with the value of\nthe TIMESTAMP data type.
See MDEV-10018 for more information.\n\nMariaDB does not currently support
time zone literals that contain time zone\nidentifiers. See MDEV-11829 for
more information.\n\nLimitations\n-----------\n\n* Because the TIMESTAMP
value is stored as Epoch Seconds, the timestamp value\n\'1970-01-01
00:00:00\' (UTC) is reserved since the second #0 is used to\nrepresent
\'0000-00-00 00:00:00\'.\n* In MariaDB 5.5 and before there could
only be one TIMESTAMP column per table\nthat had CURRENT_TIMESTAMP defined
as its default value. This limit has no\nlonger applied since MariaDB
10.0.\n\nSQL_MODE=MAXDB\n--------------\n\nIf the SQL_MODE is set to MAXDB,
TIMESTAMP fields will be silently converted\nto DATETIME.\n\nInternal
Format\n---------------\n\nIn MariaDB 10.1.2 a new temporal format was
introduced from MySQL 5.6 that\nalters how the TIME, DATETIME and TIMESTAMP
columns operate at lower levels.\nThese changes allow these temporal data
types to have fractional parts and\nnegative values. You can disable this
feature using the\nmysql56_temporal_format system variable.\n\nTables that
include TIMESTAMP values that were created on an older version of\nMariaDB
or that were created while the mysql56_temporal_format system variable\nwas
disabled continue to store data using the older data type format.\n\nIn
order to update table columns from the older format to the newer
format,\nexecute an ALTER TABLE... MODIFY COLUMN statement that changes the
column to\nthe *same* data type. This change may be needed if you want to
export the\ntable\'s tablespace and import it onto a server that
has\nmysql56_temporal_format=ON set (see MDEV-15225).\n\nFor instance, if
you have a TIMESTAMP column in your table:\n\nSHOW VARIABLES LIKE
\'mysql56_temporal_format\';\n\n+-------------------------+-------+\n|
Variable_name | Value |\n+-------------------------+-------+\n|
mysql56_temporal_format | ON
|\n+-------------------------+-------+\n\nALTER TABLE example_table MODIFY
ts_col TIMESTAMP;\n\nWhen MariaDB executes the ALTER TABLE statement, it
converts the data from the\nolder temporal format to the newer one.\n\nIn
the event that you have several tables and columns using temporal
data\ntypes that you want to switch over to the new format, make sure the
system\nvariable is enabled, then perform a dump and restore using
mysqldump. The\ncolumns using relevant temporal data types are restored
using the new temporal\nformat.\n\nStarting from MariaDB 10.5.1 columns
with old temporal formats are marked with\na /* mariadb-5.3 */ comment in
the output of SHOW CREATE TABLE, SHOW COLUMNS,\nDESCRIBE statements, as
well as in the COLUMN_TYPE column of the\nINFORMATION_SCHEMA.COLUMNS
Table.\n\nSHOW CREATE TABLE
mariadb5312_timestamp\\G\n*************************** 1. row
***************************\n Table: mariadb5312_timestamp\nCreate Table:
CREATE TABLE `mariadb5312_timestamp` (\n `ts0` timestamp /* mariadb-5.3 */
NOT NULL DEFAULT current_timestamp() ON\nUPDATE current_timestamp(),\n
`ts6` timestamp(6) /* mariadb-5.3 */ NOT NULL DEFAULT
\'0000-00-00\n00:00:00.000000\'\n) ENGINE=MyISAM DEFAULT
CHARSET=latin1\n\nNote: Prior to MySQL 4.1 a different format for the
TIMESTAMP datatype was\nused. This format is unsupported in MariaDB 5.1 and
upwards.\n\nExamples\n--------\n\nCREATE TABLE t (id INT, ts
TIMESTAMP);\n\nDESC
t;\n+-------+-----------+------+-----+-------------------+-------------------------\n---+\n|
Field | Type | Null | Key | Default | Extra
\n
|\n+-------+-----------+------+-----+-------------------+-------------------------\n---+\n|
id | int(11) | YES | | NULL |
\n |\n| ts | timestamp | NO | | CURRENT_TIMESTAMP | on
update\nCURRENT_TIMESTAMP
|\n+-------+-----------+------+-----+-------------------+-------------------------\n---+\n\nINSERT
INTO t(id) VALUES (1),(2);\n\nSELECT * FROM
t;\n+------+---------------------+\n| id | ts
|\n+------+---------------------+\n| 1 | 2013-07-22 12:50:05 |\n| 2 |
2013-07-22 12:50:05 |\n+------+---------------------+\n\nINSERT INTO t
VALUES (3,NULL),(4,\'2001-07-22 12:12:12\');\n\nSELECT * FROM
t;\n+------+---------------------+\n| id | ts
|\n+------+---------------------+\n| 1 | 2013-07-22 12:50:05 |\n| 2 |
2013-07-22 12:50:05 |\n| 3 | 2013-07-22 12:51:56 |\n| 4 | 2001-07-22
12:12:12 |\n+------+---------------------+\n\nConverting to Unix
epoch:\n\nSELECT ts, UNIX_TIMESTAMP(ts) FROM
t;\n+---------------------+--------------------+\n| ts |
UNIX_TIMESTAMP(ts) |\n+---------------------+--------------------+\n|
2013-07-22 12:50:05 | 1374490205 |\n| 2013-07-22 12:50:05 |
1374490205 |\n| 2013-07-22 12:51:56 | 1374490316 |\n| 2001-07-22
12:12:12 | 995796732
|\n+---------------------+--------------------+\n\nUpdate also changes the
timestamp:\n\nUPDATE t set id=5 WHERE id=1;\n\nSELECT * FROM
t;\n+------+---------------------+\n| id | ts
|\n+------+---------------------+\n| 5 | 2013-07-22 14:52:33 |\n| 2 |
2013-07-22 12:50:05 |\n| 3 | 2013-07-22 12:51:56 |\n| 4 | 2001-07-22
12:12:12 |\n+------+---------------------+\n\nDefault NULL:\n\nCREATE TABLE
t2 (id INT, ts TIMESTAMP NULL ON UPDATE CURRENT_TIMESTAMP);\n\nINSERT INTO
t(id) VALUES (1),(2);\n\nSELECT * FROM t2;\n\nINSERT INTO t2(id) VALUES
(1),(2);\n\nSELECT * FROM t2;\n+------+------+\n| id | ts
|\n+------+------+\n| 1 | NULL |\n| 2 | NULL
|\n+------+------+\n\nUPDATE t2 SET id=3 WHERE id=1;\n\nSELECT * FROM
t2;\n+------+---------------------+\n| id | ts
|\n+------+---------------------+\n| 3 | 2013-07-22 15:32:22 |\n| 2 |
NULL |\n+------+---------------------+\n\nOnly the first
timestamp is automatically inserted and updated:\n\nCREATE TABLE t3 (id
INT, ts1 TIMESTAMP, ts2 TIMESTAMP);\n\nINSERT INTO t3(id) VALUES
(1),(2);\n\nSELECT * FROM
t3;\n+------+---------------------+---------------------+\n| id | ts1
| ts2
|\n+------+---------------------+---------------------+\n| 1 |
2013-07-22 15:35:07 | 0000-00-00 00:00:00 |\n| 2 | 2013-07-22 15:35:07 |
0000-00-00 00:00:00
|\n+------+---------------------+---------------------+\n\nDESC
t3;\n+-------+-----------+------+-----+---------------------+-----------------------\n-----+\n|
Field | Type | Null | Key | Default | Extra
\n
|\n+-------+-----------+------+-----+---------------------+-----------------------\n-----+\n|
id | int(11) | YES | | NULL |
\n |\n| ts1 | timestamp | NO | | CURRENT_TIMESTAMP | on
update\nCURRENT_TIMESTAMP |\n| ts2 | timestamp | NO | | 0000-00-00
00:00:00 | \n
|\n+-------+-----------+------+-----+---------------------+-----------------------\n-----+\n\nExplicitly
setting a timestamp with the CURRENT_TIMESTAMP function:\n\nINSERT INTO
t3(id,ts2) VALUES (3,CURRENT_TIMESTAMP());\n\nSELECT * FROM
t3;\n+------+---------------------+---------------------+\n| id | ts1
| ts2
|\n+------+---------------------+---------------------+\n| 1 |
2013-07-22 15:35:07 | 0000-00-00 00:00:00 |\n| 2 | 2013-07-22 15:35:07 |
0000-00-00 00:00:00 |\n| 3 | 2013-07-22 15:38:52 | 2013-07-22 15:38:52
|\n+------+---------------------+---------------------+\n\nSpecifying the
timestamp as NOT NULL:\n\nCREATE TABLE t4 (id INT, ts TIMESTAMP NOT
NULL);\n\nINSERT INTO t4(id) VALUES (1);\nSELECT SLEEP(1);\nINSERT INTO
t4(id,ts) VALUES (2,NULL);\n\nSELECT * FROM t4;\n\nURL:
https://mariadb.com/kb/en/timestamp/','','https://mariadb.com/kb/en/timestamp/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(291,23,'YEAR Data
Type','Syntax\n------\n\nYEAR[(4)]\n\nDescription\n-----------\n\nA
year in two-digit or four-digit format. The default is four-digit
format.\nNote that the two-digit format has been deprecated since MariaDB
5.5.27.\n\nIn four-digit format, the allowable values are 1901 to 2155, and
0000. In\ntwo-digit format, the allowable values are 70 to 69, representing
years from\n1970 to 2069. MariaDB displays YEAR values in YYYY format, but
allows you to\nassign values to YEAR columns using either strings or
numbers.\n\nInserting numeric zero has a different result for YEAR(4) and
YEAR(2). For\nYEAR(2), the value 00 reflects the year 2000. For YEAR(4),
the value 0000\nreflects the year zero. This only applies to numeric zero.
String zero always\nreflects the year
2000.\n\nExamples\n--------\n\nAccepting a string or a number:\n\nCREATE
TABLE y(y YEAR);\n\nINSERT INTO y VALUES
(1990),(\'2012\');\n\nSELECT * FROM y;\n+------+\n| y
|\n+------+\n| 1990 |\n| 2012 |\n+------+\n\nWith strict_mode set, the
default from MariaDB 10.2.4:\n\nOut of range:\n\nINSERT INTO y VALUES
(1005),(\'3080\');\nERROR 1264 (22003): Out of range value for
column \'y\' at row 1\n\nINSERT INTO y VALUES
(\'2013-12-12\');\nERROR 1265 (01000): Data truncated for column
\'y\' at row 1\n\nSELECT * FROM y;\n+------+\n| y
|\n+------+\n| 1990 |\n| 2012 |\n+------+\n\nWith strict_mode unset, the
default until MariaDB 10.2.3:\n\nOut of range:\n\nINSERT INTO y VALUES
(1005),(\'3080\');\nQuery OK, 2 rows affected, 2 warnings (0.05
sec)\nRecords: 2 Duplicates: 0 Warnings: 2\n\nSHOW
WARNINGS;\n+---------+------+--------------------------------------------+\n|
Level | Code | Message
|\n+---------+------+--------------------------------------------+\n|
Warning | 1264 | Out of range value for column \'y\' at row 1
|\n| Warning | 1264 | Out of range value for column \'y\' at row
2
|\n+---------+------+--------------------------------------------+\n\nSELECT
* FROM y;\n+------+\n| y |\n+------+\n| 1990 |\n| 2012 |\n| 0000 |\n|
0000 |\n+------+\n\nTruncating:\n\nINSERT INTO y VALUES
(\'2013-12-12\');\nQuery OK, 1 row affected, 1 warning (0.05
sec)\n\nSHOW
WARNINGS;\n+---------+------+----------------------------------------+\n|
Level | Code | Message
|\n+---------+------+----------------------------------------+\n| Warning |
1265 | Data truncated for column \'y\' at row 1
|\n+---------+------+----------------------------------------+\n\nSELECT *
FROM y;\n+------+\n| y |\n+------+\n| 1990 |\n| 2012 |\n| 0000 |\n| 0000
|\n| 2013 |\n+------+\n\nDifference between YEAR(2) and YEAR(4), and string
and numeric zero:\n\nCREATE TABLE y2(y YEAR(4), y2 YEAR(2));\nQuery OK, 0
rows affected, 1 warning (0.40 sec)\n\nNote (Code 1287):
\'YEAR(2)\' is deprecated and will be removed in a
future\nrelease. \n Please use YEAR(4) instead\n\nINSERT INTO y2
VALUES(0,0),(\'0\',\'0\');\n\nSELECT YEAR(y),YEAR(y2)
FROM y2;\n+---------+----------+\n| YEAR(y) | YEAR(y2)
|\n+---------+----------+\n| 0 | 2000 |\n| 2000 | 2000
|\n+---------+----------+\n\nURL:
https://mariadb.com/kb/en/year-data-type/','','https://mariadb.com/kb/en/year-data-type/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(292,23,'AUTO_INCREMENT','Description\n-----------\n\nThe
AUTO_INCREMENT attribute can be used to generate a unique identity for
new\nrows. When you insert a new record to the table (or upon adding
an\nAUTO_INCREMENT attribute with the ALTER TABLE statement), and
the\nauto_increment field is NULL or DEFAULT (in the case of an INSERT),
the value\nwill automatically be incremented. This also applies to 0,
unless the\nNO_AUTO_VALUE_ON_ZERO SQL_MODE is enabled.\n\nAUTO_INCREMENT
columns start from 1 by default. The automatically generated\nvalue can
never be lower than 0.\n\nEach table can have only one AUTO_INCREMENT
column. It must defined as a key\n(not necessarily the PRIMARY KEY or
UNIQUE key). In some storage engines\n(including the default InnoDB), if
the key consists of multiple columns, the\nAUTO_INCREMENT column must be
the first column. Storage engines that permit\nthe column to be placed
elsewhere are Aria, MyISAM, MERGE, Spider, TokuDB,\nBLACKHOLE, FederatedX
and Federated.\n\nCREATE TABLE animals (\n id MEDIUMINT NOT NULL
AUTO_INCREMENT,\n name CHAR(30) NOT NULL,\n PRIMARY KEY (id)\n
);\n\nINSERT INTO animals (name) VALUES\n
(\'dog\'),(\'cat\'),(\'penguin\'),\n
(\'fox\'),(\'whale\'),(\'ostrich\');\n\nSELECT
* FROM animals;\n+----+---------+\n| id | name |\n+----+---------+\n| 1
| dog |\n| 2 | cat |\n| 3 | penguin |\n| 4 | fox |\n| 5 |
whale |\n| 6 | ostrich |\n+----+---------+\n\nSERIAL is an alias for
BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE.\n\nCREATE TABLE t (id
SERIAL, c CHAR(1)) ENGINE=InnoDB;\n\nSHOW CREATE TABLE t
\\G\n*************************** 1. row ***************************\n
Table: t\nCreate Table: CREATE TABLE `t` (\n `id` bigint(20) unsigned NOT
NULL AUTO_INCREMENT,\n `c` char(1) DEFAULT NULL,\n UNIQUE KEY `id`
(`id`)\n) ENGINE=InnoDB DEFAULT CHARSET=latin1\n\nSetting or Changing the
Auto_Increment Value\n--------------------------------------------\n\nYou
can use an ALTER TABLE statement to assign a new value to
the\nauto_increment table option, or set the insert_id server system
variable to\nchange the next AUTO_INCREMENT value inserted by the current
session.\n\nLAST_INSERT_ID() can be used to see the last AUTO_INCREMENT
value inserted by\nthe current session.\n\nALTER TABLE animals
AUTO_INCREMENT=8;\n\nINSERT INTO animals (name) VALUES
(\'aardvark\');\n\nSELECT * FROM animals;\n+----+-----------+\n|
id | name |\n+----+-----------+\n| 1 | dog |\n| 2 | cat
|\n| 3 | penguin |\n| 4 | fox |\n| 5 | whale |\n| 6 |
ostrich |\n| 8 | aardvark |\n+----+-----------+\n\nSET
insert_id=12;\n\nINSERT INTO animals (name) VALUES
(\'gorilla\');\n\nSELECT * FROM animals;\n+----+-----------+\n|
id | name |\n+----+-----------+\n| 1 | dog |\n| 2 | cat
|\n| 3 | penguin |\n| 4 | fox |\n| 5 | whale |\n| 6 |
ostrich |\n| 8 | aardvark |\n| 12 | gorilla
|\n+----+-----------+\n\nInnoDB\n------\n\nUntil MariaDB 10.2.3, InnoDB
used an auto-increment counter that is stored in\nmemory. When the server
restarts, the counter is re-initialized to the highest\nvalue used in the
table, which cancels the effects of any AUTO_INCREMENT = N\noption in the
table statements.\n\nFrom MariaDB 10.2.4, this restriction has been lifted
and AUTO_INCREMENT is\npersistent.\n\nSee also AUTO_INCREMENT Handling in
InnoDB.\n\nSetting Explicit Values\n-----------------------\n\nIt is
possible to specify a value for an AUTO_INCREMENT column. If the key
is\nprimary or unique, the value must not already exist in the key.\n\nIf
the new value is higher than the current maximum value, the
AUTO_INCREMENT\nvalue is updated, so the next value will be higher. If the
new value is lower\nthan the current maximum value, the AUTO_INCREMENT
value remains unchanged.\n\nThe following example demonstrates these
behaviors:\n\nCREATE TABLE t (id INTEGER UNSIGNED AUTO_INCREMENT PRIMARY
KEY) ENGINE =\nInnoDB;\n\nINSERT INTO t VALUES (NULL);\nSELECT id FROM
t;\n+----+\n| id |\n+----+\n| 1 |\n+----+\n\nINSERT INTO t VALUES (10); --
higher value\nSELECT id FROM t;\n+----+\n| id |\n+----+\n| 1 |\n| 10
|\n+----+\n\nINSERT INTO t VALUES (2); -- lower value\nINSERT INTO t VALUES
(NULL); -- auto value\nSELECT id FROM t;\n+----+\n| id |\n+----+\n| 1 |\n|
2 |\n| 10 |\n| 11 |\n+----+\n\nThe ARCHIVE storage engine does not allow
to insert a value that is lower than\nthe current maximum.\n\nMissing
Values\n--------------\n\nAn AUTO_INCREMENT column normally has missing
values. This happens because if\na row is deleted, or an AUTO_INCREMENT
value is explicitly updated, old values\nare never re-used. The REPLACE
statement also deletes a row, and its value is\nwasted. With InnoDB, values
can be reserved by a transaction; but if the\ntransaction fails (for
example, because of a ROLLBACK) the reserved value will\nbe lost.\n\nThus
AUTO_INCREMENT values can be used to sort results in a
chronological\norder, but not to create a numeric
sequence.\n\nReplication\n-----------\n\nTo make master-master or Galera
safe to use AUTO_INCREMENT one should use the\nsystem variables
auto_increment_increment and auto_increment_offset to\ngenerate unique
values for each server.\n\nCHECK Constraints, DEFAULT Values and Virtual
Columns\n-----------------------------------------------------\n\nMariaDB
starting with 10.2.6\n----------------------------\nFrom MariaDB 10.2.6
auto_increment columns are no longer permitted in CHECK\nconstraints,
DEFAULT value expressions and virtual columns. They were\npermitted in
earlier versions, but did not work correctly. See MDEV-11117.\n\nGenerating
Auto_Increment Values When Adding the
Attribute\n----------------------------------------------------------\n\nCREATE
OR REPLACE TABLE t1 (a INT);\nINSERT t1 VALUES (0),(0),(0);\nALTER TABLE t1
MODIFY a INT NOT NULL AUTO_INCREMENT PRIMARY KEY;\nSELECT * FROM
t1;\n+---+\n| a |\n+---+\n| 1 |\n| 2 |\n| 3 |\n+---+\n\nCREATE OR REPLACE
TABLE t1 (a INT);\nINSERT t1 VALUES (5),(0),(8),(0);\nALTER TABLE t1 MODIFY
a INT NOT NULL AUTO_INCREMENT PRIMARY KEY;\nSELECT * FROM t1;\n+---+\n| a
|\n+---+\n| 5 |\n| 6 |\n| 8 |\n| 9 |\n+---+\n\nIf the NO_AUTO_VALUE_ON_ZERO
SQL_MODE is set, zero values will not be\nautomatically incremented:\n\nSET
SQL_MODE=\'no_auto_value_on_zero\';\nCREATE OR REPLACE TABLE t1
(a INT);\nINSERT t1 VALUES (3), (0);\nALTER TABLE t1 MODIFY a INT NOT NULL
AUTO_INCREMENT PRIMARY KEY;\nSELECT * FROM t1;\n+---+\n| a |\n+---+\n| 0
|\n| 3 |\n+---+\n\nURL:
https://mariadb.com/kb/en/auto_increment/','','https://mariadb.com/kb/en/auto_increment/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(293,24,'Using Compound Statements Outside of Stored
Programs','Compound statements can also be used outside of stored
programs.\n\ndelimiter |\nIF @have_innodb THEN\n CREATE TABLE IF NOT EXISTS
innodb_index_stats (\n database_name VARCHAR(64) NOT NULL,\n
table_name VARCHAR(64) NOT NULL,\n index_name VARCHAR(64) NOT
NULL,\n last_update TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON
UPDATE\nCURRENT_TIMESTAMP,\n stat_name VARCHAR(64) NOT NULL,\n
stat_value BIGINT UNSIGNED NOT NULL,\n sample_size BIGINT
UNSIGNED,\n stat_description VARCHAR(1024) NOT NULL,\n PRIMARY KEY
(database_name, table_name, index_name, stat_name)\n ) ENGINE=INNODB
DEFAULT CHARSET=utf8 COLLATE=utf8_bin STATS_PERSISTENT=0;\nEND IF|\nQuery
OK, 0 rows affected, 2 warnings (0.00 sec)\n\nNote, that using compound
statements this way is subject to following\nlimitations:\n\n* Only BEGIN,
IF, CASE, LOOP, WHILE, REPEAT statements may start a compound\nstatement
outside of stored programs.\n* BEGIN must use the BEGIN NOT ATOMIC syntax
(otherwise it\'ll be confused with\nBEGIN that starts a
transaction).\n* A compound statement might not start with a label.\n* A
compound statement is parsed completely—note \"2 warnings\" in
the above\nexample, even if the condition was false (InnoDB was, indeed,
disabled), and\nthe CREATE TABLE statement was not executed, it was still
parsed and the\nparser produced \"Unknown storage engine\"
warning.\n\nInside a compound block first three limitations do not apply,
one can use\nanything that can be used inside a stored program —
including labels,\ncondition handlers, variables, and so on:\n\nBEGIN NOT
ATOMIC\n DECLARE foo CONDITION FOR 1146;\n DECLARE x INT DEFAULT 0;\n
DECLARE CONTINUE HANDLER FOR SET x=1;\n INSERT INTO test.t1 VALUES
(\"hndlr1\", val, 2);\n END|\n\nExample how to use IF:\n\nIF
(1>0) THEN BEGIN NOT ATOMIC SELECT 1; END ; END IF;;\n\nExample of how
to use WHILE loop:\n\nDELIMITER |\nBEGIN NOT ATOMIC\n DECLARE x INT
DEFAULT 0;\n WHILE x <= 10 DO\n SET x = x + 1;\n SELECT x;\n END
WHILE;\nEND|\nDELIMITER
;\n\nURL:\nhttps://mariadb.com/kb/en/using-compound-statements-outside-of-stored-programs/','','https://mariadb.com/kb/en/using-compound-statements-outside-of-stored-programs/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(294,24,'BEGIN END','Syntax\n------\n\n[begin_label:] BEGIN
[NOT ATOMIC]\n [statement_list]\nEND [end_label]\n\nNOT ATOMIC is required
when used outside of a stored procedure. Inside stored\nprocedures or
within an anonymous block, BEGIN alone starts a new
anonymous\nblock.\n\nDescription\n-----------\n\nBEGIN ... END syntax is
used for writing compound statements. A compound\nstatement can contain
multiple statements, enclosed by the BEGIN and END\nkeywords.
statement_list represents a list of one or more statements,
each\nterminated by a semicolon (i.e., ;) statement delimiter.
statement_list is\noptional, which means that the empty compound statement
(BEGIN END) is legal.\n\nNote that END will perform a commit. If you are
running in autocommit mode,\nevery statement will be committed separately.
If you are not running in\nautocommit mode, you must execute a COMMIT or
ROLLBACK after END to get the\ndatabase up to date.\n\nUse of multiple
statements requires that a client is able to send statement\nstrings
containing the ; statement delimiter. This is handled in the
mysql\ncommand-line client with the DELIMITER command. Changing the
;\nend-of-statement delimiter (for example, to //) allows ; to be used in
a\nprogram body.\n\nA compound statement within a stored program can be
labeled. end_label cannot\nbe given unless begin_label also is present. If
both are present, they must be\nthe same.\n\nBEGIN ... END constructs can
be nested. Each block can define its own\nvariables, a CONDITION, a HANDLER
and a CURSOR, which don\'t exist in the outer\nblocks. The most local
declarations override the outer objects which use the\nsame name (see
example below).\n\nThe declarations order is the following:\n\n* DECLARE
local variables;\n* DECLARE CONDITIONs;\n* DECLARE CURSORs;\n* DECLARE
HANDLERs;\n\nNote that DECLARE HANDLER contains another BEGIN ... END
construct.\n\nHere is an example of a very simple, anonymous
block:\n\nBEGIN NOT ATOMIC\nSET @a=1;\nCREATE TABLE test.t1(a
INT);\nEND|\n\nBelow is an example of nested blocks in a stored
procedure:\n\nCREATE PROCEDURE t( )\nBEGIN\n DECLARE x TINYINT UNSIGNED
DEFAULT 1;\n BEGIN\n DECLARE x CHAR(2) DEFAULT \'02\';\n
DECLARE y TINYINT UNSIGNED DEFAULT 10;\n SELECT x, y;\n END;\n SELECT
x;\nEND;\n\nIn this example, a TINYINT variable, x is declared in the
outter block. But in\nthe inner block x is re-declared as a CHAR and an y
variable is declared. The\ninner SELECT shows the \"new\" value
of x, and the value of y. But when x is\nselected in the outer block, the
\"old\" value is returned. The final SELECT\ndoesn\'t try to
read y, because it doesn\'t exist in that context.\n\nURL:
https://mariadb.com/kb/en/begin-end/','','https://mariadb.com/kb/en/begin-end/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(295,24,'CASE Statement','Syntax\n------\n\nCASE
case_value\n WHEN when_value THEN statement_list\n [WHEN when_value THEN
statement_list] ...\n [ELSE statement_list]\nEND CASE\n\nOr:\n\nCASE\n
WHEN search_condition THEN statement_list\n [WHEN search_condition THEN
statement_list] ...\n [ELSE statement_list]\nEND
CASE\n\nDescription\n-----------\n\nThe text on this page describes the
CASE statement for stored programs. See\nthe CASE OPERATOR for details on
the CASE operator outside of stored programs.\n\nThe CASE statement for
stored programs implements a complex conditional\nconstruct. If a
search_condition evaluates to true, the corresponding SQL\nstatement list
is executed. If no search condition matches, the statement list\nin the
ELSE clause is executed. Each statement_list consists of one or
more\nstatements.\n\nThe CASE statement cannot have an ELSE NULL clause,
and it is terminated with\nEND CASE instead of END. implements a complex
conditional construct. If a\nsearch_condition evaluates to true, the
corresponding SQL statement list is\nexecuted. If no search condition
matches, the statement list in the ELSE\nclause is executed. Each
statement_list consists of one or more statements.\n\nIf no when_value or
search_condition matches the value tested and the CASE\nstatement contains
no ELSE clause, a Case not found for CASE statement error\nresults.\n\nEach
statement_list consists of one or more statements; an empty\nstatement_list
is not allowed. To handle situations where no value is matched\nby any WHEN
clause, use an ELSE containing an empty BEGIN ... END block, as\nshown in
this example:\n\nDELIMITER |\nCREATE PROCEDURE p()\nBEGIN\n DECLARE v INT
DEFAULT 1;\n CASE v\n WHEN 2 THEN SELECT v;\n WHEN 3 THEN SELECT 0;\n
ELSE BEGIN END;\n END CASE;\nEND;\n|\n\nThe indentation used here in the
ELSE clause is for purposes of clarity only,\nand is not otherwise
significant. See Delimiters in the mysql client for more\non the use of the
delimiter command.\n\nNote: The syntax of the CASE statement used inside
stored programs differs\nslightly from that of the SQL CASE expression
described in CASE OPERATOR. The\nCASE statement cannot have an ELSE NULL
clause, and it is terminated with END\nCASE instead of END.\n\nURL:
https://mariadb.com/kb/en/case-statement/','','https://mariadb.com/kb/en/case-statement/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(296,24,'DECLARE CONDITION','Syntax\n------\n\nDECLARE
condition_name CONDITION FOR condition_value\n\ncondition_value:\n
SQLSTATE [VALUE] sqlstate_value\n |
mysql_error_code\n\nDescription\n-----------\n\nThe DECLARE ... CONDITION
statement defines a named error condition. It\nspecifies a condition that
needs specific handling and associates a name with\nthat condition. Later,
the name can be used in a DECLARE ... HANDLER, SIGNAL\nor RESIGNAL
statement (as long as the statement is located in the same BEGIN\n... END
block).\n\nConditions must be declared after local variables, but before
CURSORs and\nHANDLERs.\n\nA condition_value for DECLARE ... CONDITION can
be an SQLSTATE value (a\n5-character string literal) or a MySQL error code
(a number). You should not\nuse SQLSTATE value \'00000\' or MySQL
error code 0, because those indicate\nsucess rather than an error
condition. If you try, or if you specify an\ninvalid SQLSTATE value, an
error like this is produced:\n\nERROR 1407 (42000): Bad SQLSTATE:
\'00000\'\n\nFor a list of SQLSTATE values and MariaDB error
codes, see MariaDB Error Codes.\n\nURL:
https://mariadb.com/kb/en/declare-condition/','','https://mariadb.com/kb/en/declare-condition/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(297,24,'DECLARE HANDLER','Syntax\n------\n\nDECLARE
handler_type HANDLER\n FOR condition_value [, condition_value] ...\n
statement\n\nhandler_type:\n CONTINUE\n | EXIT\n |
UNDO\n\ncondition_value:\n SQLSTATE [VALUE] sqlstate_value\n |
condition_name\n | SQLWARNING\n | NOT FOUND\n | SQLEXCEPTION\n |
mariadb_error_code\n\nDescription\n-----------\n\nThe DECLARE ... HANDLER
statement specifies handlers that each may deal with\none or more
conditions. If one of these conditions occurs, the specified\nstatement is
executed. statement can be a simple statement (for example, SET\nvar_name =
value), or it can be a compound statement written using BEGIN
and\nEND.\n\nHandlers must be declared after local variables, a CONDITION
and a CURSOR.\n\nFor a CONTINUE handler, execution of the current program
continues after\nexecution of the handler statement. For an EXIT handler,
execution terminates\nfor the BEGIN ... END compound statement in which the
handler is declared.\n(This is true even if the condition occurs in an
inner block.) The UNDO\nhandler type statement is not supported.\n\nIf a
condition occurs for which no handler has been declared, the
default\naction is EXIT.\n\nA condition_value for DECLARE ... HANDLER can
be any of the following values:\n\n* An SQLSTATE value (a 5-character
string literal) or a MariaDB error\ncode (a number). You should not use
SQLSTATE value \'00000\' or MariaDB\nerror code 0, because those
indicate sucess rather than an error\ncondition. For a list of SQLSTATE
values and MariaDB error codes, see\nMariaDB Error Codes.\n* A condition
name previously specified with DECLARE ... CONDITION. It must be\nin the
same stored program. See DECLARE CONDITION.\n* SQLWARNING is shorthand for
the class of SQLSTATE values that begin\nwith \'01\'.\n* NOT
FOUND is shorthand for the class of SQLSTATE values that begin\nwith
\'02\'. This is relevant only the context of cursors and is used
to\ncontrol what happens when a cursor reaches the end of a data set.
If\nno more rows are available, a No Data condition occurs with
SQLSTATE\nvalue 02000. To detect this condition, you can set up a handler
for it\n(or for a NOT FOUND condition). An example is shown in Cursor
Overview. This\ncondition also occurs for SELECT ... INTO var_list
statements that retrieve no\nrows.\n* SQLEXCEPTION is shorthand for the
class of SQLSTATE values that do\nnot begin with \'00\',
\'01\', or \'02\'.\n\nWhen an error raises, in some
cases it could be handled by multiple HANDLERs.\nFor example, there may be
an handler for 1050 error, a separate handler for\nthe 42S01 SQLSTATE, and
another separate handler for the SQLEXCEPTION class:\nin theory all
occurrences of HANDLER may catch the 1050 error, but MariaDB\nchooses the
HANDLER with the highest precedence. Here are the precedence rules:\n\n*
Handlers which refer to an error code have the highest precedence.\n*
Handlers which refer to a SQLSTATE come next.\n* Handlers which refer to an
error class have the lowest precedence.\n\nIn some cases, a statement could
produce multiple errors. If this happens, in\nsome cases multiple handlers
could have the highest precedence. In such cases,\nthe choice of the
handler is indeterminate.\n\nNote that if an error occurs within a CONTINUE
HANDLER block, it can be\nhandled by another HANDLER. However, a HANDLER
which is already in the stack\n(that is, it has been called to handle an
error and its execution didn\'t\nfinish yet) cannot handle new
errors—this prevents endless loops. For example,\nsuppose that a stored
procedure contains a CONTINUE HANDLER for SQLWARNING and\nanother CONTINUE
HANDLER for NOT FOUND. At some point, a NOT FOUND error\noccurs, and the
execution enters the NOT FOUND HANDLER. But within that\nhandler, a warning
occurs, and the execution enters the SQLWARNING HANDLER. If\nanother NOT
FOUND error occurs, it cannot be handled again by the NOT FOUND\nHANDLER,
because its execution is not finished.\n\nWhen a DECLARE HANDLER block can
handle more than one error condition, it may\nbe useful to know which
errors occurred. To do so, you can use the GET\nDIAGNOSTICS
statement.\n\nAn error that is handled by a DECLARE HANDLER construct can
be issued again\nusing the RESIGNAL statement.\n\nBelow is an example using
DECLARE HANDLER:\n\nCREATE TABLE test.t (s1 INT, PRIMARY KEY
(s1));\n\nDELIMITER //\n\nCREATE PROCEDURE handlerdemo ( )\n BEGIN\n
DECLARE CONTINUE HANDLER FOR SQLSTATE \'23000\' SET @x2 = 1;\n
SET @x = 1;\n INSERT INTO test.t VALUES (1);\n SET @x = 2;\n INSERT
INTO test.t VALUES (1);\n SET @x = 3;\n END;\n //\n\nDELIMITER
;\n\nCALL handlerdemo( );\n\nSELECT @x;\n+------+\n| @x |\n+------+\n|
3 |\n+------+\n\nURL:
https://mariadb.com/kb/en/declare-handler/','','https://mariadb.com/kb/en/declare-handler/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(298,24,'DECLARE Variable','Syntax\n------\n\nDECLARE
var_name [, var_name] ... [[ROW] TYPE OF]] type [DEFAULT
value]\n\nDescription\n-----------\n\nThis statement is used to declare
local variables within stored programs. To\nprovide a default value for the
variable, include a DEFAULT clause. The value\ncan be specified as an
expression (even subqueries are permitted); it need not\nbe a constant. If
the DEFAULT clause is missing, the initial value is NULL.\n\nLocal
variables are treated like stored routine parameters with respect to\ndata
type and overflow checking. See CREATE PROCEDURE.\n\nLocal variables must
be declared before CONDITIONs, CURSORs and HANDLERs.\n\nLocal variable
names are not case sensitive.\n\nThe scope of a local variable is within
the BEGIN ... END block where it is\ndeclared. The variable can be referred
to in blocks nested within the\ndeclaring block, except those blocks that
declare a variable with the same\nname.\n\nTYPE OF / ROW TYPE
OF\n---------------------\n\nMariaDB starting with
10.3\n--------------------------\nTYPE OF and ROW TYPE OF anchored data
types for stored routines were\nintroduced in MariaDB 10.3.\n\nAnchored
data types allow a data type to be defined based on another object,\nsuch
as a table row, rather than specifically set in the declaration. If
the\nanchor object changes, so will the anchored data type. This can lead
to\nroutines being easier to maintain, so that if the data type in the
table is\nchanged, it will automatically be changed in the routine as
well.\n\nVariables declared with ROW TYPE OF will have the same features as
implicit\nROW variables. It is not possible to use ROW TYPE OF variables in
a LIMIT\nclause.\n\nThe real data type of TYPE OF and ROW TYPE OF
table_name will become known at\nthe very beginning of the stored routine
call. ALTER TABLE or DROP TABLE\nstatements performed inside the current
routine on the tables that appear in\nanchors won\'t affect the data
type of the anchored variables, even if the\nvariable is declared after an
ALTER TABLE or DROP TABLE statement.\n\nThe real data type of a ROW TYPE OF
cursor_name variable will become known\nwhen execution enters into the
block where the variable is declared. Data type\ninstantiation will happen
only once. In a cursor ROW TYPE OF variable that is\ndeclared inside a
loop, its data type will become known on the very first\niteration and
won\'t change on further loop iterations.\n\nThe tables referenced in
TYPE OF and ROW TYPE OF declarations will be checked\nfor existence at the
beginning of the stored routine call. CREATE PROCEDURE or\nCREATE FUNCTION
will not check the referenced tables for
existence.\n\nExamples\n--------\n\nTYPE OF and ROW TYPE OF from MariaDB
10.3:\n\nDECLARE tmp TYPE OF t1.a; -- Get the data type from the column
{{a}} in the\ntable {{t1}}\n\nDECLARE rec1 ROW TYPE OF t1; -- Get the row
data type from the table {{t1}}\n\nDECLARE rec2 ROW TYPE OF cur1; -- Get
the row data type from the cursor\n{{cur1}}\n\nURL:
https://mariadb.com/kb/en/declare-variable/','','https://mariadb.com/kb/en/declare-variable/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(299,24,'FOR','MariaDB starting with
10.3\n--------------------------\nFOR loops were introduced in MariaDB
10.3.\n\nSyntax\n------\n\nInteger range FOR loop:\n\n[begin_label:]\nFOR
var_name IN [ REVERSE ] lower_bound .. upper_bound\nDO statement_list\nEND
FOR [ end_label ]\n\nExplicit cursor FOR loop\n\n[begin_label:]\nFOR
record_name IN cursor_name [ ( cursor_actual_parameter_list)]\nDO
statement_list\nEND FOR [ end_label ]\n\nExplicit cursor FOR loop (Oracle
mode)\n\n[begin_label:]\nFOR record_name IN cursor_name [ (
cursor_actual_parameter_list)]\nLOOP\n statement_list\nEND LOOP [ end_label
]\n\nImplicit cursor FOR loop\n\n[begin_label:]\nFOR record_name IN (
select_statement )\nDO statement_list\nEND FOR [ end_label
]\n\nDescription\n-----------\n\nFOR loops allow code to be executed a
fixed number of times.\n\nIn an integer range FOR loop, MariaDB will
compare the lower bound and upper\nbound values, and assign the lower bound
value to a counter. If REVERSE is not\nspecified, and the upper bound value
is greater than or equal to the counter,\nthe counter will be incremented
and the statement will continue, after which\nthe loop is entered again. If
the upper bound value is greater than the\ncounter, the loop will be
exited.\n\nIf REVERSE is specified, the counter is decremented, and the
upper bound value\nneeds to be less than or equal for the loop to
continue.\n\nExamples\n--------\n\nIntger range FOR loop:\n\nCREATE TABLE
t1 (a INT);\n\nDELIMITER //\n\nFOR i IN 1..3\nDO\n INSERT INTO t1 VALUES
(i);\nEND FOR;\n//\n\nDELIMITER ;\n\nSELECT * FROM t1;\n+------+\n| a
|\n+------+\n| 1 |\n| 2 |\n| 3 |\n+------+\n\nREVERSE integer
range FOR loop:\n\nCREATE OR REPLACE TABLE t1 (a INT);\n\nDELIMITER //\nFOR
i IN REVERSE 4..12\n DO\n INSERT INTO t1 VALUES (i);\nEND FOR;\n//\nQuery
OK, 9 rows affected (0.422 sec)\n\nDELIMITER ;\n\nSELECT * FROM
t1;\n+------+\n| a |\n+------+\n| 12 |\n| 11 |\n| 10 |\n| 9
|\n| 8 |\n| 7 |\n| 6 |\n| 5 |\n| 4 |\n+------+\n\nExplicit
cursor in Oracle mode:\n\nSET sql_mode=ORACLE;\n\nCREATE OR REPLACE TABLE
t1 (a INT, b VARCHAR(32));\n\nINSERT INTO t1 VALUES
(10,\'b0\');\nINSERT INTO t1 VALUES
(11,\'b1\');\nINSERT INTO t1 VALUES
(12,\'b2\');\n\nDELIMITER //\n\nCREATE OR REPLACE PROCEDURE p1(pa
INT) AS \n CURSOR cur(va INT) IS\n SELECT a, b FROM t1 WHERE
a=va;\nBEGIN\n FOR rec IN cur(pa)\n LOOP\n SELECT rec.a, rec.b;\n END
LOOP;\nEND;\n//\n\nDELIMITER ;\n\nCALL p1(10);\n+-------+-------+\n| rec.a
| rec.b |\n+-------+-------+\n| 10 | b0 |\n+-------+-------+\n\nCALL
p1(11);\n+-------+-------+\n| rec.a | rec.b |\n+-------+-------+\n| 11 |
b1 |\n+-------+-------+\n\nCALL p1(12);\n+-------+-------+\n| rec.a |
rec.b |\n+-------+-------+\n| 12 | b2 |\n+-------+-------+\n\nCALL
p1(13);\nQuery OK, 0 rows affected (0.000 sec)\n\nURL:
https://mariadb.com/kb/en/for/','','https://mariadb.com/kb/en/for/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(300,24,'GOTO','MariaDB starting with
10.3\n--------------------------\nThe GOTO statement was introduced in
MariaDB 10.3 for Oracle compatibility.\n\nSyntax\n------\n\nGOTO
label\n\nDescription\n-----------\n\nThe GOTO statement causes the code to
jump to the specified label, and\ncontinue operating from there. It is only
accepted when in Oracle mode.\n\nExample\n-------\n\nSET
sql_mode=ORACLE;\n\nDELIMITER //\n\nCREATE OR REPLACE PROCEDURE p1
AS\n\nBEGIN\n\nSELECT 1;\n GOTO label;\n SELECT 2;\n
<<label>>\n SELECT 3;\n\nEND;\n\n//\n\nDELIMITER\n\ncall
p1();\n+---+\n| 1 |\n+---+\n| 1 |\n+---+\n1 row in set (0.000
sec)\n\n+---+\n| 3 |\n+---+\n| 3 |\n+---+\n1 row in set (0.000 sec)\n\nURL:
https://mariadb.com/kb/en/goto/','','https://mariadb.com/kb/en/goto/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(301,24,'IF','Syntax\n------\n\nIF search_condition THEN
statement_list\n [ELSEIF search_condition THEN statement_list] ...\n
[ELSE statement_list]\nEND IF;\n\nDescription\n-----------\n\nIF implements
a basic conditional construct. If the search_condition evaluates\nto true,
the corresponding SQL statement list is executed. If no\nsearch_condition
matches, the statement list in the ELSE clause is executed.\nEach
statement_list consists of one or more statements.\n\nURL:
https://mariadb.com/kb/en/if/','','https://mariadb.com/kb/en/if/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(302,24,'ITERATE','Syntax\n------\n\nITERATE
label\n\nITERATE can appear only within LOOP, REPEAT, and WHILE statements.
ITERATE\nmeans \"do the loop again\", and uses the
statement\'s label to determine which\nstatements to repeat. The label
must be in the same stored program, not in a\ncaller procedure.\n\nIf you
try to use ITERATE with a non-existing label, or if the label
is\nassociated to a construct which is not a loop, the following error will
be\nproduced:\n\nERROR 1308 (42000): ITERATE with no matching label:
<label_name>\n\nBelow is an example of how ITERATE might be
used:\n\nCREATE PROCEDURE doiterate(p1 INT)\nBEGIN\n label1: LOOP\n SET p1
= p1 + 1;\n IF p1 < 10 THEN ITERATE label1; END IF;\n LEAVE label1;\n
END LOOP label1;\n SET @x = p1;\nEND\n\nURL:
https://mariadb.com/kb/en/iterate/','','https://mariadb.com/kb/en/iterate/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(303,24,'Labels','Syntax\n------\n\nlabel:
<construct>\n[label]\n\nLabels are MariaDB identifiers which can be
used to identify a BEGIN ... END\nconstruct or a loop. They have a maximum
length of 16 characters and can be\nquoted with backticks (i.e..,
`).\n\nLabels have a start part and an end part. The start part must
precede the\nportion of code it refers to, must be followed by a colon (:)
and can be on\nthe same or different line. The end part is optional and
adds nothing, but can\nmake the code more readable. If used, the end part
must precede the\nconstruct\'s delimiter (;). Constructs identified by
a label can be nested.\nEach construct can be identified by only one
label.\n\nLabels need not be unique in the stored program they belong to.
However, a\nlabel for an inner loop cannot be identical to a label for an
outer loop. In\nthis case, the following error would be produced:\n\nERROR
1309 (42000): Redefining label <label_name>\n\nLEAVE and ITERATE
statements can be used to exit or repeat a portion of code\nidentified by a
label. They must be in the same Stored Routine, Trigger or\nEvent which
contains the target label.\n\nBelow is an example using a simple label that
is used to exit a LOOP:\n\nCREATE PROCEDURE `test_sp`()\nBEGIN\n
`my_label`:\n LOOP\n SELECT \'looping\';\n LEAVE
`my_label`;\n END LOOP;\n SELECT \'out of loop\';\nEND;\n\nThe
following label is used to exit a procedure, and has an end part:\n\nCREATE
PROCEDURE `test_sp`()\n`my_label`:\nBEGIN\n IF @var = 1 THEN\n LEAVE
`my_label`;\n END IF;\n DO something();\nEND `my_label`;\n\nURL:
https://mariadb.com/kb/en/labels/','','https://mariadb.com/kb/en/labels/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(304,24,'LEAVE','Syntax\n------\n\nLEAVE label\n\nThis
statement is used to exit the flow control construct that has the
given\nlabel. The label must be in the same stored program, not in a
caller\nprocedure. LEAVE can be used within BEGIN ... END or loop
constructs (LOOP,\nREPEAT, WHILE). In Stored Procedures, Triggers and
Events, LEAVE can refer to\nthe outmost BEGIN ... END construct; in that
case, the program exits the\nprocedure. In Stored Functions, RETURN can be
used instead.\n\nNote that LEAVE cannot be used to exit a DECLARE HANDLER
block.\n\nIf you try to LEAVE a non-existing label, or if you try to LEAVE
a HANDLER\nblock, the following error will be produced:\n\nERROR 1308
(42000): LEAVE with no matching label: <label_name>\n\nThe following
example uses LEAVE to exit the procedure if a condition is true:\n\nCREATE
PROCEDURE proc(IN p TINYINT)\nCONTAINS SQL\n`whole_proc`:\nBEGIN\n SELECT
1;\n IF p < 1 THEN\n LEAVE `whole_proc`;\n END IF;\n SELECT
2;\nEND;\n\nCALL proc(0);\n+---+\n| 1 |\n+---+\n| 1 |\n+---+\n\nURL:
https://mariadb.com/kb/en/leave/','','https://mariadb.com/kb/en/leave/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(305,24,'LOOP','Syntax\n------\n\n[begin_label:] LOOP\n
statement_list\nEND LOOP [end_label]\n\nDescription\n-----------\n\nLOOP
implements a simple loop construct, enabling repeated execution of
the\nstatement list, which consists of one or more statements, each
terminated by a\nsemicolon (i.e., ;) statement delimiter. The statements
within the loop are\nrepeated until the loop is exited; usually this is
accomplished with a LEAVE\nstatement.\n\nA LOOP statement can be labeled.
end_label cannot be given unless begin_label\nalso is present. If both are
present, they must be the same.\n\nSee Delimiters in the mysql client for
more on delimiter usage in the client.\n\nURL:
https://mariadb.com/kb/en/loop/','','https://mariadb.com/kb/en/loop/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(306,24,'REPEAT LOOP','Syntax\n------\n\n[begin_label:]
REPEAT\n statement_list\nUNTIL search_condition\nEND REPEAT
[end_label]\n\nThe statement list within a REPEAT statement is repeated
until the\nsearch_condition is true. Thus, a REPEAT always enters the loop
at least once.\nstatement_list consists of one or more statements, each
terminated by a\nsemicolon (i.e., ;) statement delimiter.\n\nA REPEAT
statement can be labeled. end_label cannot be given unless\nbegin_label
also is present. If both are present, they must be the same.\n\nSee
Delimiters in the mysql client for more on client delimiter
usage.\n\nDELIMITER //\n\nCREATE PROCEDURE dorepeat(p1 INT)\n BEGIN\n SET
@x = 0;\n REPEAT SET @x = @x + 1; UNTIL @x > p1 END REPEAT;\n
END\n//\n\nCALL dorepeat(1000)//\n\nSELECT @x//\n+------+\n| @x
|\n+------+\n| 1001 |\n+------+\n\nURL:
https://mariadb.com/kb/en/repeat-loop/','','https://mariadb.com/kb/en/repeat-loop/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(307,24,'RESIGNAL','Syntax\n------\n\nRESIGNAL
[error_condition]\n [SET error_property\n [, error_property]
...]\n\nerror_condition:\n SQLSTATE [VALUE] \'sqlstate_value\'\n
| condition_name\n\nerror_property:\n error_property_name =
<error_property_value>\n\nerror_property_name:\n CLASS_ORIGIN\n |
SUBCLASS_ORIGIN\n | MESSAGE_TEXT\n | MYSQL_ERRNO\n | CONSTRAINT_CATALOG\n |
CONSTRAINT_SCHEMA\n | CONSTRAINT_NAME\n | CATALOG_NAME\n | SCHEMA_NAME\n |
TABLE_NAME\n | COLUMN_NAME\n |
CURSOR_NAME\n\nDescription\n-----------\n\nThe syntax of RESIGNAL and its
semantics are very similar to SIGNAL. This\nstatement can only be used
within an error HANDLER. It produces an error, like\nSIGNAL. RESIGNAL
clauses are the same as SIGNAL, except that they all are\noptional, even
SQLSTATE. All the properties which are not specified in\nRESIGNAL, will be
identical to the properties of the error that was received\nby the error
HANDLER. For a description of the clauses, see diagnostics area.\n\nNote
that RESIGNAL does not empty the diagnostics area: it just appends\nanother
error condition.\n\nRESIGNAL, without any clauses, produces an error which
is identical to the\nerror that was received by HANDLER.\n\nIf used out of
a HANDLER construct, RESIGNAL produces the following error:\n\nERROR 1645
(0K000): RESIGNAL when handler not active\n\nIn MariaDB 5.5, if a HANDLER
contained a CALL to another procedure, that\nprocedure could use RESIGNAL.
Since MariaDB 10.0, trying to do this raises the\nabove error.\n\nFor a
list of SQLSTATE values and MariaDB error codes, see MariaDB Error
Codes.\n\nThe following procedure tries to query two tables which
don\'t exist, producing\na 1146 error in both cases. Those errors will
trigger the HANDLER. The first\ntime the error will be ignored and the
client will not receive it, but the\nsecond time, the error is re-signaled,
so the client will receive it.\n\nCREATE PROCEDURE test_error( )\nBEGIN\n
DECLARE CONTINUE HANDLER\n FOR 1146\n BEGIN\n IF @hide_errors IS FALSE
THEN\n RESIGNAL;\n END IF;\n END;\n SET @hide_errors = TRUE;\n SELECT
\'Next error will be ignored\' AS msg;\n SELECT `c` FROM
`temptab_one`;\n SELECT \'Next error won\'\'t be
ignored\' AS msg;\n SET @hide_errors = FALSE;\n SELECT `c` FROM
`temptab_two`;\nEND;\n\nCALL test_error(
);\n\n+----------------------------+\n| msg
|\n+----------------------------+\n| Next error will be ignored
|\n+----------------------------+\n\n+-----------------------------+\n| msg
|\n+-----------------------------+\n| Next error
won\'t be ignored |\n+-----------------------------+\n\nERROR 1146
(42S02): Table \'test.temptab_two\' doesn\'t exist\n\nThe
following procedure re-signals an error, modifying only the error
message\nto clarify the cause of the problem.\n\nCREATE PROCEDURE
test_error()\nBEGIN\n DECLARE CONTINUE HANDLER\n FOR 1146\n BEGIN\n
RESIGNAL SET\n MESSAGE_TEXT = \'`temptab` does not exist\';\n
END;\n SELECT `c` FROM `temptab`;\nEND;\n\nCALL test_error( );\nERROR 1146
(42S02): `temptab` does not exist\n\nAs explained above, this works on
MariaDB 5.5, but produces a 1645 error since\n10.0.\n\nCREATE PROCEDURE
handle_error()\nBEGIN\n RESIGNAL;\nEND;\nCREATE PROCEDURE p()\nBEGIN\n
DECLARE EXIT HANDLER FOR SQLEXCEPTION CALL p();\n SIGNAL SQLSTATE
\'45000\';\nEND;\n\nURL:
https://mariadb.com/kb/en/resignal/','','https://mariadb.com/kb/en/resignal/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(308,24,'RETURN','Syntax\n------\n\nRETURN expr\n\nThe
RETURN statement terminates execution of a stored function and returns
the\nvalue expr to the function caller. There must be at least one RETURN
statement\nin a stored function. If the function has multiple exit points,
all exit\npoints must have a RETURN.\n\nThis statement is not used in
stored procedures, triggers, or events. LEAVE\ncan be used instead.\n\nThe
following example shows that RETURN can return the result of a
scalar\nsubquery:\n\nCREATE FUNCTION users_count() RETURNS BOOL\n READS SQL
DATA\nBEGIN\n RETURN (SELECT COUNT(DISTINCT User) FROM
mysql.user);\nEND;\n\nURL:
https://mariadb.com/kb/en/return/','','https://mariadb.com/kb/en/return/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(309,24,'SELECT INTO','Syntax\n------\n\nSELECT col_name [,
col_name] ...\n INTO var_name [, var_name] ...\n
table_expr\n\nDescription\n-----------\n\nSELECT ... INTO enables selected
columns to be stored directly into variables.\nNo resultset is produced.
The query should return a single row. If the query\nreturns no rows, a
warning with error code 1329 occurs (No data), and the\nvariable values
remain unchanged. If the query returns multiple rows, error\n1172 occurs
(Result consisted of more than one row). If it is possible that\nthe
statement may retrieve multiple rows, you can use LIMIT 1 to limit
the\nresult set to a single row.\n\nThe INTO clause can also be specified
at the end of the statement.\n\nIn the context of such statements that
occur as part of events executed by the\nEvent Scheduler, diagnostics
messages (not only errors, but also warnings) are\nwritten to the error
log, and, on Windows, to the application event log.\n\nThis statement can
be used with both local variables and user-defined\nvariables.\n\nFor the
complete syntax, see SELECT.\n\nAnother way to set a variable\'s value
is the SET statement.\n\nSELECT ... INTO results are not stored in the
query cache even if SQL_CACHE
is\nspecified.\n\nExamples\n--------\n\nSELECT id, data INTO @x,@y \nFROM
test.t1 LIMIT 1;\nSELECT * from t1 where t1.a=@x and t1.b=@y\n\nIf you want
to use this construct with UNION you have to use the syntax:\n\nSELECT *
INTO @x FROM (SELECT t1.a FROM t1 UNION SELECT t2.a FROM t2);\n\nURL:
https://mariadb.com/kb/en/selectinto/','','https://mariadb.com/kb/en/selectinto/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(310,24,'SIGNAL','Syntax\n------\n\nSIGNAL error_condition\n
[SET error_property\n [, error_property] ...]\n\nerror_condition:\n
SQLSTATE [VALUE] \'sqlstate_value\'\n |
condition_name\n\nerror_property:\n error_property_name =
<error_property_value>\n\nerror_property_name:\n CLASS_ORIGIN\n |
SUBCLASS_ORIGIN\n | MESSAGE_TEXT\n | MYSQL_ERRNO\n | CONSTRAINT_CATALOG\n |
CONSTRAINT_SCHEMA\n | CONSTRAINT_NAME\n | CATALOG_NAME\n | SCHEMA_NAME\n |
TABLE_NAME\n | COLUMN_NAME\n | CURSOR_NAME\n\nSIGNAL empties the
diagnostics area and produces a custom error. This\nstatement can be used
anywhere, but is generally useful when used inside a\nstored program. When
the error is produced, it can be caught by a HANDLER. If\nnot, the current
stored program, or the current statement, will terminate with\nthe
specified error.\n\nSometimes an error HANDLER just needs to SIGNAL the
same error it received,\noptionally with some changes. Usually the RESIGNAL
statement is the most\nconvenient way to do this.\n\nerror_condition can be
an SQLSTATE value or a named error condition defined\nvia DECLARE
CONDITION. SQLSTATE must be a constant string consisting of
five\ncharacters. These codes are standard to ODBC and ANSI SQL. For
customized\nerrors, the recommended SQLSTATE is \'45000\'. For a
list of SQLSTATE values\nused by MariaDB, see the MariaDB Error Codes page.
The SQLSTATE can be read\nvia the API method mysql_sqlstate( ).\n\nTo
specify error properties user-defined variables and local variables can
be\nused, as well as character set conversions (but you can\'t set a
collation).\n\nThe error properties, their type and their default values
are explained in the\ndiagnostics area page.\n\nErrors\n------\n\nIf the
SQLSTATE is not valid, the following error like this will be
produced:\n\nERROR 1407 (42000): Bad SQLSTATE: \'123456\'\n\nIf a
property is specified more than once, an error like this will be
produced:\n\nERROR 1641 (42000): Duplicate condition information item
\'MESSAGE_TEXT\'\n\nIf you specify a condition name which is not
declared, an error like this will\nbe produced:\n\nERROR 1319 (42000):
Undefined CONDITION: cond_name\n\nIf MYSQL_ERRNO is out of range, you will
get an error like this:\n\nERROR 1231 (42000): Variable
\'MYSQL_ERRNO\' can\'t be set to the value of
\'0\'\n\nExamples\n--------\n\nHere\'s what happens if
SIGNAL is used in the client to generate errors:\n\nSIGNAL SQLSTATE
\'01000\';\nQuery OK, 0 rows affected, 1 warning (0.00
sec)\n\nSHOW
WARNINGS;\n\n+---------+------+------------------------------------------+\n|
Level | Code | Message
|\n+---------+------+------------------------------------------+\n| Warning
| 1642 | Unhandled user-defined warning condition
|\n+---------+------+------------------------------------------+\n1 row in
set (0.06 sec)\n\nSIGNAL SQLSTATE \'02000\';\nERROR 1643 (02000):
Unhandled user-defined not found condition\n\nHow to specify MYSQL_ERRNO
and MESSAGE_TEXT properties:\n\nSIGNAL SQLSTATE \'45000\' SET
MYSQL_ERRNO=30001, MESSAGE_TEXT=\'H\nello, world!\';\n\nERROR
30001 (45000): Hello, world!\n\nThe following code shows how to use user
variables, local variables and\ncharacter set conversion with
SIGNAL:\n\nCREATE PROCEDURE test_error(x INT)\nBEGIN\n DECLARE errno
SMALLINT UNSIGNED DEFAULT 31001;\n SET @errmsg = \'Hello,
world!\';\n IF x = 1 THEN\n SIGNAL SQLSTATE \'45000\'
SET\n MYSQL_ERRNO = errno,\n MESSAGE_TEXT = @errmsg;\n ELSE\n SIGNAL
SQLSTATE \'45000\' SET\n MYSQL_ERRNO = errno,\n MESSAGE_TEXT
= _utf8\'Hello, world!\';\n END IF;\nEND;\n\nHow to use named
error conditions:\n\nCREATE PROCEDURE test_error(n INT)\nBEGIN\n DECLARE
`too_big` CONDITION FOR SQLSTATE \'45000\';\n IF n > 10 THEN\n
SIGNAL `too_big`;\n END IF;\nEND;\n\nIn this example, we\'ll define
a HANDLER for an error code. When the error\noccurs, we SIGNAL a more
informative error which makes sense for our procedure:\n\nCREATE PROCEDURE
test_error()\nBEGIN\n DECLARE EXIT HANDLER\n FOR 1146\n BEGIN\n SIGNAL
SQLSTATE \'45000\' SET\n MESSAGE_TEXT = \'Temporary tables
not found; did you call init()\nprocedure?\';\n END;\n -- this will
produce a 1146 error\n SELECT `c` FROM `temptab`;\nEND;\n\nURL:
https://mariadb.com/kb/en/signal/','','https://mariadb.com/kb/en/signal/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(311,24,'WHILE','Syntax\n------\n\n[begin_label:] WHILE
search_condition DO\n statement_list\nEND WHILE
[end_label]\n\nDescription\n-----------\n\nThe statement list within a
WHILE statement is repeated as long as the\nsearch_condition is true.
statement_list consists of one or more statements.\nIf the loop must be
executed at least once, REPEAT ... LOOP can be used\ninstead.\n\nA WHILE
statement can be labeled. end_label cannot be given unless
begin_label\nalso is present. If both are present, they must be the
same.\n\nExamples\n--------\n\nCREATE PROCEDURE dowhile()\nBEGIN\n DECLARE
v1 INT DEFAULT 5;\n\nWHILE v1 > 0 DO\n ...\n SET v1 = v1 - 1;\n END
WHILE;\nEND\n\nURL:
https://mariadb.com/kb/en/while/','','https://mariadb.com/kb/en/while/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(312,24,'Cursor Overview','Description\n-----------\n\nA
cursor is a structure that allows you to go over records sequentially,
and\nperform processing based on the result.\n\nMariaDB permits cursors
inside stored programs, and MariaDB cursors are\nnon-scrollable, read-only
and asensitive.\n\n* Non-scrollable means that the rows can only be fetched
in the order\nspecified by the SELECT statement. Rows cannot be skipped,
you cannot jump to\na specific row, and you cannot fetch rows in reverse
order.\n* Read-only means that data cannot be updated through the
cursor.\n* Asensitive means that the cursor points to the actual underlying
data. This\nkind of cursor is quicker than the alternative, an insensitive
cursor, as no\ndata is copied to a temporary table. However, changes to the
data being used\nby the cursor will affect the cursor data.\n\nCursors are
created with a DECLARE CURSOR statement and opened with an OPEN\nstatement.
Rows are read with a FETCH statement before the cursor is finally\nclosed
with a CLOSE statement.\n\nWhen FETCH is issued and there are no more rows
to extract, the following\nerror is produced:\n\nERROR 1329 (02000): No
data - zero rows fetched, selected, or processed\n\nTo avoid problems, a
DECLARE HANDLER statement is generally used. The HANDLER\nshould handler
the 1329 error, or the \'02000\' SQLSTATE, or the NOT FOUND
error\nclass.\n\nOnly SELECT statements are allowed for cursors, and they
cannot be contained\nin a variable - so, they cannot be composed
dynamically. However, it is\npossible to SELECT from a view. Since the
CREATE VIEW statement can be\nexecuted as a prepared statement, it is
possible to dynamically create the\nview that is queried by the
cursor.\n\nFrom MariaDB 10.3.0, cursors can have parameters. Cursor
parameters can appear\nin any part of the DECLARE CURSOR select_statement
where a stored procedure\nvariable is allowed (select list, WHERE, HAVING,
LIMIT etc). See DECLARE\nCURSOR and OPEN for syntax, and below for an
example:\n\nExamples\n--------\n\nCREATE TABLE c1(i INT);\n\nCREATE TABLE
c2(i INT);\n\nCREATE TABLE c3(i INT);\n\nDELIMITER //\n\nCREATE PROCEDURE
p1()\nBEGIN\n DECLARE done INT DEFAULT FALSE;\n DECLARE x, y INT;\n DECLARE
cur1 CURSOR FOR SELECT i FROM test.c1;\n DECLARE cur2 CURSOR FOR SELECT i
FROM test.c2;\n DECLARE CONTINUE HANDLER FOR NOT FOUND SET done =
TRUE;\n\nOPEN cur1;\n OPEN cur2;\n\nread_loop: LOOP\n FETCH cur1 INTO x;\n
FETCH cur2 INTO y;\n IF done THEN\n LEAVE read_loop;\n END IF;\n IF x
< y THEN\n INSERT INTO test.c3 VALUES (x);\n ELSE\n INSERT INTO
test.c3 VALUES (y);\n END IF;\n END LOOP;\n\nCLOSE cur1;\n CLOSE
cur2;\nEND; //\n\nDELIMITER ;\n\nINSERT INTO c1
VALUES(5),(50),(500);\n\nINSERT INTO c2 VALUES(10),(20),(30);\n\nCALL
p1;\n\nSELECT * FROM c3;\n+------+\n| i |\n+------+\n| 5 |\n| 20
|\n| 30 |\n+------+\n\nFrom MariaDB 10.3.0\n\nDROP PROCEDURE IF EXISTS
p1;\nDROP TABLE IF EXISTS t1;\nCREATE TABLE t1 (a INT, b
VARCHAR(10));\n\nINSERT INTO t1 VALUES
(1,\'old\'),(2,\'old\'),(3,\'old\'),(4,\'old\'),(5,\'old\');\n\nDELIMITER
//\n\nCREATE PROCEDURE p1(min INT,max INT)\nBEGIN\n DECLARE done INT
DEFAULT FALSE;\n DECLARE va INT;\n DECLARE cur CURSOR(pmin INT, pmax INT)
FOR SELECT a FROM t1 WHERE a BETWEEN\npmin AND pmax;\n DECLARE CONTINUE
HANDLER FOR NOT FOUND SET done=TRUE;\n OPEN cur(min,max);\n read_loop:
LOOP\n FETCH cur INTO va;\n IF done THEN\n LEAVE read_loop;\n END
IF;\n INSERT INTO t1 VALUES (va,\'new\');\n END LOOP;\n CLOSE
cur;\nEND;\n//\n\nDELIMITER ;\n\nCALL p1(2,4);\n\nSELECT * FROM
t1;\n+------+------+\n| a | b |\n+------+------+\n| 1 | old |\n|
2 | old |\n| 3 | old |\n| 4 | old |\n| 5 | old |\n| 2 |
new |\n| 3 | new |\n| 4 | new |\n+------+------+\n\nURL:
https://mariadb.com/kb/en/cursor-overview/','','https://mariadb.com/kb/en/cursor-overview/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(313,24,'DECLARE CURSOR','Syntax\n------\n\n<= MariaDB
10.2\n\nDECLARE cursor_name CURSOR FOR select_statement\n\nFrom MariaDB
10.3\n\nDECLARE cursor_name CURSOR [(cursor_formal_parameter[,...])]
FOR\nselect_statement\n\ncursor_formal_parameter:\n name type [collate
clause]\n\nFrom MariaDB 10.8\n\nDECLARE cursor_name CURSOR
[(cursor_formal_parameter[,...])]
FOR\nselect_statement\n\ncursor_formal_parameter:\n [IN] name type
[collate clause]\n\nDescription\n-----------\n\nThis statement declares a
cursor. Multiple cursors may be declared in a stored\nprogram, but each
cursor in a given block must have a unique name.\n\nselect_statement is not
executed until the OPEN statement is executed. It is\nimportant to remember
this if the query produces an error, or calls functions\nwhich have side
effects.\n\nA SELECT associated to a cursor can use variables, but the
query itself cannot\nbe a variable, and cannot be dynamically composed. The
SELECT statement cannot\nhave an INTO clause.\n\nCursors must be declared
before HANDLERs, but after local variables
and\nCONDITIONs.\n\nParameters\n----------\n\nMariaDB starting with
10.3.0\n----------------------------\nFrom MariaDB 10.3.0, cursors can have
parameters. This is a non-standard SQL\nextension. Cursor parameters can
appear in any part of the DECLARE CURSOR\nselect_statement where a stored
procedure variable is allowed (select list,\nWHERE, HAVING, LIMIT
etc).\n\nIN\n--\n\nMariaDB starting with
10.8.0\n----------------------------\nFrom MariaDB 10.8.0 preview release,
the IN qualifier is supported in the\ncursor_format_parameter part of the
syntax.\n\nSee Cursor Overview for an example.\n\nURL:
https://mariadb.com/kb/en/declare-cursor/','','https://mariadb.com/kb/en/declare-cursor/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(314,24,'OPEN','Syntax\n------\n\n<= MariaDB 10.2\n\nOPEN
cursor_name\n\nFrom MariaDB 10.3\n\nOPEN cursor_name
[expression[,...]];\n\nDescription\n-----------\n\nThis statement opens a
cursor which was previously declared with DECLARE\nCURSOR.\n\nThe query
associated to the DECLARE CURSOR is executed when OPEN is executed.\nIt is
important to remember this if the query produces an error, or
calls\nfunctions which have side effects.\n\nThis is necessary in order to
FETCH rows from a cursor.\n\nSee Cursor Overview for an example.\n\nURL:
https://mariadb.com/kb/en/open/','','https://mariadb.com/kb/en/open/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(315,24,'FETCH','Syntax\n------\n\nFETCH cursor_name INTO
var_name [, var_name] ...\n\nDescription\n-----------\n\nThis statement
fetches the next row (if a row exists) using the specified open\ncursor,
and advances the cursor pointer.\n\nvar_name can be a local variable, but
not a user-defined variable.\n\nIf no more rows are available, a No Data
condition occurs with SQLSTATE value\n02000. To detect this condition, you
can set up a handler for it (or for a NOT\nFOUND condition).\n\nSee Cursor
Overview for an example.\n\nURL:
https://mariadb.com/kb/en/fetch/','','https://mariadb.com/kb/en/fetch/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(316,24,'CLOSE','Syntax\n------\n\nCLOSE
cursor_name\n\nDescription\n-----------\n\nThis statement closes a
previously opened cursor. The cursor must have been\npreviously opened or
else an error occurs.\n\nIf not closed explicitly, a cursor is closed at
the end of the compound\nstatement in which it was declared.\n\nSee Cursor
Overview for an example.\n\nURL:
https://mariadb.com/kb/en/close/','','https://mariadb.com/kb/en/close/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(317,25,'BUFFER','A synonym for ST_BUFFER.\n\nURL:
https://mariadb.com/kb/en/buffer/','','https://mariadb.com/kb/en/buffer/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(318,25,'CONVEXHULL','A synonym for ST_CONVEXHULL.\n\nURL:
https://mariadb.com/kb/en/convexhull/','','https://mariadb.com/kb/en/convexhull/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(319,25,'GEOMETRYCOLLECTION','Syntax\n------\n\nGeometryCollection(g1,g2,...)\n\nDescription\n-----------\n\nConstructs
a WKB GeometryCollection. If any argument is not a well-formed
WKB\nrepresentation of a geometry, the return value is
NULL.\n\nExamples\n--------\n\nCREATE TABLE gis_geometrycollection (g
GEOMETRYCOLLECTION);\nSHOW FIELDS FROM gis_geometrycollection;\nINSERT INTO
gis_geometrycollection VALUES\n
(GeomCollFromText(\'GEOMETRYCOLLECTION(POINT(0 0), LINESTRING(0
0,10\n10))\')),\n (GeometryFromWKB(AsWKB(GeometryCollection(Point(44,
6),\nLineString(Point(3, 6), Point(7, 9)))))),\n
(GeomFromText(\'GeometryCollection()\')),\n
(GeomFromText(\'GeometryCollection EMPTY\'));\n\nURL:
https://mariadb.com/kb/en/geometrycollection/','','https://mariadb.com/kb/en/geometrycollection/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(320,25,'LINESTRING','Syntax\n------\n\nLineString(pt1,pt2,...)\n\nDescription\n-----------\n\nConstructs
a WKB LineString value from a number of WKB Point arguments. If
any\nargument is not a WKB Point, the return value is NULL. If the number
of Point\narguments is less than two, the return value is
NULL.\n\nExamples\n--------\n\nSET @ls = \'LineString(1 1,2 2,3
3)\';\n\nSELECT
AsText(EndPoint(GeomFromText(@ls)));\n+-------------------------------------+\n|
AsText(EndPoint(GeomFromText(@ls)))
|\n+-------------------------------------+\n| POINT(3 3)
|\n+-------------------------------------+\n\nCREATE TABLE gis_line
(g LINESTRING);\nINSERT INTO gis_line VALUES\n
(LineFromText(\'LINESTRING(0 0,0 10,10 0)\')),\n
(LineStringFromText(\'LINESTRING(10 10,20 10,20 20,10 20,10
10)\')),\n (LineStringFromWKB(AsWKB(LineString(Point(10, 10),
Point(40, 10)))));\n\nURL:
https://mariadb.com/kb/en/linestring/','','https://mariadb.com/kb/en/linestring/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(321,25,'MULTILINESTRING','Syntax\n------\n\nMultiLineString(ls1,ls2,...)\n\nDescription\n-----------\n\nConstructs
a WKB MultiLineString value using WKB LineString arguments. If
any\nargument is not a WKB LineString, the return value is
NULL.\n\nExample\n-------\n\nCREATE TABLE gis_multi_line (g
MULTILINESTRING);\nINSERT INTO gis_multi_line VALUES\n
(MultiLineStringFromText(\'MULTILINESTRING((10 48,10 21,10 0),(16 0,16
23,16\n48))\')),\n (MLineFromText(\'MULTILINESTRING((10 48,10
21,10 0))\')),\n
(MLineFromWKB(AsWKB(MultiLineString(LineString(Point(1, 2), \n Point(3,
5)), LineString(Point(2, 5),Point(5, 8),Point(21, 7))))));\n\nURL:
https://mariadb.com/kb/en/multilinestring/','','https://mariadb.com/kb/en/multilinestring/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(322,25,'MULTIPOINT','Syntax\n------\n\nMultiPoint(pt1,pt2,...)\n\nDescription\n-----------\n\nConstructs
a WKB MultiPoint value using WKB Point arguments. If any argument\nis not a
WKB Point, the return value is NULL.\n\nExamples\n--------\n\nSET @g =
ST_GEOMFROMTEXT(\'MultiPoint( 1 1, 2 2, 5 3, 7 2, 9 3, 8 4, 6 6, 6
9,\n4 9, 1 5 )\');\n\nCREATE TABLE gis_multi_point (g
MULTIPOINT);\nINSERT INTO gis_multi_point VALUES\n
(MultiPointFromText(\'MULTIPOINT(0 0,10 10,10 20,20 20)\')),\n
(MPointFromText(\'MULTIPOINT(1 1,11 11,11 21,21 21)\')),\n
(MPointFromWKB(AsWKB(MultiPoint(Point(3, 6), Point(4, 10)))));\n\nURL:
https://mariadb.com/kb/en/multipoint/','','https://mariadb.com/kb/en/multipoint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(323,25,'MULTIPOLYGON','Syntax\n------\n\nMultiPolygon(poly1,poly2,...)\n\nDescription\n-----------\n\nConstructs
a WKB MultiPolygon value from a set of WKB Polygon arguments. If\nany
argument is not a WKB Polygon, the return value is
NULL.\n\nExample\n-------\n\nCREATE TABLE gis_multi_polygon (g
MULTIPOLYGON);\nINSERT INTO gis_multi_polygon VALUES\n
(MultiPolygonFromText(\'MULTIPOLYGON(((28 26,28 0,84 0,84 42,28
26),(52\n18,66 23,73 9,48 6,52 18)),\n ((59 18,67 18,67 13,59 13,59
18)))\')),\n (MPolyFromText(\'MULTIPOLYGON(((28 26,28 0,84 0,84
42,28 26),(52 18,66\n23,73 9,48 6,52 18)),\n ((59 18,67 18,67 13,59
13,59 18)))\')),\n
(MPolyFromWKB(AsWKB(MultiPolygon(Polygon(LineString(\n Point(0, 3),
Point(3, 3), Point(3, 0), Point(0, 3)))))));\n\nURL:
https://mariadb.com/kb/en/multipolygon/','','https://mariadb.com/kb/en/multipolygon/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(324,25,'POINT','Syntax\n------\n\nPoint(x,y)\n\nDescription\n-----------\n\nConstructs
a WKB Point using the given coordinates.\n\nExamples\n--------\n\nSET @g =
ST_GEOMFROMTEXT(\'Point(1 1)\');\n\nCREATE TABLE gis_point (g
POINT);\nINSERT INTO gis_point VALUES\n (PointFromText(\'POINT(10
10)\')),\n (PointFromText(\'POINT(20 10)\')),\n
(PointFromText(\'POINT(20 20)\')),\n
(PointFromWKB(AsWKB(PointFromText(\'POINT(10 20)\'))));\n\nURL:
https://mariadb.com/kb/en/point/','','https://mariadb.com/kb/en/point/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(325,25,'PointOnSurface','A synonym for
ST_PointOnSurface.\n\nURL:
https://mariadb.com/kb/en/pointonsurface/','','https://mariadb.com/kb/en/pointonsurface/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(326,25,'POLYGON','Syntax\n------\n\nPolygon(ls1,ls2,...)\n\nDescription\n-----------\n\nConstructs
a WKB Polygon value from a number of WKB LineString arguments. If\nany
argument does not represent the WKB of a LinearRing (that is, not a
closed\nand simple LineString) the return value is NULL.\n\nNote that
according to the OpenGIS standard, a POLYGON should have exactly
one\nExteriorRing and all other rings should lie within that ExteriorRing
and thus\nbe the InteriorRings. Practically, however, some systems,
including MariaDB\'s,\npermit polygons to have several
\'ExteriorRings\'. In the case of there being\nmultiple,
non-overlapping exterior rings ST_NUMINTERIORRINGS() will return
1.\n\nExamples\n--------\n\nSET @g = ST_GEOMFROMTEXT(\'POLYGON((1 1,1
5,4 9,6 9,9 3,7 2,1 1))\');\n\nCREATE TABLE gis_polygon (g
POLYGON);\nINSERT INTO gis_polygon VALUES\n
(PolygonFromText(\'POLYGON((10 10,20 10,20 20,10 20,10
10))\')),\n (PolyFromText(\'POLYGON((0 0,50 0,50 50,0 50,0 0),
(10 10,20 10,20 20,10\n20,10 10))\')),\n
(PolyFromWKB(AsWKB(Polygon(LineString(Point(0, 0), Point(30, 0),
Point(30,\n30), Point(0, 0))))));\n\nNon-overlapping
\'polygon\':\n\nSELECT
ST_NumInteriorRings(ST_PolyFromText(\'POLYGON((0 0,10 0,10 10,0 10,0
0),\n (-1 -1,-5 -1,-5 -5,-1 -5,-1 -1))\')) AS
NumInteriorRings;\n+------------------+\n| NumInteriorRings
|\n+------------------+\n| 1 |\n+------------------+\n\nURL:
https://mariadb.com/kb/en/polygon/','','https://mariadb.com/kb/en/polygon/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(327,25,'ST_BUFFER','Syntax\n------\n\nST_BUFFER(g1,r)\nBUFFER(g1,r)\n\nDescription\n-----------\n\nReturns
a geometry that represents all points whose distance from geometry g1\nis
less than or equal to distance, or radius, r.\n\nUses for this function
could include creating for example a new geometry\nrepresenting a buffer
zone around an island.\n\nBUFFER() is a
synonym.\n\nExamples\n--------\n\nDetermining whether a point is within a
buffer zone:\n\nSET @g1 = ST_GEOMFROMTEXT(\'POLYGON((10 10, 10 20, 20
20, 20 10, 10 10))\');\n\nSET @g2 = ST_GEOMFROMTEXT(\'POINT(8
8)\');\n\nSELECT
ST_WITHIN(@g2,ST_BUFFER(@g1,5));\n+---------------------------------+\n|
ST_WITHIN(@g2,ST_BUFFER(@g1,5)) |\n+---------------------------------+\n|
1
|\n+---------------------------------+\n\nSELECT
ST_WITHIN(@g2,ST_BUFFER(@g1,1));\n+---------------------------------+\n|
ST_WITHIN(@g2,ST_BUFFER(@g1,1)) |\n+---------------------------------+\n|
0
|\n+---------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_buffer/','','https://mariadb.com/kb/en/st_buffer/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(328,25,'ST_CONVEXHULL','MariaDB starting with
10.1.2\n----------------------------\nST_ConvexHull() was introduced in
MariaDB
10.1.2\n\nSyntax\n------\n\nST_ConvexHull(g)\nConvexHull(g)\n\nDescription\n-----------\n\nGiven
a geometry, returns a geometry that is the minimum convex
geometry\nenclosing all geometries within the set. Returns NULL if the
geometry value is\nNULL or an empty value.\n\nST_ConvexHull() and
ConvexHull() are synonyms.\n\nExamples\n--------\n\nThe ConvexHull of a
single point is simply the single point:\n\nSET @g =
ST_GEOMFROMTEXT(\'Point(0 0)\');\n\nSELECT
ST_ASTEXT(ST_CONVEXHULL(@g));\n+------------------------------+\n|
ST_ASTEXT(ST_CONVEXHULL(@g)) |\n+------------------------------+\n| POINT(0
0) |\n+------------------------------+\n\nSET @g =
ST_GEOMFROMTEXT(\'MultiPoint(0 0, 1 2, 2 3)\');\n\nSELECT
ST_ASTEXT(ST_CONVEXHULL(@g));\n+------------------------------+\n|
ST_ASTEXT(ST_CONVEXHULL(@g)) |\n+------------------------------+\n|
POLYGON((0 0,1 2,2 3,0 0)) |\n+------------------------------+\n\nSET @g
= ST_GEOMFROMTEXT(\'MultiPoint( 1 1, 2 2, 5 3, 7 2, 9 3, 8 4, 6 6, 6
9,\n4 9, 1 5 )\');\n\nSELECT
ST_ASTEXT(ST_CONVEXHULL(@g));\n+----------------------------------------+\n|
ST_ASTEXT(ST_CONVEXHULL(@g))
|\n+----------------------------------------+\n| POLYGON((1 1,1 5,4 9,6 9,9
3,7 2,1 1)) |\n+----------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_convexhull/','','https://mariadb.com/kb/en/st_convexhull/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(329,25,'ST_INTERSECTION','Syntax\n------\n\nST_INTERSECTION(g1,g2)\n\nDescription\n-----------\n\nReturns
a geometry that is the intersection, or shared portion, of geometry g1\nand
geometry g2.\n\nExamples\n--------\n\nSET @g1 =
ST_GEOMFROMTEXT(\'POINT(2 1)\');\n\nSET @g2 =
ST_GEOMFROMTEXT(\'LINESTRING(2 1, 0 2)\');\n\nSELECT
ASTEXT(ST_INTERSECTION(@g1,@g2));\n+----------------------------------+\n|
ASTEXT(ST_INTERSECTION(@g1,@g2)) |\n+----------------------------------+\n|
POINT(2 1)
|\n+----------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_intersection/','','https://mariadb.com/kb/en/st_intersection/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(330,25,'ST_POINTONSURFACE','MariaDB starting with
10.1.2\n----------------------------\nST_POINTONSURFACE() was introduced in
MariaDB
10.1.2\n\nSyntax\n------\n\nST_PointOnSurface(g)\nPointOnSurface(g)\n\nDescription\n-----------\n\nGiven
a geometry, returns a POINT guaranteed to intersect a surface.
However,\nsee MDEV-7514.\n\nST_PointOnSurface() and PointOnSurface() are
synonyms.\n\nURL:
https://mariadb.com/kb/en/st_pointonsurface/','','https://mariadb.com/kb/en/st_pointonsurface/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(331,25,'ST_SYMDIFFERENCE','Syntax\n------\n\nST_SYMDIFFERENCE(g1,g2)\n\nDescription\n-----------\n\nReturns
a geometry that represents the portions of geometry g1 and geometry
g2\nthat don\'t intersect.\n\nExamples\n--------\n\nSET @g1 =
ST_GEOMFROMTEXT(\'LINESTRING(10 20, 10 40)\');\n\nSET @g2 =
ST_GEOMFROMTEXT(\'LINESTRING(10 15, 10 25)\');\n\nSELECT
ASTEXT(ST_SYMDIFFERENCE(@g1,@g2));\n+----------------------------------------------+\n|
ASTEXT(ST_SYMDIFFERENCE(@g1,@g2))
|\n+----------------------------------------------+\n| MULTILINESTRING((10
15,10 20),(10 25,10 40))
|\n+----------------------------------------------+\n\nSET @g2 =
ST_GeomFromText(\'LINESTRING(10 20, 10 41)\');\n\nSELECT
ASTEXT(ST_SYMDIFFERENCE(@g1,@g2));\n+-----------------------------------+\n|
ASTEXT(ST_SYMDIFFERENCE(@g1,@g2))
|\n+-----------------------------------+\n| LINESTRING(10 40,10 41)
|\n+-----------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_symdifference/','','https://mariadb.com/kb/en/st_symdifference/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(332,25,'ST_UNION','Syntax\n------\n\nST_UNION(g1,g2)\n\nDescription\n-----------\n\nReturns
a geometry that is the union of the geometry g1 and geometry
g2.\n\nExamples\n--------\n\nSET @g1 = GEOMFROMTEXT(\'POINT (0
2)\');\n\nSET @g2 = GEOMFROMTEXT(\'POINT (2 0)\');\n\nSELECT
ASTEXT(ST_UNION(@g1,@g2));\n+---------------------------+\n|
ASTEXT(ST_UNION(@g1,@g2)) |\n+---------------------------+\n| MULTIPOINT(2
0,0 2) |\n+---------------------------+\n\nSET @g1 =
GEOMFROMTEXT(\'POLYGON((0 0,0 3,3 3,3 0,0 0))\');\n\nSET @g2 =
GEOMFROMTEXT(\'POLYGON((2 2,4 2,4 4,2 4,2 2))\');\n\nSELECT
ASTEXT(ST_UNION(@g1,@g2));\n+------------------------------------------------+\n|
ASTEXT(ST_UNION(@g1,@g2))
|\n+------------------------------------------------+\n| POLYGON((0 0,0 3,2
3,2 4,4 4,4 2,3 2,3 0,0 0))
|\n+------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_union/','','https://mariadb.com/kb/en/st_union/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(333,26,'SHOW GRANTS','Syntax\n------\n\nSHOW GRANTS [FOR
user|role]\n\nDescription\n-----------\n\nThe SHOW GRANTS statement lists
privileges granted to a particular user or\nrole.\n\nUsers\n-----\n\nThe
statement lists the GRANT statement or statements that must be issued
to\nduplicate the privileges that are granted to a MariaDB user account.
The\naccount is named using the same format as for the GRANT statement;
for\nexample, \'jeffrey\'@\'localhost\'. If you specify
only the user name part of the\naccount name, a host name part of
\'%\' is used. For additional information\nabout specifying
account names, see GRANT.\n\nSHOW GRANTS FOR
\'root\'@\'localhost\';\n+---------------------------------------------------------------------+\n|
Grants for root@localhost
|\n+---------------------------------------------------------------------+\n|
GRANT ALL PRIVILEGES ON *.* TO \'root\'@\'localhost\'
WITH GRANT OPTION
|\n+---------------------------------------------------------------------+\n\nTo
list the privileges granted to the account that you are using to connect
to\nthe server, you can use any of the following statements:\n\nSHOW
GRANTS;\nSHOW GRANTS FOR CURRENT_USER;\nSHOW GRANTS FOR
CURRENT_USER();\n\nIf SHOW GRANTS FOR CURRENT_USER (or any of the
equivalent syntaxes) is used in\nDEFINER context (such as within a stored
procedure that is defined with SQL\nSECURITY DEFINER), the grants displayed
are those of the definer and not the\ninvoker.\n\nNote that the DELETE
HISTORY privilege, introduced in MariaDB 10.3.4, was\ndisplayed as DELETE
VERSIONING ROWS when running SHOW GRANTS until MariaDB\n10.3.15
(MDEV-17655).\n\nRoles\n-----\n\nSHOW GRANTS can also be used to view the
privileges granted to a role.\n\nExample\n-------\n\nSHOW GRANTS FOR
journalist;\n+------------------------------------------+\n| Grants for
journalist
|\n+------------------------------------------+\n| GRANT USAGE ON *.* TO
\'journalist\' |\n| GRANT DELETE ON `test`.* TO
\'journalist\'
|\n+------------------------------------------+\n\nFOR
PUBLIC\n----------\n\nMariaDB starting with
10.11\n---------------------------\nGRANT ... TO PUBLIC was introduced in
MariaDB 10.11 to grant privileges to all\nusers. SHOW GRANTS FOR PUBLIC
shows all these grants.\n\nSHOW GRANTS FOR
public;\n+------------------------------------------------+\n| Grants for
PUBLIC
|\n+------------------------------------------------+\n| GRANT ALL
PRIVILEGES ON `dev_db`.* TO `PUBLIC`
|\n+------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/show-grants/','','https://mariadb.com/kb/en/show-grants/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(334,26,'SHOW CREATE USER','Syntax\n------\n\nSHOW CREATE
USER user_name\n\nDescription\n-----------\n\nShows the CREATE USER
statement that created the given user. The statement\nrequires the SELECT
privilege for the mysql database, except for the
current\nuser.\n\nExamples\n--------\n\nCREATE USER foo4@test require
cipher \'text\' \n issuer \'foo_issuer\' subject
\'foo_subject\';\n\nSHOW CREATE USER
foo4@test\\G\n*************************** 1. row
***************************\nCREATE USER
\'foo4\'@\'test\' \n REQUIRE ISSUER
\'foo_issuer\'\n SUBJECT \'foo_subject\'\n CIPHER
\'text\'\n\nUser Password Expiry:\n\nCREATE USER
\'monty\'@\'localhost\' PASSWORD EXPIRE INTERVAL 120
DAY;\n\nSHOW CREATE USER
\'monty\'@\'localhost\';\n+------------------------------------------------------------------+\n|
CREATE USER for monty@localhost
|\n+------------------------------------------------------------------+\n|
CREATE USER \'monty\'@\'localhost\' PASSWORD EXPIRE
INTERVAL 120 DAY
|\n+------------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/show-create-user/','','https://mariadb.com/kb/en/show-create-user/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(335,26,'SHOW COLUMNS','Syntax\n------\n\nSHOW [FULL]
{COLUMNS | FIELDS} FROM tbl_name [FROM db_name]\n [LIKE
\'pattern\' | WHERE expr]\n\nDescription\n-----------\n\nSHOW
COLUMNS displays information about the columns in a given table. It
also\nworks for views. The LIKE clause, if present on its own, indicates
which\ncolumn names to match. The WHERE and LIKE clauses can be given to
select rows\nusing more general conditions, as discussed in Extended
SHOW.\n\nIf the data types differ from what you expect them to be based on
a CREATE\nTABLE statement, note that MariaDB sometimes changes data types
when you\ncreate or alter a table. The conditions under which this occurs
are described\nin the Silent Column Changes article.\n\nThe FULL keyword
causes the output to include the column collation and\ncomments, as well as
the privileges you have for each column.\n\nYou can use db_name.tbl_name as
an alternative to the tbl_name FROM db_name\nsyntax. In other words, these
two statements are equivalent:\n\nSHOW COLUMNS FROM mytable FROM
mydb;\nSHOW COLUMNS FROM mydb.mytable;\n\nSHOW COLUMNS displays the
following values for each table column:\n\nField indicates the column
name.\n\nType indicates the column data type.\n\nCollation indicates the
collation for non-binary string columns, or NULL for\nother columns. This
value is displayed only if you use the FULL keyword.\n\nThe Null field
contains YES if NULL values can be stored in the column, NO if\nnot.\n\nThe
Key field indicates whether the column is indexed:\n\n* If Key is empty,
the column either is not indexed or is indexed only as a\n secondary column
in a multiple-column, non-unique index.\n* If Key is PRI, the column is a
PRIMARY KEY or\n is one of the columns in a multiple-column PRIMARY KEY.\n*
If Key is UNI, the column is the first column of a unique-valued\n index
that cannot contain NULL values.\n* If Key is MUL, multiple occurrences of
a given value are allowed\n within the column. The column is the first
column of a non-unique index or a\n unique-valued index that can contain
NULL values.\n\nIf more than one of the Key values applies to a given
column of a table, Key\ndisplays the one with the highest priority, in the
order PRI, UNI, MUL.\n\nA UNIQUE index may be displayed as PRI if it cannot
contain NULL values and\nthere is no PRIMARY KEY in the table. A UNIQUE
index may display as MUL if\nseveral columns form a composite UNIQUE index;
although the combination of the\ncolumns is unique, each column can still
hold multiple occurrences of a given\nvalue.\n\nThe Default field indicates
the default value that is assigned to the column.\n\nThe Extra field
contains any additional information that is available about a\ngiven
column.\n\n+------------------------+---------------------------------------------------+\n|
Value | Description
|\n+------------------------+---------------------------------------------------+\n|
AUTO_INCREMENT | The column was created with the AUTO_INCREMENT
|\n| | keyword.
|\n+------------------------+---------------------------------------------------+\n|
PERSISTENT | The column was created with the PERSISTENT
|\n| | keyword. (New in 5.3)
|\n+------------------------+---------------------------------------------------+\n|
VIRTUAL | The column was created with the VIRTUAL keyword.
|\n| | (New in 5.3)
|\n+------------------------+---------------------------------------------------+\n|
on update | The column is a TIMESTAMP column that is
|\n| CURRENT_TIMESTAMP | automatically updated on INSERT and UPDATE.
|\n+------------------------+---------------------------------------------------+\n\nPrivileges
indicates the privileges you have for the column. This value is\ndisplayed
only if you use the FULL keyword.\n\nComment indicates any comment the
column has. This value is displayed only if\nyou use the FULL
keyword.\n\nSHOW FIELDS is a synonym for SHOW COLUMNS. Also DESCRIBE and
EXPLAIN can be\nused as shortcuts.\n\nYou can also list a table\'s
columns with:\n\nmysqlshow db_name tbl_name\n\nSee the mysqlshow command
for more details.\n\nThe DESCRIBE statement provides information similar to
SHOW COLUMNS. The\ninformation_schema.COLUMNS table provides similar, but
more complete,\ninformation.\n\nThe SHOW CREATE TABLE, SHOW TABLE STATUS,
and SHOW INDEX statements also\nprovide information about
tables.\n\nExamples\n--------\n\nSHOW COLUMNS FROM
city;\n+------------+----------+------+-----+---------+----------------+\n|
Field | Type | Null | Key | Default | Extra
|\n+------------+----------+------+-----+---------+----------------+\n| Id
| int(11) | NO | PRI | NULL | auto_increment |\n| Name |
char(35) | NO | | | |\n| Country | char(3)
| NO | UNI | | |\n| District | char(20) | YES |
MUL | | |\n| Population | int(11) | NO | | 0
|
|\n+------------+----------+------+-----+---------+----------------+\n\nSHOW
COLUMNS FROM employees WHERE Type LIKE
\'Varchar%\';\n+---------------+-------------+------+-----+---------+-------+\n|
Field | Type | Null | Key | Default | Extra
|\n+---------------+-------------+------+-----+---------+-------+\n|
first_name | varchar(30) | NO | MUL | NULL | |\n| last_name
| varchar(40) | NO | | NULL | |\n| position |
varchar(25) | NO | | NULL | |\n| home_address | varchar(50)
| NO | | NULL | |\n| home_phone | varchar(12) | NO |
| NULL | |\n| employee_code | varchar(25) | NO | UNI | NULL
|
|\n+---------------+-------------+------+-----+---------+-------+\n\nURL:
https://mariadb.com/kb/en/show-columns/','','https://mariadb.com/kb/en/show-columns/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(336,26,'SHOW CREATE TABLE','Syntax\n------\n\nSHOW CREATE
TABLE tbl_name\n\nDescription\n-----------\n\nShows the CREATE TABLE
statement that created the given table. The statement\nrequires the SELECT
privilege for the table. This statement also works with\nviews and
SEQUENCE.\n\nSHOW CREATE TABLE quotes table and column names according to
the value of the\nsql_quote_show_create server system variable.\n\nCertain
SQL_MODE values can result in parts of the original CREATE statement\nnot
being included in the output. MariaDB-specific table options,
column\noptions, and index options are not included in the output of this
statement if\nthe NO_TABLE_OPTIONS, NO_FIELD_OPTIONS and NO_KEY_OPTIONS
SQL_MODE flags are\nused. All MariaDB-specific table attributes are also
not shown when a\nnon-MariaDB/MySQL emulation mode is used, which includes
ANSI, DB2,\nPOSTGRESQL, MSSQL, MAXDB or ORACLE.\n\nInvalid table options,
column options and index options are normally commented\nout (note, that it
is possible to create a table with invalid options, by\naltering a table of
a different engine, where these options were valid). To\nhave them
uncommented, enable the IGNORE_BAD_TABLE_OPTIONS SQL_MODE. Remember\nthat
replaying a CREATE TABLE statement with uncommented invalid options
will\nfail with an error, unless the IGNORE_BAD_TABLE_OPTIONS SQL_MODE is
in effect.\n\nNote that SHOW CREATE TABLE is not meant to provide metadata
about a table. It\nprovides information about how the table was declared,
but the real table\nstructure could differ a bit. For example, if an index
has been declared as\nHASH, the CREATE TABLE statement returned by SHOW
CREATE TABLE will declare\nthat index as HASH; however, it is possible that
the index is in fact a BTREE,\nbecause the storage engine does not support
HASH.\n\nMariaDB starting with
10.2.1\n----------------------------\nMariaDB 10.2.1 permits TEXT and BLOB
data types to be assigned a DEFAULT\nvalue. As a result, from MariaDB
10.2.1, SHOW CREATE TABLE will append a\nDEFAULT NULL to nullable TEXT or
BLOB fields if no specific default is\nprovided.\n\nMariaDB starting with
10.2.2\n----------------------------\nFrom MariaDB 10.2.2, numbers are no
longer quoted in the DEFAULT clause in\nSHOW CREATE statement. Previously,
MariaDB quoted numbers.\n\nIndex Order\n-----------\n\nIndexes are sorted
and displayed in the following order, which may differ from\nthe order of
the CREATE TABLE statement.\n\n* PRIMARY KEY\n* UNIQUE keys where all
column are NOT NULL\n* UNIQUE keys that don\'t contain partial
segments\n* Other UNIQUE keys\n* LONG UNIQUE keys\n* Normal keys\n*
Fulltext keys\n\nSee sql/sql_table.cc for
details.\n\nExamples\n--------\n\nSHOW CREATE TABLE
t\\G\n*************************** 1. row ***************************\n
Table: t\nCreate Table: CREATE TABLE `t` (\n `id` int(11) NOT NULL
AUTO_INCREMENT,\n `s` char(60) DEFAULT NULL,\n PRIMARY KEY (`id`)\n)
ENGINE=InnoDB DEFAULT CHARSET=latin1\n\nWith sql_quote_show_create
off:\n\nSHOW CREATE TABLE t\\G\n*************************** 1. row
***************************\n Table: t\nCreate Table: CREATE TABLE t (\n
id int(11) NOT NULL AUTO_INCREMENT,\n s char(60) DEFAULT NULL,\n PRIMARY
KEY (id)\n) ENGINE=InnoDB DEFAULT CHARSET=latin1\n\nUnquoted numeric
DEFAULTs, from MariaDB 10.2.2:\n\nCREATE TABLE td (link TINYINT DEFAULT
1);\n\nSHOW CREATE TABLE td\\G\n*************************** 1. row
***************************\n Table: td\nCreate Table: CREATE TABLE `td`
(\n `link` tinyint(4) DEFAULT 1\n) ENGINE=InnoDB DEFAULT
CHARSET=latin1\n\nQuoted numeric DEFAULTs, until MariaDB 10.2.1:\n\nCREATE
TABLE td (link TINYINT DEFAULT 1);\n\nSHOW CREATE TABLE
td\\G\n*************************** 1. row ***************************\n
Table: td\nCreate Table: CREATE TABLE `td` (\n `link` tinyint(4) DEFAULT
\'1\'\n) ENGINE=InnoDB DEFAULT CHARSET=latin1\n\nSQL_MODE
impacting the output:\n\nSELECT
@@sql_mode;\n+------------------------------------------------------------------------------\n------------+\n|
@@sql_mode
\n
|\n+------------------------------------------------------------------------------\n------------+\n|\nSTRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SU\nSTITUTION
|\n+------------------------------------------------------------------------------\n------------+\n\nCREATE
TABLE `t1` (\n `id` int(11) NOT NULL AUTO_INCREMENT,\n `msg`
varchar(100) DEFAULT NULL,\n PRIMARY KEY (`id`)\n ) ENGINE=InnoDB
DEFAULT CHARSET=latin1\n;\n\nSHOW CREATE TABLE
t1\\G\n*************************** 1. row ***************************\n
Table: t1\nCreate Table: CREATE TABLE `t1` (\n `id` int(11) NOT NULL
AUTO_INCREMENT,\n `msg` varchar(100) DEFAULT NULL,\n PRIMARY KEY (`id`)\n)
ENGINE=InnoDB DEFAULT CHARSET=latin1\n\nSET SQL_MODE=ORACLE;\n\nSHOW CREATE
TABLE t1\\G\n*************************** 1. row
***************************\n Table: t1\nCreate Table: CREATE TABLE
\"t1\" (\n \"id\" int(11) NOT NULL,\n \"msg\"
varchar(100) DEFAULT NULL,\n PRIMARY KEY (\"id\")\n\nURL:
https://mariadb.com/kb/en/show-create-table/','','https://mariadb.com/kb/en/show-create-table/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(337,26,'SHOW INDEX','Syntax\n------\n\nSHOW {INDEX |
INDEXES | KEYS} \n FROM tbl_name [FROM db_name]\n [WHERE
expr]\n\nDescription\n-----------\n\nSHOW INDEX returns table index
information. The format resembles that of the\nSQLStatistics call in
ODBC.\n\nYou can use db_name.tbl_name as an alternative to the tbl_name
FROM db_name\nsyntax. These two statements are equivalent:\n\nSHOW INDEX
FROM mytable FROM mydb;\nSHOW INDEX FROM mydb.mytable;\n\nSHOW KEYS and
SHOW INDEXES are synonyms for SHOW INDEX.\n\nYou can also list a
table\'s indexes with the mariadb-show/mysqlshow command:\n\nmysqlshow
-k db_name tbl_name\n\nThe information_schema.STATISTICS table stores
similar information.\n\nThe following fields are returned by SHOW
INDEX.\n\n+------------------------+---------------------------------------------------+\n|
Field | Description
|\n+------------------------+---------------------------------------------------+\n|
Table | Table name
|\n+------------------------+---------------------------------------------------+\n|
Non_unique | 1 if the index permits duplicate values, 0 if
|\n| | values must be unique.
|\n+------------------------+---------------------------------------------------+\n|
Key_name | Index name. The primary key is always named
|\n| | PRIMARY.
|\n+------------------------+---------------------------------------------------+\n|
Seq_in_index | The column\'s sequence in the index,
beginning |\n| | with 1.
|\n+------------------------+---------------------------------------------------+\n|
Column_name | Column name.
|\n+------------------------+---------------------------------------------------+\n|
Collation | Either A, if the column is sorted in ascending
|\n| | order in the index, or NULL if it\'s not
sorted.
|\n+------------------------+---------------------------------------------------+\n|
Cardinality | Estimated number of unique values in the index.
|\n| | The cardinality statistics are calculated at
|\n| | various times, and can help the optimizer
make |\n| | improved decisions.
|\n+------------------------+---------------------------------------------------+\n|
Sub_part | NULL if the entire column is included in the
|\n| | index, or the number of included characters
if |\n| | not.
|\n+------------------------+---------------------------------------------------+\n|
Packed | NULL if the index is not packed, otherwise how
|\n| | the index is packed.
|\n+------------------------+---------------------------------------------------+\n|
Null | NULL if NULL values are permitted in the column,
|\n| | an empty string if NULLs are not permitted.
|\n+------------------------+---------------------------------------------------+\n|
Index_type | The index type, which can be BTREE, FULLTEXT,
|\n| | HASH or RTREE. See Storage Engine Index
Types.
|\n+------------------------+---------------------------------------------------+\n|
Comment | Other information, such as whether the index is
|\n| | disabled.
|\n+------------------------+---------------------------------------------------+\n|
Index_comment | Contents of the COMMENT attribute when the index
|\n| | was created.
|\n+------------------------+---------------------------------------------------+\n|
Ignored | Whether or not an index will be ignored by the
|\n| | optimizer. See Ignored Indexes. From MariaDB
|\n| | 10.6.0.
|\n+------------------------+---------------------------------------------------+\n\nThe
WHERE and LIKE clauses can be given to select rows using more
general\nconditions, as discussed in Extended
SHOW.\n\nExamples\n--------\n\nCREATE TABLE IF NOT EXISTS
`employees_example` (\n `id` int(11) NOT NULL AUTO_INCREMENT,\n
`first_name` varchar(30) NOT NULL,\n `last_name` varchar(40) NOT NULL,\n
`position` varchar(25) NOT NULL,\n `home_address` varchar(50) NOT NULL,\n
`home_phone` varchar(12) NOT NULL,\n `employee_code` varchar(25) NOT
NULL,\n PRIMARY KEY (`id`),\n UNIQUE KEY `employee_code`
(`employee_code`),\n KEY `first_name` (`first_name`,`last_name`)\n)
ENGINE=Aria;\n\nINSERT INTO `employees_example` (`first_name`, `last_name`,
`position`,\n`home_address`, `home_phone`, `employee_code`)\n VALUES\n
(\'Mustapha\', \'Mond\', \'Chief Executive
Officer\', \'692 Promiscuous
Plaza\',\n\'326-555-3492\', \'MM1\'),\n
(\'Henry\', \'Foster\', \'Store Manager\',
\'314 Savage Circle\',
\'326-555-3847\',\n\'HF1\'),\n (\'Bernard\',
\'Marx\', \'Cashier\', \'1240 Ambient
Avenue\', \'326-555-8456\', \'BM1\'),\n
(\'Lenina\', \'Crowne\', \'Cashier\',
\'281 Bumblepuppy Boulevard\',
\'328-555-2349\',\n\'LC1\'),\n (\'Fanny\',
\'Crowne\', \'Restocker\', \'1023 Bokanovsky
Lane\', \'326-555-6329\',\n\'FC1\'),\n
(\'Helmholtz\', \'Watson\', \'Janitor\',
\'944 Soma Court\', \'329-555-2478\',
\'HW1\');\n\nSHOW INDEXES FROM
employees_example\\G\n*************************** 1. row
***************************\n Table: employees_example\n Non_unique: 0\n
Key_name: PRIMARY\n Seq_in_index: 1\n Column_name: id\n Collation: A\n
Cardinality: 6\n Sub_part: NULL\n Packed: NULL\n Null:\n Index_type:
BTREE\n Comment:\nIndex_comment: \n Ignored:
NO\n*************************** 2. row ***************************\n
Table: employees_example\n Non_unique: 0\n Key_name: employee_code\n
Seq_in_index: 1\n Column_name: employee_code\n Collation: A\n Cardinality:
6\n Sub_part: NULL\n Packed: NULL\n Null:\n Index_type: BTREE\n
Comment:\nIndex_comment: \n Ignored: NO\n*************************** 3.
row ***************************\n Table: employees_example\n Non_unique:
1\n Key_name: first_name\n Seq_in_index: 1\n Column_name: first_name\n
Collation: A\n Cardinality: NULL\n Sub_part: NULL\n Packed: NULL\n
Null:\n Index_type: BTREE\n Comment:\nIndex_comment: \n Ignored:
NO\n*************************** 4. row ***************************\n
Table: employees_example\n Non_unique: 1\n Key_name: first_name\n
Seq_in_index: 2\n Column_name: last_name\n Collation: A\n Cardinality:
NULL\n Sub_part: NULL\n Packed: NULL\n Null:\n Index_type: BTREE\n
Comment:\nIndex_comment: \n Ignored: NO\n\nURL:
https://mariadb.com/kb/en/show-index/','','https://mariadb.com/kb/en/show-index/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(338,26,'SHOW EXPLAIN','Syntax\n------\n\nSHOW EXPLAIN
[FORMAT=JSON] FOR <connection_id>;\nEXPLAIN [FORMAT=JSON] FOR
CONNECTION <connection_id>;\n\nDescription\n-----------\n\nThe SHOW
EXPLAIN command allows one to get an EXPLAIN (that is, a description\nof a
query plan) of a query running in a certain connection.\n\nSHOW EXPLAIN FOR
<connection_id>;\n\nwill produce an EXPLAIN output for the query that
connection number\nconnection_id is running. The connection id can be
obtained with SHOW\nPROCESSLIST.\n\nSHOW EXPLAIN FOR
1;\n+------+-------------+-------+-------+---------------+------+---------+------+-\n-------+-------------+\n|
id | select_type | table | type | possible_keys | key | key_len | ref
|\nrows | Extra
|\n+------+-------------+-------+-------+---------------+------+---------+------+-\n-------+-------------+\n|
1 | SIMPLE | tbl | index | NULL | a | 5 | NULL
|\n1000107 | Using index
|\n+------+-------------+-------+-------+---------------+------+---------+------+-\n-------+-------------+\n1
row in set, 1 warning (0.00 sec)\n\nThe output is always accompanied with a
warning which shows the query the\ntarget connection is running (this shows
what the EXPLAIN is for):\n\nSHOW
WARNINGS;\n+-------+------+------------------------+\n| Level | Code |
Message |\n+-------+------+------------------------+\n| Note
| 1003 | select sum(a) from tbl
|\n+-------+------+------------------------+\n1 row in set (0.00
sec)\n\nEXPLAIN FOR CONNECTION\n----------------------\n\nMariaDB starting
with 10.9\n--------------------------\nThe EXPLAIN FOR CONNECTION syntax
was added for MySQL compatibility.\n\nFORMAT=JSON\n-----------\n\nMariaDB
starting with 10.9\n--------------------------\nSHOW EXPLAIN [FORMAT=JSON]
FOR <connection_id> extends SHOW EXPLAIN to return\nmore detailed
JSON output.\n\nPossible Errors\n---------------\n\nThe output can be only
produced if the target connection is currently running\na query, which has
a ready query plan. If this is not the case, the output\nwill be:\n\nSHOW
EXPLAIN FOR 2;\nERROR 1932 (HY000): Target is not running an EXPLAINable
command\n\nYou will get this error when:\n\n* the target connection is not
running a command for which one can run EXPLAIN\n* the target connection is
running a command for which one can run EXPLAIN, but\nthere is no query
plan yet (for example, tables are open and locks are\n acquired before the
query plan is produced)\n\nDifferences Between SHOW EXPLAIN and EXPLAIN
Outputs\n----------------------------------------------------\n\nBackground\n----------\n\nIn
MySQL, EXPLAIN execution takes a slightly different route from the way
the\nreal query (typically the SELECT) is optimized. This is unfortunate,
and has\ncaused a number of bugs in EXPLAIN. (For example, see MDEV-326,
MDEV-410, and\nlp:1013343. lp:992942 is not directly about EXPLAIN, but it
also would not\nhave existed if MySQL didn\'t try to delete parts of a
query plan in the middle\nof the query)\n\nSHOW EXPLAIN examines a running
SELECT, and hence its output may be slightly\ndifferent from what EXPLAIN
SELECT would produce. We did our best to make sure\nthat either the
difference is negligible, or SHOW EXPLAIN\'s output is closer\nto
reality than EXPLAIN\'s output.\n\nList of Recorded
Differences\n----------------------------\n\n* SHOW EXPLAIN may have
Extra=\'no matching row in const table\', where EXPLAIN\nwould
produce Extra=\'Impossible WHERE ...\'\n* For queries with
subqueries, SHOW EXPLAIN may print select_type==PRIMARY\nwhere regular
EXPLAIN used to print select_type==SIMPLE, or vice versa.\n\nRequired
Permissions\n--------------------\n\nRunning SHOW EXPLAIN requires the same
permissions as running SHOW PROCESSLIST\nwould.\n\nURL:
https://mariadb.com/kb/en/show-explain/','','https://mariadb.com/kb/en/show-explain/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(339,26,'BACKUP STAGE','MariaDB starting with
10.4.1\n----------------------------\nThe BACKUP STAGE commands were
introduced in MariaDB 10.4.1.\n\nThe BACKUP STAGE commands are a set of
commands to make it possible to make an\nefficient external backup
tool.\n\nSyntax\n------\n\nBACKUP STAGE [START | FLUSH | BLOCK_DDL |
BLOCK_COMMIT | END ]\n\nIn the following text, a transactional table means
InnoDB or \"InnoDB-like\nengine with redo log that can lock redo
purges and can be copied without locks\nby an outside
process\".\n\nGoals with BACKUP STAGE
Commands\n--------------------------------\n\n* To be able to do a majority
of the backup with the minimum possible server\nlocks. Especially for
transactional tables (InnoDB, MyRocks etc) there is only\nneed for a very
short block of new commits while copying statistics and log\ntables.\n* DDL
are only needed to be blocked for a very short duration of the
backup\nwhile mariabackup is copying the tables affected by DDL during the
initial\npart of the backup.\n* Most non transactional tables (those that
are not in use) will be copied\nduring BACKUP STAGE START. The exceptions
are system statistic and log tables\nthat are not blocked during the backup
until BLOCK_COMMIT.\n* Should work efficiently with backup tools that use
disk snapshots.\n* Should work as efficiently as possible for all table
types that store data\non the local disks.\n* As little copying as possible
under higher level stages/locks. For example,\n.frm (dictionary) and .trn
(trigger) files should be copying while copying the\ntable data.\n\nBACKUP
STAGE Commands\n---------------------\n\nBACKUP STAGE
START\n------------------\n\nThe START stage is designed for the following
tasks:\n\n* Blocks purge of redo files for storage engines that needs this
(Aria)\n* Start logging of DDL commands into \'datadir\'/ddl.log.
This may take a short\ntime as the command has to wait until there are no
active DDL commands.\n\nBACKUP STAGE FLUSH\n------------------\n\nThe FLUSH
stage is designed for the following tasks:\n\n* FLUSH all changes for
inactive non-transactional tables, except for\nstatistics and log
tables.\n* Close all tables that are not in use, to ensure they are marked
as closed\nfor the backup.\n* BLOCK all new write locks for all non
transactional tables (except\nstatistics and log tables). The command will
not wait for tables that are in\nuse by read-only transactions.\n\nDDLs
don\'t have to be blocked at this stage as they can\'t cause the
table to\nbe in an inconsistent state. This is true also for
non-transactional tables.\n\nBACKUP STAGE
BLOCK_DDL\n----------------------\n\nThe BLOCK_DDL stage is designed for
the following tasks:\n\n* Wait for all statements using write locked
non-transactional tables to end.\n* Blocks CREATE TABLE, DROP TABLE,
TRUNCATE TABLE, and RENAME TABLE.\n* Blocks also start off a new ALTER
TABLE and the final rename phase of ALTER\nTABLE. Running ALTER TABLES are
not blocked.\n\nBACKUP STAGE BLOCK_COMMIT\n-------------------------\n\nThe
BLOCK_COMMIT stage is designed for the following tasks:\n\n* Lock the
binary log and commit/rollback to ensure that no changes are\ncommitted to
any tables. If there are active commits or data to be copied to\nthe binary
log this will be allowed to finish. Active transactions will not\naffect
BLOCK_COMMIT.\n* This doesn\'t lock temporary tables that are not used
by replication. However\nthese will be blocked when it\'s time to
write to the binary log.\n* Lock system log tables and statistics tables,
flush them and mark them\nclosed.\n\nWhen the BLOCK_COMMIT\'s stages
return, this is the \'backup time\'. Everything\ncommitted will
be in the backup and everything not committed will roll
back.\n\nTransactional engines will continue to do changes to the redo log
during the\nBLOCK COMMIT stage, but this is not important as all of these
will roll back\nlater as the changes will not be committed.\n\nBACKUP STAGE
END\n----------------\n\nThe END stage is designed for the following
tasks:\n\n* End DDL logging\n* Free resources\n\nUsing BACKUP STAGE
Commands with Backup
Tools\n---------------------------------------------\n\nUsing BACKUP STAGE
Commands with
Mariabackup\n--------------------------------------------\n\nThe BACKUP
STAGE commands are a set of commands to make it possible to make
an\nefficient external backup tool. How Mariabackup uses these commands
depends on\nwhether you are using the version that is bundled with MariaDB
Community\nServer or the version that is bundled with MariaDB Enterprise
Server. See\nMariabackup and BACKUP STAGE Commands for some examples on how
Mariabackup\nuses these commands.\n\nIf you would like to use a version of
Mariabackup that uses the BACKUP STAGE\ncommands in an efficient way, then
one option is to use MariaDB Enterprise\nBackup that is bundled with
MariaDB Enterprise Server.\n\nUsing BACKUP STAGE Commands with Storage
Snapshots\n--------------------------------------------------\n\nThe BACKUP
STAGE commands are a set of commands to make it possible to make
an\nefficient external backup tool. These commands could even be used by
tools\nthat perform backups by taking a snapshot of a file system, SAN, or
some other\nkind of storage device. See Storage Snapshots and BACKUP STAGE
Commands for\nsome examples on how to use each BACKUP STAGE command in an
efficient way.\n\nPrivileges\n----------\n\nBACKUP STAGE requires the
RELOAD privilege.\n\nNotes\n-----\n\n* Only one connection can run BACKUP
STAGE START. If a second connection\ntries, it will wait until the first
one has executed BACKUP STAGE END.\n* If the user skips a BACKUP STAGE,
then all intermediate backup stages will\nautomatically be run. This will
allow us to add new stages within the BACKUP\nSTAGE hierarchy in the future
with even more precise locks without causing\nproblems for tools using an
earlier version of the BACKUP STAGE implementation.\n* One can use the
max_statement_time or lock_wait_timeout system variables to\nensure that a
BACKUP STAGE command doesn\'t block the server too long.\n* DDL
logging will only be available in MariaDB Enterprise Server 10.2
and\nlater.\n* A disconnect will automatically release backup stages.\n*
There is no easy way to see which is the current stage.\n\nURL:
https://mariadb.com/kb/en/backup-stage/','','https://mariadb.com/kb/en/backup-stage/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(340,26,'BACKUP LOCK','MariaDB starting with
10.4.2\n----------------------------\nThe BACKUP LOCK command was
introduced in MariaDB 10.4.2.\n\nBACKUP LOCK blocks a table from DDL
statements. This is mainly intended to be\nused by tools like mariabackup
that need to ensure there are no DDLs on a\ntable while the table files are
opened. For example, for an Aria table that\nstores data in 3 files with
extensions .frm, .MAI and .MAD. Normal read/write\noperations can continue
as normal.\n\nSyntax\n------\n\nTo lock a table:\n\nBACKUP LOCK
table_name\n\nTo unlock a table:\n\nBACKUP UNLOCK\n\nUsage in a Backup
Tool\n----------------------\n\nBACKUP LOCK [database.]table_name;\n - Open
all files related to a table (for example, t.frm, t.MAI and t.MYD)\nBACKUP
UNLOCK;\n- Copy data\n- Close files\n\nThis ensures that all files are from
the same generation, that is created at\nthe same time by the MariaDB
server. This works, because the open files will\npoint to the original
table files which will not be affected if there is any\nALTER TABLE while
copying the files.\n\nPrivileges\n----------\n\nBACKUP LOCK requires the
RELOAD privilege.\n\nNotes\n-----\n\n* The idea is that the BACKUP LOCK
should be held for as short a time as\npossible by the backup tool. The
time to take an uncontested lock is very\nshort! One can easily do 50,000
locks/unlocks per second on low end hardware.\n* One should use different
connections for BACKUP STAGE commands and
BACKUP\nLOCK.\n\nImplementation\n--------------\n\n* Internally, BACKUP
LOCK is implemented by taking an MDLSHARED_HIGH_PRIO MDL\nlock on the table
object, which protects the table from any DDL operations.\n\nURL:
https://mariadb.com/kb/en/backup-lock/','','https://mariadb.com/kb/en/backup-lock/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(341,26,'FLUSH','Syntax\n------\n\nFLUSH [NO_WRITE_TO_BINLOG
| LOCAL]\n flush_option [, flush_option] ...\n\nor when flushing
tables:\n\nFLUSH [NO_WRITE_TO_BINLOG | LOCAL] TABLES [table_list]
[table_flush_option]\n\nwhere table_list is a list of tables separated by ,
(comma).\n\nDescription\n-----------\n\nThe FLUSH statement clears or
reloads various internal caches used by MariaDB.\nTo execute FLUSH, you
must have the RELOAD privilege. See GRANT.\n\nThe RESET statement is
similar to FLUSH. See RESET.\n\nYou cannot issue a FLUSH statement from
within a stored function or a trigger.\nDoing so within a stored procedure
is permitted, as long as it is not called\nby a stored function or trigger.
See Stored Routine Limitations, Stored\nFunction Limitations and Trigger
Limitations.\n\nIf a listed table is a view, an error like the following
will be produced:\n\nERROR 1347 (HY000): \'test.v\' is not BASE
TABLE\n\nBy default, FLUSH statements are written to the binary log and
will be\nreplicated. The NO_WRITE_TO_BINLOG keyword (LOCAL is an alias)
will ensure the\nstatement is not written to the binary log.\n\nThe
different flush options
are:\n\n+---------------------------+------------------------------------------------+\n|
Option | Description
|\n+---------------------------+------------------------------------------------+\n|
CHANGED_PAGE_BITMAPS | XtraDB only. Internal command used for backup
|\n| | purposes. See the Information Schema
|\n| | CHANGED_PAGE_BITMAPS Table.
|\n+---------------------------+------------------------------------------------+\n|
CLIENT_STATISTICS | Reset client statistics (see SHOW
|\n| | CLIENT_STATISTICS).
|\n+---------------------------+------------------------------------------------+\n|
DES_KEY_FILE | Reloads the DES key file (Specified with the
|\n| | --des-key-file startup option).
|\n+---------------------------+------------------------------------------------+\n|
HOSTS | Flush the hostname cache (used for converting
|\n| | ip to host names and for unblocking
blocked |\n| | hosts. See max_connect_errors
and |\n| |
performance_schema.host_cache
|\n+---------------------------+------------------------------------------------+\n|
INDEX_STATISTICS | Reset index statistics (see SHOW
|\n| | INDEX_STATISTICS).
|\n+---------------------------+------------------------------------------------+\n|
[ERROR | ENGINE | | Close and reopen the specified log type, or
|\n| GENERAL | SLOW | BINARY | all log types if none are specified. FLUSH
|\n| | RELAY] LOGS | RELAY LOGS [connection-name] can be
used to |\n| | flush the relay logs for a
specific |\n| | connection. Only one
connection can be |\n| | specified per
FLUSH command. See Multi-source |\n| |
replication. FLUSH ENGINE LOGS will delete |\n|
| all unneeded Aria redo logs. Since MariaDB |\n|
| 10.1.30 and MariaDB 10.2.11, FLUSH BINARY |\n|
| LOGS DELETE_DOMAIN_ID=(list-of-domains) can |\n|
| be used to discard obsolete GTID domains from |\n|
| the server\'s binary log state. In order for
|\n| | this to be successful, no event group from
|\n| | the listed GTID domains can be present
in |\n| | existing binary log files. If some
still |\n| | exist, then they must be
purged prior to |\n| | executing this
command. If the command |\n| | completes
successfully, then it also rotates |\n| | the
binary log.
|\n+---------------------------+------------------------------------------------+\n|
MASTER | Deprecated option, use RESET MASTER instead.
|\n+---------------------------+------------------------------------------------+\n|
PRIVILEGES | Reload all privileges from the privilege
|\n| | tables in the mysql database. If the
server |\n| | is started with
--skip-grant-table option, |\n| | this will
activate the privilege tables again.
|\n+---------------------------+------------------------------------------------+\n|
QUERY CACHE | Defragment the query cache to better utilize
|\n| | its memory. If you want to reset the query
|\n| | cache, you can do it with RESET QUERY
CACHE.
|\n+---------------------------+------------------------------------------------+\n|
QUERY_RESPONSE_TIME | See the QUERY_RESPONSE_TIME plugin.
|\n+---------------------------+------------------------------------------------+\n|
SLAVE | Deprecated option, use RESET REPLICA or RESET
|\n| | SLAVE instead.
|\n+---------------------------+------------------------------------------------+\n|
SSL | Used to dynamically reinitialize the
server\'s |\n| | TLS context by reloading
the files defined by |\n| | several TLS system
variables. See FLUSH SSL |\n| | for more
information. This command was first |\n| |
added in MariaDB 10.4.1.
|\n+---------------------------+------------------------------------------------+\n|
STATUS | Resets all server status variables that can
|\n| | be reset to 0. Not all global status
|\n| | variables support this, so not all
global |\n| | values are reset. See FLUSH
STATUS for more |\n| | information.
|\n+---------------------------+------------------------------------------------+\n|
TABLE | Close tables given as options or all open
|\n| | tables if no table list was used. From
|\n| | MariaDB 10.4.1, using without any
table list |\n| | will only close tables not in
use, and tables |\n| | not locked by the FLUSH
TABLES connection. If |\n| | there are no locked
tables, FLUSH TABLES will |\n| | be instant and
will not cause any waits, as |\n| | it no
longer waits for tables in use. When a |\n| |
table list is provided, from MariaDB 10.4.1, |\n|
| the server will wait for the end of any |\n|
| transactions that are using the tables. |\n|
| Previously, FLUSH TABLES only waited for the |\n|
| statements to complete.
|\n+---------------------------+------------------------------------------------+\n|
TABLES | Same as FLUSH TABLE.
|\n+---------------------------+------------------------------------------------+\n|
TABLES ... FOR EXPORT | For InnoDB tables, flushes table changes to
|\n| | disk to permit binary table copies while
the |\n| | server is running. See FLUSH TABLES
... FOR |\n| | EXPORT for more.
|\n+---------------------------+------------------------------------------------+\n|
TABLES WITH READ LOCK | Closes all open tables. New tables are only
|\n| | allowed to be opened with read locks until
an |\n| | UNLOCK TABLES is given.
|\n+---------------------------+------------------------------------------------+\n|
TABLES WITH READ LOCK | As TABLES WITH READ LOCK but also disable all
|\n| AND DISABLE CHECKPOINT | checkpoint writes by transactional table
|\n| | engines. This is useful when doing a
disk |\n| | snapshot of all tables.
|\n+---------------------------+------------------------------------------------+\n|
TABLE_STATISTICS | Reset table statistics (see SHOW
|\n| | TABLE_STATISTICS).
|\n+---------------------------+------------------------------------------------+\n|
USER_RESOURCES | Resets all per hour user resources. This
|\n| | enables clients that have exhausted their
|\n| | resources to connect again.
|\n+---------------------------+------------------------------------------------+\n|
USER_STATISTICS | Reset user statistics (see SHOW
|\n| | USER_STATISTICS).
|\n+---------------------------+------------------------------------------------+\n|
USER_VARIABLES | Reset user variables (see User-defined
|\n| | variables).
|\n+---------------------------+------------------------------------------------+\n\nYou
can also use the mysqladmin client to flush things. Use mysqladmin
--help\nto examine what flush commands it supports.\n\nFLUSH RELAY
LOGS\n----------------\n\nFLUSH RELAY LOGS
\'connection_name\';\n\nCompatibility with
MySQL\n------------------------\n\nMariaDB starting with
10.7.0\n----------------------------\nThe FOR CHANNEL keyword was added for
MySQL compatibility. This is identical\nas using the channel_name directly
after the FLUSH command.\n\nFor example, one can now use:\n\nFLUSH RELAY
LOGS FOR CHANNEL \'connection_name\';\n\nFLUSH
STATUS\n------------\n\nServer status variables can be reset by executing
the following:\n\nFLUSH STATUS;\n\nGlobal Status Variables that Support
FLUSH STATUS\n-------------------------------------------------\n\nNot all
global status variables support being reset by FLUSH STATUS.\nCurrently,
the following status variables are reset by FLUSH STATUS:\n\n*
Aborted_clients\n* Aborted_connects\n* Binlog_cache_disk_use\n*
Binlog_cache_use\n* Binlog_stmt_cache_disk_use\n* Binlog_stmt_cache_use\n*
Connection_errors_accept\n* Connection_errors_internal\n*
Connection_errors_max_connections\n* Connection_errors_peer_address\n*
Connection_errors_select\n* Connection_errors_tcpwrap\n*
Created_tmp_files\n* Delayed_errors\n* Delayed_writes\n*
Feature_check_constraint\n* Feature_delay_key_write\n*
Max_used_connections\n* Opened_plugin_libraries\n*
Performance_schema_accounts_lost\n*
Performance_schema_cond_instances_lost\n* Performance_schema_digest_lost\n*
Performance_schema_file_handles_lost\n*
Performance_schema_file_instances_lost\n* Performance_schema_hosts_lost\n*
Performance_schema_locker_lost\n*
Performance_schema_mutex_instances_lost\n*
Performance_schema_rwlock_instances_lost\n*
Performance_schema_session_connect_attrs_lost\n*
Performance_schema_socket_instances_lost\n*
Performance_schema_stage_classes_lost\n*
Performance_schema_statement_classes_lost\n*
Performance_schema_table_handles_lost\n*
Performance_schema_table_instances_lost\n*
Performance_schema_thread_instances_lost\n*
Performance_schema_users_lost\n* Qcache_hits\n* Qcache_inserts\n*
Qcache_lowmem_prunes\n* Qcache_not_cached\n*
Rpl_semi_sync_master_no_times\n* Rpl_semi_sync_master_no_tx\n*
Rpl_semi_sync_master_timefunc_failures\n*
Rpl_semi_sync_master_wait_pos_backtraverse\n*
Rpl_semi_sync_master_yes_tx\n* Rpl_transactions_multi_engine\n*
Server_audit_writes_failed\n* Slave_retried_transactions\n*
Slow_launch_threads\n* Ssl_accept_renegotiates\n* Ssl_accepts\n*
Ssl_callback_cache_hits\n* Ssl_client_connects\n*
Ssl_connect_renegotiates\n* Ssl_ctx_verify_depth\n* Ssl_ctx_verify_mode\n*
Ssl_finished_accepts\n* Ssl_finished_connects\n* Ssl_session_cache_hits\n*
Ssl_session_cache_misses\n* Ssl_session_cache_overflows\n*
Ssl_session_cache_size\n* Ssl_session_cache_timeouts\n*
Ssl_sessions_reused\n* Ssl_used_session_cache_entries\n*
Subquery_cache_hit\n* Subquery_cache_miss\n* Table_locks_immediate\n*
Table_locks_waited\n* Tc_log_max_pages_used\n* Tc_log_page_waits\n*
Transactions_gtid_foreign_engine\n* Transactions_multi_engine\n\nThe
different usage of FLUSH TABLES\n-----------------------------------\n\nThe
purpose of FLUSH TABLES\n---------------------------\n\nThe purpose of
FLUSH TABLES is to clean up the open table cache and table\ndefinition
cache from not in use tables. This frees up memory and file\ndescriptors.
Normally this is not needed as the caches works on a FIFO bases,\nbut can
be useful if the server seams to use up to much memory for some
reason.\n\nThe purpose of FLUSH TABLES WITH READ LOCK
\n-------------------------------------------\n\nFLUSH TABLES WITH READ
LOCK is useful if you want to take a backup of some\ntables. When FLUSH
TABLES WITH READ LOCK returns, all write access to tables\nare blocked and
all tables are marked as \'properly closed\' on disk. The
tables\ncan still be used for read operations.\n\nThe purpose of FLUSH
TABLES table_list\n--------------------------------------\n\nFLUSH TABLES
table_list is useful if you want to copy a table object/files to\nor from
the server. This command puts a lock that stops new users of the table\nand
will wait until everyone has stopped using the table. The table is
then\nremoved from the table definition and table cache.\n\nNote that
it\'s up to the user to ensure that no one is accessing the
table\nbetween FLUSH TABLES and the table is copied to or from the server.
This can\nbe secured by using LOCK
TABLES.\n','','https://mariadb.com/kb/en/flush/');
update help_topic set description = CONCAT(description, '\nIf there
are any tables locked by the connection that is using FLUSH TABLES\nall the
locked tables will be closed as part of the flush and reopened
and\nrelocked before FLUSH TABLES returns. This allows one to copy the
table after\nFLUSH TABLES returns without having any writes on the table.
For now this\nworks works with most tables, except InnoDB as InnoDB may do
background purges\non the table even while it\'s write locked.\n\nThe
purpose of FLUSH TABLES table_list WITH READ
LOCK\n-----------------------------------------------------\n\nFLUSH TABLES
table_list WITH READ LOCK should work as FLUSH TABLES WITH READ\nLOCK, but
only those tables that are listed will be properly closed. However\nin
practice this works exactly like FLUSH TABLES WITH READ LOCK as the
FLUSH\ncommand has anyway to wait for all WRITE operations to end because
we are\ndepending on a global read lock for this code. In the future we
should\nconsider fixing this to instead use meta data
locks.\n\nImplementation of FLUSH TABLES commands in MariaDB 10.4.8 and
above\n-------------------------------------------------------------------\n\nImplementation
of FLUSH TABLES\n------------------------------\n\n* Free memory and file
descriptors not in use\n\nImplementation of FLUSH TABLES WITH READ
LOCK\n---------------------------------------------\n\n* Lock all tables
read only for simple old style backup.\n* All background writes are
suspended and tables are marked as closed.\n* No statement requiring table
changes are allowed for any user until UNLOCK\nTABLES.\n\nInstead of using
FLUSH TABLE WITH READ LOCK one should in most cases instead\nuse BACKUP
STAGE BLOCK_COMMIT.\n\nImplementation of FLUSH TABLES
table_list\n-----------------------------------------\n\n* Free memory and
file descriptors for tables not in use from table list.\n* Lock given
tables as read only.\n* Wait until all translations has ended that uses any
of the given tables.\n* Wait until all background writes are suspended and
tables are marked as\nclosed.\n\nImplementation of FLUSH TABLES table_list
FOR EXPORT\n----------------------------------------------------\n\n* Free
memory and file descriptors for tables not in use from table list\n* Lock
given tables as read.\n* Wait until all background writes are suspended and
tables are marked as\nclosed.\n* Check that all tables supports FOR
EXPORT\n* No changes to these tables allowed until UNLOCK TABLES\n\nThis is
basically the same behavior as in old MariaDB version if one first\nlock
the tables, then do FLUSH TABLES. The tables will be copyable until\nUNLOCK
TABLES.\n\nFLUSH SSL\n---------\n\nMariaDB starting with
10.4\n--------------------------\nThe FLUSH SSL command was first added in
MariaDB 10.4.\n\nIn MariaDB 10.4 and later, the FLUSH SSL command can be
used to dynamically\nreinitialize the server\'s TLS context. This is
most useful if you need to\nreplace a certificate that is about to expire
without restarting the server.\n\nThis operation is performed by reloading
the files defined by the following\nTLS system variables:\n\n* ssl_cert\n*
ssl_key\n* ssl_ca\n* ssl_capath\n* ssl_crl\n* ssl_crlpath\n\nThese TLS
system variables are not dynamic, so their values can not be
changed\nwithout restarting the server.\n\nIf you want to dynamically
reinitialize the server\'s TLS context, then you\nneed to change the
certificate and key files at the relevant paths defined by\nthese TLS
system variables, without actually changing the values of the\nvariables.
See MDEV-19341 for more information.\n\nReducing Memory
Usage\n---------------------\n\nTo flush some of the global caches that
take up memory, you could execute the\nfollowing command:\n\nFLUSH LOCAL
HOSTS,\n QUERY CACHE,\n TABLE_STATISTICS,\n INDEX_STATISTICS,\n
USER_STATISTICS;\n\nURL: https://mariadb.com/kb/en/flush/') WHERE
help_topic_id = 341;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(342,26,'FLUSH QUERY CACHE','Description\n-----------\n\nYou
can defragment the query cache to better utilize its memory with the
FLUSH\nQUERY CACHE statement. The statement does not remove any queries
from the\ncache.\n\nThe RESET QUERY CACHE statement removes all query
results from the query\ncache. The FLUSH TABLES statement also does
this.\n\nURL:
https://mariadb.com/kb/en/flush-query-cache/','','https://mariadb.com/kb/en/flush-query-cache/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(343,26,'FLUSH TABLES FOR EXPORT','Syntax\n------\n\nFLUSH
TABLES table_name [, table_name] FOR
EXPORT\n\nDescription\n-----------\n\nFLUSH TABLES ... FOR EXPORT flushes
changes to the specified tables to disk so\nthat binary copies can be made
while the server is still running. This works\nfor Archive, Aria, CSV,
InnoDB, MyISAM, MERGE, and XtraDB tables.\n\nThe table is read locked until
one has issued UNLOCK TABLES.\n\nIf a storage engine does not support FLUSH
TABLES FOR EXPORT, a 1031 error\n(SQLSTATE \'HY000\') is
produced.\n\nIf FLUSH TABLES ... FOR EXPORT is in effect in the session,
the following\nstatements will produce an error if attempted:\n\n* FLUSH
TABLES WITH READ LOCK\n* FLUSH TABLES ... WITH READ LOCK\n* FLUSH TABLES
... FOR EXPORT\n* Any statement trying to update any table\n\nIf any of the
following statements is in effect in the session, attempting\nFLUSH TABLES
... FOR EXPORT will produce an error.\n\n* FLUSH TABLES ... WITH READ
LOCK\n* FLUSH TABLES ... FOR EXPORT\n* LOCK TABLES ... READ\n* LOCK TABLES
... WRITE\n\nFLUSH FOR EXPORT is not written to the binary log.\n\nThis
statement requires the RELOAD and the LOCK TABLES privileges.\n\nIf one of
the specified tables cannot be locked, none of the tables will
be\nlocked.\n\nIf a table does not exist, an error like the following will
be produced:\n\nERROR 1146 (42S02): Table \'test.xxx\'
doesn\'t exist\n\nIf a table is a view, an error like the following
will be produced:\n\nERROR 1347 (HY000): \'test.v\' is not BASE
TABLE\n\nExample\n-------\n\nFLUSH TABLES test.t1 FOR EXPORT;\n# Copy
files related to the table (see below)\nUNLOCK TABLES;\n\nFor a full
description, please see copying MariaDB tables.\n\nURL:
https://mariadb.com/kb/en/flush-tables-for-export/','','https://mariadb.com/kb/en/flush-tables-for-export/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(344,26,'SHOW RELAYLOG EVENTS','The terms master and slave
have historically been used in replication, but the\nterms terms primary
and replica are now preferred. The old terms are used\nstill used in parts
of the documentation, and in MariaDB commands, although\nMariaDB 10.5 has
begun the process of renaming. The documentation process is\nongoing. See
MDEV-18777 to follow progress on this effort.\n\nSyntax\n------\n\nSHOW
RELAYLOG [\'connection_name\'] EVENTS\n [IN
\'log_name\'] [FROM pos] [LIMIT [offset,] row_count]\n [ FOR
CHANNEL \'channel_name\']\n\nDescription\n-----------\n\nOn
replicas, this command shows the events in the relay log. If
\'log_name\' is\nnot specified, the first relay log is
shown.\n\nSyntax for the LIMIT clause is the same as for SELECT ...
LIMIT.\n\nUsing the LIMIT clause is highly recommended because the SHOW
RELAYLOG EVENTS\ncommand returns the complete contents of the relay log,
which can be quite\nlarge.\n\nThis command does not return events related
to setting user and system\nvariables. If you need those, use
mariadb-binlog/mysqlbinlog.\n\nOn the primary, this command does
nothing.\n\nRequires the REPLICA MONITOR privilege (>= MariaDB 10.5.9),
the REPLICATION\nSLAVE ADMIN privilege (>= MariaDB 10.5.2) or the
REPLICATION SLAVE privilege\n(<= MariaDB
10.5.1).\n\nconnection_name\n---------------\n\nIf there is only one
nameless primary, or the default primary (as specified by\nthe
default_master_connection system variable) is intended,
connection_name\ncan be omitted. If provided, the SHOW RELAYLOG statement
will apply to the\nspecified primary. connection_name is
case-insensitive.\n\nMariaDB starting with
10.7.0\n----------------------------\nThe FOR CHANNEL keyword was added for
MySQL compatibility. This is identical\nas using the channel_name directly
after SHOW RELAYLOG.\n\nURL:
https://mariadb.com/kb/en/show-relaylog-events/','','https://mariadb.com/kb/en/show-relaylog-events/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(345,26,'SHOW SLAVE STATUS','Syntax\n------\n\nSHOW SLAVE
[\"connection_name\"] STATUS [FOR CHANNEL
\"connection_name\"]\nSHOW REPLICA
[\"connection_name\"] STATUS -- From MariaDB 10.5.1\n\nor\n\nSHOW
ALL SLAVES STATUS\nSHOW ALL REPLICAS STATUS -- From MariaDB
10.5.1\n\nDescription\n-----------\n\nThis statement is to be run on a
replica and provides status information on\nessential parameters of the
replica threads.\n\nThis statement requires the SUPER privilege, the
REPLICATION_CLIENT privilege,\nor, from MariaDB 10.5.2, the REPLICATION
SLAVE ADMIN privilege, or, from\nMariaDB 10.5.9, the REPLICA MONITOR
privilege.\n\nMulti-Source\n------------\n\nThe ALL and
\"connection_name\" options allow you to connect to many
primaries\nat the same time.\n\nALL SLAVES (or ALL REPLICAS from MariaDB
10.5.1) gives you a list of all\nconnections to the primary nodes.\n\nThe
rows will be sorted according to Connection_name.\n\nIf you specify a
connection_name, you only get the information about that\nconnection. If
connection_name is not used, then the name set
by\ndefault_master_connection is used. If the connection name doesn\'t
exist you\nwill get an error: There is no master connection for
\'xxx\'.\n\nMariaDB starting with
10.7.0\n----------------------------\nThe FOR CHANNEL keyword was added for
MySQL compatibility. This is identical\nas using the channel_name directly
after SHOW SLAVE.\n\nColumn
Descriptions\n-------------------\n\n+---------------+---------------------------------------+-------------------+\n|
Name | Description | Added
|\n+---------------+---------------------------------------+-------------------+\n|
Connection_na | Name of the primary connection. |
|\n| e | Returned with SHOW ALL SLAVES STATUS |
|\n| | (or SHOW ALL REPLICAS STATUS from |
|\n| | MariaDB 10.5.1) only. |
|\n+---------------+---------------------------------------+-------------------+\n|
Slave_SQL_Sta | State of SQL thread. Returned with |
|\n| e | SHOW ALL SLAVES STATUS (or SHOW ALL |
|\n| | REPLICAS STATUS from MariaDB 10.5.1) |
|\n| | only. See Slave SQL Thread States. |
|\n+---------------+---------------------------------------+-------------------+\n|
Slave_IO_Stat | State of I/O thread. See Slave I/O |
|\n| | Thread States. |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_host | Master host that the replica is |
|\n| | connected to. |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_user | Account user name being used to |
|\n| | connect to the primary. |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_port | The port being used to connect to |
|\n| | the primary. |
|\n+---------------+---------------------------------------+-------------------+\n|
Connect_Retry | Time in seconds between retries to |
|\n| | connect. The default is 60. The |
|\n| | CHANGE MASTER TO statement can set |
|\n| | this. The master-retry-count option |
|\n| | determines the maximum number of |
|\n| | reconnection attempts. |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_Log_Fi | Name of the primary binary log file |
|\n| e | that the I/O thread is currently |
|\n| | reading from. |
|\n+---------------+---------------------------------------+-------------------+\n|
Read_Master_L | Position up to which the I/O thread |
|\n| g_Pos | has read in the current primary |
|\n| | binary log file. |
|\n+---------------+---------------------------------------+-------------------+\n|
Relay_Log_Fil | Name of the relay log file that the |
|\n| | SQL thread is currently processing. |
|\n+---------------+---------------------------------------+-------------------+\n|
Relay_Log_Pos | Position up to which the SQL thread |
|\n| | has finished processing in the |
|\n| | current relay log file. |
|\n+---------------+---------------------------------------+-------------------+\n|
Relay_Master_ | Name of the primary binary log file |
|\n| og_File | that contains the most recent event |
|\n| | executed by the SQL thread. |
|\n+---------------+---------------------------------------+-------------------+\n|
Slave_IO_Runn | Whether the replica I/O thread is |
|\n| ng | running and connected (Yes), running |
|\n| | but not connected to a primary |
|\n| | (Connecting) or not running (No). |
|\n+---------------+---------------------------------------+-------------------+\n|
Slave_SQL_Run | Whether or not the SQL thread is |
|\n| ing | running. |
|\n+---------------+---------------------------------------+-------------------+\n|
Replicate_Do_ | Databases specified for replicating |
|\n| B | with the replicate_do_db option. |
|\n+---------------+---------------------------------------+-------------------+\n|
Replicate_Ign | Databases specified for ignoring |
|\n| re_DB | with the replicate_ignore_db option. |
|\n+---------------+---------------------------------------+-------------------+\n|
Replicate_Do_ | Tables specified for replicating |
|\n| able | with the replicate_do_table option. |
|\n+---------------+---------------------------------------+-------------------+\n|
Replicate_Ign | Tables specified for ignoring with |
|\n| re_Table | the replicate_ignore_table option. |
|\n+---------------+---------------------------------------+-------------------+\n|
Replicate_Wil | Tables specified for replicating |
|\n| _Do_Table | with the replicate_wild_do_table |
|\n| | option. |
|\n+---------------+---------------------------------------+-------------------+\n|
Replicate_Wil | Tables specified for ignoring with |
|\n| _Ignore_Table | the replicate_wild_ignore_table |
|\n| | option. |
|\n+---------------+---------------------------------------+-------------------+\n|
Last_Errno | Alias for Last_SQL_Errno (see below) |
|\n+---------------+---------------------------------------+-------------------+\n|
Last Error | Alias for Last_SQL_Error (see below) |
|\n+---------------+---------------------------------------+-------------------+\n|
Skip_Counter | Number of events that a replica |
|\n| | skips from the master, as recorded |
|\n| | in the sql_slave_skip_counter system |
|\n| | variable. |
|\n+---------------+---------------------------------------+-------------------+\n|
Exec_Master_L | Position up to which the SQL thread |
|\n| g_Pos | has processed in the current master |
|\n| | binary log file. Can be used to |
|\n| | start a new replica from a current |
|\n| | replica with the CHANGE MASTER TO |
|\n| | ... MASTER_LOG_POS option. |
|\n+---------------+---------------------------------------+-------------------+\n|
Relay_Log_Spa | Total size of all relay log files |
|\n| e | combined. |
|\n+---------------+---------------------------------------+-------------------+\n|
Until_Conditi | |
|\n| n | |
|\n+---------------+---------------------------------------+-------------------+\n|
Until_Log_Fil | The MASTER_LOG_FILE value of the |
|\n| | START SLAVE UNTIL condition. |
|\n+---------------+---------------------------------------+-------------------+\n|
Until_Log_Pos | The MASTER_LOG_POS value of the |
|\n| | START SLAVE UNTIL condition. |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_SSL_Al | Whether an SSL connection is |
|\n| owed | permitted (Yes), not permitted (No) |
|\n| | or permitted but without the replica |
|\n| | having SSL support enabled (Ignored) |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_SSL_CA | The MASTER_SSL_CA option of the |
|\n| File | CHANGE MASTER TO statement. |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_SSL_CA | The MASTER_SSL_CAPATH option of the |
|\n| Path | CHANGE MASTER TO statement. |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_SSL_Ce | The MASTER_SSL_CERT option of the |
|\n| t | CHANGE MASTER TO statement. |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_SSL_Ci | The MASTER_SSL_CIPHER option of the |
|\n| her | CHANGE MASTER TO statement. |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_SSL_Ke | The MASTER_SSL_KEY option of the |
|\n| | CHANGE MASTER TO statement. |
|\n+---------------+---------------------------------------+-------------------+\n|
Seconds_Behin | Difference between the timestamp |
|\n| _Master | logged on the master for the event |
|\n| | that the replica is currently |
|\n| | processing, and the current |
|\n| | timestamp on the replica. Zero if |
|\n| | the replica is not currently |
|\n| | processing an event. With parallel |
|\n| | replication, seconds_behind_master
| |\n| | is updated only after
transactions | |\n| | commit.
|
|\n+---------------+---------------------------------------+-------------------+\n|
Master_SSL_Ve | The MASTER_SSL_VERIFY_SERVER_CERT |
|\n| ify_Server_Ce | option of the CHANGE MASTER TO |
|\n| t | statement. |
|\n+---------------+---------------------------------------+-------------------+\n|
Last_IO_Errno | Error code of the most recent error |
|\n| | that caused the I/O thread to stop |
|\n| | (also recorded in the replica\'s |
|\n| | error log). 0 means no error. RESET |
|\n| | SLAVE or RESET MASTER will reset |
|\n| | this value.
|
|\n+---------------+---------------------------------------+-------------------+\n|
Last_IO_Error | Error message of the most recent |
|\n| | error that caused the I/O thread to |
|\n| | stop (also recorded in the replica\'s |
|\n| | error log). An empty string means no |
|\n| | error. RESET SLAVE or RESET MASTER |
|\n| | will reset this value.
|
|\n+---------------+---------------------------------------+-------------------+\n|
Last_SQL_Errn | Error code of the most recent error |
|\n| | that caused the SQL thread to stop |
|\n| | (also recorded in the replica\'s |
|\n| | error log). 0 means no error. RESET |
|\n| | SLAVE or RESET MASTER will reset |
|\n| | this value.
|
|\n+---------------+---------------------------------------+-------------------+\n|
Last_SQL_Erro | Error message of the most recent |
|\n| | error that caused the SQL thread to |
|\n| | stop (also recorded in the replica\'s |
|','','https://mariadb.com/kb/en/show-replica-status/');
update help_topic set description = CONCAT(description, '\n|
| error log). An empty string means no | |\n|
| error. RESET SLAVE or RESET MASTER | |\n|
| will reset this value. |
|\n+---------------+---------------------------------------+-------------------+\n|
Replicate_Ign | List of server_ids that are |
|\n| re_Server_Ids | currently being ignored for |
|\n| | replication purposes, or an empty |
|\n| | string for none, as specified in the |
|\n| | IGNORE_SERVER_IDS option of the |
|\n| | CHANGE MASTER TO statement. |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_Server | The master\'s server_id value. |
|\n| Id | |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_SSL_Cr | The MASTER_SSL_CRL option of the |
|\n| | CHANGE MASTER TO statement. |
|\n+---------------+---------------------------------------+-------------------+\n|
Master_SSL_Cr | The MASTER_SSL_CRLPATH option of the |
|\n| path | CHANGE MASTER TO statement. |
|\n+---------------+---------------------------------------+-------------------+\n|
Using_Gtid | Whether or not global transaction |
|\n| | ID\'s are being used for replication |
|\n| | (can be No, Slave_Pos, or |
|\n| | Current_Pos). |
|\n+---------------+---------------------------------------+-------------------+\n|
Gtid_IO_Pos | Current global transaction ID value. |
|\n+---------------+---------------------------------------+-------------------+\n|
Retried_trans | Number of retried transactions for |
|\n| ctions | this connection. Returned with SHOW |
|\n| | ALL SLAVES STATUS only. |
|\n+---------------+---------------------------------------+-------------------+\n|
Max_relay_log | Max relay log size for this |
|\n| size | connection. Returned with SHOW ALL |
|\n| | SLAVES STATUS only. |
|\n+---------------+---------------------------------------+-------------------+\n|
Executed_log_ | How many log entries the replica has |
|\n| ntries | executed. Returned with SHOW ALL |
|\n| | SLAVES STATUS only. |
|\n+---------------+---------------------------------------+-------------------+\n|
Slave_receive | How many heartbeats we have got from |
|\n| _heartbeats | the master. Returned with SHOW ALL |
|\n| | SLAVES STATUS only. |
|\n+---------------+---------------------------------------+-------------------+\n|
Slave_heartbe | How often to request a heartbeat |
|\n| t_period | packet from the master (in seconds). |
|\n| | Returned with SHOW ALL SLAVES STATUS |
|\n| | only. |
|\n+---------------+---------------------------------------+-------------------+\n|
Gtid_Slave_Po | GTID of the last event group |
|\n| | replicated on a replica server, for |
|\n| | each replication domain, as stored |
|\n| | in the gtid_slave_pos system |
|\n| | variable. Returned with SHOW ALL |
|\n| | SLAVES STATUS only. |
|\n+---------------+---------------------------------------+-------------------+\n|
SQL_Delay | Value specified by MASTER_DELAY in | MariaDB 10.2.3
|\n| | CHANGE MASTER (or 0 if none). |
|\n+---------------+---------------------------------------+-------------------+\n|
SQL_Remaining | When the replica is delaying the | MariaDB 10.2.3
|\n| Delay | execution of an event due to |
|\n| | MASTER_DELAY, this is the number of |
|\n| | seconds of delay remaining before |
|\n| | the event will be applied. |
|\n| | Otherwise, the value is NULL. |
|\n+---------------+---------------------------------------+-------------------+\n|
Slave_SQL_Run | The state of the SQL driver threads, | MariaDB 10.2.3
|\n| ing_State | same as in SHOW PROCESSLIST. When |
|\n| | the replica is delaying the |
|\n| | execution of an event due to |
|\n| | MASTER_DELAY, this field displays: |
|\n| | \"Waiting until MASTER_DELAY seconds
| |\n| | after master executed
event\". |
|\n+---------------+---------------------------------------+-------------------+\n|
Slave_DDL_Gro | This status variable counts the | MariaDB 10.3.7
|\n| ps | occurrence of DDL statements. This |
|\n| | is a replica-side counter for |
|\n| | optimistic parallel replication. |
|\n+---------------+---------------------------------------+-------------------+\n|
Slave_Non_Tra | This status variable counts the | MariaDB 10.3.7
|\n| sactional_Gro | occurrence of non-transactional |
|\n| ps | event groups. This is a |
|\n| | replica-side counter for optimistic |
|\n| | parallel replication. |
|\n+---------------+---------------------------------------+-------------------+\n|
Slave_Transac | This status variable counts the | MariaDB 10.3.7
|\n| ional_Groups | occurrence of transactional event |
|\n| | groups. This is a replica-side |
|\n| | counter for optimistic parallel |
|\n| | replication. |
|\n+---------------+---------------------------------------+-------------------+\n\nSHOW
REPLICA STATUS\n-------------------\n\nMariaDB starting with
10.5.1\n----------------------------\nSHOW REPLICA STATUS is an alias for
SHOW SLAVE STATUS from MariaDB 10.5.1.\n\nExamples\n--------\n\nIf you
issue this statement using the mysql client, you can use a \\G
statement\nterminator rather than a semicolon to obtain a more readable
vertical layout.\n\nSHOW SLAVE STATUS\\G\n*************************** 1.
row ***************************\n Slave_IO_State: Waiting for master
to send event\n Master_Host: db01.example.com\n
Master_User: replicant\n Master_Port: 3306\n Connect_Retry:
60\n Master_Log_File: mariadb-bin.000010\n Read_Master_Log_Pos:
548\n Relay_Log_File: relay-bin.000004\n Relay_Log_Pos: 837\n
Relay_Master_Log_File: mariadb-bin.000010\n Slave_IO_Running: Yes\n
Slave_SQL_Running: Yes\n Replicate_Do_DB:\n
Replicate_Ignore_DB:\n Replicate_Do_Table:\n
Replicate_Ignore_Table:\n Replicate_Wild_Do_Table:\n
Replicate_Wild_Ignore_Table:\n Last_Errno: 0\n
Last_Error:\n Skip_Counter: 0\n Exec_Master_Log_Pos: 548\n
Relay_Log_Space: 1497\n Until_Condition: None\n
Until_Log_File:\n Until_Log_Pos: 0\n Master_SSL_Allowed: No\n
Master_SSL_CA_File:\n Master_SSL_CA_Path:\n Master_SSL_Cert:\n
Master_SSL_Cipher:\n Master_SSL_Key:\n Seconds_Behind_Master:
0\nMaster_SSL_Verify_Server_Cert: No\n Last_IO_Errno: 0\n
Last_IO_Error:\n Last_SQL_Errno: 0\n Last_SQL_Error:\n
Replicate_Ignore_Server_Ids:\n Master_Server_Id: 101\n
Master_SSL_Crl:\n Master_SSL_Crlpath:\n Using_Gtid: No\n
Gtid_IO_Pos:\n\nSHOW ALL SLAVES STATUS\\G\n*************************** 1.
row ***************************\n Connection_name:\n
Slave_SQL_State: Slave has read all relay log; waiting for the\nslave I/O
thread to update it\n Slave_IO_State: Waiting for master to send
event\n Master_Host: db01.example.com\n Master_User:
replicant\n Master_Port: 3306\n Connect_Retry: 60\n
Master_Log_File: mariadb-bin.000010\n Read_Master_Log_Pos: 3608\n
Relay_Log_File: relay-bin.000004\n Relay_Log_Pos: 3897\n
Relay_Master_Log_File: mariadb-bin.000010\n Slave_IO_Running: Yes\n
Slave_SQL_Running: Yes\n Replicate_Do_DB:\n
Replicate_Ignore_DB:\n Replicate_Do_Table:\n
Replicate_Ignore_Table:\n Replicate_Wild_Do_Table:\n
Replicate_Wild_Ignore_Table:\n Last_Errno: 0\n
Last_Error:\n Skip_Counter: 0\n Exec_Master_Log_Pos: 3608\n
Relay_Log_Space: 4557\n Until_Condition: None\n
Until_Log_File:\n Until_Log_Pos: 0\n Master_SSL_Allowed: No\n
Master_SSL_CA_File:\n Master_SSL_CA_Path:\n Master_SSL_Cert:\n
Master_SSL_Cipher:\n Master_SSL_Key:\n Seconds_Behind_Master:
0\nMaster_SSL_Verify_Server_Cert: No\n Last_IO_Errno: 0\n
Last_IO_Error:\n Last_SQL_Errno: 0\n Last_SQL_Error:\n
Replicate_Ignore_Server_Ids:\n Master_Server_Id: 101\n
Master_SSL_Crl:\n Master_SSL_Crlpath:\n Using_Gtid: No\n
Gtid_IO_Pos:\n Retried_transactions: 0\n Max_relay_log_size:
104857600\n Executed_log_entries: 40\n Slave_received_heartbeats: 11\n
Slave_heartbeat_period: 1800.000\n Gtid_Slave_Pos: 0-101-2320\n\nYou
can also access some of the variables directly from status
variables:\n\nSET @@default_master_connection=\"test\" ;\nshow
status like \"%slave%\"\n\nVariable_name
Value\nCom_show_slave_hosts 0\nCom_show_slave_status
0\nCom_start_all_slaves 0\nCom_start_slave 0\nCom_stop_all_slaves
0\nCom_stop_slave 0\nRpl_semi_sync_slave_status
OFF\nSlave_connections 0\nSlave_heartbeat_period
1800.000\nSlave_open_temp_tables 0\nSlave_received_heartbeats
0\nSlave_retried_transactions 0\nSlave_running OFF\nSlaves_connected
0\nSlaves_running 1\n\nURL:
https://mariadb.com/kb/en/show-replica-status/') WHERE help_topic_id =
345;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(346,26,'SHOW MASTER STATUS','Syntax\n------\n\nSHOW MASTER
STATUS\nSHOW BINLOG STATUS -- From MariaDB
10.5.2\n\nDescription\n-----------\n\nProvides status information about the
binary log files of the primary.\n\nThis statement requires the SUPER
privilege, the REPLICATION_CLIENT privilege,\nor, from MariaDB 10.5.2, the
BINLOG MONITOR privilege.\n\nTo see information about the current GTIDs in
the binary log, use the\ngtid_binlog_pos variable.\n\nSHOW MASTER STATUS
was renamed to SHOW BINLOG STATUS in MariaDB 10.5.2, but\nthe old name
remains an alias for compatibility purposes.\n\nExample\n-------\n\nSHOW
MASTER
STATUS;\n+--------------------+----------+--------------+------------------+\n|
File | Position | Binlog_Do_DB | Binlog_Ignore_DB
|\n+--------------------+----------+--------------+------------------+\n|
mariadb-bin.000016 | 475 | |
|\n+--------------------+----------+--------------+------------------+\nSELECT
@@global.gtid_binlog_pos;\n+--------------------------+\n|
@@global.gtid_binlog_pos |\n+--------------------------+\n| 0-1-2
|\n+--------------------------+\n\nURL:
https://mariadb.com/kb/en/show-binlog-status/','','https://mariadb.com/kb/en/show-binlog-status/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(347,26,'SHOW SLAVE HOSTS','Syntax\n------\n\nSHOW SLAVE
HOSTS\nSHOW REPLICA HOSTS -- from MariaDB
10.5.1\n\nDescription\n-----------\n\nThis command is run on the primary
and displays a list of replicas that are\ncurrently registered with it.
Only replicas started with the\n--report-host=host_name option are visible
in this list.\n\nThe output looks like this:\n\nSHOW SLAVE
HOSTS;\n+------------+-----------+------+-----------+\n| Server_id | Host
| Port | Master_id |\n+------------+-----------+------+-----------+\n|
192168010 | iconnect2 | 3306 | 192168011 |\n| 1921680101 | athena | 3306
| 192168011 |\n+------------+-----------+------+-----------+\n\n*
Server_id: The unique server ID of the replica server, as configured in
the\nserver\'s option file, or on the command line with
--server-id=value.\n* Host: The host name of the replica server, as
configured in the server\'s\noption file, or on the command line with
--report-host=host_name. Note that\nthis can differ from the machine name
as configured in the operating system.\n* Port: The port the replica server
is listening on.\n* Master_id: The unique server ID of the primary server
that the replica\nserver is replicating from.\n\nSome MariaDB and MySQL
versions report another variable, rpl_recovery_rank.\nThis variable was
never used, and was eventually removed in MariaDB 10.1.2 .\n\nRequires the
REPLICATION MASTER ADMIN privilege (>= MariaDB 10.5.2) or
the\nREPLICATION SLAVE privilege (<= MariaDB 10.5.1).\n\nSHOW REPLICA
HOSTS\n------------------\n\nMariaDB starting with
10.5.1\n----------------------------\nSHOW REPLICA HOSTS is an alias for
SHOW SLAVE HOSTS from MariaDB 10.5.1.\n\nURL:
https://mariadb.com/kb/en/show-replica-hosts/','','https://mariadb.com/kb/en/show-replica-hosts/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(348,26,'SHOW PLUGINS','Syntax\n------\n\nSHOW
PLUGINS;\n\nDescription\n-----------\n\nSHOW PLUGINS displays information
about installed plugins. The Library column\nindicates the plugin library -
if it is NULL, the plugin is built-in and\ncannot be uninstalled.\n\nThe
PLUGINS table in the information_schema database contains more
detailed\ninformation.\n\nFor specific information about storage engines (a
particular type of plugin),\nsee the information_schema.ENGINES table and
the SHOW ENGINES statement.\n\nExamples\n--------\n\nSHOW
PLUGINS;\n+----------------------------+----------+--------------------+-------------+---\n-----+\n|
Name | Status | Type | Library
|\nLicense
|\n+----------------------------+----------+--------------------+-------------+---\n-----+\n|
binlog | ACTIVE | STORAGE ENGINE | NULL
|\nGPL |\n| mysql_native_password | ACTIVE | AUTHENTICATION
| NULL |\nGPL |\n| mysql_old_password | ACTIVE |
AUTHENTICATION | NULL |\nGPL |\n| MRG_MyISAM
| ACTIVE | STORAGE ENGINE | NULL |\nGPL |\n| MyISAM
| ACTIVE | STORAGE ENGINE | NULL |\nGPL |\n|
CSV | ACTIVE | STORAGE ENGINE | NULL
|\nGPL |\n| MEMORY | ACTIVE | STORAGE ENGINE
| NULL |\nGPL |\n| FEDERATED | ACTIVE |
STORAGE ENGINE | NULL |\nGPL |\n| PERFORMANCE_SCHEMA
| ACTIVE | STORAGE ENGINE | NULL |\nGPL |\n| Aria
| ACTIVE | STORAGE ENGINE | NULL |\nGPL |\n|
InnoDB | ACTIVE | STORAGE ENGINE | NULL
|\nGPL |\n| INNODB_TRX | ACTIVE | INFORMATION SCHEMA
| NULL |\nGPL |\n...\n| INNODB_SYS_FOREIGN | ACTIVE |
INFORMATION SCHEMA | NULL |\nGPL |\n| INNODB_SYS_FOREIGN_COLS
| ACTIVE | INFORMATION SCHEMA | NULL |\nGPL |\n| SPHINX
| ACTIVE | STORAGE ENGINE | NULL |\nGPL |\n|
ARCHIVE | ACTIVE | STORAGE ENGINE | NULL
|\nGPL |\n| BLACKHOLE | ACTIVE | STORAGE ENGINE
| NULL |\nGPL |\n| FEEDBACK | DISABLED |
INFORMATION SCHEMA | NULL |\nGPL |\n| partition
| ACTIVE | STORAGE ENGINE | NULL |\nGPL |\n| pam
| ACTIVE | AUTHENTICATION | auth_pam.so |\nGPL
|\n+----------------------------+----------+--------------------+-------------+---\n-----+\n\nURL:
https://mariadb.com/kb/en/show-plugins/','','https://mariadb.com/kb/en/show-plugins/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(349,26,'SHOW PLUGINS SONAME','Syntax\n------\n\nSHOW
PLUGINS SONAME { library | LIKE \'pattern\' | WHERE expr
};\n\nDescription\n-----------\n\nSHOW PLUGINS SONAME displays information
about compiled-in and all server\nplugins in the plugin_dir directory,
including plugins that haven\'t
been\ninstalled.\n\nExamples\n--------\n\nSHOW PLUGINS SONAME
\'ha_example.so\';\n+----------+---------------+----------------+---------------+---------+\n|
Name | Status | Type | Library | License
|\n+----------+---------------+----------------+---------------+---------+\n|
EXAMPLE | NOT INSTALLED | STORAGE ENGINE | ha_example.so | GPL |\n|
UNUSABLE | NOT INSTALLED | DAEMON | ha_example.so | GPL
|\n+----------+---------------+----------------+---------------+---------+\n\nThere
is also a corresponding information_schema table, called
ALL_PLUGINS,\nwhich contains more complete information.\n\nURL:
https://mariadb.com/kb/en/show-plugins-soname/','','https://mariadb.com/kb/en/show-plugins-soname/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(350,26,'SET','Syntax\n------\n\nSET variable_assignment [,
variable_assignment] ...\n\nvariable_assignment:\n user_var_name = expr\n
| [GLOBAL | SESSION] system_var_name = expr\n | [@@global. | @@session. |
@@]system_var_name = expr\n\nOne can also set a user variable in any
expression with this syntax:\n\nuser_var_name:=
expr\n\nDescription\n-----------\n\nThe SET statement assigns values to
different types of variables that affect\nthe operation of the server or
your client. Older versions of MySQL employed\nSET OPTION, but this syntax
was deprecated in favor of SET without OPTION, and\nwas removed in MariaDB
10.0.\n\nChanging a system variable by using the SET statement does not
make the change\npermanently. To do so, the change must be made in a
configuration file.\n\nFor setting variables on a per-query basis, see SET
STATEMENT.\n\nSee SHOW VARIABLES for documentation on viewing server system
variables.\n\nSee Server System Variables for a list of all the system
variables.\n\nGLOBAL / SESSION\n----------------\n\nWhen setting a system
variable, the scope can be specified as either GLOBAL or\nSESSION.\n\nA
global variable change affects all new sessions. It does not affect
any\ncurrently open sessions, including the one that made the change.\n\nA
session variable change affects the current session only.\n\nIf the
variable has a session value, not specifying either GLOBAL or SESSION\nwill
be the same as specifying SESSION. If the variable only has a
global\nvalue, not specifying GLOBAL or SESSION will apply to the change to
the global\nvalue.\n\nDEFAULT\n-------\n\nSetting a global variable to
DEFAULT will restore it to the server default,\nand setting a session
variable to DEFAULT will restore it to the current\nglobal
value.\n\nExamples\n--------\n\n* innodb_sync_spin_loops is a global
variable.\n* skip_parallel_replication is a session variable.\n*
max_error_count is both global and session.\n\nSELECT VARIABLE_NAME,
SESSION_VALUE, GLOBAL_VALUE FROM\n INFORMATION_SCHEMA.SYSTEM_VARIABLES
WHERE \n VARIABLE_NAME IN (\'max_error_count\',
\'skip_parallel_replication\',\n\'innodb_sync_spin_loops\');\n+---------------------------+---------------+--------------+\n|
VARIABLE_NAME | SESSION_VALUE | GLOBAL_VALUE
|\n+---------------------------+---------------+--------------+\n|
MAX_ERROR_COUNT | 64 | 64 |\n|
SKIP_PARALLEL_REPLICATION | OFF | NULL |\n|
INNODB_SYNC_SPIN_LOOPS | NULL | 30
|\n+---------------------------+---------------+--------------+\n\nSetting
the session values:\n\nSET max_error_count=128;Query OK, 0 rows affected
(0.000 sec)\n\nSET skip_parallel_replication=ON;Query OK, 0 rows affected
(0.000 sec)\n\nSET innodb_sync_spin_loops=60;\nERROR 1229 (HY000): Variable
\'innodb_sync_spin_loops\' is a GLOBAL variable \n and should be
set with SET GLOBAL\n\nSELECT VARIABLE_NAME, SESSION_VALUE, GLOBAL_VALUE
FROM\n INFORMATION_SCHEMA.SYSTEM_VARIABLES WHERE \n VARIABLE_NAME IN
(\'max_error_count\',
\'skip_parallel_replication\',\n\'innodb_sync_spin_loops\');\n+---------------------------+---------------+--------------+\n|
VARIABLE_NAME | SESSION_VALUE | GLOBAL_VALUE
|\n+---------------------------+---------------+--------------+\n|
MAX_ERROR_COUNT | 128 | 64 |\n|
SKIP_PARALLEL_REPLICATION | ON | NULL |\n|
INNODB_SYNC_SPIN_LOOPS | NULL | 30
|\n+---------------------------+---------------+--------------+\n\nSetting
the global values:\n\nSET GLOBAL max_error_count=256;\n\nSET GLOBAL
skip_parallel_replication=ON;\nERROR 1228 (HY000): Variable
\'skip_parallel_replication\' is a SESSION variable \n and
can\'t be used with SET GLOBAL\n\nSET GLOBAL
innodb_sync_spin_loops=120;\n\nSELECT VARIABLE_NAME, SESSION_VALUE,
GLOBAL_VALUE FROM\n INFORMATION_SCHEMA.SYSTEM_VARIABLES WHERE \n
VARIABLE_NAME IN (\'max_error_count\',
\'skip_parallel_replication\',\n\'innodb_sync_spin_loops\');\n+---------------------------+---------------+--------------+\n|
VARIABLE_NAME | SESSION_VALUE | GLOBAL_VALUE
|\n+---------------------------+---------------+--------------+\n|
MAX_ERROR_COUNT | 128 | 256 |\n|
SKIP_PARALLEL_REPLICATION | ON | NULL |\n|
INNODB_SYNC_SPIN_LOOPS | NULL | 120
|\n+---------------------------+---------------+--------------+\n\nSHOW
VARIABLES will by default return the session value unless the variable
is\nglobal only.\n\nSHOW VARIABLES LIKE
\'max_error_count\';\n+-----------------+-------+\n|
Variable_name | Value |\n+-----------------+-------+\n| max_error_count |
128 |\n+-----------------+-------+\n\nSHOW VARIABLES LIKE
\'skip_parallel_replication\';\n+---------------------------+-------+\n|
Variable_name | Value
|\n+---------------------------+-------+\n| skip_parallel_replication | ON
|\n+---------------------------+-------+\n\nSHOW VARIABLES LIKE
\'innodb_sync_spin_loops\';\n+------------------------+-------+\n|
Variable_name | Value |\n+------------------------+-------+\n|
innodb_sync_spin_loops | 120
|\n+------------------------+-------+\n\nUsing the inplace
syntax:\n\nSELECT (@a:=1);\n+---------+\n| (@a:=1) |\n+---------+\n|
1 |\n+---------+\n\nSELECT @a;\n+------+\n| @a |\n+------+\n| 1
|\n+------+\n\nURL:
https://mariadb.com/kb/en/set/','','https://mariadb.com/kb/en/set/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(351,26,'SET CHARACTER SET','Syntax\n------\n\nSET
{CHARACTER SET | CHARSET}\n {charset_name |
DEFAULT}\n\nDescription\n-----------\n\nSets the character_set_client and
character_set_results session system\nvariables to the specified character
set and collation_connection to the value\nof collation_database, which
implicitly sets character_set_connection to the\nvalue of
character_set_database.\n\nThis maps all strings sent between the current
client and the server with the\ngiven mapping.\n\nExample\n-------\n\nSHOW
VARIABLES LIKE
\'character_set\\_%\';\n+--------------------------+--------+\n|
Variable_name | Value
|\n+--------------------------+--------+\n| character_set_client | utf8
|\n| character_set_connection | utf8 |\n| character_set_database |
latin1 |\n| character_set_filesystem | binary |\n| character_set_results
| utf8 |\n| character_set_server | latin1 |\n| character_set_system
| utf8 |\n+--------------------------+--------+\n\nSHOW VARIABLES LIKE
\'collation%\';\n+----------------------+-------------------+\n|
Variable_name | Value
|\n+----------------------+-------------------+\n| collation_connection |
utf8_general_ci |\n| collation_database | latin1_swedish_ci |\n|
collation_server | latin1_swedish_ci
|\n+----------------------+-------------------+\n\nSET CHARACTER SET
utf8mb4;\n\nSHOW VARIABLES LIKE
\'character_set\\_%\';\n+--------------------------+---------+\n|
Variable_name | Value
|\n+--------------------------+---------+\n| character_set_client |
utf8mb4 |\n| character_set_connection | latin1 |\n| character_set_database
| latin1 |\n| character_set_filesystem | binary |\n|
character_set_results | utf8mb4 |\n| character_set_server | latin1
|\n| character_set_system | utf8
|\n+--------------------------+---------+\n\nSHOW VARIABLES LIKE
\'collation%\';\n+----------------------+-------------------+\n|
Variable_name | Value
|\n+----------------------+-------------------+\n| collation_connection |
latin1_swedish_ci |\n| collation_database | latin1_swedish_ci |\n|
collation_server | latin1_swedish_ci
|\n+----------------------+-------------------+\n\nURL:
https://mariadb.com/kb/en/set-character-set/','','https://mariadb.com/kb/en/set-character-set/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(352,26,'SET NAMES','Syntax\n------\n\nSET NAMES
{\'charset_name\'\n [COLLATE \'collation_name\'] |
DEFAULT}\n\nDescription\n-----------\n\nSets the character_set_client,
character_set_connection, character_set_results\nand, implicitly, the
collation_connection session system variables to the\nspecified character
set and collation.\n\nThis determines which character set the client will
use to send statements to\nthe server, and the server will use for sending
results back to the client.\n\nucs2, utf16, utf16le and utf32 are not valid
character sets for SET NAMES, as\nthey cannot be used as client character
sets.\n\nThe collation clause is optional. If not defined (or if DEFAULT is
specified),\nthe default collation for the character set will be
used.\n\nQuotes are optional for the character set or collation
clauses.\n\nExamples\n--------\n\nSELECT VARIABLE_NAME, SESSION_VALUE \n
FROM INFORMATION_SCHEMA.SYSTEM_VARIABLES WHERE\n VARIABLE_NAME LIKE
\'character_set_c%\' OR\n VARIABLE_NAME LIKE
\'character_set_re%\' OR\n VARIABLE_NAME LIKE
\'collation_c%\';\n+--------------------------+-----------------+\n|
VARIABLE_NAME | SESSION_VALUE
|\n+--------------------------+-----------------+\n| CHARACTER_SET_RESULTS
| utf8 |\n| CHARACTER_SET_CONNECTION | utf8 |\n|
CHARACTER_SET_CLIENT | utf8 |\n| COLLATION_CONNECTION |
utf8_general_ci |\n+--------------------------+-----------------+\n\nSET
NAMES big5;\n\nSELECT VARIABLE_NAME, SESSION_VALUE \n FROM
INFORMATION_SCHEMA.SYSTEM_VARIABLES WHERE\n VARIABLE_NAME LIKE
\'character_set_c%\' OR\n VARIABLE_NAME LIKE
\'character_set_re%\' OR\n VARIABLE_NAME LIKE
\'collation_c%\';\n+--------------------------+-----------------+\n|
VARIABLE_NAME | SESSION_VALUE
|\n+--------------------------+-----------------+\n| CHARACTER_SET_RESULTS
| big5 |\n| CHARACTER_SET_CONNECTION | big5 |\n|
CHARACTER_SET_CLIENT | big5 |\n| COLLATION_CONNECTION |
big5_chinese_ci |\n+--------------------------+-----------------+\n\nSET
NAMES \'latin1\' COLLATE \'latin1_bin\';\n\nSELECT
VARIABLE_NAME, SESSION_VALUE \n FROM INFORMATION_SCHEMA.SYSTEM_VARIABLES
WHERE\n VARIABLE_NAME LIKE \'character_set_c%\' OR\n
VARIABLE_NAME LIKE \'character_set_re%\' OR\n VARIABLE_NAME LIKE
\'collation_c%\';\n+--------------------------+---------------+\n|
VARIABLE_NAME | SESSION_VALUE
|\n+--------------------------+---------------+\n| CHARACTER_SET_RESULTS
| latin1 |\n| CHARACTER_SET_CONNECTION | latin1 |\n|
CHARACTER_SET_CLIENT | latin1 |\n| COLLATION_CONNECTION |
latin1_bin |\n+--------------------------+---------------+\n\nSET NAMES
DEFAULT;\n\nSELECT VARIABLE_NAME, SESSION_VALUE \n FROM
INFORMATION_SCHEMA.SYSTEM_VARIABLES WHERE\n VARIABLE_NAME LIKE
\'character_set_c%\' OR\n VARIABLE_NAME LIKE
\'character_set_re%\' OR\n VARIABLE_NAME LIKE
\'collation_c%\';\n+--------------------------+-------------------+\n|
VARIABLE_NAME | SESSION_VALUE
|\n+--------------------------+-------------------+\n|
CHARACTER_SET_RESULTS | latin1 |\n| CHARACTER_SET_CONNECTION
| latin1 |\n| CHARACTER_SET_CLIENT | latin1 |\n|
COLLATION_CONNECTION | latin1_swedish_ci
|\n+--------------------------+-------------------+\n\nURL:
https://mariadb.com/kb/en/set-names/','','https://mariadb.com/kb/en/set-names/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(353,26,'SET SQL_LOG_BIN','Syntax\n------\n\nSET [SESSION]
sql_log_bin = {0|1}\n\nDescription\n-----------\n\nSets the sql_log_bin
system variable, which disables or enables binary logging\nfor the current
connection, if the client has the SUPER privilege. The\nstatement is
refused with an error if the client does not have that privilege.\n\nBefore
MariaDB 5.5 and before MySQL 5.6 one could also set sql_log_bin as
a\nglobal variable. This was disabled as this was too dangerous as it
could\ndamage replication.\n\nURL:
https://mariadb.com/kb/en/set-sql_log_bin/','','https://mariadb.com/kb/en/set-sql_log_bin/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(354,26,'SET STATEMENT','MariaDB starting with
10.1.2\n----------------------------\nPer-query variables were introduced
in MariaDB 10.1.2\n\nSET STATEMENT can be used to set the value of a system
variable for the\nduration of the statement. It is also possible to set
multiple variables.\n\nSyntax\n------\n\nSET STATEMENT var1=value1 [,
var2=value2, ...] \n FOR <statement>\n\nwhere varN is a system
variable (list of allowed variables is provided below),\nand valueN is a
constant literal.\n\nDescription\n-----------\n\nSET STATEMENT var1=value1
FOR stmt\n\nis roughly equivalent to\n\nSET @save_value=@@var1;\nSET
SESSION var1=value1;\nstmt;\nSET SESSION var1=@save_value;\n\nThe server
parses the whole statement before executing it, so any variables\nset in
this fashion that affect the parser may not have the expected
effect.\nExamples include the charset variables, sql_mode=ansi_quotes,
etc.\n\nExamples\n--------\n\nOne can limit statement execution time
max_statement_time:\n\nSET STATEMENT max_statement_time=1000 FOR SELECT ...
;\n\nOne can switch on/off individual optimizations:\n\nSET STATEMENT
optimizer_switch=\'materialization=off\' FOR SELECT ....;\n\nIt
is possible to enable MRR/BKA for a query:\n\nSET STATEMENT
join_cache_level=6, optimizer_switch=\'mrr=on\' FOR SELECT
...\n\nNote that it makes no sense to try to set a session variable inside
a SET\nSTATEMENT:\n\n#USELESS STATEMENT\nSET STATEMENT sort_buffer_size =
100000 for SET SESSION sort_buffer_size =\n200000;\n\nFor the above, after
setting sort_buffer_size to 200000 it will be reset to\nits original state
(the state before the SET STATEMENT started) after the\nstatement
execution.\n\nLimitations\n-----------\n\nThere are a number of variables
that cannot be set on per-query basis. These\ninclude:\n\n* autocommit\n*
character_set_client\n* character_set_connection\n*
character_set_filesystem\n* collation_connection\n*
default_master_connection\n* debug_sync\n* interactive_timeout\n*
gtid_domain_id\n* last_insert_id\n* log_slow_filter\n*
log_slow_rate_limit\n* log_slow_verbosity\n* long_query_time\n*
min_examined_row_limit\n* profiling\n* profiling_history_size\n*
query_cache_type\n* rand_seed1\n* rand_seed2\n* skip_replication\n*
slow_query_log\n* sql_log_off\n* tx_isolation\n*
wait_timeout\n\nSource\n------\n\n* The feature was originally implemented
as a Google Summer of Code 2009\nproject by Joseph Lukas. \n* Percona
Server 5.6 included it as Per-query variable statement\n* MariaDB ported
the patch and fixed many bugs. The task in MariaDB Jira
is\nMDEV-5231.\n\nURL:
https://mariadb.com/kb/en/set-statement/','','https://mariadb.com/kb/en/set-statement/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(355,26,'SET Variable','Syntax\n------\n\nSET var_name =
expr [, var_name = expr] ...\n\nDescription\n-----------\n\nThe SET
statement in stored programs is an extended version of the general
SET\nstatement. Referenced variables may be ones declared inside a stored
program,\nglobal system variables, or user-defined variables.\n\nThe SET
statement in stored programs is implemented as part of the\npre-existing
SET syntax. This allows an extended syntax of SET a=x, b=y, ...\nwhere
different variable types (locally declared variables, global and
session\nserver variables, user-defined variables) can be mixed. This also
allows\ncombinations of local variables and some options that make sense
only for\nsystem variables; in that case, the options are recognized but
ignored.\n\nSET can be used with both local variables and user-defined
variables.\n\nWhen setting several variables using the columns returned by
a query, SELECT\nINTO should be preferred.\n\nTo set many variables to the
same value, the LAST_VALUE( ) function can be\nused.\n\nBelow is an example
of how a user-defined variable may be set:\n\nSET @x = 1;\n\nURL:
https://mariadb.com/kb/en/set-variable/','','https://mariadb.com/kb/en/set-variable/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(356,26,'About SHOW','SHOW has many forms that provide
information about databases, tables, columns,\nor status information about
the server. These include:\n\n* SHOW AUTHORS\n* SHOW CHARACTER SET
[like_or_where]\n* SHOW COLLATION [like_or_where]\n* SHOW [FULL] COLUMNS
FROM tbl_name [FROM db_name] [like_or_where]\n* SHOW CONTRIBUTORS\n* SHOW
CREATE DATABASE db_name\n* SHOW CREATE EVENT event_name\n* SHOW CREATE
PACKAGE package_name\n* SHOW CREATE PACKAGE BODY package_name\n* SHOW
CREATE PROCEDURE proc_name\n* SHOW CREATE TABLE tbl_name\n* SHOW CREATE
TRIGGER trigger_name\n* SHOW CREATE VIEW view_name\n* SHOW DATABASES
[like_or_where]\n* SHOW ENGINE engine_name {STATUS | MUTEX}\n* SHOW
[STORAGE] ENGINES\n* SHOW ERRORS [LIMIT [offset,] row_count]\n* SHOW [FULL]
EVENTS\n* SHOW FUNCTION CODE func_name\n* SHOW FUNCTION STATUS
[like_or_where]\n* SHOW GRANTS FOR user\n* SHOW INDEX FROM tbl_name [FROM
db_name]\n* SHOW INNODB STATUS\n* SHOW OPEN TABLES [FROM db_name]
[like_or_where]\n* SHOW PLUGINS\n* SHOW PROCEDURE CODE proc_name\n* SHOW
PROCEDURE STATUS [like_or_where]\n* SHOW PRIVILEGES\n* SHOW [FULL]
PROCESSLIST\n* SHOW PROFILE [types] [FOR QUERY n] [OFFSET n] [LIMIT n]\n*
SHOW PROFILES\n* SHOW [GLOBAL | SESSION] STATUS [like_or_where]\n* SHOW
TABLE STATUS [FROM db_name] [like_or_where]\n* SHOW TABLES [FROM db_name]
[like_or_where]\n* SHOW TRIGGERS [FROM db_name] [like_or_where]\n* SHOW
[GLOBAL | SESSION] VARIABLES [like_or_where]\n* SHOW WARNINGS [LIMIT
[offset,] row_count]\n\nlike_or_where:\n LIKE \'pattern\'\n |
WHERE expr\n\nIf the syntax for a given SHOW statement includes a LIKE
\'pattern\' part,\n\'pattern\' is a string that can
contain the SQL \"%\" and \"_\" wildcard\ncharacters.
The pattern is useful for restricting statement output to
matching\nvalues.\n\nSeveral SHOW statements also accept a WHERE clause
that provides more\nflexibility in specifying which rows to display. See
Extended Show.\n\nURL:
https://mariadb.com/kb/en/about-show/','','https://mariadb.com/kb/en/about-show/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(357,26,'Extended Show','The following SHOW statements can
be extended by using a WHERE clause and a\nLIKE clause to refine the
results:\n\n* SHOW CHARACTER SET\n* SHOW COLLATION\n* SHOW COLUMNS\n* SHOW
DATABASES\n* SHOW FUNCTION STATUS\n* SHOW INDEX\n* SHOW OPEN TABLES\n* SHOW
PACKAGE STATUS\n* SHOW PACKAGE BODY STATUS\n* SHOW INDEX\n* SHOW PROCEDURE
STATUS\n* SHOW STATUS\n* SHOW TABLE STATUS\n* SHOW TABLES\n* SHOW
TRIGGERS\n* SHOW VARIABLES\n\nAs with a regular SELECT, the WHERE clause
can be used for the specific\ncolumns returned, and the LIKE clause with
the regular wildcards.\n\nExamples\n--------\n\nSHOW
TABLES;\n+----------------------+\n| Tables_in_test
|\n+----------------------+\n| animal_count |\n| animals
|\n| are_the_mooses_loose |\n| aria_test2 |\n| t1
|\n| view1 |\n+----------------------+\n\nShowing the
tables beginning with a only.\n\nSHOW TABLES WHERE Tables_in_test LIKE
\'a%\';\n+----------------------+\n| Tables_in_test
|\n+----------------------+\n| animal_count |\n| animals
|\n| are_the_mooses_loose |\n| aria_test2
|\n+----------------------+\n\nVariables whose name starts with aria and
with a valued of greater than 8192:\n\nSHOW VARIABLES WHERE Variable_name
LIKE \'aria%\' AND Value
>8192;\n+------------------------------+---------------------+\n|
Variable_name | Value
|\n+------------------------------+---------------------+\n|
aria_checkpoint_log_activity | 1048576 |\n| aria_log_file_size
| 1073741824 |\n| aria_max_sort_file_size |
9223372036853727232 |\n| aria_pagecache_buffer_size | 134217728
|\n| aria_sort_buffer_size | 134217728
|\n+------------------------------+---------------------+\n\nShortcut, just
returning variables whose name begins with aria.\n\nSHOW VARIABLES LIKE
\'aria%\';\n+------------------------------------------+---------------------+\n|
Variable_name | Value
|\n+------------------------------------------+---------------------+\n|
aria_block_size | 8192 |\n|
aria_checkpoint_interval | 30 |\n|
aria_checkpoint_log_activity | 1048576 |\n|
aria_force_start_after_recovery_failures | 0 |\n|
aria_group_commit | none |\n|
aria_group_commit_interval | 0 |\n|
aria_log_file_size | 1073741824 |\n|
aria_log_purge_type | immediate |\n|
aria_max_sort_file_size | 9223372036853727232 |\n|
aria_page_checksum | ON |\n|
aria_pagecache_age_threshold | 300 |\n|
aria_pagecache_buffer_size | 134217728 |\n|
aria_pagecache_division_limit | 100 |\n|
aria_recover | NORMAL |\n|
aria_repair_threads | 1 |\n|
aria_sort_buffer_size | 134217728 |\n|
aria_stats_method | nulls_unequal |\n|
aria_sync_log_dir | NEWFILE |\n|
aria_used_for_temp_tables | ON
|\n+------------------------------------------+---------------------+\n\nURL:
https://mariadb.com/kb/en/extended-show/','','https://mariadb.com/kb/en/extended-show/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(358,26,'SHOW AUTHORS','Syntax\n------\n\nSHOW
AUTHORS\n\nDescription\n-----------\n\nThe SHOW AUTHORS statement displays
information about the people who work on\nMariaDB. For each author, it
displays Name, Location, and Comment values. All\ncolumns are encoded as
latin1.\n\nThese include:\n\n* First the active people in MariaDB are
listed.\n* Then the active people in MySQL.\n* Last the people that have
contributed to MariaDB/MySQL in the past.\n\nThe order is somewhat related
to importance of the contribution given to the\nMariaDB project, but this
is not 100% accurate. There is still room for\nimprovement and
debate...\n\nExample\n-------\n\nSHOW
AUTHORS\\G\n*************************** 1. row
***************************\n Name: Michael (Monty) Widenius\nLocation:
Tusby, Finland\n Comment: Lead developer and main
author\n*************************** 2. row ***************************\n
Name: Sergei Golubchik\nLocation: Kerpen, Germany\n Comment: Architect,
Full-text search, precision math, plugin framework,\nmerges
etc\n*************************** 3. row ***************************\n
Name: Igor Babaev\nLocation: Bellevue, USA\n Comment: Optimizer, keycache,
core work\n*************************** 4. row ***************************\n
Name: Sergey Petrunia\nLocation: St. Petersburg, Russia\n Comment:
Optimizer\n*************************** 5. row ***************************\n
Name: Oleksandr Byelkin\nLocation: Lugansk, Ukraine\n Comment: Query Cache
(4.0), Subqueries (4.1), Views (5.0)\n*************************** 6. row
***************************\n Name: Timour Katchaounov\nLocation: Sofia ,
Bulgaria\n Comment: Optimizer\n*************************** 7. row
***************************\n Name: Kristian Nielsen\nLocation:
Copenhagen, Denmark\n Comment: Replication, Async client prototocol,
General buildbot stuff\n*************************** 8. row
***************************\n Name: Alexander (Bar) Barkov\nLocation:
Izhevsk, Russia\n Comment: Unicode and character
sets\n*************************** 9. row ***************************\n
Name: Alexey Botchkov (Holyfoot)\nLocation: Izhevsk, Russia\n Comment: GIS
extensions, embedded server, precision math\n***************************
10. row ***************************\n Name: Daniel Bartholomew\nLocation:
Raleigh, USA\n Comment: MariaDB documentation, Buildbot,
releases\n*************************** 11. row ***************************\n
Name: Colin Charles\nLocation: Selangor, Malesia\n Comment: MariaDB
documentation, talks at a LOT of conferences\n***************************
12. row ***************************\n Name: Sergey Vojtovich\nLocation:
Izhevsk, Russia\n Comment: initial implementation of plugin architecture,
maintained native\nstorage engines (MyISAM, MEMORY, ARCHIVE, etc), rewrite
of table cache\n*************************** 13. row
***************************\n Name: Vladislav Vaintroub\nLocation:
Mannheim, Germany\n Comment: MariaDB Java connector, new thread pool,
Windows optimizations\n*************************** 14. row
***************************\n Name: Elena Stepanova\nLocation: Sankt
Petersburg, Russia\n Comment: QA, test cases\n***************************
15. row ***************************\n Name: Georg Richter\nLocation:
Heidelberg, Germany\n Comment: New LGPL C connector, PHP
connector\n*************************** 16. row
***************************\n Name: Jan Lindström\nLocation: Ylämylly,
Finland\n Comment: Working on InnoDB\n*************************** 17. row
***************************\n Name: Lixun Peng\nLocation: Hangzhou,
China\n Comment: Multi Source replication\n*************************** 18.
row ***************************\n Name: Olivier Bertrand\nLocation: Paris,
France\n Comment: CONNECT storage engine\n*************************** 19.
row ***************************\n Name: Kentoku Shiba\nLocation: Tokyo,
Japan\n Comment: Spider storage engine, metadata_lock_info Information
schema\n*************************** 20. row ***************************\n
Name: Percona\nLocation: CA, USA\n Comment: XtraDB, microslow patches,
extensions to slow log\n*************************** 21. row
***************************\n Name: Vicentiu Ciorbaru\nLocation:
Bucharest, Romania\n Comment: Roles\n*************************** 22. row
***************************\n Name: Sudheera Palihakkara\nLocation: \n
Comment: PCRE Regular Expressions\n*************************** 23. row
***************************\n Name: Pavel Ivanov\nLocation: USA\n Comment:
Some patches and bug fixes\n*************************** 24. row
***************************\n Name: Konstantin Osipov\nLocation: Moscow,
Russia\n Comment: Prepared statements (4.1), Cursors (5.0), GET_LOCK
(10.0)\n*************************** 25. row ***************************\n
Name: Ian Gilfillan\nLocation: South Africa\n Comment: MariaDB
documentation\n*************************** 26. row
***************************\n Name: Federico Razolli\nLocation: Italy\n
Comment: MariaDB documentation Italian
translation\n*************************** 27. row
***************************\n Name: Guilhem Bichot\nLocation: Bordeaux,
France\n Comment: Replication (since 4.0)\n*************************** 28.
row ***************************\n Name: Andrei Elkin\nLocation: Espoo,
Finland\n Comment: Replication\n*************************** 29. row
***************************\n Name: Dmitri Lenev\nLocation: Moscow,
Russia\n Comment: Time zones support (4.1), Triggers
(5.0)\n*************************** 30. row ***************************\n
Name: Marc Alff\nLocation: Denver, CO, USA\n Comment: Signal, Resignal,
Performance schema\n*************************** 31. row
***************************\n Name: Mikael Ronström\nLocation: Stockholm,
Sweden\n Comment: NDB Cluster, Partitioning, online alter
table\n*************************** 32. row ***************************\n
Name: Ingo Strüwing\nLocation: Berlin, Germany\n Comment: Bug fixing in
MyISAM, Merge tables etc\n*************************** 33. row
***************************\n Name: Marko Mäkelä\nLocation: Helsinki,
Finland\n Comment: InnoDB core developer\n...\n\nURL:
https://mariadb.com/kb/en/show-authors/','','https://mariadb.com/kb/en/show-authors/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(359,26,'SHOW BINARY LOGS','Syntax\n------\n\nSHOW BINARY
LOGS\nSHOW MASTER LOGS\n\nDescription\n-----------\n\nLists the binary log
files on the server. This statement is used as part of\nthe procedure
described in PURGE BINARY LOGS, that shows how to determine\nwhich logs can
be purged.\n\nThis statement requires the SUPER privilege, the
REPLICATION_CLIENT privilege,\nor, from MariaDB 10.5.2, the BINLOG MONITOR
privilege.\n\nExamples\n--------\n\nSHOW BINARY
LOGS;\n+--------------------+-----------+\n| Log_name | File_size
|\n+--------------------+-----------+\n| mariadb-bin.000001 | 19039
|\n| mariadb-bin.000002 | 717389 |\n| mariadb-bin.000003 | 300
|\n| mariadb-bin.000004 | 333 |\n| mariadb-bin.000005 | 899
|\n| mariadb-bin.000006 | 125 |\n| mariadb-bin.000007 | 18907
|\n| mariadb-bin.000008 | 19530 |\n| mariadb-bin.000009 | 151
|\n| mariadb-bin.000010 | 151 |\n| mariadb-bin.000011 | 125
|\n| mariadb-bin.000012 | 151 |\n| mariadb-bin.000013 | 151
|\n| mariadb-bin.000014 | 125 |\n| mariadb-bin.000015 | 151
|\n| mariadb-bin.000016 | 314
|\n+--------------------+-----------+\n\nURL:
https://mariadb.com/kb/en/show-binary-logs/','','https://mariadb.com/kb/en/show-binary-logs/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(360,26,'SHOW BINLOG EVENTS','Syntax\n------\n\nSHOW BINLOG
EVENTS\n [IN \'log_name\'] [FROM pos] [LIMIT [offset,]
row_count]\n\nDescription\n-----------\n\nShows the events in the binary
log. If you do not specify \'log_name\', the\nfirst binary log is
displayed.\n\nRequires the BINLOG MONITOR privilege (>= MariaDB 10.5.2)
or the REPLICATION\nSLAVE privilege (<= MariaDB
10.5.1).\n\nExample\n-------\n\nSHOW BINLOG EVENTS IN
\'mysql_sandbox10019-bin.000002\';\n+-------------------------------+-----+-------------------+-----------+--------\n----+------------------------------------------------+\n|
Log_name | Pos | Event_type | Server_id
|\nEnd_log_pos | Info
|\n+-------------------------------+-----+-------------------+-----------+--------\n----+------------------------------------------------+\n|
mysql_sandbox10019-bin.000002 | 4 | Format_desc | 1 |
\n 248 | Server ver: 10.0.19-MariaDB-log, Binlog ver: 4 |\n|
mysql_sandbox10019-bin.000002 | 248 | Gtid_list | 1 |
\n 273 | [] |\n|
mysql_sandbox10019-bin.000002 | 273 | Binlog_checkpoint | 1 |
\n 325 | mysql_sandbox10019-bin.000002 |\n|
mysql_sandbox10019-bin.000002 | 325 | Gtid | 1 |
\n 363 | GTID 0-1-1 |\n|
mysql_sandbox10019-bin.000002 | 363 | Query | 1 |
\n 446 | CREATE DATABASE blog |\n|
mysql_sandbox10019-bin.000002 | 446 | Gtid | 1 |
\n 484 | GTID 0-1-2 |\n|
mysql_sandbox10019-bin.000002 | 484 | Query | 1 |
\n 571 | use `blog`; CREATE TABLE bb (id INT)
|\n+-------------------------------+-----+-------------------+-----------+--------\n----+------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/show-binlog-events/','','https://mariadb.com/kb/en/show-binlog-events/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(361,26,'SHOW CHARACTER SET','Syntax\n------\n\nSHOW
CHARACTER SET\n [LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nThe SHOW CHARACTER SET statement shows
all available character sets. The LIKE\nclause, if present on its own,
indicates which character set names to match.\nThe WHERE and LIKE clauses
can be given to select rows using more general\nconditions, as discussed in
Extended SHOW.\n\nThe same information can be queried from the Information
Schema CHARACTER_SETS\ntable.\n\nSee Setting Character Sets and Collations
for details on specifying the\ncharacter set at the server, database, table
and column levels.\n\nExamples\n--------\n\nSHOW CHARACTER SET LIKE
\'latin%\';\n+---------+-----------------------------+-------------------+--------+\n|
Charset | Description | Default collation | Maxlen
|\n+---------+-----------------------------+-------------------+--------+\n|
latin1 | cp1252 West European | latin1_swedish_ci | 1 |\n|
latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 |\n|
latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 |\n|
latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1
|\n+---------+-----------------------------+-------------------+--------+\n\nSHOW
CHARACTER SET WHERE Maxlen LIKE
\'2\';\n+---------+---------------------------+-------------------+--------+\n|
Charset | Description | Default collation | Maxlen
|\n+---------+---------------------------+-------------------+--------+\n|
big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 |\n| sjis
| Shift-JIS Japanese | sjis_japanese_ci | 2 |\n| euckr |
EUC-KR Korean | euckr_korean_ci | 2 |\n| gb2312 |
GB2312 Simplified Chinese | gb2312_chinese_ci | 2 |\n| gbk | GBK
Simplified Chinese | gbk_chinese_ci | 2 |\n| ucs2 | UCS-2
Unicode | ucs2_general_ci | 2 |\n| cp932 | SJIS for
Windows Japanese | cp932_japanese_ci | 2
|\n+---------+---------------------------+-------------------+--------+\n\nURL:
https://mariadb.com/kb/en/show-character-set/','','https://mariadb.com/kb/en/show-character-set/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(362,26,'SHOW CLIENT_STATISTICS','Syntax\n------\n\nSHOW
CLIENT_STATISTICS\n\nDescription\n-----------\n\nThe SHOW CLIENT_STATISTICS
statement is part of the User Statistics feature.\nIt was removed as a
separate statement in MariaDB 10.1.1, but effectively\nreplaced by the
generic SHOW information_schema_table statement.
The\ninformation_schema.CLIENT_STATISTICS table holds statistics about
client\nconnections.\n\nThe userstat system variable must be set to 1 to
activate this feature. See\nthe User Statistics and
information_schema.CLIENT_STATISTICS articles for
more\ninformation.\n\nExample\n-------\n\nSHOW
CLIENT_STATISTICS\\G\n*************************** 1. row
***************************\n Client: localhost\n
Total_connections: 35\nConcurrent_connections: 0\n Connected_time: 708\n
Busy_time: 2.5557979999999985\n Cpu_time: 0.04123740000000002\n
Bytes_received: 3883\n Bytes_sent: 21595\n Binlog_bytes_written: 0\n
Rows_read: 18\n Rows_sent: 115\n Rows_deleted: 0\n
Rows_inserted: 0\n Rows_updated: 0\n Select_commands: 70\n
Update_commands: 0\n Other_commands: 0\n Commit_transactions: 1\n
Rollback_transactions: 0\n Denied_connections: 0\n Lost_connections: 0\n
Access_denied: 0\n Empty_queries: 35\n\nURL:
https://mariadb.com/kb/en/show-client-statistics/','','https://mariadb.com/kb/en/show-client-statistics/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(363,26,'SHOW CONTRIBUTORS','Syntax\n------\n\nSHOW
CONTRIBUTORS\n\nDescription\n-----------\n\nThe SHOW CONTRIBUTORS statement
displays information about the companies and\npeople who financially
contribute to MariaDB. For each contributor, it\ndisplays Name, Location,
and Comment values. All columns are encoded as latin1.\n\nIt displays all
members and sponsors of the MariaDB Foundation as well as\nother financial
contributors.\n\nExample\n-------\n\nSHOW
CONTRIBUTORS;\n+---------------------+-------------------------------+------------------------\n------------------------------------+\n|
Name | Location | Comment
\n
|\n+---------------------+-------------------------------+------------------------\n------------------------------------+\n|
Alibaba Cloud | https://www.alibabacloud.com/ | Platinum Sponsor
of\nthe MariaDB Foundation |\n| Tencent Cloud |
https://cloud.tencent.com | Platinum Sponsor of\nthe MariaDB Foundation
|\n| Microsoft | https://microsoft.com/ |
Platinum Sponsor of\nthe MariaDB Foundation |\n| MariaDB
Corporation | https://mariadb.com | Founding member,\nPlatinum
Sponsor of the MariaDB Foundation |\n| ServiceNow |
https://servicenow.com | Platinum Sponsor of\nthe MariaDB Foundation
|\n| Intel | https://www.intel.com |
Platinum Sponsor of\nthe MariaDB Foundation |\n| SIT
| https://sit.org | Platinum Sponsor of\nthe
MariaDB Foundation |\n| Visma |
https://visma.com | Gold Sponsor of the\nMariaDB Foundation
|\n| DBS | https://dbs.com |
Gold Sponsor of the\nMariaDB Foundation |\n| IBM
| https://www.ibm.com | Gold Sponsor of the\nMariaDB
Foundation |\n| Automattic |
https://automattic.com | Silver Sponsor of the\nMariaDB Foundation
|\n| Percona | https://www.percona.com/ |
Sponsor of the MariaDB\nFoundation |\n| Galera
Cluster | https://galeracluster.com | Sponsor of the
MariaDB\nFoundation |\n| Google |
USA | Sponsoring encryption,\nparallel
replication and GTID |\n| Facebook | USA
| Sponsoring\nnon-blocking API, LIMIT ROWS EXAMINED etc
|\n| Ronald Bradford | Brisbane, Australia | EFF contribution
for\nUC2006 Auction |\n| Sheeri Kritzer |
Boston, Mass. USA | EFF contribution for\nUC2006 Auction
|\n| Mark Shuttleworth | London, UK. |
EFF contribution for\nUC2006 Auction
|\n+---------------------+-------------------------------+------------------------\n------------------------------------+\n\nURL:
https://mariadb.com/kb/en/show-contributors/','','https://mariadb.com/kb/en/show-contributors/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(364,26,'SHOW CREATE DATABASE','Syntax\n------\n\nSHOW
CREATE {DATABASE | SCHEMA} db_name\n\nDescription\n-----------\n\nShows the
CREATE DATABASE statement that creates the given database. SHOW\nCREATE
SCHEMA is a synonym for SHOW CREATE DATABASE. SHOW CREATE DATABASE\nquotes
database names according to the value of the sql_quote_show_create\nserver
system variable.\n\nExamples\n--------\n\nSHOW CREATE DATABASE
test;\n+----------+-----------------------------------------------------------------+\n|
Database | Create Database
|\n+----------+-----------------------------------------------------------------+\n|
test | CREATE DATABASE `test` /*!40100 DEFAULT CHARACTER SET latin1 */
|\n+----------+-----------------------------------------------------------------+\n\nSHOW
CREATE SCHEMA
test;\n+----------+-----------------------------------------------------------------+\n|
Database | Create Database
|\n+----------+-----------------------------------------------------------------+\n|
test | CREATE DATABASE `test` /*!40100 DEFAULT CHARACTER SET latin1 */
|\n+----------+-----------------------------------------------------------------+\n\nWith
sql_quote_show_create off:\n\nSHOW CREATE DATABASE
test;\n+----------+---------------------------------------------------------------+\n|
Database | Create Database
|\n+----------+---------------------------------------------------------------+\n|
test | CREATE DATABASE test /*!40100 DEFAULT CHARACTER SET latin1 */
|\n+----------+---------------------------------------------------------------+\n\nWith
a comment, from MariaDB 10.5:\n\nSHOW CREATE DATABASE
p;\n+----------+-------------------------------------------------------------------\n------------------+\n|
Database | Create Database
\n
|\n+----------+-------------------------------------------------------------------\n------------------+\n|
p | CREATE DATABASE `p` /*!40100 DEFAULT CHARACTER SET latin1
*/\nCOMMENT \'presentations\'
|\n+----------+-------------------------------------------------------------------\n------------------+\n\nURL:
https://mariadb.com/kb/en/show-create-database/','','https://mariadb.com/kb/en/show-create-database/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(365,26,'SHOW CREATE EVENT','Syntax\n------\n\nSHOW CREATE
EVENT event_name\n\nDescription\n-----------\n\nThis statement displays the
CREATE EVENT statement needed to re-create a given\nevent, as well as the
SQL_MODE that was used when the trigger has been created\nand the character
set used by the connection. To find out which events are\npresent, use SHOW
EVENTS.\n\nThe output of this statement is unreliably affected by
the\nsql_quote_show_create server system variable -
see\nhttp://bugs.mysql.com/bug.php?id=12719\n\nThe
information_schema.EVENTS table provides similar, but more
complete,\ninformation.\n\nExamples\n--------\n\nSHOW CREATE EVENT
test.e_daily\\G\n*************************** 1. row
***************************\n Event: e_daily\n sql_mode:\n
time_zone: SYSTEM\n Create Event: CREATE EVENT `e_daily`\n ON
SCHEDULE EVERY 1 DAY\n STARTS CURRENT_TIMESTAMP + INTERVAL 6
HOUR\n ON COMPLETION NOT PRESERVE\n ENABLE\n
COMMENT \'Saves total number of sessions then\n
clears the table each day\'\n DO BEGIN\n INSERT
INTO site_activity.totals (time, total)\n SELECT
CURRENT_TIMESTAMP, COUNT(*)\n FROM site_activity.sessions;\n
DELETE FROM site_activity.sessions;\n
END\ncharacter_set_client: latin1\ncollation_connection:
latin1_swedish_ci\n Database Collation: latin1_swedish_ci\n\nURL:
https://mariadb.com/kb/en/show-create-event/','','https://mariadb.com/kb/en/show-create-event/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(366,26,'SHOW CREATE FUNCTION','Syntax\n------\n\nSHOW
CREATE FUNCTION func_name\n\nDescription\n-----------\n\nThis statement is
similar to SHOW CREATE PROCEDURE but for stored functions.\n\nThe output of
this statement is unreliably affected by the\nsql_quote_show_create server
system variable -
see\nhttp://bugs.mysql.com/bug.php?id=12719\n\nExample\n-------\n\nSHOW
CREATE FUNCTION VatCents\\G\n*************************** 1. row
***************************\n Function: VatCents\n sql_mode:\n
Create Function: CREATE DEFINER=`root`@`localhost`
FUNCTION\n`VatCents`(price DECIMAL(10,2)) RETURNS int(11)\n
DETERMINISTIC\nBEGIN\n DECLARE x INT;\n SET x = price * 114;\n RETURN
x;\nEND\ncharacter_set_client: utf8\ncollation_connection:
utf8_general_ci\n Database Collation: latin1_swedish_ci\n\nURL:
https://mariadb.com/kb/en/show-create-function/','','https://mariadb.com/kb/en/show-create-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(367,26,'SHOW CREATE PACKAGE','MariaDB starting with
10.3.5\n----------------------------\nOracle-style packages were introduced
in MariaDB 10.3.5.\n\nSyntax\n------\n\nSHOW CREATE PACKAGE [ db_name . ]
package_name\n\nDescription\n-----------\n\nThe SHOW CREATE PACKAGE
statement can be used when Oracle SQL_MODE is set.\n\nShows the CREATE
statement that creates the given package
specification.\n\nExamples\n--------\n\nSHOW CREATE PACKAGE
employee_tools\\G\n*************************** 1. row
***************************\n Package: employee_tools\n
sql_mode:\nPIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,ORACLE,NO_KEY_OPTIONS,NO_TABLE_OPTIONS\nNO_FIELD_OPTIONS,NO_AUTO_CREATE_USER\n
Create Package: CREATE DEFINER=\"root\"@\"localhost\"
PACKAGE\n\"employee_tools\" AS\n FUNCTION getSalary(eid INT)
RETURN DECIMAL(10,2);\n PROCEDURE raiseSalary(eid INT, amount
DECIMAL(10,2));\n PROCEDURE raiseSalaryStd(eid INT);\n PROCEDURE hire(ename
TEXT, esalary DECIMAL(10,2));\nEND\ncharacter_set_client:
utf8\ncollation_connection: utf8_general_ci\n Database Collation:
latin1_swedish_ci\n\nURL:
https://mariadb.com/kb/en/show-create-package/','','https://mariadb.com/kb/en/show-create-package/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(368,26,'SHOW CREATE PACKAGE BODY','MariaDB starting with
10.3.5\n----------------------------\nOracle-style packages were introduced
in MariaDB 10.3.5.\n\nSyntax\n------\n\nSHOW CREATE PACKAGE BODY [ db_name
. ] package_name\n\nDescription\n-----------\n\nThe SHOW CREATE PACKAGE
BODY statement can be used when Oracle SQL_MODE is set.\n\nShows the CREATE
statement that creates the given package body (i.e.
the\nimplementation).\n\nExamples\n--------\n\nSHOW CREATE PACKAGE BODY
employee_tools\\G\n*************************** 1. row
***************************\n Package body: employee_tools\n
sql_mode:\nPIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,ORACLE,NO_KEY_OPTIONS,NO_TABLE_OPTIONS\nNO_FIELD_OPTIONS,NO_AUTO_CREATE_USER\n
Create Package Body: CREATE
DEFINER=\"root\"@\"localhost\" PACKAGE
BODY\n\"employee_tools\" AS\n\nstdRaiseAmount
DECIMAL(10,2):=500;\n\nPROCEDURE log (eid INT, ecmnt TEXT) AS\n BEGIN\n
INSERT INTO employee_log (id, cmnt) VALUES (eid, ecmnt);\n
END;\n\nPROCEDURE hire(ename TEXT, esalary DECIMAL(10,2)) AS\n eid INT;\n
BEGIN\n INSERT INTO employee (name, salary) VALUES (ename, esalary);\n
eid:= last_insert_id();\n log(eid, \'hire \' || ename);\n
END;\n\nFUNCTION getSalary(eid INT) RETURN DECIMAL(10,2) AS\n nSalary
DECIMAL(10,2);\n BEGIN\n SELECT salary INTO nSalary FROM employee WHERE
id=eid;\n log(eid, \'getSalary id=\' || eid || \'
salary=\' || nSalary);\n RETURN nSalary;\n END;\n\nPROCEDURE
raiseSalary(eid INT, amount DECIMAL(10,2)) AS\n BEGIN\n UPDATE employee
SET salary=salary+amount WHERE id=eid;\n log(eid, \'raiseSalary
id=\' || eid || \' amount=\' || amount);\n END;\n\nPROCEDURE
raiseSalaryStd(eid INT) AS\n BEGIN\n raiseSalary(eid, stdRaiseAmount);\n
log(eid, \'raiseSalaryStd id=\' || eid);\n END;\n\nBEGIN \n
log(0, \'Session \' || connection_id() || \' \' ||
current_user || \' started\');\nEND\ncharacter_set_client:
utf8\ncollation_connection: utf8_general_ci\n Database Collation:
latin1_swedish_ci\n\nURL:
https://mariadb.com/kb/en/show-create-package-body/','','https://mariadb.com/kb/en/show-create-package-body/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(369,26,'SHOW CREATE PROCEDURE','Syntax\n------\n\nSHOW
CREATE PROCEDURE proc_name\n\nDescription\n-----------\n\nThis statement is
a MariaDB extension. It returns the exact string that can be\nused to
re-create the named stored procedure, as well as the SQL_MODE that
was\nused when the trigger has been created and the character set used by
the\nconnection.. A similar statement, SHOW CREATE FUNCTION, displays
information\nabout stored functions.\n\nBoth statements require that you
are the owner of the routine or have the\nSELECT privilege on the
mysql.proc table. When neither is true, the statements\ndisplay NULL for
the Create Procedure or Create Function field.\n\nWarning Users with SELECT
privileges on mysql.proc or USAGE privileges on *.*\ncan view the text of
routines, even when they do not have privileges for the\nfunction or
procedure itself.\n\nThe output of these statements is unreliably affected
by the\nsql_quote_show_create server system variable -
see\nhttp://bugs.mysql.com/bug.php?id=12719\n\nExamples\n--------\n\nHere\'s
a comparison of the SHOW CREATE PROCEDURE and SHOW CREATE
FUNCTION\nstatements.\n\nSHOW CREATE PROCEDURE
test.simpleproc\\G\n*************************** 1. row
***************************\n Procedure: simpleproc\n sql_mode:\n
Create Procedure: CREATE PROCEDURE `simpleproc`(OUT param1 INT)\n
BEGIN\n SELECT COUNT(*) INTO param1 FROM t;\n
END\ncharacter_set_client: latin1\ncollation_connection:
latin1_swedish_ci\n Database Collation: latin1_swedish_ci\n\nSHOW CREATE
FUNCTION test.hello\\G\n*************************** 1. row
***************************\n Function: hello\n sql_mode:\n
Create Function: CREATE FUNCTION `hello`(s CHAR(20))\n RETURNS
CHAR(50)\n RETURN CONCAT(\'Hello,
\',s,\'!\')\ncharacter_set_client:
latin1\ncollation_connection: latin1_swedish_ci\n Database Collation:
latin1_swedish_ci\n\nWhen the user issuing the statement does not have
privileges on the routine,\nattempting to CALL the procedure raises Error
1370.\n\nCALL test.prc1();\nError 1370 (42000): execute command denieed to
user \'test_user\'@\'localhost\'\nfor routine
\'test\'.\'prc1\'\n\nIf the user neither has privilege
to the routine nor the SELECT privilege on\nmysql.proc table, it raises
Error 1305, informing them that the procedure does\nnot exist.\n\nSHOW
CREATE TABLES test.prc1\\G\nError 1305 (42000): PROCEDURE prc1 does not
exist\n\nURL:
https://mariadb.com/kb/en/show-create-procedure/','','https://mariadb.com/kb/en/show-create-procedure/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(370,26,'SHOW CREATE SEQUENCE','MariaDB starting with
10.3.1\n----------------------------\nSequences were introduced in MariaDB
10.3.\n\nSyntax\n------\n\nSHOW CREATE SEQUENCE
sequence_name;\n\nDescription\n-----------\n\nShows the CREATE SEQUENCE
statement that created the given sequence. The\nstatement requires the
SELECT privilege for the table.\n\nExample\n-------\n\nCREATE SEQUENCE s1
START WITH 50;\nSHOW CREATE SEQUENCE s1\\G;\n*************************** 1.
row ***************************\n Table: s1\nCreate Table: CREATE
SEQUENCE `s1` start with 50 minvalue 1 maxvalue\n9223372036854775806 \n
increment by 1 cache 1000 nocycle ENGINE=InnoDB\n\nNotes\n-----\n\nIf you
want to see the underlying table structure used for the SEQUENCE you\ncan
use SHOW CREATE TABLE on the SEQUENCE. You can also use SELECT to read
the\ncurrent recorded state of the SEQUENCE:\n\nSHOW CREATE TABLE
s1\\G\n*************************** 1. row ***************************\n
Table: s1\nCreate Table: CREATE TABLE `s1` (\n `next_not_cached_value`
bigint(21) NOT NULL,\n `minimum_value` bigint(21) NOT NULL,\n
`maximum_value` bigint(21) NOT NULL,\n `start_value` bigint(21) NOT NULL
COMMENT \'start value when sequences is\ncreated \n or value if
RESTART is used\',\n `increment` bigint(21) NOT NULL COMMENT
\'increment value\',\n `cache_size` bigint(21) unsigned NOT
NULL,\n `cycle_option` tinyint(1) unsigned NOT NULL COMMENT \'0 if no
cycles are\nallowed, \n 1 if the sequence should begin a new cycle when
maximum_value is passed\',\n `cycle_count` bigint(21) NOT NULL COMMENT
\'How many cycles have been done\'\n) ENGINE=InnoDB
SEQUENCE=1\n\nSELECT * FROM s1\\G\n*************************** 1. row
***************************\nnext_not_cached_value: 50\n minimum_value:
1\n maximum_value: 9223372036854775806\n start_value: 50\n
increment: 1\n cache_size: 1000\n cycle_option: 0\n cycle_count:
0\n\nURL:
https://mariadb.com/kb/en/show-create-sequence/','','https://mariadb.com/kb/en/show-create-sequence/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(371,26,'SHOW CREATE TRIGGER','Syntax\n------\n\nSHOW CREATE
TRIGGER trigger_name\n\nDescription\n-----------\n\nThis statement shows a
CREATE TRIGGER statement that creates the given\ntrigger, as well as the
SQL_MODE that was used when the trigger has been\ncreated and the character
set used by the connection.\n\nThe output of this statement is unreliably
affected by the\nsql_quote_show_create server system variable -
see\nhttp://bugs.mysql.com/bug.php?id=12719\n\nExamples\n--------\n\nSHOW
CREATE TRIGGER example\\G\n*************************** 1. row
***************************\n Trigger: example\n
sql_mode:\nONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,STRICT_ALL_TABLES\n,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO\n\nENGINE_SUBSTITUTION\nSQL
Original Statement: CREATE DEFINER=`root`@`localhost` TRIGGER
example\nBEFORE\n INSERT ON t FOR EACH ROW\nBEGIN\n SET NEW.c = NEW.c *
2;\nEND\n character_set_client: cp850\n collation_connection:
cp850_general_ci\n Database Collation: utf8_general_ci\n Created:
2016-09-29 13:53:34.35\n\nMariaDB starting with
10.2.3\n----------------------------\nThe Created column was added in MySQL
5.7 and MariaDB 10.2.3 as part of\nintroducing multiple trigger events per
action.\n\nURL:
https://mariadb.com/kb/en/show-create-trigger/','','https://mariadb.com/kb/en/show-create-trigger/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(372,26,'SHOW CREATE VIEW','Syntax\n------\n\nSHOW CREATE
VIEW view_name\n\nDescription\n-----------\n\nThis statement shows a CREATE
VIEW statement that creates the given view, as\nwell as the character set
used by the connection when the view was created.\nThis statement also
works with views.\n\nSHOW CREATE VIEW quotes table, column and stored
function names according to\nthe value of the sql_quote_show_create server
system variable.\n\nExamples\n--------\n\nSHOW CREATE VIEW
example\\G\n*************************** 1. row
***************************\n View: example\n Create View: CREATE
ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL\nSECURITY DEFINER VIEW
`example` AS (select `t`.`id` AS `id`,`t`.`s` AS `s`
from\n`t`)\ncharacter_set_client: cp850\ncollation_connection:
cp850_general_ci\n\nWith sql_quote_show_create off:\n\nSHOW CREATE VIEW
example\\G\n*************************** 1. row
***************************\n View: example\n Create View: CREATE
ALGORITHM=UNDEFINED DEFINER=root@localhost SQL\nSECU\nRITY DEFINER VIEW
example AS (select t.id AS id,t.s AS s from t)\ncharacter_set_client:
cp850\ncollation_connection: cp850_general_ci\n\nGrants\n------\n\nTo be
able to see a view, you need to have the SHOW VIEW and the
SELECT\nprivilege on the view:\n\nGRANT SHOW VIEW,SELECT ON
test_database.test_view TO
\'test\'@\'localhost\';\n\nURL:
https://mariadb.com/kb/en/show-create-view/','','https://mariadb.com/kb/en/show-create-view/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(373,26,'SHOW DATABASES','Syntax\n------\n\nSHOW {DATABASES
| SCHEMAS}\n [LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nSHOW DATABASES lists the databases on
the MariaDB server host. SHOW SCHEMAS is\na synonym for SHOW DATABASES. The
LIKE clause, if present on its own,\nindicates which database names to
match. The WHERE and LIKE clauses can be\ngiven to select rows using more
general conditions, as discussed in Extended\nSHOW.\n\nYou see only those
databases for which you have some kind of privilege, unless\nyou have the
global SHOW DATABASES privilege. You can also get this list using\nthe
mysqlshow command.\n\nIf the server was started with the
--skip-show-database option, you cannot use\nthis statement at all unless
you have the SHOW DATABASES privilege.\n\nThe list of results returned by
SHOW DATABASES is based on directories in the\ndata directory, which is how
MariaDB implements databases. It\'s possible that\noutput includes
directories that do not correspond to actual databases.\n\nThe Information
Schema SCHEMATA table also contains database
information.\n\nExamples\n--------\n\nSHOW
DATABASES;\n+--------------------+\n| Database
|\n+--------------------+\n| information_schema |\n| mysql
|\n| performance_schema |\n| test
|\n+--------------------+\n\nSHOW DATABASES LIKE
\'m%\';\n+---------------+\n| Database (m%)
|\n+---------------+\n| mysql |\n+---------------+\n\nURL:
https://mariadb.com/kb/en/show-databases/','','https://mariadb.com/kb/en/show-databases/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(374,26,'SHOW ENGINE','Syntax\n------\n\nSHOW ENGINE
engine_name {STATUS | MUTEX}\n\nDescription\n-----------\n\nSHOW ENGINE
displays operational information about a storage engine. The\nfollowing
statements currently are supported:\n\nSHOW ENGINE INNODB STATUS\nSHOW
ENGINE INNODB MUTEX\nSHOW ENGINE PERFORMANCE_SCHEMA STATUS\nSHOW ENGINE
ROCKSDB STATUS\n\nIf the Sphinx Storage Engine is installed, the following
is also supported:\n\nSHOW ENGINE SPHINX STATUS\n\nSee SHOW ENGINE SPHINX
STATUS.\n\nOlder (and now removed) synonyms were SHOW INNODB STATUS for
SHOW ENGINE\nINNODB STATUS and SHOW MUTEX STATUS for SHOW ENGINE INNODB
MUTEX.\n\nSHOW ENGINE INNODB STATUS\n-------------------------\n\nSHOW
ENGINE INNODB STATUS displays extensive information from the
standard\nInnoDB Monitor about the state of the InnoDB storage engine. See
SHOW ENGINE\nINNODB STATUS for more.\n\nSHOW ENGINE INNODB
MUTEX\n------------------------\n\nSHOW ENGINE INNODB MUTEX displays InnoDB
mutex statistics.\n\nThe statement displays the following output
fields:\n\n* Type: Always InnoDB.\n* Name: The source file where the mutex
is implemented, and the line number\n in the file where the mutex is
created. The line number is dependent on the\nMariaDB version.\n* Status:
This field displays the following values if UNIV_DEBUG was defined\nat
compilation time (for example, in include/univ.h in the InnoDB part of
the\nsource tree). Only the os_waits value is displayed if UNIV_DEBUG was
not\ndefined. Without UNIV_DEBUG, the information on which the output is
based is\ninsufficient to distinguish regular mutexes and mutexes that
protect\n rw-locks (which allow multiple readers or a single writer).
Consequently, the\n output may appear to contain multiple rows for the same
mutex.\ncount indicates how many times the mutex was requested.\nspin_waits
indicates how many times the spinlock had to run.\nspin_rounds indicates
the number of spinlock rounds. (spin_rounds divided by\n spin_waits
provides the average round count.)\nos_waits indicates the number of
operating system waits. This occurs when\n the spinlock did not work (the
mutex was not locked during the spinlock and\n it was necessary to yield to
the operating system and wait).\nos_yields indicates the number of times a
the thread trying to lock a mutex\n gave up its timeslice and yielded to
the operating system (on the\n presumption that allowing other threads to
run will free the mutex so that\n it can be locked).\nos_wait_times
indicates the amount of time (in ms) spent in operating system\n waits, if
the timed_mutexes system variable is 1 (ON). If timed_mutexes is 0\n (OFF),
timing is disabled, so os_wait_times is 0. timed_mutexes is off by\n
default.\n\nInformation from this statement can be used to diagnose system
problems. For\nexample, large values of spin_waits and spin_rounds may
indicate scalability\nproblems.\n\nThe information_schema.INNODB_MUTEXES
table provides similar information.\n\nSHOW ENGINE PERFORMANCE_SCHEMA
STATUS\n-------------------------------------\n\nThis statement shows how
much memory is used for performance_schema tables and\ninternal
buffers.\n\nThe output contains the following fields:\n\n* Type: Always
performance_schema.\n* Name: The name of a table, the name of an internal
buffer, or the\nperformance_schema word, followed by a dot and an
attribute. Internal buffers\nnames are enclosed by parenthesis.
performance_schema means that the attribute\nrefers to the whole database
(it is a total). \n* Status: The value for the attribute.\n\nThe following
attributes are shown, in this order, for all tables:\n\n* row_size: The
memory used for an individual record. This value will never\nchange.\n*
row_count: The number of rows in the table or buffer. For some tables,
this\nvalue depends on a server system variable.\n* memory: For tables and
performance_schema, this is the result of row_size *\nrow_count.\n\nFor
internal buffers, the attributes are:\n\n* count\n* size\n\nSHOW ENGINE
ROCKSDB STATUS\n--------------------------\n\nSee also MyRocks Performance
Troubleshooting\n\nURL:
https://mariadb.com/kb/en/show-engine/','','https://mariadb.com/kb/en/show-engine/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(375,26,'SHOW ENGINE INNODB STATUS','SHOW ENGINE INNODB
STATUS is a specific form of the SHOW ENGINE statement that\ndisplays the
InnoDB Monitor output, which is extensive InnoDB information\nwhich can be
useful in diagnosing problems.\n\nThe following sections are displayed\n\n*
Status: Shows the timestamp, monitor name and the number of seconds, or
the\nelapsed time between the current time and the time the InnoDB Monitor
output\nwas last displayed. The per-second averages are based upon this
time.\n* BACKGROUND THREAD: srv_master_thread lines show work performed by
the main\nbackground thread.\n* SEMAPHORES: Threads waiting for a semaphore
and stats on how the number of\ntimes threads have needed a spin or a wait
on a mutex or rw-lock semaphore. If\nthis number of threads is large, there
may be I/O or contention issues.\nReducing the size of the
innodb_thread_concurrency system variable may help if\ncontention is
related to thread scheduling. Spin rounds per wait shows the\nnumber of
spinlock rounds per OS wait for a mutex. \n* LATEST FOREIGN KEY ERROR: Only
shown if there has been a foreign key\nconstraint error, it displays the
failed statement and information about the\nconstraint and the related
tables.\n* LATEST DETECTED DEADLOCK: Only shown if there has been a
deadlock, it\ndisplays the transactions involved in the deadlock and the
statements being\nexecuted, held and required locked and the transaction
rolled back to.\n* TRANSACTIONS: The output of this section can help
identify lock contention,\nas well as reasons for the deadlocks.\n* FILE
I/O: InnoDB thread information as well as pending I/O operations and\nI/O
performance statistics.\n* INSERT BUFFER AND ADAPTIVE HASH INDEX: InnoDB
insert buffer (old name for\nthe change buffer) and adaptive hash index
status information, including the\nnumber of each type of operation
performed, and adaptive hash index\nperformance.\n* LOG: InnoDB log
information, including current log sequence number, how far\nthe log has
been flushed to disk, the position at which InnoDB last took a\ncheckpoint,
pending writes and write performance statistics.\n* BUFFER POOL AND MEMORY:
Information on buffer pool pages read and written,\nwhich allows you to see
the number of data file I/O operations performed by\nyour queries. See
InnoDB Buffer Pool for more. Similar information is also\navailable from
the INFORMATION_SCHEMA.INNODB_BUFFER_POOL_STATS table.\n* ROW
OPERATIONS:Information about the main thread, including the number
and\nperformance rate for each type of row operation.\n\nIf the
innodb_status_output_locks system variable is set to 1, extended
lock\ninformation will be displayed.\n\nExample
output:\n\n=====================================\n2019-09-06 12:44:13
0x7f93cc236700 INNODB MONITOR
OUTPUT\n=====================================\nPer second averages
calculated from the last 4 seconds\n-----------------\nBACKGROUND
THREAD\n-----------------\nsrv_master_thread loops: 2 srv_active, 0
srv_shutdown, 83698 srv_idle\nsrv_master_thread log flush and writes:
83682\n----------\nSEMAPHORES\n----------\nOS WAIT ARRAY INFO: reservation
count 15\nOS WAIT ARRAY INFO: signal count 8\nRW-shared spins 0, rounds 20,
OS waits 7\nRW-excl spins 0, rounds 0, OS waits 0\nRW-sx spins 0, rounds 0,
OS waits 0\nSpin rounds per wait: 20.00 RW-shared, 0.00 RW-excl, 0.00
RW-sx\n------------\nTRANSACTIONS\n------------\nTrx id counter 236\nPurge
done for trx\'s n:o < 236 undo n:o < 0 state: running\nHistory
list length 22\nLIST OF TRANSACTIONS FOR EACH SESSION:\n---TRANSACTION
421747401994584, not started\n0 lock struct(s), heap size 1136, 0 row
lock(s)\n---TRANSACTION 421747401990328, not started\n0 lock struct(s),
heap size 1136, 0 row lock(s)\n--------\nFILE I/O\n--------\nI/O thread 0
state: waiting for completed aio requests (insert buffer thread)\nI/O
thread 1 state: waiting for completed aio requests (log thread)\nI/O thread
2 state: waiting for completed aio requests (read thread)\nI/O thread 3
state: waiting for completed aio requests (read thread)\nI/O thread 4
state: waiting for completed aio requests (read thread)\nI/O thread 5
state: waiting for completed aio requests (read thread)\nI/O thread 6
state: waiting for completed aio requests (write thread)\nI/O thread 7
state: waiting for completed aio requests (write thread)\nI/O thread 8
state: waiting for completed aio requests (write thread)\nI/O thread 9
state: waiting for completed aio requests (write thread)\nPending normal
aio reads: [0, 0, 0, 0] , aio writes: [0, 0, 0, 0] ,\n ibuf aio reads:, log
i/o\'s:, sync i/o\'s:\nPending flushes (fsync) log: 0; buffer
pool: 0\n286 OS file reads, 171 OS file writes, 22 OS fsyncs\n0.00 reads/s,
0 avg bytes/read, 0.00 writes/s, 0.00
fsyncs/s\n-------------------------------------\nINSERT BUFFER AND ADAPTIVE
HASH INDEX\n-------------------------------------\nIbuf: size 1, free list
len 0, seg size 2, 0 merges\nmerged operations:\n insert 0, delete mark 0,
delete 0\ndiscarded operations:\n insert 0, delete mark 0, delete 0\nHash
table size 34679, node heap has 0 buffer(s)\nHash table size 34679, node
heap has 0 buffer(s)\nHash table size 34679, node heap has 0
buffer(s)\nHash table size 34679, node heap has 0 buffer(s)\nHash table
size 34679, node heap has 0 buffer(s)\nHash table size 34679, node heap has
0 buffer(s)\nHash table size 34679, node heap has 0 buffer(s)\nHash table
size 34679, node heap has 0 buffer(s)\n0.00 hash searches/s, 0.00 non-hash
searches/s\n---\nLOG\n---\nLog sequence number 445926\nLog flushed up to
445926\nPages flushed up to 445926\nLast checkpoint at 445917\n0 pending
log flushes, 0 pending chkp writes\n18 log i/o\'s done, 0.00 log
i/o\'s/second\n----------------------\nBUFFER POOL AND
MEMORY\n----------------------\nTotal large memory allocated
167772160\nDictionary memory allocated 50768\nBuffer pool size 8012\nFree
buffers 7611\nDatabase pages 401\nOld database pages 0\nModified
db pages 0\nPercent of dirty pages(LRU & free pages): 0.000\nMax dirty
pages percent: 75.000\nPending reads 0\nPending writes: LRU 0, flush list
0, single page 0\nPages made young 0, not young 0\n0.00 youngs/s, 0.00
non-youngs/s\nPages read 264, created 137, written 156\n0.00 reads/s, 0.00
creates/s, 0.00 writes/s\nNo buffer pool page gets since the last
printout\nPages read ahead 0.00/s, evicted without access 0.00/s, Random
read ahead\n0.00/s\nLRU len: 401, unzip_LRU len: 0\nI/O sum[0]:cur[0],
unzip sum[0]:cur[0]\n--------------\nROW OPERATIONS\n--------------\n0
queries inside InnoDB, 0 queries in queue\n0 read views open inside
InnoDB\nProcess ID=4267, Main thread ID=140272021272320, state:
sleeping\nNumber of rows inserted 1, updated 0, deleted 0, read 1\n0.00
inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s\nNumber of system
rows inserted 0, updated 0, deleted 0, read 0\n0.00 inserts/s, 0.00
updates/s, 0.00 deletes/s, 0.00 reads/s\n----------------------------\nEND
OF INNODB MONITOR OUTPUT\n============================\n\nURL:
https://mariadb.com/kb/en/show-engine-innodb-status/','','https://mariadb.com/kb/en/show-engine-innodb-status/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(376,26,'SHOW ENGINES','Syntax\n------\n\nSHOW [STORAGE]
ENGINES\n\nDescription\n-----------\n\nSHOW ENGINES displays status
information about the server\'s storage engines.\nThis is particularly
useful for checking whether a storage engine is\nsupported, or to see what
the default engine is. SHOW TABLE TYPES is a\ndeprecated synonym.\n\nThe
information_schema.ENGINES table provides the same information.\n\nSince
storage engines are plugins, different information about them is
also\nshown in the information_schema.PLUGINS table and by the SHOW
PLUGINS\nstatement.\n\nNote that both MySQL\'s InnoDB and
Percona\'s XtraDB replacement are labeled as\nInnoDB. However, if
XtraDB is in use, it will be specified in the COMMENT\nfield. See XtraDB
and InnoDB. The same applies to FederatedX.\n\nThe output consists of the
following columns:\n\n* Engine indicates the engine\'s name.\n*
Support indicates whether the engine is installed, and whether it is
the\ndefault engine for the current session.\n* Comment is a brief
description.\n* Transactions, XA and Savepoints indicate whether
transactions, XA\ntransactions and transaction savepoints are supported by
the engine.\n\nExamples\n--------\n\nSHOW
ENGINES\\G\n*************************** 1. row
***************************\n Engine: InnoDB\n Support: DEFAULT\n
Comment: Supports transactions, row-level locking, and foreign
keys\nTransactions: YES\n XA: YES\n Savepoints:
YES\n*************************** 2. row ***************************\n
Engine: CSV\n Support: YES\n Comment: CSV storage engine\nTransactions:
NO\n XA: NO\n Savepoints: NO\n*************************** 3. row
***************************\n Engine: MyISAM\n Support: YES\n Comment:
MyISAM storage engine\nTransactions: NO\n XA: NO\n Savepoints:
NO\n*************************** 4. row ***************************\n
Engine: BLACKHOLE\n Support: YES\n Comment: /dev/null storage engine
(anything you write to it disappears)\nTransactions: NO\n XA: NO\n
Savepoints: NO\n*************************** 5. row
***************************\n Engine: FEDERATED\n Support: YES\n
Comment: FederatedX pluggable storage engine\nTransactions: YES\n XA:
NO\n Savepoints: YES\n*************************** 6. row
***************************\n Engine: MRG_MyISAM\n Support: YES\n
Comment: Collection of identical MyISAM tables\nTransactions: NO\n XA:
NO\n Savepoints: NO\n*************************** 7. row
***************************\n Engine: ARCHIVE\n Support: YES\n Comment:
Archive storage engine\nTransactions: NO\n XA: NO\n Savepoints:
NO\n*************************** 8. row ***************************\n
Engine: MEMORY\n Support: YES\n Comment: Hash based, stored in memory,
useful for temporary tables\nTransactions: NO\n XA: NO\n Savepoints:
NO\n*************************** 9. row ***************************\n
Engine: PERFORMANCE_SCHEMA\n Support: YES\n Comment: Performance
Schema\nTransactions: NO\n XA: NO\n Savepoints:
NO\n*************************** 10. row ***************************\n
Engine: Aria\n Support: YES\n Comment: Crash-safe tables with MyISAM
heritage\nTransactions: NO\n XA: NO\n Savepoints: NO\n10 rows in set
(0.00 sec)\n\nURL:
https://mariadb.com/kb/en/show-engines/','','https://mariadb.com/kb/en/show-engines/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(377,26,'SHOW ERRORS','Syntax\n------\n\nSHOW ERRORS [LIMIT
[offset,] row_count]\nSHOW ERRORS [LIMIT row_count OFFSET offset]\nSHOW
COUNT(*) ERRORS\n\nDescription\n-----------\n\nThis statement is similar to
SHOW WARNINGS, except that instead of displaying\nerrors, warnings, and
notes, it displays only errors.\n\nThe LIMIT clause has the same syntax as
for the SELECT statement.\n\nThe SHOW COUNT(*) ERRORS statement displays
the number of errors. You can also\nretrieve this number from the
error_count variable.\n\nSHOW COUNT(*) ERRORS;\nSELECT
@@error_count;\n\nThe value of error_count might be greater than the number
of messages\ndisplayed by SHOW WARNINGS if the max_error_count system
variable is set so\nlow that not all messages are stored.\n\nFor a list of
MariaDB error codes, see MariaDB Error
Codes.\n\nExamples\n--------\n\nSELECT f();\nERROR 1305 (42000): FUNCTION f
does not exist\n\nSHOW COUNT(*) ERRORS;\n+-----------------------+\n|
@@session.error_count |\n+-----------------------+\n| 1
|\n+-----------------------+\n\nSHOW
ERRORS;\n+-------+------+---------------------------+\n| Level | Code |
Message
|\n+-------+------+---------------------------+\n| Error | 1305 | FUNCTION
f does not exist |\n+-------+------+---------------------------+\n\nURL:
https://mariadb.com/kb/en/show-errors/','','https://mariadb.com/kb/en/show-errors/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(378,26,'SHOW EVENTS','Syntax\n------\n\nSHOW EVENTS [{FROM
| IN} schema_name]\n [LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nShows information about Event Manager
events (created with CREATE EVENT).\nRequires the EVENT privilege. Without
any arguments, SHOW EVENTS lists all of\nthe events in the current
schema:\n\nSELECT CURRENT_USER(),
SCHEMA();\n+----------------+----------+\n| CURRENT_USER() | SCHEMA()
|\n+----------------+----------+\n| jon@ghidora | myschema
|\n+----------------+----------+\n\nSHOW
EVENTS\\G\n*************************** 1. row ***************************\n
Db: myschema\n Name: e_daily\n Definer: jon@ghidora\n
Time zone: SYSTEM\n Type: RECURRING\n Execute at: NULL\n
Interval value: 10\n Interval field: SECOND\n Starts: 2006-02-09
10:41:23\n Ends: NULL\n Status: ENABLED\n Originator:
0\ncharacter_set_client: latin1\ncollation_connection: latin1_swedish_ci\n
Database Collation: latin1_swedish_ci\n\nTo see the event action, use SHOW
CREATE EVENT instead, or look at the\ninformation_schema.EVENTS
table.\n\nTo see events for a specific schema, use the FROM clause. For
example, to see\nevents for the test schema, use the following
statement:\n\nSHOW EVENTS FROM test;\n\nThe LIKE clause, if present,
indicates which event names to match. The WHERE\nclause can be given to
select rows using more general conditions, as discussed\nin Extended
Show.\n\nURL:
https://mariadb.com/kb/en/show-events/','','https://mariadb.com/kb/en/show-events/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(379,26,'SHOW FUNCTION STATUS','Syntax\n------\n\nSHOW
FUNCTION STATUS\n [LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nThis statement is similar to SHOW
PROCEDURE STATUS but for stored functions.\n\nThe LIKE clause, if present
on its own, indicates which function names to\nmatch.\n\nThe WHERE and LIKE
clauses can be given to select rows using more general\nconditions, as
discussed in Extended SHOW.\n\nThe information_schema.ROUTINES table
contains more detailed information.\n\nExamples\n--------\n\nShowing all
stored functions:\n\nSHOW FUNCTION STATUS\\G\n***************************
1. row ***************************\n Db: test\n Name:
VatCents\n Type: FUNCTION\n Definer: root@localhost\n
Modified: 2013-06-01 12:40:31\n Created: 2013-06-01 12:40:31\n
Security_type: DEFINER\n Comment:\ncharacter_set_client:
utf8\ncollation_connection: utf8_general_ci\n Database Collation:
latin1_swedish_ci\n\nStored functions whose name starts with
\'V\':\n\nSHOW FUNCTION STATUS LIKE \'V%\'
\\G\n*************************** 1. row ***************************\n
Db: test\n Name: VatCents\n Type: FUNCTION\n Definer:
root@localhost\n Modified: 2013-06-01 12:40:31\n Created:
2013-06-01 12:40:31\n Security_type: DEFINER\n
Comment:\ncharacter_set_client: utf8\ncollation_connection:
utf8_general_ci\n Database Collation: latin1_swedish_ci\n\nStored functions
with a security type of \'DEFINER\':\n\nSHOW FUNCTION STATUS
WHERE Security_type LIKE \'DEFINER\'
\\G\n*************************** 1. row ***************************\n
Db: test\n Name: VatCents\n Type: FUNCTION\n Definer:
root@localhost\n Modified: 2013-06-01 12:40:31\n Created:
2013-06-01 12:40:31\n Security_type: DEFINER\n
Comment:\ncharacter_set_client: utf8\ncollation_connection:
utf8_general_ci\n Database Collation: latin1_swedish_ci\n\nURL:
https://mariadb.com/kb/en/show-function-status/','','https://mariadb.com/kb/en/show-function-status/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(380,26,'SHOW LOCALES','SHOW LOCALES was introduced as part
of the Information Schema plugin extension.\n\nSHOW LOCALES is used to
return locales information as part of the Locales\nplugin. While the
information_schema.LOCALES table has 8 columns, the SHOW\nLOCALES statement
will only display 4 of them:\n\nExample\n-------\n\nSHOW
LOCALES;\n+-----+-------+-------------------------------------+------------------------+\n|
Id | Name | Description | Error_Message_Language
|\n+-----+-------+-------------------------------------+------------------------+\n|
0 | en_US | English - United States | english
|\n| 1 | en_GB | English - United Kingdom | english
|\n| 2 | ja_JP | Japanese - Japan | japanese
|\n| 3 | sv_SE | Swedish - Sweden | swedish
|\n...\n\nURL:
https://mariadb.com/kb/en/show-locales/','','https://mariadb.com/kb/en/show-locales/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(381,26,'SHOW OPEN TABLES','Syntax\n------\n\nSHOW OPEN
TABLES [FROM db_name]\n [LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nSHOW OPEN TABLES lists the
non-TEMPORARY tables that are currently open in the\ntable cache. See
http://dev.mysql.com/doc/refman/5.1/en/table-cache.html.\n\nThe FROM and
LIKE clauses may be used.\n\nThe FROM clause, if present, restricts the
tables shown to those present in\nthe db_name database.\n\nThe LIKE clause,
if present on its own, indicates which table names to match.\nThe WHERE and
LIKE clauses can be given to select rows using more general\nconditions, as
discussed in Extended SHOW.\n\nThe following information is
returned:\n\n+---------------------------+------------------------------------------------+\n|
Column | Description
|\n+---------------------------+------------------------------------------------+\n|
Database | Database name.
|\n+---------------------------+------------------------------------------------+\n|
Name | Table name.
|\n+---------------------------+------------------------------------------------+\n|
In_use | Number of table instances being used.
|\n+---------------------------+------------------------------------------------+\n|
Name_locked | 1 if the table is name-locked, e.g. if it is
|\n| | being dropped or renamed, otherwise 0.
|\n+---------------------------+------------------------------------------------+\n\nBefore
MariaDB 5.5, each use of, for example, LOCK TABLE ... WRITE
would\nincrement In_use for that table. With the implementation of the
metadata\nlocking improvements in MariaDB 5.5, LOCK TABLE... WRITE acquires
a strong MDL\nlock, and concurrent connections will wait on this MDL lock,
so any subsequent\nLOCK TABLE... WRITE will not increment
In_use.\n\nExample\n-------\n\nSHOW OPEN
TABLES;\n+----------+---------------------------+--------+-------------+\n|
Database | Table | In_use | Name_locked
|\n+----------+---------------------------+--------+-------------+\n...\n|
test | xjson | 0 | 0 |\n| test |
jauthor | 0 | 0 |\n| test | locks
| 1 | 0
|\n...\n+----------+---------------------------+--------+-------------+\n\nURL:
https://mariadb.com/kb/en/show-open-tables/','','https://mariadb.com/kb/en/show-open-tables/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(382,26,'SHOW PACKAGE BODY STATUS','MariaDB starting with
10.3.5\n----------------------------\nOracle-style packages were introduced
in MariaDB 10.3.5.\n\nSyntax\n------\n\nSHOW PACKAGE BODY STATUS\n [LIKE
\'pattern\' | WHERE expr]\n\nDescription\n-----------\n\nThe SHOW
PACKAGE BODY STATUS statement returns characteristics of stored\npackage
bodies (implementations), such as the database, name, type,
creator,\ncreation and modification dates, and character set information. A
similar\nstatement, SHOW PACKAGE STATUS, displays information about stored
package\nspecifications.\n\nThe LIKE clause, if present, indicates which
package names to match. The WHERE\nand LIKE clauses can be given to select
rows using more general conditions, as\ndiscussed in Extended SHOW.\n\nThe
ROUTINES table in the INFORMATION_SCHEMA database contains more
detailed\ninformation.\n\nExamples\n--------\n\nSHOW PACKAGE BODY STATUS
LIKE \'pkg1\'\\G\n*************************** 1. row
***************************\n Db: test\n Name: pkg1\n
Type: PACKAGE BODY\n Definer: root@localhost\n Modified:
2018-02-27 14:44:14\n Created: 2018-02-27 14:44:14\n Security_type:
DEFINER\n Comment: This is my first package
body\ncharacter_set_client: utf8\ncollation_connection: utf8_general_ci\n
Database Collation: latin1_swedish_ci\n\nURL:
https://mariadb.com/kb/en/show-package-body-status/','','https://mariadb.com/kb/en/show-package-body-status/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(383,26,'SHOW PACKAGE STATUS','MariaDB starting with
10.3.5\n----------------------------\nOracle-style packages were introduced
in MariaDB 10.3.5.\n\nSyntax\n------\n\nSHOW PACKAGE STATUS\n [LIKE
\'pattern\' | WHERE expr]\n\nDescription\n-----------\n\nThe SHOW
PACKAGE STATUS statement returns characteristics of stored
package\nspecifications, such as the database, name, type, creator,
creation and\nmodification dates, and character set information. A similar
statement, SHOW\nPACKAGE BODY STATUS, displays information about stored
package bodies (i.e.\nimplementations).\n\nThe LIKE clause, if present,
indicates which package names to match. The WHERE\nand LIKE clauses can be
given to select rows using more general conditions, as\ndiscussed in
Extended SHOW.\n\nThe ROUTINES table in the INFORMATION_SCHEMA database
contains more detailed\ninformation.\n\nExamples\n--------\n\nSHOW PACKAGE
STATUS LIKE \'pkg1\'\\G\n*************************** 1. row
***************************\n Db: test\n Name: pkg1\n
Type: PACKAGE\n Definer: root@localhost\n Modified: 2018-02-27
14:38:15\n Created: 2018-02-27 14:38:15\n Security_type: DEFINER\n
Comment: This is my first package\ncharacter_set_client:
utf8\ncollation_connection: utf8_general_ci\n Database Collation:
latin1_swedish_ci\n\nURL:
https://mariadb.com/kb/en/show-package-status/','','https://mariadb.com/kb/en/show-package-status/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(384,26,'SHOW PRIVILEGES','Syntax\n------\n\nSHOW
PRIVILEGES\n\nDescription\n-----------\n\nSHOW PRIVILEGES shows the list of
system privileges that the MariaDB server\nsupports. The exact list of
privileges depends on the version of your server.\n\nNote that before
MariaDB 10.3.23, MariaDB 10.4.13 and MariaDB 10.5.2 , the\nDelete history
privilege displays as Delete versioning rows
(MDEV-20382).\n\nExample\n-------\n\nFrom MariaDB 10.5.9\n\nSHOW
PRIVILEGES;\n+--------------------------+---------------------------------------+-----------\n--------------------------------------------------------+\n|
Privilege | Context | Comment
\n
|\n+--------------------------+---------------------------------------+-----------\n--------------------------------------------------------+\n|
Alter | Tables | To
alter\nthe table |\n| Alter
routine | Functions,Procedures | To alter\nor
drop stored functions/procedures |\n| Create
| Databases,Tables,Indexes | To create\nnew databases
and tables |\n| Create routine |
Databases | To use\nCREATE FUNCTION/PROCEDURE
|\n| Create temporary tables | Databases
| To use\nCREATE TEMPORARY TABLE
|\n| Create view | Tables
| To create\nnew views
|\n| Create user | Server Admin
| To create\nnew users
|\n| Delete | Tables | To
delete\nexisting rows |\n|
Delete history | Tables | To
delete\nversioning table historical rows |\n| Drop
| Databases,Tables | To
drop\ndatabases, tables, and views |\n| Event
| Server Admin | To\ncreate,
alter, drop and execute events |\n| Execute
| Functions,Procedures | To\nexecute stored
routines |\n| File
| File access on server | To read\nand write files on
the server |\n| Grant option |
Databases,Tables,Functions,Procedures | To give\nto other users those
privileges you possess |\n| Index |
Tables | To create\nor drop indexes
|\n| Insert | Tables
| To insert\ndata into tables
|\n| Lock tables | Databases
| To use\nLOCK TABLES (together with SELECT privilege)
|\n| Process | Server Admin
| To view\nthe plain text of currently executing queries
|\n| Proxy | Server Admin | To
make\nproxy user possible |\n|
References | Databases,Tables | To
have\nreferences on tables |\n|
Reload | Server Admin | To
reload\nor refresh tables, logs and privileges |\n|
Binlog admin | Server | To
purge\nbinary logs |\n|
Binlog monitor | Server | To
use\nSHOW BINLOG STATUS and SHOW BINARY LOG |\n|
Binlog replay | Server | To
use\nBINLOG (generated by mariadb-binlog) |\n|
Replication master admin | Server |
To\nmonitor connected slaves |\n|
Replication slave admin | Server |
To\nstart/stop slave and apply binlog events |\n|
Slave monitor | Server | To
use\nSHOW SLAVE STATUS and SHOW RELAYLOG EVENTS |\n|
Replication slave | Server Admin | To
read\nbinary log events from the master |\n|
Select | Tables |
To\nretrieve rows from table |\n|
Show databases | Server Admin | To
see\nall databases with SHOW DATABASES |\n| Show
view | Tables | To see\nviews
with SHOW CREATE VIEW |\n| Shutdown
| Server Admin | To shut\ndown the server
|\n| Super |
Server Admin | To use\nKILL thread, SET GLOBAL,
CHANGE MASTER, etc. |\n| Trigger | Tables
| To use\ntriggers
|\n| Create tablespace | Server Admin
| To\ncreate/alter/drop tablespaces
|\n| Update | Tables
| To update\nexisting rows
|\n| Set user | Server | To
create\nviews and stored routines with a different definer |\n|
Federated admin | Server |
To\nexecute the CREATE SERVER, ALTER SERVER, DROP SERVER statements |\n|
Connection admin | Server | To
bypass\nconnection limits and kill other users\' connections |\n|
Read_only admin | Server |
To\nperform write operations even if @@read_only=ON |\n|
Usage | Server Admin |
No\nprivileges - allow connect only
|\n+--------------------------+---------------------------------------+-----------\n--------------------------------------------------------+\n41
rows in set (0.000 sec)\n\nURL:
https://mariadb.com/kb/en/show-privileges/','','https://mariadb.com/kb/en/show-privileges/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(385,26,'SHOW PROCEDURE CODE','Syntax\n------\n\nSHOW
PROCEDURE CODE proc_name\n\nDescription\n-----------\n\nThis statement is a
MariaDB extension that is available only for servers that\nhave been built
with debugging support. It displays a representation of the\ninternal
implementation of the named stored procedure. A similar statement,\nSHOW
FUNCTION CODE, displays information about stored functions.\n\nBoth
statements require that you be the owner of the routine or have
SELECT\naccess to the mysql.proc table.\n\nIf the named routine is
available, each statement produces a result set. Each\nrow in the result
set corresponds to one \"instruction\" in the routine. The\nfirst
column is Pos, which is an ordinal number beginning with 0. The
second\ncolumn is Instruction, which contains an SQL statement (usually
changed from\nthe original source), or a directive which has meaning only
to the\nstored-routine handler.\n\nExamples\n--------\n\nDELIMITER
//\n\nCREATE PROCEDURE p1 ()\n BEGIN\n DECLARE fanta INT DEFAULT 55;\n
DROP TABLE t2;\n LOOP\n INSERT INTO t3 VALUES (fanta);\n END LOOP;\n
END//\nQuery OK, 0 rows affected (0.00 sec)\n\nSHOW PROCEDURE CODE
p1//\n+-----+----------------------------------------+\n| Pos | Instruction
|\n+-----+----------------------------------------+\n| 0 | set fanta@0 55
|\n| 1 | stmt 9 \"DROP TABLE t2\"
|\n| 2 | stmt 5 \"INSERT INTO t3 VALUES (fanta)\"
|\n| 3 | jump 2
|\n+-----+----------------------------------------+\n\nURL:
https://mariadb.com/kb/en/show-procedure-code/','','https://mariadb.com/kb/en/show-procedure-code/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(386,26,'SHOW PROCEDURE STATUS','Syntax\n------\n\nSHOW
PROCEDURE STATUS\n [LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nThis statement is a MariaDB extension.
It returns characteristics of a stored\nprocedure, such as the database,
name, type, creator, creation and\nmodification dates, and character set
information. A similar statement, SHOW\nFUNCTION STATUS, displays
information about stored functions.\n\nThe LIKE clause, if present,
indicates which procedure or function names to\nmatch. The WHERE and LIKE
clauses can be given to select rows using more\ngeneral conditions, as
discussed in Extended SHOW.\n\nThe ROUTINES table in the INFORMATION_SCHEMA
database contains more detailed\ninformation.\n\nExamples\n--------\n\nSHOW
PROCEDURE STATUS LIKE \'p1\'\\G\n*************************** 1.
row ***************************\n Db: test\n Name: p1\n
Type: PROCEDURE\n Definer: root@localhost\n Modified:
2010-08-23 13:23:03\n Created: 2010-08-23 13:23:03\n Security_type:
DEFINER\n Comment:\ncharacter_set_client:
latin1\ncollation_connection: latin1_swedish_ci\n Database Collation:
latin1_swedish_ci\n\nURL:
https://mariadb.com/kb/en/show-procedure-status/','','https://mariadb.com/kb/en/show-procedure-status/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(387,26,'SHOW PROCESSLIST','Syntax\n------\n\nSHOW [FULL]
PROCESSLIST\n\nDescription\n-----------\n\nSHOW PROCESSLIST shows you which
threads are running. You can also get this\ninformation from the
information_schema.PROCESSLIST table or the mysqladmin\nprocesslist
command. If you have the PROCESS privilege, you can see all\nthreads.
Otherwise, you can see only your own threads (that is, threads\nassociated
with the MariaDB account that you are using). If you do not use the\nFULL
keyword, only the first 100 characters of each statement are shown in
the\nInfo field.\n\nThe columns shown in SHOW PROCESSLIST
are:\n\n+---------------------+------------------------------------------------------+\n|
Name | Description
|\n+---------------------+------------------------------------------------------+\n|
ID | The client\'s process ID.
|\n+---------------------+------------------------------------------------------+\n|
USER | The username associated with the process.
|\n+---------------------+------------------------------------------------------+\n|
HOST | The host the client is connected to.
|\n+---------------------+------------------------------------------------------+\n|
DB | The default database of the process (NULL if no
|\n| | default).
|\n+---------------------+------------------------------------------------------+\n|
COMMAND | The command type. See Thread Command Values.
|\n+---------------------+------------------------------------------------------+\n|
TIME | The amount of time, in seconds, the process has
|\n| | been in its current state. For a replica SQL
thread |\n| | before MariaDB 10.1, this is the time in
seconds |\n| | between the last replicated
event\'s timestamp and |\n| | the replica
machine\'s real time.
|\n+---------------------+------------------------------------------------------+\n|
STATE | See Thread States.
|\n+---------------------+------------------------------------------------------+\n|
INFO | The statement being executed.
|\n+---------------------+------------------------------------------------------+\n|
PROGRESS | The total progress of the process (0-100%) (see
|\n| | Progress Reporting).
|\n+---------------------+------------------------------------------------------+\n\nSee
TIME_MS column in information_schema.PROCESSLIST for differences in
the\nTIME column between MariaDB and MySQL.\n\nThe
information_schema.PROCESSLIST table contains the following
additional\ncolumns:\n\n+---------------------+------------------------------------------------------+\n|
Name | Description
|\n+---------------------+------------------------------------------------------+\n|
TIME_MS | The amount of time, in milliseconds, the process
|\n| | has been in its current state.
|\n+---------------------+------------------------------------------------------+\n|
STAGE | The stage the process is currently in.
|\n+---------------------+------------------------------------------------------+\n|
MAX_STAGE | The maximum number of stages.
|\n+---------------------+------------------------------------------------------+\n|
PROGRESS | The progress of the process within the current
|\n| | stage (0-100%).
|\n+---------------------+------------------------------------------------------+\n|
MEMORY_USED | The amount of memory used by the process.
|\n+---------------------+------------------------------------------------------+\n|
EXAMINED_ROWS | The number of rows the process has examined.
|\n+---------------------+------------------------------------------------------+\n|
QUERY_ID | Query ID.
|\n+---------------------+------------------------------------------------------+\n\nNote
that the PROGRESS field from the information schema, and the
PROGRESS\nfield from SHOW PROCESSLIST display different results. SHOW
PROCESSLIST shows\nthe total progress, while the information schema shows
the progress for the\ncurrent stage only.\n\nThreads can be killed using
their thread_id or their query_id, with the KILL\nstatement.\n\nSince
queries on this table are locking, if the performance_schema is
enabled,\nyou may want to query the THREADS table
instead.\n\nExamples\n--------\n\nSHOW
PROCESSLIST;\n+----+-----------------+-----------+------+---------+------+-------------------\n----+------------------+----------+\n|
Id | User | Host | db | Command | Time | State
\n | Info | Progress
|\n+----+-----------------+-----------+------+---------+------+-------------------\n----+------------------+----------+\n|
2 | event_scheduler | localhost | NULL | Daemon | 2693 | Waiting on
empty\nqueue | NULL | 0.000 |\n| 4 | root |
localhost | NULL | Query | 0 | Table lock \n | SHOW PROCESSLIST
| 0.000
|\n+----+-----------------+-----------+------+---------+------+-------------------\n----+------------------+----------+\n\nURL:
https://mariadb.com/kb/en/show-processlist/','','https://mariadb.com/kb/en/show-processlist/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(388,26,'SHOW PROFILE','Syntax\n------\n\nSHOW PROFILE [type
[, type] ... ]\n [FOR QUERY n]\n [LIMIT row_count [OFFSET
offset]]\n\ntype:\n ALL\n | BLOCK IO\n | CONTEXT SWITCHES\n | CPU\n |
IPC\n | MEMORY\n | PAGE FAULTS\n | SOURCE\n |
SWAPS\n\nDescription\n-----------\n\nThe SHOW PROFILE and SHOW PROFILES
statements display profiling information\nthat indicates resource usage for
statements executed during the course of the\ncurrent session.\n\nProfiling
is controlled by the profiling session variable, which has a default\nvalue
of 0 (OFF). Profiling is enabled by setting profiling to 1 or ON:\n\nSET
profiling = 1;\n\nSHOW PROFILES displays a list of the most recent
statements sent to the\nmaster. The size of the list is controlled by the
profiling_history_size\nsession variable, which has a default value of 15.
The maximum value is 100.\nSetting the value to 0 has the practical effect
of disabling profiling.\n\nAll statements are profiled except SHOW PROFILES
and SHOW PROFILE, so you will\nfind neither of those statements in the
profile list. Malformed statements are\nprofiled. For example, SHOW
PROFILING is an illegal statement, and a syntax\nerror occurs if you try to
execute it, but it will show up in the profiling\nlist.\n\nSHOW PROFILE
displays detailed information about a single statement. Without\nthe FOR
QUERY n clause, the output pertains to the most recently
executed\nstatement. If FOR QUERY n is included, SHOW PROFILE displays
information for\nstatement n. The values of n correspond to the Query_ID
values displayed by\nSHOW PROFILES.\n\nThe LIMIT row_count clause may be
given to limit the output to row_count rows.\nIf LIMIT is given, OFFSET
offset may be added to begin the output offset rows\ninto the full set of
rows.\n\nBy default, SHOW PROFILE displays Status and Duration columns. The
Status\nvalues are like the State values displayed by SHOW PROCESSLIST,
although there\nmight be some minor differences in interpretation for the
two statements for\nsome status values
(see\nhttp://dev.mysql.com/doc/refman/5.6/en/thread-information.html).\n\nOptional
type values may be specified to display specific additional types
of\ninformation:\n\n* ALL displays all information\n* BLOCK IO displays
counts for block input and output operations\n* CONTEXT SWITCHES displays
counts for voluntary and involuntary context\nswitches\n* CPU displays user
and system CPU usage times\n* IPC displays counts for messages sent and
received\n* MEMORY is not currently implemented\n* PAGE FAULTS displays
counts for major and minor page faults\n* SOURCE displays the names of
functions from the source code, together with\nthe name and line number of
the file in which the function occurs\n* SWAPS displays swap
counts\n\nProfiling is enabled per session. When a session ends, its
profiling\ninformation is lost.\n\nThe information_schema.PROFILING table
contains similar information.\n\nExamples\n--------\n\nSELECT
@@profiling;\n+-------------+\n| @@profiling |\n+-------------+\n|
0 |\n+-------------+\n\nSET profiling = 1;\n\nUSE test;\n\nDROP TABLE IF
EXISTS t1;\n\nCREATE TABLE T1 (id INT);\n\nSHOW
PROFILES;\n+----------+------------+--------------------------+\n| Query_ID
| Duration | Query
|\n+----------+------------+--------------------------+\n| 1 |
0.00009200 | SELECT DATABASE() |\n| 2 | 0.00023800 | show
databases |\n| 3 | 0.00018900 | show tables
|\n| 4 | 0.00014700 | DROP TABLE IF EXISTS t1 |\n| 5 |
0.24476900 | CREATE TABLE T1 (id INT)
|\n+----------+------------+--------------------------+\n\nSHOW
PROFILE;\n+----------------------+----------+\n| Status |
Duration |\n+----------------------+----------+\n| starting |
0.000042 |\n| checking permissions | 0.000044 |\n| creating table |
0.244645 |\n| After create | 0.000013 |\n| query end |
0.000003 |\n| freeing items | 0.000016 |\n| logging slow query |
0.000003 |\n| cleaning up | 0.000003
|\n+----------------------+----------+\n\nSHOW PROFILE FOR QUERY
4;\n+--------------------+----------+\n| Status | Duration
|\n+--------------------+----------+\n| starting | 0.000126 |\n|
query end | 0.000004 |\n| freeing items | 0.000012 |\n|
logging slow query | 0.000003 |\n| cleaning up | 0.000002
|\n+--------------------+----------+\n\nSHOW PROFILE CPU FOR QUERY
5;\n+----------------------+----------+----------+------------+\n| Status
| Duration | CPU_user | CPU_system
|\n+----------------------+----------+----------+------------+\n| starting
| 0.000042 | 0.000000 | 0.000000 |\n| checking permissions |
0.000044 | 0.000000 | 0.000000 |\n| creating table | 0.244645 |
0.000000 | 0.000000 |\n| After create | 0.000013 | 0.000000 |
0.000000 |\n| query end | 0.000003 | 0.000000 | 0.000000 |\n|
freeing items | 0.000016 | 0.000000 | 0.000000 |\n| logging slow
query | 0.000003 | 0.000000 | 0.000000 |\n| cleaning up |
0.000003 | 0.000000 | 0.000000
|\n+----------------------+----------+----------+------------+\n\nURL:
https://mariadb.com/kb/en/show-profile/','','https://mariadb.com/kb/en/show-profile/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(389,26,'SHOW PROFILES','Syntax\n------\n\nSHOW
PROFILES\n\nDescription\n-----------\n\nThe SHOW PROFILES statement
displays profiling information that indicates\nresource usage for
statements executed during the course of the current\nsession. It is used
together with SHOW PROFILE.\n\nURL:
https://mariadb.com/kb/en/show-profiles/','','https://mariadb.com/kb/en/show-profiles/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(390,26,'SHOW QUERY_RESPONSE_TIME','It is possible to use
SHOW QUERY_RESPONSE_TIME as an alternative for\nretrieving information from
the QUERY_RESPONSE_TIME plugin.\n\nThis was introduced as part of the
Information Schema plugin extension.\n\nURL:
https://mariadb.com/kb/en/show-query_response_time/','','https://mariadb.com/kb/en/show-query_response_time/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(391,26,'SHOW STATUS','Syntax\n------\n\nSHOW [GLOBAL |
SESSION] STATUS\n [LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nSHOW STATUS provides server status
information. This information also can be\nobtained using the mysqladmin
extended-status command, or by querying the\nInformation Schema
GLOBAL_STATUS and SESSION_STATUS tables. The LIKE clause,\nif present,
indicates which variable names to match. The WHERE clause can be\ngiven to
select rows using more general conditions.\n\nWith the GLOBAL modifier,
SHOW STATUS displays the status values for all\nconnections to MariaDB.
With SESSION, it displays the status values for the\ncurrent connection. If
no modifier is present, the default is SESSION. LOCAL\nis a synonym for
SESSION. If you see a lot of 0 values, the reason is probably\nthat you
have used SHOW STATUS with a new connection instead of SHOW
GLOBAL\nSTATUS.\n\nSome status variables have only a global value. For
these, you get the same\nvalue for both GLOBAL and SESSION.\n\nSee Server
Status Variables for a full list, scope and description of the\nvariables
that can be viewed with SHOW STATUS.\n\nThe LIKE clause, if present on its
own, indicates which variable name to match.\n\nThe WHERE and LIKE clauses
can be given to select rows using more general\nconditions, as discussed in
Extended SHOW.\n\nExamples\n--------\n\nFull output from MariaDB
10.1.17:\n\nSHOW GLOBAL
STATUS;\n+--------------------------------------------------------------+---------------\n------------------------+\n|
Variable_name | Value
\n
|\n+--------------------------------------------------------------+---------------\n------------------------+\n|
Aborted_clients | 0
\n |\n| Aborted_connects
| 0 \n |\n| Access_denied_errors
| 0 \n |\n| Acl_column_grants
| 0 \n |\n|
Acl_database_grants | 2
\n |\n| Acl_function_grants
| 0 \n |\n| Acl_procedure_grants
| 0 \n |\n| Acl_proxy_users
| 2 \n |\n|
Acl_role_grants | 0
\n |\n| Acl_roles
| 0 \n |\n| Acl_table_grants
| 0 \n |\n| Acl_users
| 6 \n |\n|
Aria_pagecache_blocks_not_flushed | 0
\n |\n| Aria_pagecache_blocks_unused
| 15706 \n |\n| Aria_pagecache_blocks_used
| 0 \n |\n|
Aria_pagecache_read_requests | 0
\n |\n| Aria_pagecache_reads
| 0 \n |\n| Aria_pagecache_write_requests
| 0 \n |\n|
Aria_pagecache_writes | 0
\n |\n| Aria_transaction_log_syncs
| 0 \n |\n| Binlog_commits
| 0 \n |\n|
Binlog_group_commits | 0
\n |\n| Binlog_group_commit_trigger_count
| 0 \n |\n| Binlog_group_commit_trigger_lock_wait
| 0 \n |\n|
Binlog_group_commit_trigger_timeout | 0
\n |\n| Binlog_snapshot_file
| \n |\n| Binlog_snapshot_position
| 0 \n |\n|
Binlog_bytes_written | 0
\n |\n| Binlog_cache_disk_use
| 0 \n |\n| Binlog_cache_use
| 0 \n |\n|
Binlog_stmt_cache_disk_use | 0
\n |\n| Binlog_stmt_cache_use
| 0 \n |\n| Busy_time
| 0.000000 \n |\n| Bytes_received
| 432 \n |\n|
Bytes_sent | 15183
\n |\n| Com_admin_commands
| 1 \n |\n| Com_alter_db
| 0 \n |\n|
Com_alter_db_upgrade | 0
\n |\n| Com_alter_event
| 0 \n |\n| Com_alter_function
| 0 \n |\n|
Com_alter_procedure | 0
\n |\n| Com_alter_server
| 0 \n |\n| Com_alter_table
| 0 \n |\n|
Com_alter_tablespace | 0
\n |\n| Com_analyze
| 0 \n |\n| Com_assign_to_keycache
| 0 \n |\n| Com_begin
| 0 \n |\n|
Com_binlog | 0
\n |\n| Com_call_procedure
| 0 \n |\n| Com_change_db
| 0 \n |\n| Com_change_master
| 0 \n |\n|
Com_check | 0
\n |\n| Com_checksum
| 0 \n |\n| Com_commit
| 0 \n |\n| Com_compound_sql
| 0 \n |\n|
Com_create_db | 0
\n |\n| Com_create_event
| 0 \n |\n| Com_create_function
| 0 \n |\n| Com_create_index
| 0 \n |\n|
Com_create_procedure | 0
\n |\n| Com_create_role
| 0 \n |\n| Com_create_server
| 0 \n |\n| Com_create_table
| 0 \n |\n|
Com_create_temporary_table | 0
\n |\n| Com_create_trigger
| 0 \n |\n| Com_create_udf
| 0 \n |\n| Com_create_user
| 0 \n |\n|
Com_create_view | 0
\n |\n| Com_dealloc_sql
| 0 \n |\n| Com_delete
| 0 \n |\n| Com_delete_multi
| 0 \n |\n|
Com_do | 0
\n |\n| Com_drop_db
| 0 \n |\n| Com_drop_event
| 0 \n |\n| Com_drop_function
| 0 \n |\n|
Com_drop_index | 0
\n |\n| Com_drop_procedure
| 0 \n |\n| Com_drop_role
| 0 \n |\n| Com_drop_server
| 0 \n |\n|
Com_drop_table | 0
\n |\n| Com_drop_temporary_table
| 0 \n |\n| Com_drop_trigger
| 0 \n |\n| Com_drop_user
| 0 \n |\n|
Com_drop_view | 0
\n |\n| Com_empty_query
| 0 \n |\n| Com_execute_sql
| 0 \n |\n| Com_flush
| 0 \n |\n|
Com_get_diagnostics | 0
\n |\n| Com_grant
| 0 \n |\n| Com_grant_role
| 0 \n |\n| Com_ha_close
| 0 \n |\n|
Com_ha_open | 0
\n |\n| Com_ha_read
| 0 \n |\n| Com_help
| 0 \n |\n| Com_insert
| 0 \n |\n|
Com_insert_select | 0
\n |\n| Com_install_plugin
| 0 \n |\n| Com_kill
| 0 \n |\n| Com_load
| 0 \n |\n|
Com_lock_tables | 0
\n |\n| Com_optimize
| 0 \n |\n| Com_preload_keys
| 0 \n |\n| Com_prepare_sql
| 0 \n |\n|
Com_purge | 0
\n |\n| Com_purge_before_date
| 0 \n |\n| Com_release_savepoint
| 0 \n |\n| Com_rename_table
| 0 \n |\n|
Com_rename_user | 0
\n |\n| Com_repair
| 0 \n |\n| Com_replace
| 0 \n |\n| Com_replace_select
| 0 \n |\n|
Com_reset | 0
\n |\n| Com_resignal
| 0 \n |\n| Com_revoke
| 0 \n |\n| Com_revoke_all
| 0 \n |\n|
Com_revoke_role | 0
\n |\n| Com_rollback
| 0 \n |\n| Com_rollback_to_savepoint
| 0 \n |\n| Com_savepoint
| 0 \n |\n|
Com_select | 1
\n |\n| Com_set_option
| 0 \n |\n| Com_show_authors
| 0 \n |\n|
Com_show_binlog_events | 0
\n |\n| Com_show_binlogs
| 0 \n |\n| Com_show_charsets
| 0 \n |\n|
Com_show_collations | 0
\n |\n| Com_show_contributors
| 0 \n |\n| Com_show_create_db
| 0 \n |\n|
Com_show_create_event | 0
\n |\n| Com_show_create_func
| 0 \n |\n| Com_show_create_proc
| 0 \n |\n|
Com_show_create_table | 0
\n |\n| Com_show_create_trigger
| 0 \n |\n| Com_show_databases
| 0 \n |\n|
Com_show_engine_logs | 0
\n
|','','https://mariadb.com/kb/en/show-status/');
update help_topic set description = CONCAT(description, '\n|
Com_show_engine_mutex | 0
\n |\n| Com_show_engine_status
| 0 \n |\n| Com_show_errors
| 0 \n |\n| Com_show_events
| 0 \n |\n|
Com_show_explain | 0
\n |\n| Com_show_fields
| 0 \n |\n| Com_show_function_status
| 0 \n |\n| Com_show_generic
| 0 \n |\n|
Com_show_grants | 0
\n |\n| Com_show_keys
| 0 \n |\n| Com_show_master_status
| 0 \n |\n|
Com_show_open_tables | 0
\n |\n| Com_show_plugins
| 0 \n |\n| Com_show_privileges
| 0 \n |\n|
Com_show_procedure_status | 0
\n |\n| Com_show_processlist
| 0 \n |\n| Com_show_profile
| 0 \n |\n| Com_show_profiles
| 0 \n |\n|
Com_show_relaylog_events | 0
\n |\n| Com_show_slave_hosts
| 0 \n |\n| Com_show_slave_status
| 0 \n |\n| Com_show_status
| 2 \n |\n|
Com_show_storage_engines | 0
\n |\n| Com_show_table_status
| 0 \n |\n| Com_show_tables
| 0 \n |\n| Com_show_triggers
| 0 \n |\n|
Com_show_variables | 0
\n |\n| Com_show_warnings
| 0 \n |\n| Com_shutdown
| 0 \n |\n| Com_signal
| 0 \n |\n|
Com_start_all_slaves | 0
\n |\n| Com_start_slave
| 0 \n |\n| Com_stmt_close
| 0 \n |\n| Com_stmt_execute
| 0 \n |\n|
Com_stmt_fetch | 0
\n |\n| Com_stmt_prepare
| 0 \n |\n| Com_stmt_reprepare
| 0 \n |\n| Com_stmt_reset
| 0 \n |\n|
Com_stmt_send_long_data | 0
\n |\n| Com_stop_all_slaves
| 0 \n |\n| Com_stop_slave
| 0 \n |\n| Com_truncate
| 0 \n |\n|
Com_uninstall_plugin | 0
\n |\n| Com_unlock_tables
| 0 \n |\n| Com_update
| 0 \n |\n| Com_update_multi
| 0 \n |\n|
Com_xa_commit | 0
\n |\n| Com_xa_end
| 0 \n |\n| Com_xa_prepare
| 0 \n |\n| Com_xa_recover
| 0 \n |\n|
Com_xa_rollback | 0
\n |\n| Com_xa_start
| 0 \n |\n| Compression
| OFF \n |\n|
Connection_errors_accept | 0
\n |\n| Connection_errors_internal
| 0 \n |\n| Connection_errors_max_connections
| 0 \n |\n|
Connection_errors_peer_address | 0
\n |\n| Connection_errors_select
| 0 \n |\n| Connection_errors_tcpwrap
| 0 \n |\n| Connections
| 4 \n |\n|
Cpu_time | 0.000000
\n |\n| Created_tmp_disk_tables
| 0 \n |\n| Created_tmp_files
| 6 \n |\n| Created_tmp_tables
| 2 \n |\n|
Delayed_errors | 0
\n |\n| Delayed_insert_threads
| 0 \n |\n| Delayed_writes
| 0 \n |\n| Delete_scan
| 0 \n |\n|
Empty_queries | 0
\n |\n| Executed_events
| 0 \n |\n| Executed_triggers
| 0 \n |\n|
Feature_delay_key_write | 0
\n |\n| Feature_dynamic_columns
| 0 \n |\n| Feature_fulltext
| 0 \n |\n| Feature_gis
| 0 \n |\n|
Feature_locale | 0
\n |\n| Feature_subquery
| 0 \n |\n| Feature_timezone
| 0 \n |\n| Feature_trigger
| 0 \n |\n|
Feature_xml | 0
\n |\n| Flush_commands
| 1 \n |\n| Handler_commit
| 1 \n |\n| Handler_delete
| 0 \n |\n|
Handler_discover | 0
\n |\n| Handler_external_lock
| 0 \n |\n| Handler_icp_attempts
| 0 \n |\n| Handler_icp_match
| 0 \n |\n|
Handler_mrr_init | 0
\n |\n| Handler_mrr_key_refills
| 0 \n |\n| Handler_mrr_rowid_refills
| 0 \n |\n| Handler_prepare
| 0 \n |\n|
Handler_read_first | 3
\n |\n| Handler_read_key
| 0 \n |\n| Handler_read_last
| 0 \n |\n| Handler_read_next
| 0 \n |\n|
Handler_read_prev | 0
\n |\n| Handler_read_retry
| 0 \n |\n| Handler_read_rnd
| 0 \n |\n|
Handler_read_rnd_deleted | 0
\n |\n| Handler_read_rnd_next
| 537 \n |\n| Handler_rollback
| 0 \n |\n| Handler_savepoint
| 0 \n |\n|
Handler_savepoint_rollback | 0
\n |\n| Handler_tmp_update
| 0 \n |\n| Handler_tmp_write
| 516 \n |\n| Handler_update
| 0 \n |\n|
Handler_write | 0
\n |\n| Innodb_available_undo_logs
| 128 \n |\n| Innodb_background_log_sync
| 222 \n |\n|
Innodb_buffer_pool_bytes_data | 2523136
\n |\n| Innodb_buffer_pool_bytes_dirty
| 0 \n |\n| Innodb_buffer_pool_dump_status
| Dumping\nbuffer pool(s) not yet started |\n|
Innodb_buffer_pool_load_status |
Loading\nbuffer pool(s) not yet started |\n| Innodb_buffer_pool_pages_data
| 154 \n |\n|
Innodb_buffer_pool_pages_dirty | 0
\n |\n| Innodb_buffer_pool_pages_flushed
| 1 \n |\n| Innodb_buffer_pool_pages_free
| 8037 \n |\n|
Innodb_buffer_pool_pages_lru_flushed | 0
\n |\n| Innodb_buffer_pool_pages_made_not_young
| 0 \n |\n| Innodb_buffer_pool_pages_made_young
| 0 \n |\n|
Innodb_buffer_pool_pages_misc | 0
\n |\n| Innodb_buffer_pool_pages_old
| 0 \n |\n| Innodb_buffer_pool_pages_total
| 8191 \n |\n|
Innodb_buffer_pool_read_ahead | 0
\n |\n| Innodb_buffer_pool_read_ahead_evicted
| 0 \n |\n| Innodb_buffer_pool_read_ahead_rnd
| 0 \n |\n|
Innodb_buffer_pool_read_requests | 558
\n |\n| Innodb_buffer_pool_reads
| 155 \n |\n| Innodb_buffer_pool_wait_free
| 0 \n |\n|
Innodb_buffer_pool_write_requests | 1
\n |\n| Innodb_checkpoint_age
| 0 \n |\n| Innodb_checkpoint_max_age
| 80826164 \n |\n| Innodb_data_fsyncs
| 5 \n |\n|
Innodb_data_pending_fsyncs | 0
\n |\n| Innodb_data_pending_reads
| 0 \n |\n| Innodb_data_pending_writes
| 0 \n |\n| Innodb_data_read
| 2609664 \n |\n|
Innodb_data_reads | 172
\n |\n| Innodb_data_writes
| 5 \n |\n| Innodb_data_written
| 34304 \n |\n|
Innodb_dblwr_pages_written | 1
\n |\n| Innodb_dblwr_writes
| 1 \n |\n| Innodb_deadlocks
| 0 \n |\n|
Innodb_have_atomic_builtins | ON
\n |\n| Innodb_history_list_length
| 0 \n |\n| Innodb_ibuf_discarded_delete_marks
| 0 \n |\n|
Innodb_ibuf_discarded_deletes | 0
\n |\n| Innodb_ibuf_discarded_inserts
| 0 \n |\n| Innodb_ibuf_free_list
| 0 \n |\n|
Innodb_ibuf_merged_delete_marks | 0
\n |\n| Innodb_ibuf_merged_deletes
| 0 \n |\n| Innodb_ibuf_merged_inserts
| 0 \n |\n| Innodb_ibuf_merges
| 0 \n
|') WHERE help_topic_id = 391;
update help_topic set description = CONCAT(description, '\n|
Innodb_ibuf_segment_size | 2
\n |\n| Innodb_ibuf_size
| 1 \n |\n| Innodb_log_waits
| 0 \n |\n|
Innodb_log_write_requests | 0
\n |\n| Innodb_log_writes
| 1 \n |\n| Innodb_lsn_current
| 1616829 \n |\n| Innodb_lsn_flushed
| 1616829 \n |\n|
Innodb_lsn_last_checkpoint | 1616829
\n |\n| Innodb_master_thread_active_loops
| 0 \n |\n| Innodb_master_thread_idle_loops
| 222 \n |\n| Innodb_max_trx_id
| 2308 \n |\n|
Innodb_mem_adaptive_hash | 2217568
\n |\n| Innodb_mem_dictionary
| 630703 \n |\n| Innodb_mem_total
| 140771328 \n |\n|
Innodb_mutex_os_waits | 1
\n |\n| Innodb_mutex_spin_rounds
| 30 \n |\n| Innodb_mutex_spin_waits
| 1 \n |\n|
Innodb_oldest_view_low_limit_trx_id | 0
\n |\n| Innodb_os_log_fsyncs
| 3 \n |\n| Innodb_os_log_pending_fsyncs
| 0 \n |\n|
Innodb_os_log_pending_writes | 0
\n |\n| Innodb_os_log_written
| 512 \n |\n| Innodb_page_size
| 16384 \n |\n|
Innodb_pages_created | 0
\n |\n| Innodb_pages_read
| 154 \n |\n| Innodb_pages_written
| 1 \n |\n|
Innodb_purge_trx_id | 0
\n |\n| Innodb_purge_undo_no
| 0 \n |\n| Innodb_read_views_memory
| 88 \n |\n|
Innodb_row_lock_current_waits | 0
\n |\n| Innodb_row_lock_time
| 0 \n |\n| Innodb_row_lock_time_avg
| 0 \n |\n|
Innodb_row_lock_time_max | 0
\n |\n| Innodb_row_lock_waits
| 0 \n |\n| Innodb_rows_deleted
| 0 \n |\n|
Innodb_rows_inserted | 0
\n |\n| Innodb_rows_read
| 0 \n |\n| Innodb_rows_updated
| 0 \n |\n|
Innodb_system_rows_deleted | 0
\n |\n| Innodb_system_rows_inserted
| 0 \n |\n| Innodb_system_rows_read
| 0 \n |\n|
Innodb_system_rows_updated | 0
\n |\n| Innodb_s_lock_os_waits
| 2 \n |\n| Innodb_s_lock_spin_rounds
| 60 \n |\n|
Innodb_s_lock_spin_waits | 2
\n |\n| Innodb_truncated_status_writes
| 0 \n |\n| Innodb_x_lock_os_waits
| 0 \n |\n|
Innodb_x_lock_spin_rounds | 0
\n |\n| Innodb_x_lock_spin_waits
| 0 \n |\n| Innodb_page_compression_saved
| 0 \n |\n|
Innodb_page_compression_trim_sect512 | 0
\n |\n| Innodb_page_compression_trim_sect1024
| 0 \n |\n| Innodb_page_compression_trim_sect2048
| 0 \n |\n|
Innodb_page_compression_trim_sect4096 | 0
\n |\n| Innodb_page_compression_trim_sect8192
| 0 \n |\n|
Innodb_page_compression_trim_sect16384 | 0
\n |\n| Innodb_page_compression_trim_sect32768
| 0 \n |\n| Innodb_num_index_pages_written
| 0 \n |\n|
Innodb_num_non_index_pages_written | 5
\n |\n| Innodb_num_pages_page_compressed
| 0 \n |\n| Innodb_num_page_compressed_trim_op
| 0 \n |\n|
Innodb_num_page_compressed_trim_op_saved | 0
\n |\n| Innodb_num_pages_page_decompressed
| 0 \n |\n|
Innodb_num_pages_page_compression_error | 0
\n |\n| Innodb_num_pages_encrypted
| 0 \n |\n| Innodb_num_pages_decrypted
| 0 \n |\n| Innodb_have_lz4
| OFF \n |\n|
Innodb_have_lzo | OFF
\n |\n| Innodb_have_lzma
| OFF \n |\n| Innodb_have_bzip2
| OFF \n |\n| Innodb_have_snappy
| OFF \n |\n|
Innodb_defragment_compression_failures | 0
\n |\n| Innodb_defragment_failures
| 0 \n |\n| Innodb_defragment_count
| 0 \n |\n|
Innodb_onlineddl_rowlog_rows | 0
\n |\n| Innodb_onlineddl_rowlog_pct_used
| 0 \n |\n| Innodb_onlineddl_pct_progress
| 0 \n |\n|
Innodb_secondary_index_triggered_cluster_reads | 0
\n |\n| Innodb_secondary_index_triggered_cluster_reads_avoided
| 0 \n |\n|
Innodb_encryption_rotation_pages_read_from_cache | 0
\n |\n| Innodb_encryption_rotation_pages_read_from_disk
| 0 \n |\n|
Innodb_encryption_rotation_pages_modified | 0
\n |\n| Innodb_encryption_rotation_pages_flushed
| 0 \n |\n|
Innodb_encryption_rotation_estimated_iops | 0
\n |\n| Innodb_scrub_background_page_reorganizations
| 0 \n |\n| Innodb_scrub_background_page_splits
| 0 \n |\n|
Innodb_scrub_background_page_split_failures_underflow | 0
\n |\n|
Innodb_scrub_background_page_split_failures_out_of_filespace | 0
\n |\n|
Innodb_scrub_background_page_split_failures_missing_index | 0
\n |\n| Innodb_scrub_background_page_split_failures_unknown
| 0 \n |\n| Key_blocks_not_flushed
| 0 \n |\n| Key_blocks_unused
| 107163 \n |\n|
Key_blocks_used | 0
\n |\n| Key_blocks_warm
| 0 \n |\n| Key_read_requests
| 0 \n |\n| Key_reads
| 0 \n |\n|
Key_write_requests | 0
\n |\n| Key_writes
| 0 \n |\n| Last_query_cost
| 0.000000 \n |\n|
Master_gtid_wait_count | 0
\n |\n| Master_gtid_wait_time
| 0 \n |\n| Master_gtid_wait_timeouts
| 0 \n |\n|
Max_statement_time_exceeded | 0
\n |\n| Max_used_connections
| 1 \n |\n| Memory_used
| 273614696 \n |\n|
Not_flushed_delayed_rows | 0
\n |\n| Open_files
| 25 \n |\n| Open_streams
| 0 \n |\n|
Open_table_definitions | 18
\n |\n| Open_tables
| 11 \n |\n| Opened_files
| 77 \n |\n|
Opened_plugin_libraries | 0
\n |\n| Opened_table_definitions
| 18 \n |\n| Opened_tables
| 18 \n |\n| Opened_views
| 0 \n |\n|
Performance_schema_accounts_lost | 0
\n |\n| Performance_schema_cond_classes_lost
| 0 \n |\n|
Performance_schema_cond_instances_lost | 0
\n |\n| Performance_schema_digest_lost
| 0 \n |\n| Performance_schema_file_classes_lost
| 0 \n |\n|
Performance_schema_file_handles_lost | 0
\n |\n| Performance_schema_file_instances_lost
| 0 \n |\n| Performance_schema_hosts_lost
| 0 \n |\n|
Performance_schema_locker_lost | 0
\n |\n| Performance_schema_mutex_classes_lost
| 0 \n |\n|
Performance_schema_mutex_instances_lost | 0
\n |\n| Performance_schema_rwlock_classes_lost
| 0 \n |\n|
Performance_schema_rwlock_instances_lost | 0
\n |\n| Performance_schema_session_connect_attrs_lost
| 0 \n |\n|
Performance_schema_socket_classes_lost | 0
\n |\n| Performance_schema_socket_instances_lost
| 0 \n |\n| Performance_schema_stage_classes_lost
| 0 \n |\n|
Performance_schema_statement_classes_lost | 0
\n |\n| Performance_schema_table_handles_lost
| 0 \n |\n|
Performance_schema_table_instances_lost | 0
\n |\n| Performance_schema_thread_classes_lost
| 0 \n |\n|
Performance_schema_thread_instances_lost | 0
\n |\n| Performance_schema_users_lost
| 0 \n |\n| Prepared_stmt_count
| 0 \n |\n| Qcache_free_blocks
| 1 \n |\n|
Qcache_free_memory | 1031336
\n |\n| Qcache_hits
| 0 \n |\n| Qcache_inserts
| 0 \n |\n|
Qcache_lowmem_prunes | 0
\n |\n| Qcache_not_cached
| 0 \n |\n| Qcache_queries_in_cache
| 0 \n |\n|
Qcache_total_blocks | 1
\n |\n| Queries
| 4 \n |\n| Questions
| 4 \n |\n| Rows_read
| 10 \n |\n|
Rows_sent | 517
\n |\n| Rows_tmp_read
| 516 \n |\n| Rpl_status
| AUTH_MASTER \n |') WHERE
help_topic_id = 391;
update help_topic set description = CONCAT(description, '\n|
Select_full_join | 0
\n |\n| Select_full_range_join
| 0 \n |\n| Select_range
| 0 \n |\n| Select_range_check
| 0 \n |\n|
Select_scan | 2
\n |\n| Slave_connections
| 0 \n |\n| Slave_heartbeat_period
| 0.000 \n |\n|
Slave_open_temp_tables | 0
\n |\n| Slave_received_heartbeats
| 0 \n |\n| Slave_retried_transactions
| 0 \n |\n| Slave_running
| OFF \n |\n|
Slave_skipped_errors | 0
\n |\n| Slaves_connected
| 0 \n |\n| Slaves_running
| 0 \n |\n|
Slow_launch_threads | 0
\n |\n| Slow_queries
| 0 \n |\n| Sort_merge_passes
| 0 \n |\n|
Sort_priority_queue_sorts | 0
\n |\n| Sort_range
| 0 \n |\n| Sort_rows
| 0 \n |\n| Sort_scan
| 0 \n |\n|
Ssl_accept_renegotiates | 0
\n |\n| Ssl_accepts
| 0 \n |\n| Ssl_callback_cache_hits
| 0 \n |\n| Ssl_cipher
| \n |\n|
Ssl_cipher_list |
\n |\n| Ssl_client_connects
| 0 \n |\n| Ssl_connect_renegotiates
| 0 \n |\n|
Ssl_ctx_verify_depth | 0
\n |\n| Ssl_ctx_verify_mode
| 0 \n |\n| Ssl_default_timeout
| 0 \n |\n|
Ssl_finished_accepts | 0
\n |\n| Ssl_finished_connects
| 0 \n |\n| Ssl_server_not_after
| \n |\n|
Ssl_server_not_before |
\n |\n| Ssl_session_cache_hits
| 0 \n |\n| Ssl_session_cache_misses
| 0 \n |\n|
Ssl_session_cache_mode | NONE
\n |\n| Ssl_session_cache_overflows
| 0 \n |\n| Ssl_session_cache_size
| 0 \n |\n|
Ssl_session_cache_timeouts | 0
\n |\n| Ssl_sessions_reused
| 0 \n |\n| Ssl_used_session_cache_entries
| 0 \n |\n| Ssl_verify_depth
| 0 \n |\n|
Ssl_verify_mode | 0
\n |\n| Ssl_version
| \n |\n| Subquery_cache_hit
| 0 \n |\n|
Subquery_cache_miss | 0
\n |\n| Syncs
| 2 \n |\n| Table_locks_immediate
| 21 \n |\n| Table_locks_waited
| 0 \n |\n|
Tc_log_max_pages_used | 0
\n |\n| Tc_log_page_size
| 4096 \n |\n| Tc_log_page_waits
| 0 \n |\n|
Threadpool_idle_threads | 0
\n |\n| Threadpool_threads
| 0 \n |\n| Threads_cached
| 0 \n |\n| Threads_connected
| 1 \n |\n|
Threads_created | 2
\n |\n| Threads_running
| 1 \n |\n| Update_scan
| 0 \n |\n| Uptime
| 223 \n |\n|
Uptime_since_flush_status | 223
\n |\n| wsrep_cluster_conf_id
|\n18446744073709551615 |\n| wsrep_cluster_size
| 0 \n |\n|
wsrep_cluster_state_uuid |
\n |\n| wsrep_cluster_status
| Disconnected \n |\n| wsrep_connected
| OFF \n |\n|
wsrep_local_bf_aborts | 0
\n |\n| wsrep_local_index
|\n18446744073709551615 |\n| wsrep_provider_name
| \n |\n|
wsrep_provider_vendor |
\n |\n| wsrep_provider_version
| \n |\n| wsrep_ready
| OFF \n |\n| wsrep_thread_count
| 0 \n
|\n+--------------------------------------------------------------+---------------\n------------------------+\n516
rows in set (0.00 sec)\n\nExample of filtered output:\n\nSHOW STATUS LIKE
\'Key%\';\n+------------------------+--------+\n| Variable_name
| Value |\n+------------------------+--------+\n|
Key_blocks_not_flushed | 0 |\n| Key_blocks_unused | 107163 |\n|
Key_blocks_used | 0 |\n| Key_blocks_warm | 0 |\n|
Key_read_requests | 0 |\n| Key_reads | 0 |\n|
Key_write_requests | 0 |\n| Key_writes | 0
|\n+------------------------+--------+\n8 rows in set (0.00 sec)\n\nURL:
https://mariadb.com/kb/en/show-status/') WHERE help_topic_id = 391;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(392,26,'SHOW TABLE STATUS','Syntax\n------\n\nSHOW TABLE
STATUS [{FROM | IN} db_name]\n [LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nSHOW TABLE STATUS works like SHOW
TABLES, but provides more extensive\ninformation about each non-TEMPORARY
table.\n\nThe LIKE clause, if present on its own, indicates which table
names to match.\nThe WHERE and LIKE clauses can be given to select rows
using more general\nconditions, as discussed in Extended SHOW.\n\nThe
following information is
returned:\n\n+---------------------------+------------------------------------------------+\n|
Column | Description
|\n+---------------------------+------------------------------------------------+\n|
Name | Table name.
|\n+---------------------------+------------------------------------------------+\n|
Engine | Table storage engine.
|\n+---------------------------+------------------------------------------------+\n|
Version | Version number from the table\'s .frm
file.
|\n+---------------------------+------------------------------------------------+\n|
Row_format | Row format (see InnoDB, Aria and MyISAM row
|\n| | formats).
|\n+---------------------------+------------------------------------------------+\n|
Rows | Number of rows in the table. Some engines,
|\n| | such as XtraDB and InnoDB may store an
|\n| | estimate.
|\n+---------------------------+------------------------------------------------+\n|
Avg_row_length | Average row length in the table.
|\n+---------------------------+------------------------------------------------+\n|
Data_length | For InnoDB/XtraDB, the index size, in pages,
|\n| | multiplied by the page size. For Aria and
|\n| | MyISAM, length of the data file, in
bytes. |\n| | For MEMORY, the approximate
allocated memory.
|\n+---------------------------+------------------------------------------------+\n|
Max_data_length | Maximum length of the data file, ie the total
|\n| | number of bytes that could be stored in
the |\n| | table. Not used in XtraDB and
InnoDB.
|\n+---------------------------+------------------------------------------------+\n|
Index_length | Length of the index file.
|\n+---------------------------+------------------------------------------------+\n|
Data_free | Bytes allocated but unused. For InnoDB tables
|\n| | in a shared tablespace, the free space of
the |\n| | shared tablespace with small safety
margin. |\n| | An estimate in the case of
partitioned tables |\n| | - see the PARTITIONS
table.
|\n+---------------------------+------------------------------------------------+\n|
Auto_increment | Next AUTO_INCREMENT value.
|\n+---------------------------+------------------------------------------------+\n|
Create_time | Time the table was created. Some engines just
|\n| | return the ctime information from the file
|\n| | system layer here, in that case the
value is |\n| | not necessarily the table
creation time but |\n| | rather the time the
file system metadata for |\n| | it had last
changed.
|\n+---------------------------+------------------------------------------------+\n|
Update_time | Time the table was last updated. On Windows,
|\n| | the timestamp is not updated on update, so
|\n| | MyISAM values will be inaccurate. In
InnoDB, |\n| | if shared tablespaces are used,
will be NULL, |\n| | while buffering can also
delay the update, so |\n| | the value will
differ from the actual time of |\n| | the last
UPDATE, INSERT or DELETE.
|\n+---------------------------+------------------------------------------------+\n|
Check_time | Time the table was last checked. Not kept by
|\n| | all storage engines, in which case will be
|\n| | NULL.
|\n+---------------------------+------------------------------------------------+\n|
Collation | Character set and collation.
|\n+---------------------------+------------------------------------------------+\n|
Checksum | Live checksum value, if any.
|\n+---------------------------+------------------------------------------------+\n|
Create_options | Extra CREATE TABLE options.
|\n+---------------------------+------------------------------------------------+\n|
Comment | Table comment provided when MariaDB created
|\n| | the table.
|\n+---------------------------+------------------------------------------------+\n|
Max_index_length | Maximum index length (supported by MyISAM and
|\n| | Aria tables). Added in MariaDB 10.3.5.
|\n+---------------------------+------------------------------------------------+\n|
Temporary | Placeholder to signal that a table is a
|\n| | temporary table. Currently always
\"N\", except |\n| | \"Y\"
for generated information_schema tables |\n| |
and NULL for views. Added in MariaDB 10.3.5.
|\n+---------------------------+------------------------------------------------+\n\nSimilar
information can be found in the information_schema.TABLES table as\nwell as
by using mysqlshow:\n\nmysqlshow --status db_name\n\nViews\n-----\n\nFor
views, all columns in SHOW TABLE STATUS are NULL except \'Name\'
and\n\'Comment\'\n\nExample\n-------\n\nshow table
status\\G\n*************************** 1. row ***************************\n
Name: bus_routes\n Engine: InnoDB\n Version: 10\n Row_format:
Dynamic\n Rows: 5\n Avg_row_length: 3276\n Data_length:
16384\nMax_data_length: 0\n Index_length: 0\n Data_free: 0\n
Auto_increment: NULL\n Create_time: 2017-05-24 11:17:46\n Update_time:
NULL\n Check_time: NULL\n Collation: latin1_swedish_ci\n Checksum:
NULL\n Create_options: \n Comment:\n\nURL:
https://mariadb.com/kb/en/show-table-status/','','https://mariadb.com/kb/en/show-table-status/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(393,26,'SHOW TABLES','Syntax\n------\n\nSHOW [FULL] TABLES
[FROM db_name]\n [LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nSHOW TABLES lists the non-TEMPORARY
tables, sequences and views in a given\ndatabase.\n\nThe LIKE clause, if
present on its own, indicates which table names to match.\nThe WHERE and
LIKE clauses can be given to select rows using more general\nconditions, as
discussed in Extended SHOW. For example, when searching for\ntables in the
test database, the column name for use in the WHERE and LIKE\nclauses will
be Tables_in_test\n\nThe FULL modifier is supported such that SHOW FULL
TABLES displays a second\noutput column. Values for the second column,
Table_type, are BASE TABLE for a\ntable, VIEW for a view and SEQUENCE for a
sequence.\n\nYou can also get this information using:\n\nmysqlshow
db_name\n\nSee mysqlshow for more details.\n\nIf you have no privileges for
a base table or view, it does not show up in the\noutput from SHOW TABLES
or mysqlshow db_name.\n\nThe information_schema.TABLES table, as well as
the SHOW TABLE STATUS\nstatement, provide extended information about
tables.\n\nExamples\n--------\n\nSHOW TABLES;\n+----------------------+\n|
Tables_in_test |\n+----------------------+\n| animal_count
|\n| animals |\n| are_the_mooses_loose |\n| aria_test2
|\n| t1 |\n| view1
|\n+----------------------+\n\nShowing the tables beginning with a
only.\n\nSHOW TABLES WHERE Tables_in_test LIKE
\'a%\';\n+----------------------+\n| Tables_in_test
|\n+----------------------+\n| animal_count |\n| animals
|\n| are_the_mooses_loose |\n| aria_test2
|\n+----------------------+\n\nShowing tables and table types:\n\nSHOW FULL
TABLES;\n+----------------+------------+\n| Tables_in_test | Table_type
|\n+----------------+------------+\n| s1 | SEQUENCE |\n|
student | BASE TABLE |\n| v1 | VIEW
|\n+----------------+------------+\n\nURL:
https://mariadb.com/kb/en/show-tables/','','https://mariadb.com/kb/en/show-tables/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(394,26,'SHOW TABLE_STATISTICS','Syntax\n------\n\nSHOW
TABLE_STATISTICS\n\nDescription\n-----------\n\nThe SHOW TABLE_STATISTICS
statementis part of the User Statistics feature. It\nwas removed as a
separate statement in MariaDB 10.1.1, but effectively\nreplaced by the
generic SHOW information_schema_table statement.
The\ninformation_schema.TABLE_STATISTICS table shows statistics on table
usage\n\nThe userstat system variable must be set to 1 to activate this
feature. See\nthe User Statistics and information_schema.TABLE_STATISTICS
articles for more\ninformation.\n\nExample\n-------\n\nSHOW
TABLE_STATISTICS\\G\n*************************** 1. row
***************************\n Table_schema: mysql\n Table_name:
proxies_priv\n Rows_read: 2\n Rows_changed:
0\nRows_changed_x_#indexes: 0\n*************************** 2. row
***************************\n Table_schema: test\n Table_name:
employees_example\n Rows_read: 7\n Rows_changed:
0\nRows_changed_x_#indexes: 0\n*************************** 3. row
***************************\n Table_schema: mysql\n Table_name:
user\n Rows_read: 16\n Rows_changed: 0\nRows_changed_x_#indexes:
0\n*************************** 4. row ***************************\n
Table_schema: mysql\n Table_name: db\n Rows_read: 2\n
Rows_changed: 0\nRows_changed_x_#indexes: 0\n\nURL:
https://mariadb.com/kb/en/show-table-statistics/','','https://mariadb.com/kb/en/show-table-statistics/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(395,26,'SHOW TRIGGERS','Syntax\n------\n\nSHOW TRIGGERS
[FROM db_name]\n [LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nSHOW TRIGGERS lists the triggers
currently defined for tables in a database\n(the default database unless a
FROM clause is given). This statement requires\nthe TRIGGER privilege
(prior to MySQL 5.1.22, it required the SUPER privilege).\n\nThe LIKE
clause, if present on its own, indicates which table names to match\nand
causes the statement to display triggers for those tables. The WHERE
and\nLIKE clauses can be given to select rows using more general
conditions, as\ndiscussed in Extended SHOW.\n\nSimilar information is
stored in the information_schema.TRIGGERS table.\n\nMariaDB starting with
10.2.3\n----------------------------\nIf there are multiple triggers for
the same action, then the triggers are\nshown in action
order.\n\nExamples\n--------\n\nFor the trigger defined at Trigger
Overview:\n\nSHOW triggers Like \'animals\'
\\G\n*************************** 1. row ***************************\n
Trigger: the_mooses_are_loose\n Event: INSERT\n Table:
animals\n Statement: BEGIN\n IF NEW.name = \'Moose\' THEN\n
UPDATE animal_count SET animal_count.animals = animal_count.animals+100;\n
ELSE \n UPDATE animal_count SET animal_count.animals =
animal_count.animals+1;\n END IF;\nEND\n Timing: AFTER\n
Created: 2016-09-29 13:53:34.35\n sql_mode:\n Definer:
root@localhost\ncharacter_set_client: utf8\ncollation_connection:
utf8_general_ci\n Database Collation: latin1_swedish_ci\n\nListing all
triggers associated with a certain table:\n\nSHOW TRIGGERS FROM test WHERE
`Table` = \'user\' \\G\n*************************** 1. row
***************************\n Trigger: user_ai\n Event: INSERT\n
Table: user\n Statement: BEGIN END\n Timing: AFTER\n
Created: 2016-09-29 13:53:34.35\n sql_mode:\n Definer:
root@%\ncharacter_set_client: utf8\ncollation_connection: utf8_general_ci\n
Database Collation: latin1_swedish_ci\n\nSHOW triggers WHERE Event Like
\'Insert\' \\G\n*************************** 1. row
***************************\n Trigger: the_mooses_are_loose\n
Event: INSERT\n Table: animals\n Statement: BEGIN\n IF NEW.name =
\'Moose\' THEN\n UPDATE animal_count SET animal_count.animals =
animal_count.animals+100;\n ELSE \n UPDATE animal_count SET
animal_count.animals = animal_count.animals+1;\n END IF;\nEND\n
Timing: AFTER\n Created: 2016-09-29 13:53:34.35\n sql_mode:\n
Definer: root@localhost\ncharacter_set_client: utf8\ncollation_connection:
utf8_general_ci\n Database Collation: latin1_swedish_ci\n\n*
character_set_client is the session value of the character_set_client
system\nvariable when the trigger was created. \n* collation_connection is
the session value of the collation_connection system\nvariable when the
trigger was\n created. \n* Database Collation is the collation of the
database \n with which the trigger is associated.\n\nThese columns were
added in MariaDB/MySQL 5.1.21.\n\nOld triggers created before MySQL 5.7 and
MariaDB 10.2.3 has NULL in the\nCreated column.\n\nURL:
https://mariadb.com/kb/en/show-triggers/','','https://mariadb.com/kb/en/show-triggers/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(396,26,'SHOW USER_STATISTICS','Syntax\n------\n\nSHOW
USER_STATISTICS\n\nDescription\n-----------\n\nThe SHOW USER_STATISTICS
statement is part of the User Statistics feature. It\nwas removed as a
separate statement in MariaDB 10.1.1, but effectively\nreplaced by the
generic SHOW information_schema_table statement.
The\ninformation_schema.USER_STATISTICS table holds statistics about user
activity.\nYou can use this table to find out such things as which user is
causing the\nmost load and which users are being abusive. You can also use
this table to\nmeasure how close to capacity the server may be.\n\nThe
userstat system variable must be set to 1 to activate this feature.
See\nthe User Statistics and information_schema.USER_STATISTICS table for
more\ninformation.\n\nExample\n-------\n\nSHOW
USER_STATISTICS\\G\n*************************** 1. row
***************************\n User: root\n Total_connections:
1\nConcurrent_connections: 0\n Connected_time: 3297\n Busy_time:
0.14113400000000006\n Cpu_time: 0.017637000000000003\n
Bytes_received: 969\n Bytes_sent: 22355\n Binlog_bytes_written: 0\n
Rows_read: 10\n Rows_sent: 67\n Rows_deleted: 0\n
Rows_inserted: 0\n Rows_updated: 0\n Select_commands: 7\n
Update_commands: 0\n Other_commands: 0\n Commit_transactions: 1\n
Rollback_transactions: 0\n Denied_connections: 0\n Lost_connections: 0\n
Access_denied: 0\n Empty_queries: 7\n\nURL:
https://mariadb.com/kb/en/show-user-statistics/','','https://mariadb.com/kb/en/show-user-statistics/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(397,26,'SHOW VARIABLES','Syntax\n------\n\nSHOW [GLOBAL |
SESSION] VARIABLES\n [LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nSHOW VARIABLES shows the values of
MariaDB system variables. This information\nalso can be obtained using the
mysqladmin variables command. The LIKE clause,\nif present, indicates which
variable names to match. The WHERE clause can be\ngiven to select rows
using more general conditions.\n\nWith the GLOBAL modifier, SHOW VARIABLES
displays the values that are used for\nnew connections to MariaDB. With
SESSION, it displays the values that are in\neffect for the current
connection. If no modifier is present, the default is\nSESSION. LOCAL is a
synonym for SESSION. With a LIKE clause, the statement\ndisplays only rows
for those variables with names that match the pattern. To\nobtain the row
for a specific variable, use a LIKE clause as shown:\n\nSHOW VARIABLES LIKE
\'maria_group_commit\';\nSHOW SESSION VARIABLES LIKE
\'maria_group_commit\';\n\nTo get a list of variables whose name
match a pattern, use the \"%\" wildcard\ncharacter in a LIKE
clause:\n\nSHOW VARIABLES LIKE \'%maria%\';\nSHOW GLOBAL
VARIABLES LIKE \'%maria%\';\n\nWildcard characters can be used in
any position within the pattern to be\nmatched. Strictly speaking, because
\"_\" is a wildcard that matches any single\ncharacter, you
should escape it as \"\\_\" to match it literally. In
practice,\nthis is rarely necessary.\n\nThe WHERE and LIKE clauses can be
given to select rows using more general\nconditions, as discussed in
Extended SHOW.\n\nSee SET for information on setting server system
variables.\n\nSee Server System Variables for a list of all the variables
that can be set.\n\nYou can also see the server variables by querying the
Information Schema\nGLOBAL_VARIABLES and SESSION_VARIABLES
tables.\n\nExamples\n--------\n\nSHOW VARIABLES LIKE
\'aria%\';\n+------------------------------------------+---------------------+\n|
Variable_name | Value
|\n+------------------------------------------+---------------------+\n|
aria_block_size | 8192 |\n|
aria_checkpoint_interval | 30 |\n|
aria_checkpoint_log_activity | 1048576 |\n|
aria_force_start_after_recovery_failures | 0 |\n|
aria_group_commit | none |\n|
aria_group_commit_interval | 0 |\n|
aria_log_file_size | 1073741824 |\n|
aria_log_purge_type | immediate |\n|
aria_max_sort_file_size | 9223372036853727232 |\n|
aria_page_checksum | ON |\n|
aria_pagecache_age_threshold | 300 |\n|
aria_pagecache_buffer_size | 134217728 |\n|
aria_pagecache_division_limit | 100 |\n|
aria_recover | NORMAL |\n|
aria_repair_threads | 1 |\n|
aria_sort_buffer_size | 134217728 |\n|
aria_stats_method | nulls_unequal |\n|
aria_sync_log_dir | NEWFILE |\n|
aria_used_for_temp_tables | ON
|\n+------------------------------------------+---------------------+\n\nSELECT
VARIABLE_NAME, SESSION_VALUE, GLOBAL_VALUE FROM\n
INFORMATION_SCHEMA.SYSTEM_VARIABLES WHERE\n VARIABLE_NAME LIKE
\'max_error_count\' OR\n VARIABLE_NAME LIKE
\'innodb_sync_spin_loops\';\n+---------------------------+---------------+--------------+\n|
VARIABLE_NAME | SESSION_VALUE | GLOBAL_VALUE
|\n+---------------------------+---------------+--------------+\n|
MAX_ERROR_COUNT | 64 | 64 |\n|
INNODB_SYNC_SPIN_LOOPS | NULL | 30
|\n+---------------------------+---------------+--------------+\n\nSET
GLOBAL max_error_count=128;\n\nSELECT VARIABLE_NAME, SESSION_VALUE,
GLOBAL_VALUE FROM\n INFORMATION_SCHEMA.SYSTEM_VARIABLES WHERE\n
VARIABLE_NAME LIKE \'max_error_count\' OR\n VARIABLE_NAME LIKE
\'innodb_sync_spin_loops\';\n+---------------------------+---------------+--------------+\n|
VARIABLE_NAME | SESSION_VALUE | GLOBAL_VALUE
|\n+---------------------------+---------------+--------------+\n|
MAX_ERROR_COUNT | 64 | 128 |\n|
INNODB_SYNC_SPIN_LOOPS | NULL | 30
|\n+---------------------------+---------------+--------------+\n\nSET
GLOBAL max_error_count=128;\n\nSHOW VARIABLES LIKE
\'max_error_count\';\n+-----------------+-------+\n|
Variable_name | Value |\n+-----------------+-------+\n| max_error_count |
64 |\n+-----------------+-------+\n\nSHOW GLOBAL VARIABLES LIKE
\'max_error_count\';\n+-----------------+-------+\n|
Variable_name | Value |\n+-----------------+-------+\n| max_error_count |
128 |\n+-----------------+-------+\n\nBecause the following variable only
has a global scope, the global value is\nreturned even when specifying
SESSION (in this case by default):\n\nSHOW VARIABLES LIKE
\'innodb_sync_spin_loops\';\n+------------------------+-------+\n|
Variable_name | Value |\n+------------------------+-------+\n|
innodb_sync_spin_loops | 30
|\n+------------------------+-------+\n\nURL:
https://mariadb.com/kb/en/show-variables/','','https://mariadb.com/kb/en/show-variables/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(398,26,'SHOW WARNINGS','Syntax\n------\n\nSHOW WARNINGS
[LIMIT [offset,] row_count]\nSHOW ERRORS [LIMIT row_count OFFSET
offset]\nSHOW COUNT(*) WARNINGS\n\nDescription\n-----------\n\nSHOW
WARNINGS shows the error, warning, and note messages that resulted
from\nthe last statement that generated messages in the current session. It
shows\nnothing if the last statement used a table and generated no
messages. (That\nis, a statement that uses a table but generates no
messages clears the message\nlist.) Statements that do not use tables and
do not generate messages have no\neffect on the message list.\n\nA note is
different to a warning in that it only appears if the sql_notes\nvariable
is set to 1 (the default), and is not converted to an error if strict\nmode
is enabled.\n\nA related statement, SHOW ERRORS, shows only the
errors.\n\nThe SHOW COUNT(*) WARNINGS statement displays the total number
of errors,\nwarnings, and notes. You can also retrieve this number from the
warning_count\nvariable:\n\nSHOW COUNT(*) WARNINGS;\nSELECT
@@warning_count;\n\nThe value of warning_count might be greater than the
number of messages\ndisplayed by SHOW WARNINGS if the max_error_count
system variable is set so\nlow that not all messages are stored.\n\nThe
LIMIT clause has the same syntax as for the SELECT statement.\n\nSHOW
WARNINGS can be used after EXPLAIN EXTENDED to see how a query
is\ninternally rewritten by MariaDB.\n\nIf the sql_notes server variable is
set to 1, Notes are included in the output\nof SHOW WARNINGS; if it is set
to 0, this statement will not show (or count)\nNotes.\n\nThe results of
SHOW WARNINGS and SHOW COUNT(*) WARNINGS are directly sent to\nthe client.
If you need to access those information in a stored program, you\ncan use
the GET DIAGNOSTICS statement instead.\n\nFor a list of MariaDB error
codes, see MariaDB Error Codes.\n\nThe mysql client also has a number of
options related to warnings. The \\W\ncommand will show warnings after
every statement, while \\w will disable this.\nStarting the client with the
--show-warnings option will show warnings after\nevery
statement.\n\nMariaDB 10.3.1 implements a stored routine error stack trace.
SHOW WARNINGS\ncan also be used to show more information. See the example
below.\n\nExamples\n--------\n\nSELECT 1/0;\n+------+\n| 1/0
|\n+------+\n| NULL |\n+------+\n\nSHOW COUNT(*)
WARNINGS;\n+-------------------------+\n| @@session.warning_count
|\n+-------------------------+\n| 1
|\n+-------------------------+\n\nSHOW
WARNINGS;\n+---------+------+---------------+\n| Level | Code | Message
|\n+---------+------+---------------+\n| Warning | 1365 | Division by 0
|\n+---------+------+---------------+\n\nStack Trace\n-----------\n\nFrom
MariaDB 10.3.1, displaying a stack trace:\n\nDELIMITER $$\nCREATE OR
REPLACE PROCEDURE p1()\n BEGIN\n DECLARE c CURSOR FOR SELECT * FROM
not_existing;\n OPEN c;\n CLOSE c;\n END;\n$$\nCREATE OR REPLACE
PROCEDURE p2()\n BEGIN\n CALL p1;\n END;\n$$\nDELIMITER ;\nCALL p2;\nERROR
1146 (42S02): Table \'test.not_existing\' doesn\'t
exist\n\nSHOW
WARNINGS;\n+-------+------+-----------------------------------------+\n|
Level | Code | Message
|\n+-------+------+-----------------------------------------+\n| Error |
1146 | Table \'test.not_existing\' doesn\'t exist |\n| Note
| 4091 | At line 6 in test.p1 |\n| Note | 4091 | At
line 4 in test.p2
|\n+-------+------+-----------------------------------------+\n\nSHOW
WARNINGS displays a stack trace, showing where the error
actually\nhappened:\n\n* Line 4 in test.p1 is the OPEN command which
actually raised the error\n* Line 3 in test.p2 is the CALL statement,
calling p1 from p2.\n\nURL:
https://mariadb.com/kb/en/show-warnings/','','https://mariadb.com/kb/en/show-warnings/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(399,26,'SHOW WSREP_MEMBERSHIP','SHOW WSREP_MEMBERSHIP is
part of the WSREP_INFO plugin.\n\nSyntax\n------\n\nSHOW
WSREP_MEMBERSHIP\n\nDescription\n-----------\n\nThe SHOW WSREP_MEMBERSHIP
statement returns Galera node cluster membership\ninformation. It returns
the same information as found in the\ninformation_schema.WSREP_MEMBERSHIP
table. Only users with the SUPER privilege\ncan access this
information.\n\nExamples\n--------\n\nSHOW
WSREP_MEMBERSHIP;\n+-------+--------------------------------------+----------+-----------------+\n|
Index | Uuid | Name | Address
|\n+-------+--------------------------------------+----------+-----------------+\n|
0 | 19058073-8940-11e4-8570-16af7bf8fced | my_node1 | 10.0.2.15:16001
|\n| 1 | 19f2b0e0-8942-11e4-9cb8-b39e8ee0b5dd | my_node3 |
10.0.2.15:16003 |\n| 2 | d85e62db-8941-11e4-b1ef-4bc9980e476d |
my_node2 | 10.0.2.15:16002
|\n+-------+--------------------------------------+----------+-----------------+\n\nURL:
https://mariadb.com/kb/en/show-wsrep_membership/','','https://mariadb.com/kb/en/show-wsrep_membership/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(400,26,'SHOW WSREP_STATUS','SHOW WSREP_STATUS is part of
the WSREP_INFO plugin.\n\nSyntax\n------\n\nSHOW
WSREP_STATUS\n\nDescription\n-----------\n\nThe SHOW WSREP_STATUS statement
returns Galera node and cluster status\ninformation. It returns the same
information as found in the\ninformation_schema.WSREP_STATUS table. Only
users with the SUPER privilege can\naccess this
information.\n\nExamples\n--------\n\nSHOW
WSREP_STATUS;\n+------------+-------------+----------------+--------------+\n|
Node_Index | Node_Status | Cluster_Status | Cluster_Size
|\n+------------+-------------+----------------+--------------+\n|
0 | Synced | Primary | 3
|\n+------------+-------------+----------------+--------------+\n\nURL:
https://mariadb.com/kb/en/show-wsrep_status/','','https://mariadb.com/kb/en/show-wsrep_status/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(401,26,'BINLOG','Syntax\n------\n\nBINLOG
\'str\'\n\nDescription\n-----------\n\nBINLOG is an internal-use
statement. It is generated by the\nmariadb-binlog/mysqlbinlog program as
the printable representation of certain\nevents in binary log files. The
\'str\' value is a base 64-encoded string the\nthat server
decodes to determine the data change indicated by the\ncorresponding event.
This statement requires the SUPER privilege (<= MariaDB\n10.5.1) or
theBINLOG REPLAY privilege (>= MariaDB 10.5.2).\n\nURL:
https://mariadb.com/kb/en/binlog/','','https://mariadb.com/kb/en/binlog/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(402,26,'PURGE BINARY LOGS','Syntax\n------\n\nPURGE {
BINARY | MASTER } LOGS\n { TO \'log_name\' | BEFORE
datetime_expr }\n\nDescription\n-----------\n\nThe PURGE BINARY LOGS
statement deletes all the binary log files listed in the\nlog index file
prior to the specified log file name or date. BINARY and MASTER\nare
synonyms. Deleted log files also are removed from the list recorded in
the\nindex file, so that the given log file becomes the first in the
list.\n\nThe datetime expression is in the format \'YYYY-MM-DD
hh:mm:ss\'.\n\nIf a replica is active but has yet to read from a
binary log file you attempt\nto delete, the statement will fail with an
error. However, if the replica is\nnot connected and has yet to read from a
log file you delete, the file will be\ndeleted, but the replica will be
unable to continue replicating once it\nconnects again.\n\nThis statement
has no effect if the server was not started with the --log-bin\noption to
enable binary logging.\n\nTo list the binary log files on the server, use
SHOW BINARY LOGS. To see which\nfiles they are reading, use SHOW SLAVE
STATUS (or SHOW REPLICA STATUS from\nMariaDB 10.5.1). You can only delete
the files that are older than the oldest\nfile that is used by the
slaves.\n\nTo delete all binary log files, use RESET MASTER. To move to a
new log file\n(for example if you want to remove the current log file), use
FLUSH LOGS\nbefore you execute PURGE LOGS.\n\nIf the expire_logs_days
server system variable is not set to 0, the server\nautomatically deletes
binary log files after the given number of days. From\nMariaDB 10.6, the
binlog_expire_logs_seconds variable allows more precise\ncontrol over
binlog deletion, and takes precedence if both are non-zero.\n\nRequires the
SUPER privilege or, from MariaDB 10.5.2, the BINLOG ADMIN\nprivilege, to
run.\n\nExamples\n--------\n\nPURGE BINARY LOGS TO
\'mariadb-bin.000063\';\n\nPURGE BINARY LOGS BEFORE
\'2013-04-21\';\n\nPURGE BINARY LOGS BEFORE \'2013-04-22
09:55:22\';\n\nURL:
https://mariadb.com/kb/en/purge-binary-logs/','','https://mariadb.com/kb/en/purge-binary-logs/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(403,26,'CACHE INDEX','Syntax\n------\n\nCACHE INDEX
\n tbl_index_list [, tbl_index_list] ...\n IN
key_cache_name\n\ntbl_index_list:\n tbl_name [[INDEX|KEY] (index_name[,
index_name] ...)]\n\nDescription\n-----------\n\nThe CACHE INDEX statement
assigns table indexes to a specific key cache. It is\nused only for MyISAM
tables.\n\nA default key cache exists and cannot be destroyed. To create
more key caches,\nthe key_buffer_size server system variable.\n\nThe
associations between tables indexes and key caches are lost on
server\nrestart. To recreate them automatically, it is necessary to
configure caches\nin a configuration file and include some CACHE INDEX (and
optionally LOAD\nINDEX) statements in the init
file.\n\nExamples\n--------\n\nThe following statement assigns indexes from
the tables t1, t2, and t3 to the\nkey cache named hot_cache:\n\nCACHE INDEX
t1, t2, t3 IN
hot_cache;\n+---------+--------------------+----------+----------+\n| Table
| Op | Msg_type | Msg_text
|\n+---------+--------------------+----------+----------+\n| test.t1 |
assign_to_keycache | status | OK |\n| test.t2 | assign_to_keycache
| status | OK |\n| test.t3 | assign_to_keycache | status | OK
|\n+---------+--------------------+----------+----------+\n\nImplementation
(for MyISAM)\n---------------------------\n\nNormally CACHE INDEX should
not take a long time to execute. Internally it\'s\nimplemented the
following way:\n\n* Find the right key cache (under
LOCK_global_system_variables)\n* Open the table with a TL_READ_NO_INSERT
lock.\n* Flush the original key cache for the given file (under key cache
lock)\n* Flush the new key cache for the given file (safety)\n* Move the
file to the new key cache (under file share lock)\n\nThe only possible long
operations are getting the locks for the table and\nflushing the original
key cache, if there were many key blocks for the file in\nit.\n\nWe plan to
also add CACHE INDEX for Aria tables if there is a need for this.\n\nURL:
https://mariadb.com/kb/en/cache-index/','','https://mariadb.com/kb/en/cache-index/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(404,26,'HELP Command','Syntax\n------\n\nHELP
search_string\n\nDescription\n-----------\n\nThe HELP command can be used
in any MariaDB client, such as the mysql\ncommand-line client, to get basic
syntax help and a short description for most\ncommands and functions.\n\nIf
you provide an argument to the HELP command, the mysql client uses it as
a\nsearch string to access server-side help. The proper operation of this
command\nrequires that the help tables in the mysql database be initialized
with help\ntopic information.\n\nIf there is no match for the search
string, the search fails. Use HELP\ncontents to see a list of the help
categories:\n\nHELP contents\nYou asked for help about help category:
\"Contents\"\nFor more information, type \'help
<item>\', where <item> is one of the
following\ncategories:\n Account Management\n Administration\n Compound
Statements\n Data Definition\n Data Manipulation\n Data Types\n Functions\n
Functions and Modifiers for Use with GROUP BY\n Geographic Features\n Help
Metadata\n Language Structure\n Plugins\n Procedures\n Sequences\n Table
Maintenance\n Transactions\n User-Defined Functions\n Utility\n\nIf a
search string matches multiple items, MariaDB shows a list of
matching\ntopics:\n\nHELP drop\nMany help items for your request exist.\nTo
make a more specific request, please type \'help
<item>\',\nwhere <item> is one of the following\ntopics:\n
ALTER TABLE\n DROP DATABASE\n DROP EVENT\n DROP FUNCTION\n DROP FUNCTION
UDF\n DROP INDEX\n DROP PACKAGE\n DROP PACKAGE BODY\n DROP PROCEDURE\n DROP
ROLE\n DROP SEQUENCE\n DROP SERVER\n DROP TABLE\n DROP TRIGGER\n DROP
USER\n DROP VIEW\n\nThen you can enter a topic as the search string to see
the help entry for that\ntopic.\n\nThe help is provided with the MariaDB
server and makes use of four help tables\nfound in the mysql database:
help_relation, help_topic, help_category and\nhelp_keyword. These tables
are populated by the mysql_install_db or\nfill_help_table.sql scripts
which, until MariaDB 10.4.7, contain data\ngenerated from an old version of
MySQL.\n\nURL:
https://mariadb.com/kb/en/help-command/','','https://mariadb.com/kb/en/help-command/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(405,26,'KILL [CONNECTION | QUERY]','Syntax\n------\n\nKILL
[HARD | SOFT] { {CONNECTION|QUERY} thread_id | QUERY ID query_id |
USER\nuser_name }\n\nDescription\n-----------\n\nEach connection to mysqld
runs in a separate thread. You can see which threads\nare running with the
SHOW PROCESSLIST statement and kill a thread with the\nKILL thread_id
statement. KILL allows the optional CONNECTION or QUERY\nmodifier:\n\n*
KILL CONNECTION is the same as KILL with no\n modifier: It terminates the
connection associated with the given thread or\nquery id.\n* KILL QUERY
terminates the statement that the connection thread_id is\n currently
executing, but leaves the connection itself intact.\n* KILL QUERY ID
terminates the query by query_id, leaving the connection\nintact.\n\nIf a
connection is terminated that has an active transaction, the
transaction\nwill be rolled back. If only a query is killed, the current
transaction will\nstay active. See also idle_transaction_timeout.\n\nIf you
have the PROCESS privilege, you can see all threads. If you have the\nSUPER
privilege, or, from MariaDB 10.5.2, the CONNECTION ADMIN privilege,
you\ncan kill all threads and statements. Otherwise, you can see and kill
only your\nown threads and statements.\n\nKilling queries that repair or
create indexes on MyISAM and Aria tables may\nresult in corrupted tables.
Use the SOFT option to avoid this!\n\nThe HARD option (default) kills a
command as soon as possible. If you use\nSOFT, then critical operations
that may leave a table in an inconsistent state\nwill not be interrupted.
Such operations include REPAIR and INDEX creation for\nMyISAM and Aria
tables (REPAIR TABLE, OPTIMIZE TABLE).\n\nKILL ... USER username will kill
all connections/queries for a given user.\nUSER can be specified one of the
following ways:\n\n* username (Kill without regard to hostname)\n*
username@hostname\n* CURRENT_USER or CURRENT_USER()\n\nIf you specify a
thread id and that thread does not exist, you get the\nfollowing
error:\n\nERROR 1094 (HY000): Unknown thread id: <thread_id>\n\nIf
you specify a query id that doesn\'t exist, you get the following
error:\n\nERROR 1957 (HY000): Unknown query id:
<query_id>\n\nHowever, if you specify a user name, no error is issued
for non-connected (or\neven non-existing) users. To check if the
connection/query has been killed,\nyou can use the ROW_COUNT()
function.\n\nA client whose connection is killed receives the following
error:\n\nERROR 1317 (70100): Query execution was interrupted\n\nTo obtain
a list of existing sessions, use the SHOW PROCESSLIST statement or\nquery
the Information Schema PROCESSLIST table.\n\nNote: You cannot use KILL with
the Embedded MySQL Server library because the\nembedded server merely runs
inside the threads of the host application. It\ndoes not create any
connection threads of its own.\n\nNote: You can also use mysqladmin kill
thread_id [,thread_id...] to kill\nconnections. To get a list of running
queries, use mysqladmin processlist. See\nmysqladmin.\n\nPercona Toolkit
contains a program, pt-kill that can be used to automatically\nkill
connections that match certain criteria. For example, it can be used
to\nterminate idle connections, or connections that have been busy for more
than\n60 seconds.\n\nURL:
https://mariadb.com/kb/en/kill/','','https://mariadb.com/kb/en/kill/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(406,26,'LOAD INDEX','Syntax\n------\n\nLOAD INDEX INTO
CACHE\n tbl_index_list [, tbl_index_list] ...\n\ntbl_index_list:\n
tbl_name\n [[INDEX|KEY] (index_name[, index_name] ...)]\n [IGNORE
LEAVES]\n\nDescription\n-----------\n\nThe LOAD INDEX INTO CACHE statement
preloads a table index into the key cache\nto which it has been assigned by
an explicit CACHE INDEX statement, or into\nthe default key cache
otherwise. LOAD INDEX INTO CACHE is used only for MyISAM\nor Aria
tables.\n\nThe IGNORE LEAVES modifier causes only blocks for the nonleaf
nodes of the\nindex to be preloaded.\n\nURL:
https://mariadb.com/kb/en/load-index/','','https://mariadb.com/kb/en/load-index/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(407,26,'RESET','Syntax\n------\n\nRESET reset_option [,
reset_option] ...\n\nDescription\n-----------\n\nThe RESET statement is
used to clear the state of various server operations.\nYou must have the
RELOAD privilege to execute RESET.\n\nRESET acts as a stronger version of
the FLUSH statement.\n\nThe different RESET options
are:\n\n+---------------------------+------------------------------------------------+\n|
Option | Description
|\n+---------------------------+------------------------------------------------+\n|
SLAVE | Deletes all relay logs from the slave and
|\n| [\"connection_name\"] [ALL] | reset the replication position
in the master |\n| | binary log.
|\n+---------------------------+------------------------------------------------+\n|
MASTER | Deletes all old binary logs, makes the binary
|\n| | index file (--log-bin-index) empty and
|\n| | creates a new binary log file. This
is |\n| | useful when you want to reset
the master to |\n| | an initial state. If you
want to just delete |\n| | old, not used binary
logs, you should use the |\n| | PURGE BINARY
LOGS command.
|\n+---------------------------+------------------------------------------------+\n|
QUERY CACHE | Removes all queries from the query cache. See
|\n| | also FLUSH QUERY CACHE.
|\n+---------------------------+------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/reset/','','https://mariadb.com/kb/en/reset/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(408,26,'SHUTDOWN','Syntax\n------\n\nSHUTDOWN [WAIT FOR ALL
{ SLAVES | REPLICAS } ]\n\nDescription\n-----------\n\nThe SHUTDOWN command
shuts the server down.\n\nWAIT FOR ALL
SLAVES\n-------------------\n\nMariaDB starting with
10.4.4\n----------------------------\nThe WAIT FOR ALL SLAVES option was
first added in MariaDB 10.4.4. WAIT FOR ALL\nREPLICAS has been a synonym
since MariaDB 10.5.1.\n\nWhen a master server is shutdown and it goes
through the normal shutdown\nprocess, the master kills client threads in
random order. By default, the\nmaster also considers its binary log dump
threads to be regular client\nthreads. As a consequence, the binary log
dump threads can be killed while\nclient threads still exist, and this
means that data can be written on the\nmaster during a normal shutdown that
won\'t be replicated. This is true even if\nsemi-synchronous
replication is being used.\n\nIn MariaDB 10.4 and later, this problem can
be solved by shutting down the\nserver with the SHUTDOWN command and by
providing the WAIT FOR ALL SLAVES\noption to the command. For
example:\n\nSHUTDOWN WAIT FOR ALL SLAVES;\n\nWhen the WAIT FOR ALL SLAVES
option is provided, the server only kills its\nbinary log dump threads
after all client threads have been killed, and it only\ncompletes the
shutdown after the last binary log has been sent to all\nconnected
replicas.\n\nSee Replication Threads: Binary Log Dump Threads and the
Shutdown Process for\nmore information.\n\nRequired
Permissions\n--------------------\n\nOne must have a SHUTDOWN privilege
(see GRANT) to use this command. It is the\nsame privilege one needs to use
the mariadb-admin/mysqladmin shutdown command.\n\nShutdown for
Upgrades\n---------------------\n\nIf you are doing a shutdown to migrate
to another major version of MariaDB,\nplease ensure that the
innodb_fast_shutdown variable is not 2 (fast crash\nshutdown). The default
of this variable is 1.\n\nExample\n-------\n\nThe following example shows
how to create an event which turns off the server\nat a certain
time:\n\nCREATE EVENT `test`.`shutd`\n ON SCHEDULE\n EVERY 1 DAY\n
STARTS \'2014-01-01 20:00:00\'\n COMMENT \'Shutdown Maria
when the office is closed\'\nDO BEGIN\n SHUTDOWN;\nEND;\n\nOther Ways
to Stop mysqld\n-------------------------\n\nYou can use the
mariadb-admin/mysqladmin shutdown command to take down
mysqld\ncleanly.\n\nYou can also use the system kill command on Unix with
signal SIGTERM (15)\n\nkill -SIGTERM pid-of-mysqld-process\n\nYou can find
the process number of the server process in the file that ends\nwith .pid
in your data directory.\n\nThe above is identical to mysqladmin
shutdown.\n\nOn windows you should use:\n\nNET STOP MySQL\n\nURL:
https://mariadb.com/kb/en/shutdown/','','https://mariadb.com/kb/en/shutdown/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(409,26,'USE','Syntax\n------\n\nUSE
db_name\n\nDescription\n-----------\n\nThe \'USE db_name\'
statement tells MariaDB to use the db_name database as the\ndefault
(current) database for subsequent statements. The database remains
the\ndefault until the end of the session or another USE statement is
issued:\n\nUSE db1;\nSELECT COUNT(*) FROM mytable; # selects from
db1.mytable\nUSE db2;\nSELECT COUNT(*) FROM mytable; # selects from
db2.mytable\n\nThe DATABASE() function (SCHEMA() is a synonym) returns the
default database.\n\nAnother way to set the default database is specifying
its name at mysql\ncommand line client startup.\n\nURL:
https://mariadb.com/kb/en/use/','','https://mariadb.com/kb/en/use/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(410,26,'SHOW FUNCTION CODE','Syntax\n------\n\nSHOW
FUNCTION CODE func_name\n\nDescription\n-----------\n\nSHOW FUNCTION CODE
shows a representation of the internal implementation of\nthe stored
function.\n\nIt is similar to SHOW PROCEDURE CODE but for stored
functions.\n\nURL:
https://mariadb.com/kb/en/show-function-code/','','https://mariadb.com/kb/en/show-function-code/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(411,26,'SHOW COLLATION','Syntax\n------\n\nSHOW COLLATION\n
[LIKE \'pattern\' | WHERE
expr]\n\nDescription\n-----------\n\nThe output from SHOW COLLATION
includes all available collations. The LIKE\nclause, if present on its own,
indicates which collation names to match. The\nWHERE and LIKE clauses can
be given to select rows using more general\nconditions, as discussed in
Extended SHOW.\n\nThe same information can be queried from the Information
Schema COLLATIONS\ntable.\n\nSee Setting Character Sets and Collations for
details on specifying the\ncollation at the server, database, table and
column levels.\n\nExamples\n--------\n\nSHOW COLLATION LIKE
\'latin1%\';\n+-------------------+---------+----+---------+----------+---------+\n|
Collation | Charset | Id | Default | Compiled | Sortlen
|\n+-------------------+---------+----+---------+----------+---------+\n|
latin1_german1_ci | latin1 | 5 | | Yes | 1 |\n|
latin1_swedish_ci | latin1 | 8 | Yes | Yes | 1 |\n|
latin1_danish_ci | latin1 | 15 | | Yes | 1 |\n|
latin1_german2_ci | latin1 | 31 | | Yes | 2 |\n|
latin1_bin | latin1 | 47 | | Yes | 1 |\n|
latin1_general_ci | latin1 | 48 | | Yes | 1 |\n|
latin1_general_cs | latin1 | 49 | | Yes | 1 |\n|
latin1_spanish_ci | latin1 | 94 | | Yes | 1
|\n+-------------------+---------+----+---------+----------+---------+\n\nSHOW
COLLATION WHERE Sortlen LIKE \'8\' AND Charset LIKE
\'utf8\';\n+--------------------+---------+-----+---------+----------+---------+\n|
Collation | Charset | Id | Default | Compiled | Sortlen
|\n+--------------------+---------+-----+---------+----------+---------+\n|
utf8_unicode_ci | utf8 | 192 | | Yes | 8 |\n|
utf8_icelandic_ci | utf8 | 193 | | Yes | 8 |\n|
utf8_latvian_ci | utf8 | 194 | | Yes | 8 |\n|
utf8_romanian_ci | utf8 | 195 | | Yes | 8 |\n|
utf8_slovenian_ci | utf8 | 196 | | Yes | 8 |\n|
utf8_polish_ci | utf8 | 197 | | Yes | 8 |\n|
utf8_estonian_ci | utf8 | 198 | | Yes | 8 |\n|
utf8_spanish_ci | utf8 | 199 | | Yes | 8 |\n|
utf8_swedish_ci | utf8 | 200 | | Yes | 8 |\n|
utf8_turkish_ci | utf8 | 201 | | Yes | 8 |\n|
utf8_czech_ci | utf8 | 202 | | Yes | 8 |\n|
utf8_danish_ci | utf8 | 203 | | Yes | 8 |\n|
utf8_lithuanian_ci | utf8 | 204 | | Yes | 8 |\n|
utf8_slovak_ci | utf8 | 205 | | Yes | 8 |\n|
utf8_spanish2_ci | utf8 | 206 | | Yes | 8 |\n|
utf8_roman_ci | utf8 | 207 | | Yes | 8 |\n|
utf8_persian_ci | utf8 | 208 | | Yes | 8 |\n|
utf8_esperanto_ci | utf8 | 209 | | Yes | 8 |\n|
utf8_hungarian_ci | utf8 | 210 | | Yes | 8 |\n|
utf8_sinhala_ci | utf8 | 211 | | Yes | 8 |\n|
utf8_croatian_ci | utf8 | 213 | | Yes | 8
|\n+--------------------+---------+-----+---------+----------+---------+\n\nURL:
https://mariadb.com/kb/en/show-collation/','','https://mariadb.com/kb/en/show-collation/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(412,27,'DELETE','Syntax\n------\n\nSingle-table
syntax:\n\nDELETE [LOW_PRIORITY] [QUICK] [IGNORE] \n FROM tbl_name
[PARTITION (partition_list)]\n [FOR PORTION OF period FROM expr1 TO
expr2]\n [WHERE where_condition]\n [ORDER BY ...]\n [LIMIT row_count]\n
[RETURNING select_expr\n [, select_expr ...]]\n\nMultiple-table
syntax:\n\nDELETE [LOW_PRIORITY] [QUICK] [IGNORE]\n tbl_name[.*] [,
tbl_name[.*]] ...\n FROM table_references\n [WHERE
where_condition]\n\nOr:\n\nDELETE [LOW_PRIORITY] [QUICK] [IGNORE]\n FROM
tbl_name[.*] [, tbl_name[.*]] ...\n USING table_references\n [WHERE
where_condition]\n\nTrimming history:\n\nDELETE HISTORY\n FROM tbl_name
[PARTITION (partition_list)]\n [BEFORE SYSTEM_TIME [TIMESTAMP|TRANSACTION]
expression]\n\nDescription\n-----------\n\n+---------------------------+------------------------------------------------+\n|
Option | Description
|\n+---------------------------+------------------------------------------------+\n|
LOW_PRIORITY | Wait until all SELECT\'s are done before
|\n| | starting the statement. Used with
storage |\n| | engines that uses table
locking (MyISAM, Aria |\n| | etc). See
HIGH_PRIORITY and LOW_PRIORITY |\n| |
clauses for details.
|\n+---------------------------+------------------------------------------------+\n|
QUICK | Signal the storage engine that it should
|\n| | expect that a lot of rows are deleted. The
|\n| | storage engine engine can do things to
speed |\n| | up the DELETE like ignoring
merging of data |\n| | blocks until all rows
are deleted from the |\n| | block (instead of
when a block is half full). |\n| | This speeds
up things at the expanse of lost |\n| | space
in data blocks. At least MyISAM and |\n| |
Aria support this feature.
|\n+---------------------------+------------------------------------------------+\n|
IGNORE | Don\'t stop the query even if a
not-critical |\n| | error occurs (like data
overflow). See How |\n| | IGNORE works for a
full description.
|\n+---------------------------+------------------------------------------------+\n\nFor
the single-table syntax, the DELETE statement deletes rows from
tbl_name\nand returns a count of the number of deleted rows. This count can
be obtained\nby calling the ROW_COUNT() function. The WHERE clause, if
given, specifies the\nconditions that identify which rows to delete. With
no WHERE clause, all rows\nare deleted. If the ORDER BY clause is
specified, the rows are deleted in the\norder that is specified. The LIMIT
clause places a limit on the number of rows\nthat can be deleted.\n\nFor
the multiple-table syntax, DELETE deletes from each tbl_name the rows
that\nsatisfy the conditions. In this case, ORDER BY and LIMIT> cannot
be used. A\nDELETE can also reference tables which are located in different
databases; see\nIdentifier Qualifiers for the syntax.\n\nwhere_condition is
an expression that evaluates to true for each row to be\ndeleted. It is
specified as described in SELECT.\n\nCurrently, you cannot delete from a
table and select from the same table in a\nsubquery.\n\nYou need the DELETE
privilege on a table to delete rows from it. You need only\nthe SELECT
privilege for any columns that are only read, such as those named\nin the
WHERE clause. See GRANT.\n\nAs stated, a DELETE statement with no WHERE
clause deletes all rows. A faster\nway to do this, when you do not need to
know the number of deleted rows, is to\nuse TRUNCATE TABLE. However, within
a transaction or if you have a lock on the\ntable, TRUNCATE TABLE cannot be
used whereas DELETE can. See TRUNCATE TABLE,\nand
LOCK.\n\nPARTITION\n---------\n\nSee Partition Pruning and Selection for
details.\n\nFOR PORTION OF\n--------------\n\nMariaDB starting with
10.4.3\n----------------------------\nSee Application Time Periods -
Deletion by Portion.\n\nRETURNING\n---------\n\nIt is possible to return a
resultset of the deleted rows for a single table to\nthe client by using
the syntax DELETE ... RETURNING select_expr [,\nselect_expr2 ...]]\n\nAny
of SQL expression that can be calculated from a single row fields
is\nallowed. Subqueries are allowed. The AS keyword is allowed, so it is
possible\nto use aliases.\n\nThe use of aggregate functions is not allowed.
RETURNING cannot be used in\nmulti-table DELETEs.\n\nMariaDB starting with
10.3.1\n----------------------------\n\nSame Source and Target
Table\n----------------------------\n\nUntil MariaDB 10.3.1, deleting from
a table with the same source and target\nwas not possible. From MariaDB
10.3.1, this is now possible. For example:\n\nDELETE FROM t1 WHERE c1 IN
(SELECT b.c1 FROM t1 b WHERE b.c2=0);\n\nMariaDB starting with
10.3.4\n----------------------------\n\nDELETE
HISTORY\n--------------\n\nOne can use DELETE HISTORY to delete historical
information from\nSystem-versioned tables.\n\nExamples\n--------\n\nHow to
use the ORDER BY and LIMIT clauses:\n\nDELETE FROM page_hit ORDER BY
timestamp LIMIT 1000000;\n\nHow to use the RETURNING clause:\n\nDELETE FROM
t RETURNING f1;\n+------+\n| f1 |\n+------+\n| 5 |\n| 50 |\n| 500
|\n+------+\n\nThe following statement joins two tables: one is only used
to satisfy a WHERE\ncondition, but no row is deleted from it; rows from the
other table are\ndeleted, instead.\n\nDELETE post FROM blog INNER JOIN post
WHERE blog.id = post.blog_id;\n\nDeleting from the Same Source and
Target\n----------------------------------------\n\nCREATE TABLE t1 (c1
INT, c2 INT);\nDELETE FROM t1 WHERE c1 IN (SELECT b.c1 FROM t1 b WHERE
b.c2=0);\n\nUntil MariaDB 10.3.1, this returned:\n\nERROR 1093 (HY000):
Table \'t1\' is specified twice, both as a target
for\n\'DELETE\' \n and as a separate source for\n\nFrom MariaDB
10.3.1:\n\nQuery OK, 0 rows affected (0.00 sec)\n\nURL:
https://mariadb.com/kb/en/delete/','','https://mariadb.com/kb/en/delete/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(413,27,'REPLACE','Syntax\n------\n\nREPLACE [LOW_PRIORITY |
DELAYED]\n [INTO] tbl_name [PARTITION (partition_list)] [(col,...)]\n
{VALUES | VALUE} ({expr | DEFAULT},...),(...),...\n[RETURNING select_expr
\n [, select_expr ...]]\n\nOr:\n\nREPLACE [LOW_PRIORITY | DELAYED]\n
[INTO] tbl_name [PARTITION (partition_list)]\n SET col={expr | DEFAULT},
...\n[RETURNING select_expr \n [, select_expr ...]]\n\nOr:\n\nREPLACE
[LOW_PRIORITY | DELAYED]\n [INTO] tbl_name [PARTITION (partition_list)]
[(col,...)]\n SELECT ...\n[RETURNING select_expr \n [, select_expr
...]]\n\nDescription\n-----------\n\nREPLACE works exactly like INSERT,
except that if an old row in the table has\nthe same value as a new row for
a PRIMARY KEY or a UNIQUE index, the old row\nis deleted before the new row
is inserted. If the table has more than one\nUNIQUE keys, it is possible
that the new row conflicts with more than one row.\nIn this case, all
conflicting rows will be deleted.\n\nThe table name can be specified in the
form db_name.tbl_name or, if a default\ndatabase is selected, in the form
tbl_name (see Identifier Qualifiers). This\nallows to use REPLACE ...
SELECT to copy rows between different databases.\n\nMariaDB starting with
10.5.0\n----------------------------\nThe RETURNING clause was introduced
in MariaDB 10.5.0\n\nBasically it works like this:\n\nBEGIN;\nSELECT 1 FROM
t1 WHERE key=# FOR UPDATE;\nIF found-row\n DELETE FROM t1 WHERE key=#
;\nENDIF\nINSERT INTO t1 VALUES (...);\nEND;\n\nThe above can be replaced
with:\n\nREPLACE INTO t1 VALUES (...)\n\nREPLACE is a MariaDB/MySQL
extension to the SQL standard. It either inserts,\nor deletes and inserts.
For other MariaDB/MySQL extensions to standard SQL ---\nthat also handle
duplicate values --- see IGNORE and INSERT ON DUPLICATE
KEY\nUPDATE.\n\nNote that unless the table has a PRIMARY KEY or UNIQUE
index, using a REPLACE\nstatement makes no sense. It becomes equivalent to
INSERT, because there is no\nindex to be used to determine whether a new
row duplicates another.\n\nValues for all columns are taken from the values
sSee Partition Pruning and\nSelection for details.pecified in the REPLACE
statement. Any missing columns\nare set to their default values, just as
happens for INSERT. You cannot refer\nto values from the current row and
use them in the new row. If you use an\nassignment such as \'SET col =
col + 1\', the reference to the column name on\nthe right hand side is
treated as DEFAULT(col), so the assignment is\nequivalent to \'SET col
= DEFAULT(col) + 1\'.\n\nTo use REPLACE, you must have both the INSERT
and DELETE privileges for the\ntable.\n\nThere are some gotchas you should
be aware of, before using REPLACE:\n\n* If there is an AUTO_INCREMENT
field, a new value will be generated.\n* If there are foreign keys, ON
DELETE action will be activated by REPLACE.\n* Triggers on DELETE and
INSERT will be activated by REPLACE.\n\nTo avoid some of these behaviors,
you can use INSERT ... ON DUPLICATE KEY\nUPDATE.\n\nThis statement
activates INSERT and DELETE triggers. See Trigger Overview
for\ndetails.\n\nPARTITION\n---------\n\nSee Partition Pruning and
Selection for details.\n\nREPLACE RETURNING\n-----------------\n\nREPLACE
... RETURNING returns a resultset of the replaced rows.\n\nThis returns the
listed columns for all the rows that are replaced, or\nalternatively, the
specified SELECT expression. Any SQL expressions which can\nbe calculated
can be used in the select expression for the RETURNING clause,\nincluding
virtual columns and aliases, expressions which use various operators\nsuch
as bitwise, logical and arithmetic operators, string functions,
date-time\nfunctions, numeric functions, control flow functions, secondary
functions and\nstored functions. Along with this, statements which have
subqueries and\nprepared statements can also be
used.\n\nExamples\n--------\n\nSimple REPLACE statement\n\nREPLACE INTO t2
VALUES (1,\'Leopard\'),(2,\'Dog\') RETURNING id2,
id2+id2 \nas Total ,id2|id2,
id2&&id2;\n+-----+-------+---------+----------+\n| id2 | Total |
id2|id2 | id2&&id2 |\n+-----+-------+---------+----------+\n| 1 |
2 | 1 | 1 |\n| 2 | 4 | 2 | 1
|\n+-----+-------+---------+----------+\n\nUsing stored functions in
RETURNING\n\nDELIMITER |\nCREATE FUNCTION f(arg INT) RETURNS INT\n BEGIN\n
RETURN (SELECT arg+arg);\n END|\n\nDELIMITER ;\nPREPARE stmt FROM
\"REPLACE INTO t2 SET id2=3, animal2=\'Fox\' RETURNING
f2(id2),\nUPPER(animal2)\";\n\nEXECUTE
stmt;\n+---------+----------------+\n| f2(id2) | UPPER(animal2)
|\n+---------+----------------+\n| 6 | FOX
|\n+---------+----------------+\n\nSubqueries in the statement\n\nREPLACE
INTO t1 SELECT * FROM t2 RETURNING (SELECT id2 FROM t2 WHERE \nid2 IN
(SELECT id2 FROM t2 WHERE id2=1)) AS new_id;\n+--------+\n| new_id
|\n+--------+\n| 1 |\n| 1 |\n| 1 |\n| 1
|\n+--------+\n\nSubqueries in the RETURNING clause that return more than
one row or column\ncannot be used..\n\nAggregate functions cannot be used
in the RETURNING clause. Since aggregate\nfunctions work on a set of values
and if the purpose is to get the row count,\nROW_COUNT() with SELECT can be
used, or it can be used in REPLACE...SEL==\nDescription\n\nREPLACE ...
RETURNING returns a resultset of the replaced rows.\n\nThis returns the
listed columns for all the rows that are replaced, or\nalternatively, the
specified SELECT expression. Any SQL expressions which can\nbe calculated
can be used in the select expression for the RETURNING clause,\nincluding
virtual columns and aliases, expressions which use various operators\nsuch
as bitwise, logical and arithmetic operators, string functions,
date-time\nfunctions, numeric functions, control flow functions, secondary
functions and\nstored functions. Along with this, statements which have
subqueries and\nprepared statements can also be
used.\n\nExamples\n--------\n\nSimple REPLACE statement\n\nREPLACE INTO t2
VALUES (1,\'Leopard\'),(2,\'Dog\') RETURNING id2,
id2+id2 \nas Total ,id2|id2,
id2&&id2;\n+-----+-------+---------+----------+\n| id2 | Total |
id2|id2 | id2&&id2 |\n+-----+-------+---------+----------+\n| 1 |
2 | 1 | 1 |\n| 2 | 4 | 2 | 1
|\n+-----+-------+---------+----------+\n\nUsing stored functions in
RETURNING\n\nDELIMITER |\nCREATE FUNCTION f(arg INT) RETURNS INT\n BEGIN\n
RETURN (SELECT arg+arg);\n END|\n\nDELIMITER ;\nPREPARE stmt FROM
\"REPLACE INTO t2 SET id2=3, animal2=\'Fox\' RETURNING
f2(id2),\nUPPER(animal2)\";\n\nEXECUTE
stmt;\n+---------+----------------+\n| f2(id2) | UPPER(animal2)
|\n+---------+----------------+\n| 6 | FOX
|\n+---------+----------------+\n\nSubqueries in the statement\n\nREPLACE
INTO t1 SELECT * FROM t2 RETURNING (SELECT id2 FROM t2 WHERE \nid2 IN
(SELECT id2 FROM t2 WHERE id2=1)) AS new_id;\n+--------+\n| new_id
|\n+--------+\n| 1 |\n| 1 |\n| 1 |\n| 1
|\n+--------+\n\nSubqueries in the RETURNING clause that return more than
one row or column\ncannot be used..\n\nAggregate functions cannot be used
in the RETURNING clause. Since aggregate\nfunctions work on a set of values
and if the purpose is to get the row count,\nROW_COUNT() with SELECT can be
used, or it can be used in\nREPLACE...SELECT...RETURNING if the table in
the RETURNING clause is not the\nsame as the REPLACE table. ECT...RETURNING
if the table in the RETURNING\nclause is not the same as the REPLACE
table.\n\nURL:
https://mariadb.com/kb/en/replace/','','https://mariadb.com/kb/en/replace/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(414,27,'UPDATE','Syntax\n------\n\nSingle-table
syntax:\n\nUPDATE [LOW_PRIORITY] [IGNORE] table_reference \n [PARTITION
(partition_list)]\n [FOR PORTION OF period FROM expr1 TO expr2]\n SET
col1={expr1|DEFAULT} [,col2={expr2|DEFAULT}] ...\n [WHERE
where_condition]\n [ORDER BY ...]\n [LIMIT row_count]\n\nMultiple-table
syntax:\n\nUPDATE [LOW_PRIORITY] [IGNORE] table_references\n SET
col1={expr1|DEFAULT} [, col2={expr2|DEFAULT}] ...\n [WHERE
where_condition]\n\nDescription\n-----------\n\nFor the single-table
syntax, the UPDATE statement updates columns of existing\nrows in the named
table with new values. The SET clause indicates which\ncolumns to modify
and the values they should be given. Each value can be given\nas an
expression, or the keyword DEFAULT to set a column explicitly to
its\ndefault value. The WHERE clause, if given, specifies the conditions
that\nidentify which rows to update. With no WHERE clause, all rows are
updated. If\nthe ORDER BY clause is specified, the rows are updated in the
order that is\nspecified. The LIMIT clause places a limit on the number of
rows that can be\nupdated.\n\nUntil MariaDB 10.3.2, for the multiple-table
syntax, UPDATE updates rows in\neach table named in table_references that
satisfy the conditions. In this\ncase, ORDER BY and LIMIT cannot be used.
This restriction was lifted in\nMariaDB 10.3.2 and both clauses can be used
with multiple-table updates. An\nUPDATE can also reference tables which are
located in different databases; see\nIdentifier Qualifiers for the
syntax.\n\nwhere_condition is an expression that evaluates to true for each
row to be\nupdated.\n\ntable_references and where_condition are as
specified as described in SELECT.\n\nFor single-table updates, assignments
are evaluated in left-to-right order,\nwhile for multi-table updates, there
is no guarantee of a particular order. If\nthe SIMULTANEOUS_ASSIGNMENT
sql_mode (available from MariaDB 10.3.5) is set,\nUPDATE statements
evaluate all assignments simultaneously.\n\nYou need the UPDATE privilege
only for columns referenced in an UPDATE that\nare actually updated. You
need only the SELECT privilege for any columns that\nare read but not
modified. See GRANT.\n\nThe UPDATE statement supports the following
modifiers:\n\n* If you use the LOW_PRIORITY keyword, execution of\n the
UPDATE is delayed until no other clients are reading from\n the table. This
affects only storage engines that use only table-level\n locking (MyISAM,
MEMORY, MERGE). See HIGH_PRIORITY and LOW_PRIORITY clauses\nfor details.\n*
If you use the IGNORE keyword, the update statement does \n not abort even
if errors occur during the update. Rows for which\n duplicate-key conflicts
occur are not updated. Rows for which columns are\n updated to values that
would cause data conversion errors are updated to the\n closest valid
values instead.\n\nPARTITION\n---------\n\nSee Partition Pruning and
Selection for details.\n\nFOR PORTION OF\n--------------\n\nMariaDB
starting with 10.4.3\n----------------------------\nSee Application Time
Periods - Updating by Portion.\n\nUPDATE Statements With the Same Source
and Target\n-------------------------------------------------\n\nMariaDB
starting with 10.3.2\n----------------------------\nFrom MariaDB 10.3.2,
UPDATE statements may have the same source and target.\n\nFor example,
given the following table:\n\nDROP TABLE t1;\nCREATE TABLE t1 (c1 INT, c2
INT);\nINSERT INTO t1 VALUES (10,10), (20,20);\n\nUntil MariaDB 10.3.1, the
following UPDATE statement would not work:\n\nUPDATE t1 SET c1=c1+1 WHERE
c2=(SELECT MAX(c2) FROM t1);\nERROR 1093 (HY000): Table \'t1\' is
specified twice, \n both as a target for \'UPDATE\' and as a
separate source for data\n\nFrom MariaDB 10.3.2, the statement executes
successfully:\n\nUPDATE t1 SET c1=c1+1 WHERE c2=(SELECT MAX(c2) FROM
t1);\n\nSELECT * FROM t1;\n+------+------+\n| c1 | c2
|\n+------+------+\n| 10 | 10 |\n| 21 | 20
|\n+------+------+\n\nExample\n-------\n\nSingle-table syntax:\n\nUPDATE
table_name SET column1 = value1, column2 = value2 WHERE
id=100;\n\nMultiple-table syntax:\n\nUPDATE tab1, tab2 SET tab1.column1 =
value1, tab1.column2 = value2 WHERE\ntab1.id = tab2.id;\n\nURL:
https://mariadb.com/kb/en/update/','','https://mariadb.com/kb/en/update/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(415,27,'IGNORE','The IGNORE option tells the server to
ignore some common errors.\n\nIGNORE can be used with the following
statements:\n\n* DELETE\n* INSERT (see also INSERT IGNORE)\n* LOAD DATA
INFILE\n* UPDATE\n* ALTER TABLE\n* CREATE TABLE ... SELECT\n* INSERT ...
SELECT\n\nThe logic used:\n\n* Variables out of ranges are replaced with
the maximum/minimum value.\n\n* SQL_MODEs STRICT_TRANS_TABLES,
STRICT_ALL_TABLES, NO_ZERO_IN_DATE,\nNO_ZERO_DATE are ignored.\n\n*
Inserting NULL in a NOT NULL field will insert 0 ( in a numerical\n field),
0000-00-00 ( in a date field) or an empty string ( in a character\n
field).\n\n* Rows that cause a duplicate key error or break a foreign key
constraint are\n not inserted, updated, or deleted.\n\nThe following errors
are
ignored:\n\n+---------------------+---------------------------------+--------------------+\n|
Error number | Symbolic error name | Description
|\n+---------------------+---------------------------------+--------------------+\n|
1022 | ER_DUP_KEY | Can\'t write;
|\n| | | duplicate
key in |\n| | | table
\'%s\'
|\n+---------------------+---------------------------------+--------------------+\n|
1048 | ER_BAD_NULL_ERROR | Column
\'%s\' |\n| |
| cannot be null
|\n+---------------------+---------------------------------+--------------------+\n|
1062 | ER_DUP_ENTRY | Duplicate entry
|\n| | |
\'%s\' for key %d
|\n+---------------------+---------------------------------+--------------------+\n|
1242 | ER_SUBQUERY_NO_1_ROW | Subquery returns
|\n| | | more than 1
row
|\n+---------------------+---------------------------------+--------------------+\n|
1264 | ER_WARN_DATA_OUT_OF_RANGE | Out of range
|\n| | | value for
column |\n| | |
\'%s\' at row %ld
|\n+---------------------+---------------------------------+--------------------+\n|
1265 | WARN_DATA_TRUNCATED | Data truncated
|\n| | | for column
\'%s\' |\n| |
| at row %ld
|\n+---------------------+---------------------------------+--------------------+\n|
1292 | ER_TRUNCATED_WRONG_VALUE | Truncated
|\n| | | incorrect %s
|\n| | | value:
\'%s\'
|\n+---------------------+---------------------------------+--------------------+\n|
1366 | ER_TRUNCATED_WRONG_VALUE_FOR_FI | Incorrect integer
|\n| | LD | value
|\n+---------------------+---------------------------------+--------------------+\n|
1369 | ER_VIEW_CHECK_FAILED | CHECK OPTION
|\n| | | failed
\'%s.%s\'
|\n+---------------------+---------------------------------+--------------------+\n|
1451 | ER_ROW_IS_REFERENCED_2 | Cannot delete or
|\n| | | update a
parent |\n| | | row
|\n+---------------------+---------------------------------+--------------------+\n|
1452 | ER_NO_REFERENCED_ROW_2 | Cannot add or
|\n| | | update a child
|\n| | | row: a
foreign |\n| | |
key constraint |\n| |
| fails (%s)
|\n+---------------------+---------------------------------+--------------------+\n|
1526 | ER_NO_PARTITION_FOR_GIVEN_VALUE | Table has no
|\n| | | partition for
|\n| | | value %s
|\n+---------------------+---------------------------------+--------------------+\n|
1586 | ER_DUP_ENTRY_WITH_KEY_NAME | Duplicate entry
|\n| | |
\'%s\' for key \'%s\'
|\n+---------------------+---------------------------------+--------------------+\n|
1591 | ER_NO_PARTITION_FOR_GIVEN_VALUE | Table has no
|\n| | SILENT | partition for
|\n| | | some
existing |\n| | |
values
|\n+---------------------+---------------------------------+--------------------+\n|
1748 | ER_ROW_DOES_NOT_MATCH_GIVEN_PAR | Found a row not
|\n| | ITION_SET | matching the
|\n| | | given
partition |\n| | |
set
|\n+---------------------+---------------------------------+--------------------+\n\nIgnored
errors normally generate a warning.\n\nA property of the IGNORE clause
consists in causing transactional engines and\nnon-transactional engines
(like XtraDB and Aria) to behave the same way. For\nexample, normally a
multi-row insert which tries to violate a UNIQUE contraint\nis completely
rolled back on XtraDB/InnoDB, but might be partially executed on\nAria.
With the IGNORE clause, the statement will be partially executed in
both\nengines.\n\nDuplicate key errors also generate warnings. The OLD_MODE
server variable can\nbe used to prevent this.\n\nURL:
https://mariadb.com/kb/en/ignore/','','https://mariadb.com/kb/en/ignore/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(416,27,'SELECT','Syntax\n------\n\nSELECT\n [ALL |
DISTINCT | DISTINCTROW]\n [HIGH_PRIORITY]\n [STRAIGHT_JOIN]\n
[SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT]\n [SQL_CACHE |
SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS]\n select_expr [, select_expr ...]\n [
FROM table_references\n [WHERE where_condition]\n [GROUP BY {col_name |
expr | position} [ASC | DESC], ... [WITH ROLLUP]]\n [HAVING
where_condition]\n [ORDER BY {col_name | expr | position} [ASC | DESC],
...]\n [LIMIT {[offset,] row_count | row_count OFFSET offset [ROWS
EXAMINED\nrows_limit] } |\n [OFFSET start { ROW | ROWS }]\n [FETCH {
FIRST | NEXT } [ count ] { ROW | ROWS } { ONLY | WITH TIES }]\n]\n
procedure|[PROCEDURE procedure_name(argument_list)]\n [INTO OUTFILE
\'file_name\' [CHARACTER SET charset_name] [export_options] |\n
INTO DUMPFILE \'file_name\' | INTO var_name [, var_name] ]\n
[FOR UPDATE lock_option | LOCK IN SHARE MODE
lock_option]\nexport_options:\n [{FIELDS | COLUMNS}\n [TERMINATED BY
\'string\']\n [[OPTIONALLY] ENCLOSED BY \'char\']\n
[ESCAPED BY \'char\']\n ]\n [LINES\n [STARTING BY
\'string\']\n [TERMINATED BY \'string\']\n
]\nlock_option:\n [WAIT n | NOWAIT | SKIP
LOCKED]\n\nDescription\n-----------\n\nSELECT is used to retrieve rows
selected from one or more tables, and can\ninclude UNION statements and
subqueries.\n\n* Each select_expr expression indicates a column or data
that you want to\nretrieve. You\nmust have at least one select expression.
See Select Expressions below.\n\n* The FROM clause indicates the table or
tables from which to retrieve rows.\nUse either a single table name or a
JOIN expression. See JOIN\nfor details. If no table is involved, FROM DUAL
can be specified.\n\n* Each table can also be specified as
db_name.tabl_name. Each column can also\nbe specified as tbl_name.col_name
or even db_name.tbl_name.col_name. This\nallows one to write queries which
involve multiple databases. See Identifier\nQualifiers for syntax
details.\n\n* The WHERE clause, if given, indicates the condition or\n
conditions that rows must satisfy to be selected.\n where_condition is an
expression that evaluates to true for\n each row to be selected. The
statement selects all rows if there is no WHERE\n clause.\nIn the WHERE
clause, you can use any of the functions and\n operators that MariaDB
supports, except for aggregate (summary) functions.\nSee Functions and
Operators and Functions and Modifiers for use with GROUP
BY\n(aggregate).\n\n* Use the ORDER BY clause to order the results.\n\n*
Use the LIMIT clause allows you to restrict the results to only\na certain
number of rows, optionally with an offset.\n\n* Use the GROUP BY and HAVING
clauses to group\nrows together when they have columns or computed values
in common.\n\nSELECT can also be used to retrieve rows computed without
reference to any\ntable.\n\nSelect Expressions\n------------------\n\nA
SELECT statement must contain one or more select expressions, separated
by\ncommas. Each select expression can be one of the following:\n\n* The
name of a column.\n* Any expression using functions and operators.\n* * to
select all columns from all tables in the FROM clause.\n* tbl_name.* to
select all columns from just the table tbl_name.\n\nWhen specifying a
column, you can either use just the column name or qualify\nthe column name
with the name of the table using tbl_name.col_name. The\nqualified form is
useful if you are joining multiple tables in the FROM\nclause. If you do
not qualify the column names when selecting from multiple\ntables, MariaDB
will try to find the column in each table. It is an error if\nthat column
name exists in multiple tables.\n\nYou can quote column names using
backticks. If you are qualifying column names\nwith table names, quote each
part separately as `tbl_name`.`col_name`.\n\nIf you use any grouping
functions in any of the select expressions, all rows\nin your results will
be implicitly grouped, as if you had used GROUP BY
NULL.\n\nDISTINCT\n--------\n\nA query may produce some identical rows. By
default, all rows are retrieved,\neven when their values are the same. To
explicitly specify that you want to\nretrieve identical rows, use the ALL
option. If you want duplicates to be\nremoved from the resultset, use the
DISTINCT option. DISTINCTROW is a synonym\nfor DISTINCT. See also COUNT
DISTINCT and SELECT UNIQUE in Oracle mode.\n\nINTO\n----\n\nThe INTO clause
is used to specify that the query results should be written to\na file or
variable.\n\n* SELECT INTO OUTFILE - formatting and writing the result to
an external file.\n* SELECT INTO DUMPFILE - binary-safe writing of the
unformatted results to an\nexternal file.\n* SELECT INTO Variable -
selecting and setting variables.\n\nThe reverse of SELECT INTO OUTFILE is
LOAD DATA.\n\nLIMIT\n-----\n\nRestricts the number of returned rows. See
LIMIT and LIMIT ROWS EXAMINED for\ndetails.\n\nLOCK IN SHARE MODE/FOR
UPDATE\n-----------------------------\n\nSee LOCK IN SHARE MODE and FOR
UPDATE for details on the respective locking\nclauses.\n\nOFFSET ...
FETCH\n----------------\n\nMariaDB starting with
10.6\n--------------------------\nSee SELECT ... OFFSET ... FETCH.\n\nORDER
BY\n--------\n\nOrder a resultset. See ORDER BY for
details.\n\nPARTITION\n---------\n\nSpecifies to the optimizer which
partitions are relevant for the query. Other\npartitions will not be read.
See Partition Pruning and Selection for
details.\n\nPROCEDURE\n---------\n\nPasses the whole result set to a C
Procedure. See PROCEDURE and PROCEDURE\nANALYSE (the only built-in
procedure not requiring the server to be\nrecompiled).\n\nSKIP
LOCKED\n-----------\n\nMariaDB starting with
10.6\n--------------------------\nThe SKIP LOCKED clause was introduced in
MariaDB 10.6.0.\n\nThis causes those rows that couldn\'t be locked
(LOCK IN SHARE MODE or FOR\nUPDATE) to be excluded from the result set. An
explicit NOWAIT is implied\nhere. This is only implemented on InnoDB tables
and ignored otherwise.\n\nSQL_CALC_FOUND_ROWS\n-------------------\n\nWhen
SQL_CALC_FOUND_ROWS is used, then MariaDB will calculate how many
rows\nwould have been in the result, if there would be no LIMIT clause. The
result\ncan be found by calling the function FOUND_ROWS() in your next sql
statement.\n\nmax_statement_time clause\n-------------------------\n\nBy
using max_statement_time in conjunction with SET STATEMENT, it is
possible\nto limit the execution time of individual queries. For
example:\n\nSET STATEMENT max_statement_time=100 FOR \n SELECT field1 FROM
table_name ORDER BY field1;\n\nWAIT/NOWAIT\n-----------\n\nSet the lock
wait timeout. See WAIT and NOWAIT.\n\nExamples\n--------\n\nSELECT f1,f2
FROM t1 WHERE (f3<=10) AND (f4=\'y\');\n\nSee Getting Data
from MariaDB (Beginner tutorial), or the various\nsub-articles, for more
examples.\n\nURL:
https://mariadb.com/kb/en/select/','','https://mariadb.com/kb/en/select/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(417,27,'JOIN Syntax','Description\n-----------\n\nMariaDB
supports the following JOIN syntaxes for the table_references part
of\nSELECT statements and multiple-table DELETE and UPDATE
statements:\n\ntable_references:\n table_reference [, table_reference]
...\n\ntable_reference:\n table_factor\n | join_table\n\ntable_factor:\n
tbl_name [PARTITION (partition_list)]\n
[query_system_time_period_specification] [[AS] alias] [index_hint_list]\n |
table_subquery [query_system_time_period_specification] [AS] alias\n | (
table_references )\n | { ON table_reference LEFT OUTER JOIN
table_reference\n ON conditional_expr }\n\njoin_table:\n
table_reference [INNER | CROSS] JOIN table_factor [join_condition]\n |
table_reference STRAIGHT_JOIN table_factor\n | table_reference
STRAIGHT_JOIN table_factor ON conditional_expr\n | table_reference
{LEFT|RIGHT} [OUTER] JOIN table_reference join_condition\n |
table_reference NATURAL [{LEFT|RIGHT} [OUTER]] JOIN
table_factor\n\njoin_condition:\n ON conditional_expr\n | USING
(column_list)\n\nquery_system_time_period_specification:\n FOR SYSTEM_TIME
AS OF point_in_time\n | FOR SYSTEM_TIME BETWEEN point_in_time AND
point_in_time\n | FOR SYSTEM_TIME FROM point_in_time TO point_in_time\n |
FOR SYSTEM_TIME ALL\n\npoint_in_time:\n [TIMESTAMP] expression\n |
TRANSACTION expression\n\nindex_hint_list:\n index_hint [, index_hint]
...\n\nindex_hint:\n USE {INDEX|KEY}\n [{FOR {JOIN|ORDER BY|GROUP BY}]
([index_list])\n | IGNORE {INDEX|KEY}\n [{FOR {JOIN|ORDER BY|GROUP BY}]
(index_list)\n | FORCE {INDEX|KEY}\n [{FOR {JOIN|ORDER BY|GROUP BY}]
(index_list)\n\nindex_list:\n index_name [, index_name] ...\n\nA table
reference is also known as a join expression.\n\nEach table can also be
specified as db_name.tabl_name. This allows to write\nqueries which involve
multiple databases. See Identifier Qualifiers for syntax\ndetails.\n\nThe
syntax of table_factor is extended in comparison with the SQL
Standard.\nThe latter accepts only table_reference, not a list of them
inside a pair of\nparentheses.\n\nThis is a conservative extension if we
consider each comma in a list of\ntable_reference items as equivalent to an
inner join. For example:\n\nSELECT * FROM t1 LEFT JOIN (t2, t3, t4)\n
ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c)\n\nis equivalent to:\n\nSELECT
* FROM t1 LEFT JOIN (t2 CROSS JOIN t3 CROSS JOIN t4)\n ON (t2.a=t1.a
AND t3.b=t1.b AND t4.c=t1.c)\n\nIn MariaDB, CROSS JOIN is a syntactic
equivalent to INNER JOIN (they can\nreplace each other). In standard SQL,
they are not equivalent. INNER JOIN is\nused with an ON clause, CROSS JOIN
is used otherwise.\n\nIn general, parentheses can be ignored in join
expressions containing only\ninner join operations. MariaDB also supports
nested joins
(see\nhttp://dev.mysql.com/doc/refman/5.1/en/nested-join-optimization.html).\n\nSee
System-versioned tables for more information about FOR SYSTEM_TIME
syntax.\n\nIndex hints can be specified to affect how the MariaDB optimizer
makes use of\nindexes. For more information, see How to force query
plans.\n\nExamples\n--------\n\nSELECT left_tbl.*\n FROM left_tbl LEFT JOIN
right_tbl ON left_tbl.id = right_tbl.id\n WHERE right_tbl.id IS
NULL;\n\nURL:
https://mariadb.com/kb/en/join-syntax/','','https://mariadb.com/kb/en/join-syntax/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(418,27,'Scalar Subqueries','A scalar subquery is a subquery
that returns a single value. This is the\nsimplest form of a subquery, and
can be used in most places a literal or\nsingle column value is
valid.\n\nThe data type, length and character set and collation are all
taken from the\nresult returned by the subquery. The result of a subquery
can always be NULL,\nthat is, no result returned. Even if the original
value is defined as NOT\nNULL, this is disregarded.\n\nA subquery cannot be
used where only a literal is expected, for example LOAD\nDATA INFILE
expects a literal string containing the file name, and LIMIT\nrequires a
literal integer.\n\nExamples\n--------\n\nCREATE TABLE sq1 (num
TINYINT);\n\nCREATE TABLE sq2 (num TINYINT);\n\nINSERT INTO sq1 VALUES
(1);\n\nINSERT INTO sq2 VALUES (10* (SELECT num FROM sq1));\n\nSELECT *
FROM sq2;\n+------+\n| num |\n+------+\n| 10 |\n+------+\n\nInserting a
second row means the subquery is no longer a scalar, and this\nparticular
query is not valid:\n\nINSERT INTO sq1 VALUES (2);\n\nINSERT INTO sq2
VALUES (10* (SELECT num FROM sq1));\nERROR 1242 (21000): Subquery returns
more than 1 row\n\nNo rows in the subquery, so the scalar is
NULL:\n\nINSERT INTO sq2 VALUES (10* (SELECT num FROM sq3 WHERE
num=\'3\'));\n\nSELECT * FROM sq2;\n+------+\n| num
|\n+------+\n| 10 |\n| NULL |\n+------+\n\nA more traditional scalar
subquery, as part of a WHERE clause:\n\nSELECT * FROM sq1 WHERE num =
(SELECT MAX(num)/10 FROM sq2); \n+------+\n| num |\n+------+\n| 1
|\n+------+\n\nURL:
https://mariadb.com/kb/en/subqueries-scalar-subqueries/','','https://mariadb.com/kb/en/subqueries-scalar-subqueries/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(419,27,'Row Subqueries','A row subquery is a subquery
returning a single row, as opposed to a scalar\nsubquery, which returns a
single column from a row, or a literal.\n\nExamples\n--------\n\nCREATE
TABLE staff (name VARCHAR(10), age TINYINT);\n\nCREATE TABLE customer (name
VARCHAR(10), age TINYINT);\n\nINSERT INTO staff VALUES
(\'Bilhah\',37), (\'Valerius\',61),
(\'Maia\',25);\n\nINSERT INTO customer VALUES
(\'Thanasis\',48), (\'Valerius\',61),
(\'Brion\',51);\n\nSELECT * FROM staff WHERE (name,age) = (SELECT
name,age FROM customer
WHERE\nname=\'Valerius\');\n+----------+------+\n| name | age
|\n+----------+------+\n| Valerius | 61
|\n+----------+------+\n\nFinding all rows in one table also in
another:\n\nSELECT name,age FROM staff WHERE (name,age) IN (SELECT name,age
FROM customer);\n+----------+------+\n| name | age
|\n+----------+------+\n| Valerius | 61 |\n+----------+------+\n\nURL:
https://mariadb.com/kb/en/subqueries-row-subqueries/','','https://mariadb.com/kb/en/subqueries-row-subqueries/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(420,27,'Subqueries and ALL','Subqueries using the ALL
keyword will return true if the comparison returns\ntrue for each row
returned by the subquery, or the subquery returns no
rows.\n\nSyntax\n------\n\nscalar_expression comparison_operator ALL
<Table subquery>\n\n* scalar_expression may be any expression that
evaluates to a single\nvalue\n* comparison_operator may be any one of: =,
>, <, >=, <=, <> or !=\n\nALL returns:\n\n* NULL if the
comparison operator returns NULL for at least one row returned\nby the
Table subquery or scalar_expression returns NULL.\n* FALSE if the
comparison operator returns FALSE for at least one row returned\nby the
Table subquery.\n* TRUE if the comparison operator returns TRUE for all
rows returned by the\nTable subquery, or if Table subquery returns no
rows.\n\nNOT IN is an alias for <>
ALL.\n\nExamples\n--------\n\nCREATE TABLE sq1 (num TINYINT);\n\nCREATE
TABLE sq2 (num2 TINYINT);\n\nINSERT INTO sq1 VALUES(100);\n\nINSERT INTO
sq2 VALUES(40),(50),(60);\n\nSELECT * FROM sq1 WHERE num > ALL (SELECT *
FROM sq2);\n+------+\n| num |\n+------+\n| 100 |\n+------+\n\nSince 100
> all of 40,50 and 60, the evaluation is true and the row is
returned\n\nAdding a second row to sq1, where the evaluation for that
record is false:\n\nINSERT INTO sq1 VALUES(30);\n\nSELECT * FROM sq1 WHERE
num > ALL (SELECT * FROM sq2);\n+------+\n| num |\n+------+\n| 100
|\n+------+\n\nAdding a new row to sq2, causing all evaluations to be
false:\n\nINSERT INTO sq2 VALUES(120);\n\nSELECT * FROM sq1 WHERE num >
ALL (SELECT * FROM sq2);\nEmpty set (0.00 sec)\n\nWhen the subquery returns
no results, the evaluation is still true:\n\nSELECT * FROM sq1 WHERE num
> ALL (SELECT * FROM sq2 WHERE num2 > 300);\n+------+\n| num
|\n+------+\n| 100 |\n| 30 |\n+------+\n\nEvaluating against a NULL will
cause the result to be unknown, or not true,\nand therefore return no
rows:\n\nINSERT INTO sq2 VALUES (NULL);\n\nSELECT * FROM sq1 WHERE num >
ALL (SELECT * FROM sq2);\n\nURL:
https://mariadb.com/kb/en/subqueries-and-all/','','https://mariadb.com/kb/en/subqueries-and-all/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(421,27,'Subqueries and ANY','Subqueries using the ANY
keyword will return true if the comparison returns\ntrue for at least one
row returned by the subquery.\n\nSyntax\n------\n\nThe required syntax for
an ANY or SOME quantified comparison is:\n\nscalar_expression
comparison_operator ANY <Table subquery>\n\nOr:\n\nscalar_expression
comparison_operator SOME <Table subquery>\n\n* scalar_expression may
be any expression that evaluates to a\nsingle value.\n* comparison_operator
may be any one of =, >, <, >=, <=, <> or !=.\n\nANY
returns:\n\n* TRUE if the comparison operator returns TRUE for at least one
row returned\nby the Table subquery.\n* FALSE if the comparison operator
returns FALSE for all rows returned by the\nTable subquery, or Table
subquery has zero rows.\n* NULL if the comparison operator returns NULL for
at least one row returned\nby the Table subquery and doesn\'t returns
TRUE for any of them, or if\nscalar_expression returns NULL.\n\nSOME is a
synmonym for ANY, and IN is a synonym for =
ANY\n\nExamples\n--------\n\nCREATE TABLE sq1 (num TINYINT);\n\nCREATE
TABLE sq2 (num2 TINYINT);\n\nINSERT INTO sq1 VALUES(100);\n\nINSERT INTO
sq2 VALUES(40),(50),(120);\n\nSELECT * FROM sq1 WHERE num > ANY (SELECT
* FROM sq2);\n+------+\n| num |\n+------+\n| 100 |\n+------+\n\n100 is
greater than two of the three values, and so the expression evaluates\nas
true.\n\nSOME is a synonym for ANY:\n\nSELECT * FROM sq1 WHERE num <
SOME (SELECT * FROM sq2);\n+------+\n| num |\n+------+\n| 100
|\n+------+\n\nIN is a synonym for = ANY, and here there are no matches, so
no results are\nreturned:\n\nSELECT * FROM sq1 WHERE num IN (SELECT * FROM
sq2);\nEmpty set (0.00 sec)\n\nINSERT INTO sq2 VALUES(100);\nQuery OK, 1
row affected (0.05 sec)\n\nSELECT * FROM sq1 WHERE num <> ANY (SELECT
* FROM sq2);\n+------+\n| num |\n+------+\n| 100 |\n+------+\n\nReading
this query, the results may be counter-intuitive. It may seem to read\nas
\"SELECT * FROM sq1 WHERE num does not match any results in sq2. Since
it\ndoes match 100, it could seem that the results are incorrect. However,
the\nquery returns a result if the match does not match any of sq2. Since
100\nalready does not match 40, the expression evaluates to true
immediately,\nregardless of the 100\'s matching. It may be more easily
readable to use SOME\nin a case such as this:\n\nSELECT * FROM sq1 WHERE
num <> SOME (SELECT * FROM sq2);\n+------+\n| num |\n+------+\n|
100 |\n+------+\n\nURL:
https://mariadb.com/kb/en/subqueries-and-any/','','https://mariadb.com/kb/en/subqueries-and-any/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(422,27,'Subqueries and EXISTS','Syntax\n------\n\nSELECT
... WHERE EXISTS <Table
subquery>\n\nDescription\n-----------\n\nSubqueries using the EXISTS
keyword will return true if the subquery returns\nany rows. Conversely,
subqueries using NOT EXISTS will return true only if the\nsubquery returns
no rows from the table.\n\nEXISTS subqueries ignore the columns specified
by the SELECT of the subquery,\nsince they\'re not relevant. For
example,\n\nSELECT col1 FROM t1 WHERE EXISTS (SELECT * FROM
t2);\n\nand\n\nSELECT col1 FROM t1 WHERE EXISTS (SELECT col2 FROM
t2);\n\nproduce identical results.\n\nExamples\n--------\n\nCREATE TABLE
sq1 (num TINYINT);\n\nCREATE TABLE sq2 (num2 TINYINT);\n\nINSERT INTO sq1
VALUES(100);\n\nINSERT INTO sq2 VALUES(40),(50),(60);\n\nSELECT * FROM sq1
WHERE EXISTS (SELECT * FROM sq2 WHERE num2>50);\n+------+\n| num
|\n+------+\n| 100 |\n+------+\n\nSELECT * FROM sq1 WHERE NOT EXISTS
(SELECT * FROM sq2 GROUP BY num2 HAVING\nMIN(num2)=40);\nEmpty set (0.00
sec)\n\nURL:
https://mariadb.com/kb/en/subqueries-and-exists/','','https://mariadb.com/kb/en/subqueries-and-exists/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(423,27,'Subqueries in a FROM Clause','Although subqueries
are more commonly placed in a WHERE clause, they can also\nform part of the
FROM clause. Such subqueries are commonly called derived\ntables.\n\nIf a
subquery is used in this way, you must also use an AS clause to name
the\nresult of the subquery.\n\nORACLE mode\n-----------\n\nMariaDB
starting with 10.6.0\n----------------------------\nFrom MariaDB 10.6.0,
anonymous subqueries in a FROM clause (no AS clause) are\npermitted in
ORACLE mode.\n\nExamples\n--------\n\nCREATE TABLE student (name CHAR(10),
test CHAR(10), score TINYINT);\n\nINSERT INTO student VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87), (\'Tatiana\',
\'Tuning\', 83);\n\nAssume that, given the data above, you want
to return the average total for\nall students. In other words, the average
of Chun\'s 148 (75+73), Esben\'s 74\n(43+31), etc.\n\nYou cannot
do the following:\n\nSELECT AVG(SUM(score)) FROM student GROUP BY
name;\nERROR 1111 (HY000): Invalid use of group function\n\nA subquery in
the FROM clause is however permitted:\n\nSELECT AVG(sq_sum) FROM (SELECT
SUM(score) AS sq_sum FROM student GROUP BY\nname) AS t;\n+-------------+\n|
AVG(sq_sum) |\n+-------------+\n| 134.0000 |\n+-------------+\n\nFrom
MariaDB 10.6 in ORACLE mode, the following is permitted:\n\nSELECT * FROM
(SELECT 1 FROM DUAL), (SELECT 2 FROM DUAL);\n\nURL:
https://mariadb.com/kb/en/subqueries-in-a-from-clause/','','https://mariadb.com/kb/en/subqueries-in-a-from-clause/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(424,27,'Subqueries and JOINs','A subquery can quite often,
but not in all cases, be rewritten as a JOIN.\n\nRewriting Subqueries as
JOINS\n-----------------------------\n\nA subquery using IN can be
rewritten with the DISTINCT keyword, for example:\n\nSELECT * FROM table1
WHERE col1 IN (SELECT col1 FROM table2);\n\ncan be rewritten as:\n\nSELECT
DISTINCT table1.* FROM table1, table2 WHERE table1.col1=table2.col1;\n\nNOT
IN or NOT EXISTS queries can also be rewritten. For example, these
two\nqueries returns the same result:\n\nSELECT * FROM table1 WHERE col1
NOT IN (SELECT col1 FROM table2);\nSELECT * FROM table1 WHERE NOT EXISTS
(SELECT col1 FROM table2 WHERE\ntable1.col1=table2.col1);\n\nand both can
be rewritten as:\n\nSELECT table1.* FROM table1 LEFT JOIN table2 ON
table1.id=table2.id WHERE\ntable2.id IS NULL;\n\nSubqueries that can be
rewritten as a LEFT JOIN are sometimes more efficient.\n\nUsing Subqueries
instead of JOINS\n---------------------------------\n\nThere are some
scenarios, though, which call for subqueries rather than joins:\n\n* When
you want duplicates, but not false duplicates. Suppose Table_1\n has three
rows — {1,1,2}\n — and Table_2 has two rows\n — {1,2,2}. If you need
to list the rows\n in Table_1 which are also in Table_2, only this\n
subquery-based SELECT statement will give the right answer\n
(1,1,2):\n\nSELECT Table_1.column_1 \nFROM Table_1 \nWHERE
Table_1.column_1 IN \n (SELECT Table_2.column_1\n FROM Table_2);\n\n*
This SQL statement won\'t work:\n\nSELECT Table_1.column_1 \nFROM
Table_1,Table_2 \nWHERE Table_1.column_1 = Table_2.column_1;\n\n* because
the result will be {1,1,2,2}\n — and the duplication of 2 is an error.
This SQL\n statement won\'t work either:\n\nSELECT DISTINCT
Table_1.column_1 \nFROM Table_1,Table_2 \nWHERE Table_1.column_1 =
Table_2.column_1;\n\n* because the result will be {1,2} — and\n the
removal of the duplicated 1 is an error too.\n\n* When the outermost
statement is not a query. The SQL statement:\n\nUPDATE Table_1 SET column_1
= (SELECT column_1 FROM Table_2);\n\n* can\'t be expressed using a
join unless some rare SQL3 features are used.\n\n* When the join is over an
expression. The SQL statement:\n\nSELECT * FROM Table_1 \nWHERE column_1 +
5 =\n (SELECT MAX(column_1) FROM Table_2);\n\n* is hard to express with a
join. In fact, the only way we can think of is\n this SQL
statement:\n\nSELECT Table_1.*\nFROM Table_1, \n (SELECT MAX(column_1)
AS max_column_1 FROM Table_2) AS Table_2\nWHERE Table_1.column_1 + 5 =
Table_2.max_column_1;\n\n* which still involves a parenthesized query, so
nothing is gained from the\n transformation.\n\n* When you want to see the
exception. For example, suppose the question is:\n what books are longer
than Das Kapital? These two queries are effectively\n almost the
same:\n\nSELECT DISTINCT Bookcolumn_1.* \nFROM Books
AS Bookcolumn_1 JOIN Books AS Bookcolumn_2 USING(page_count) \nWHERE title
= \'Das Kapital\';\n\nSELECT DISTINCT Bookcolumn_1.* \nFROM
Books AS Bookcolumn_1 \nWHERE Bookcolumn_1.page_count > \n (SELECT
DISTINCT page_count\n FROM Books AS Bookcolumn_2\n WHERE title =
\'Das Kapital\');\n\n* The difference is between these two SQL
statements is, if there are two\n editions of Das Kapital (with different
page counts), then the self-join\n example will return the books which are
longer than the shortest edition\n of Das Kapital. That might be the wrong
answer, since the original\n question didn\'t ask for \"...
longer than ANY book named Das Kapital\"\n (it seems to contain a
false assumption that there\'s only one edition).\n\nURL:
https://mariadb.com/kb/en/subqueries-and-joins/','','https://mariadb.com/kb/en/subqueries-and-joins/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(425,27,'Subquery Limitations','There are a number of
limitations regarding subqueries, which are discussed\nbelow. The following
tables and data will be used in the examples that follow:\n\nCREATE TABLE
staff(name VARCHAR(10),age TINYINT);\n\nCREATE TABLE customer(name
VARCHAR(10),age TINYINT);\n\nINSERT INTO staff VALUES
\n(\'Bilhah\',37), (\'Valerius\',61),
(\'Maia\',25);\n\nINSERT INTO customer VALUES
\n(\'Thanasis\',48), (\'Valerius\',61),
(\'Brion\',51);\n\nORDER BY and LIMIT\n------------------\n\nTo
use ORDER BY or limit LIMIT in subqueries both must be used.. For
example:\n\nSELECT * FROM staff WHERE name IN (SELECT name FROM customer
ORDER BY name);\n+----------+------+\n| name | age
|\n+----------+------+\n| Valerius | 61 |\n+----------+------+\n\nis
valid, but\n\nSELECT * FROM staff WHERE name IN (SELECT NAME FROM customer
ORDER BY name\nLIMIT 1);\nERROR 1235 (42000): This version of MariaDB
doesn\'t \n yet support \'LIMIT & IN/ALL/ANY/SOME
subquery\'\n\nis not.\n\nModifying and Selecting from the Same
Table\n-------------------------------------------\n\nIt\'s not
possible to both modify and select from the same table in a subquery.\nFor
example:\n\nDELETE FROM staff WHERE name = (SELECT name FROM staff WHERE
age=61);\nERROR 1093 (HY000): Table \'staff\' is specified twice,
both \n as a target for \'DELETE\' and as a separate source for
data\n\nRow Comparison Operations\n-------------------------\n\nThere is
only partial support for row comparison operations. The expression
in\n\nexpr op {ALL|ANY|SOME} subquery,\n\nmust be scalar and the subquery
can only return a single column.\n\nHowever, because of the way IN is
implemented (it is rewritten as a sequence\nof = comparisons and AND), the
expression in\n\nexpression [NOT] IN subquery\n\nis permitted to be an
n-tuple and the subquery can return rows of n-tuples.\n\nFor
example:\n\nSELECT * FROM staff WHERE (name,age) NOT IN (\n SELECT name,age
FROM customer WHERE age >=51]\n);\n+--------+------+\n| name | age
|\n+--------+------+\n| Bilhah | 37 |\n| Maia | 25
|\n+--------+------+\n\nis permitted, but\n\nSELECT * FROM staff WHERE
(name,age) = ALL (\n SELECT name,age FROM customer WHERE age
>=51\n);\nERROR 1241 (21000): Operand should contain 1 column(s)\n\nis
not.\n\nCorrelated Subqueries\n---------------------\n\nSubqueries in the
FROM clause cannot be correlated subqueries. They cannot be\nevaluated for
each row of the outer query since they are evaluated to produce\na result
set during when the query is executed.\n\nStored
Functions\n----------------\n\nA subquery can refer to a stored function
which modifies data. This is an\nextension to the SQL standard, but can
result in indeterminate outcomes. For\nexample, take:\n\nSELECT ... WHERE x
IN (SELECT f() ...);\n\nwhere f() inserts rows. The function f() could be
executed a different number\nof times depending on how the optimizer
chooses to handle the query.\n\nThis sort of construct is therefore not
safe to use in replication that is not\nrow-based, as there could be
different results on the master and the slave.\n\nURL:
https://mariadb.com/kb/en/subquery-limitations/','','https://mariadb.com/kb/en/subquery-limitations/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(426,27,'UNION','UNION is used to combine the results from
multiple SELECT statements into a\nsingle result
set.\n\nSyntax\n------\n\nSELECT ...\nUNION [ALL | DISTINCT] SELECT
...\n[UNION [ALL | DISTINCT] SELECT ...]\n[ORDER BY [column [, column
...]]]\n[LIMIT {[offset,] row_count | row_count OFFSET
offset}]\n\nDescription\n-----------\n\nUNION is used to combine the
results from multiple SELECT statements into a\nsingle result set.\n\nThe
column names from the first SELECT statement are used as the column
names\nfor the results returned. Selected columns listed in corresponding
positions\nof each SELECT statement should have the same data type. (For
example, the\nfirst column selected by the first statement should have the
same type as the\nfirst column selected by the other statements.)\n\nIf
they don\'t, the type and length of the columns in the result take
into\naccount the values returned by all of the SELECTs, so there is no
need for\nexplicit casting. Note that currently this is not the case for
recursive CTEs\n- see MDEV-12325.\n\nTable names can be specified as
db_name.tbl_name. This permits writing UNIONs\nwhich involve multiple
databases. See Identifier Qualifiers for syntax details.\n\nUNION queries
cannot be used with aggregate functions.\n\nEXCEPT and UNION have the same
operation precedence and INTERSECT has a higher\nprecedence, unless running
in Oracle mode, in which case all three have the\nsame
precedence.\n\nALL/DISTINCT\n------------\n\nThe ALL keyword causes
duplicate rows to be preserved. The DISTINCT keyword\n(the default if the
keyword is omitted) causes duplicate rows to be removed by\nthe
results.\n\nUNION ALL and UNION DISTINCT can both be present in a query. In
this case,\nUNION DISTINCT will override any UNION ALLs to its
left.\n\nMariaDB starting with 10.1.1\n----------------------------\nUntil
MariaDB 10.1.1, all UNION ALL statements required the server to create
a\ntemporary table. Since MariaDB 10.1.1, the server can in most cases
execute\nUNION ALL without creating a temporary table, improving
performance (see\nMDEV-334).\n\nORDER BY and
LIMIT\n------------------\n\nIndividual SELECTs can contain their own ORDER
BY and LIMIT clauses. In this\ncase, the individual queries need to be
wrapped between parentheses. However,\nthis does not affect the order of
the UNION, so they only are useful to limit\nthe record read by one
SELECT.\n\nThe UNION can have global ORDER BY and LIMIT clauses, which
affect the whole\nresultset. If the columns retrieved by individual SELECT
statements have an\nalias (AS), the ORDER BY must use that alias, not the
real column names.\n\nHIGH_PRIORITY\n-------------\n\nSpecifying a query as
HIGH_PRIORITY will not work inside a UNION. If applied\nto the first
SELECT, it will be ignored. Applying to a later SELECT results in\na syntax
error:\n\nERROR 1234 (42000): Incorrect usage/placement of
\'HIGH_PRIORITY\'\n\nSELECT ... INTO
...\n-------------------\n\nIndividual SELECTs cannot be written INTO
DUMPFILE or INTO OUTFILE. If the\nlast SELECT statement specifies INTO
DUMPFILE or INTO OUTFILE, the entire\nresult of the UNION will be written.
Placing the clause after any other SELECT\nwill result in a syntax
error.\n\nIf the result is a single row, SELECT ... INTO @var_name can also
be used.\n\nMariaDB starting with
10.4.0\n----------------------------\n\nParentheses\n-----------\n\nFrom
MariaDB 10.4.0, parentheses can be used to specify precedence.
Before\nthis, a syntax error would be
returned.\n\nExamples\n--------\n\nUNION between tables having different
column names:\n\n(SELECT e_name AS name, email FROM
employees)\nUNION\n(SELECT c_name AS name, email FROM
customers);\n\nSpecifying the UNION\'s global order and limiting total
rows:\n\n(SELECT name, email FROM employees)\nUNION\n(SELECT name, email
FROM customers)\nORDER BY name LIMIT 10;\n\nAdding a constant
row:\n\n(SELECT \'John Doe\' AS name,
\'john.doe@example.net\' AS email)\nUNION\n(SELECT name, email
FROM customers);\n\nDiffering types:\n\nSELECT CAST(\'x\' AS
CHAR(1)) UNION SELECT
REPEAT(\'y\',4);\n+----------------------+\n|
CAST(\'x\' AS CHAR(1)) |\n+----------------------+\n| x
|\n| yyyy |\n+----------------------+\n\nReturning
the results in order of each individual SELECT by use of a
sort\ncolumn:\n\n(SELECT 1 AS sort_column, e_name AS name, email FROM
employees)\nUNION\n(SELECT 2, c_name AS name, email FROM customers) ORDER
BY sort_column;\n\nDifference between UNION, EXCEPT and INTERSECT.
INTERSECT ALL and EXCEPT ALL\nare available from MariaDB 10.5.0.\n\nCREATE
TABLE seqs (i INT);\nINSERT INTO seqs VALUES
(1),(2),(2),(3),(3),(4),(5),(6);\n\nSELECT i FROM seqs WHERE i <= 3
UNION SELECT i FROM seqs WHERE i>=3;\n+------+\n| i |\n+------+\n|
1 |\n| 2 |\n| 3 |\n| 4 |\n| 5 |\n| 6 |\n+------+\n\nSELECT i
FROM seqs WHERE i <= 3 UNION ALL SELECT i FROM seqs WHERE
i>=3;\n+------+\n| i |\n+------+\n| 1 |\n| 2 |\n| 2 |\n|
3 |\n| 3 |\n| 3 |\n| 3 |\n| 4 |\n| 5 |\n| 6
|\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 EXCEPT SELECT i FROM seqs
WHERE i>=3;\n+------+\n| i |\n+------+\n| 1 |\n| 2
|\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 EXCEPT ALL SELECT i FROM
seqs WHERE i>=3;\n+------+\n| i |\n+------+\n| 1 |\n| 2 |\n|
2 |\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 INTERSECT SELECT i FROM
seqs WHERE i>=3;\n+------+\n| i |\n+------+\n| 3
|\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 INTERSECT ALL SELECT i
FROM seqs WHERE i>=3;\n+------+\n| i |\n+------+\n| 3 |\n| 3
|\n+------+\n\nParentheses for specifying precedence, from MariaDB
10.4.0\n\nCREATE OR REPLACE TABLE t1 (a INT);\nCREATE OR REPLACE TABLE t2
(b INT);\nCREATE OR REPLACE TABLE t3 (c INT);\n\nINSERT INTO t1 VALUES
(1),(2),(3),(4);\nINSERT INTO t2 VALUES (5),(6);\nINSERT INTO t3 VALUES
(1),(6);\n\n((SELECT a FROM t1) UNION (SELECT b FROM t2)) INTERSECT (SELECT
c FROM t3);\n+------+\n| a |\n+------+\n| 1 |\n| 6
|\n+------+\n\n(SELECT a FROM t1) UNION ((SELECT b FROM t2) INTERSECT
(SELECT c FROM t3));\n+------+\n| a |\n+------+\n| 1 |\n| 2 |\n|
3 |\n| 4 |\n| 6 |\n+------+\n\nURL:
https://mariadb.com/kb/en/union/','','https://mariadb.com/kb/en/union/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(427,27,'EXCEPT','MariaDB starting with
10.3.0\n----------------------------\nEXCEPT was introduced in MariaDB
10.3.0.\n\nThe result of EXCEPT is all records of the left SELECT result
set except\nrecords which are in right SELECT result set, i.e. it is
subtraction of two\nresult sets. From MariaDB 10.6.1, MINUS is a
synonym.\n\nSyntax\n------\n\nSELECT ...\n(INTERSECT [ALL | DISTINCT] |
EXCEPT [ALL | DISTINCT] | UNION [ALL |\nDISTINCT]) SELECT ...\n[(INTERSECT
[ALL | DISTINCT] | EXCEPT [ALL | DISTINCT] | UNION [ALL |\nDISTINCT])
SELECT ...]\n[ORDER BY [{col_name | expr | position} [ASC | DESC] [,
{col_name | expr |\nposition} [ASC | DESC] ...]]]\n[LIMIT {[offset,]
row_count | row_count OFFSET offset}\n| OFFSET start { ROW | ROWS }\n|
FETCH { FIRST | NEXT } [ count ] { ROW | ROWS } { ONLY | WITH TIES }
]\n\nPlease note:\n\n* Brackets for explicit operation precedence are not
supported; use a subquery\nin the FROM clause as a
workaround).\n\nDescription\n-----------\n\nMariaDB has supported EXCEPT
and INTERSECT in addition to UNION since MariaDB\n10.3.\n\nThe queries
before and after EXCEPT must be SELECT or VALUES statements.\n\nAll
behavior for naming columns, ORDER BY and LIMIT is the same as for
UNION.\nNote that the alternative SELECT ... OFFSET ... FETCH syntax is
only\nsupported. This allows us to use the WITH TIES clause.\n\nEXCEPT
implicitly supposes a DISTINCT operation.\n\nThe result of EXCEPT is all
records of the left SELECT result except records\nwhich are in right SELECT
result set, i.e. it is subtraction of two result\nsets.\n\nEXCEPT and UNION
have the same operation precedence and INTERSECT has a higher\nprecedence,
unless running in Oracle mode, in which case all three have the\nsame
precedence.\n\nMariaDB starting with
10.4.0\n----------------------------\n\nParentheses\n-----------\n\nFrom
MariaDB 10.4.0, parentheses can be used to specify precedence.
Before\nthis, a syntax error would be returned.\n\nMariaDB starting with
10.5.0\n----------------------------\n\nALL/DISTINCT\n------------\n\nEXCEPT
ALL and EXCEPT DISTINCT were introduced in MariaDB 10.5.0. The
ALL\noperator leaves duplicates intact, while the DISTINCT operator
removes\nduplicates. DISTINCT is the default behavior if neither operator
is supplied,\nand the only behavior prior to MariaDB
10.5.\n\nExamples\n--------\n\nShow customers which are not
employees:\n\n(SELECT e_name AS name, email FROM
customers)\nEXCEPT\n(SELECT c_name AS name, email FROM
employees);\n\nDifference between UNION, EXCEPT and INTERSECT. INTERSECT
ALL and EXCEPT ALL\nare available from MariaDB 10.5.0.\n\nCREATE TABLE seqs
(i INT);\nINSERT INTO seqs VALUES
(1),(2),(2),(3),(3),(4),(5),(6);\n\nSELECT i FROM seqs WHERE i <= 3
UNION SELECT i FROM seqs WHERE i>=3;\n+------+\n| i |\n+------+\n|
1 |\n| 2 |\n| 3 |\n| 4 |\n| 5 |\n| 6 |\n+------+\n\nSELECT i
FROM seqs WHERE i <= 3 UNION ALL SELECT i FROM seqs WHERE
i>=3;\n+------+\n| i |\n+------+\n| 1 |\n| 2 |\n| 2 |\n|
3 |\n| 3 |\n| 3 |\n| 3 |\n| 4 |\n| 5 |\n| 6
|\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 EXCEPT SELECT i FROM seqs
WHERE i>=3;\n+------+\n| i |\n+------+\n| 1 |\n| 2
|\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 EXCEPT ALL SELECT i FROM
seqs WHERE i>=3;\n+------+\n| i |\n+------+\n| 1 |\n| 2 |\n|
2 |\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 INTERSECT SELECT i FROM
seqs WHERE i>=3;\n+------+\n| i |\n+------+\n| 3
|\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 INTERSECT ALL SELECT i
FROM seqs WHERE i>=3;\n+------+\n| i |\n+------+\n| 3 |\n| 3
|\n+------+\n\nParentheses for specifying precedence, from MariaDB
10.4.0\n\nCREATE OR REPLACE TABLE t1 (a INT);\nCREATE OR REPLACE TABLE t2
(b INT);\nCREATE OR REPLACE TABLE t3 (c INT);\n\nINSERT INTO t1 VALUES
(1),(2),(3),(4);\nINSERT INTO t2 VALUES (5),(6);\nINSERT INTO t3 VALUES
(1),(6);\n\n((SELECT a FROM t1) UNION (SELECT b FROM t2)) EXCEPT (SELECT c
FROM t3);\n+------+\n| a |\n+------+\n| 2 |\n| 3 |\n| 4 |\n|
5 |\n+------+\n\n(SELECT a FROM t1) UNION ((SELECT b FROM t2) EXCEPT
(SELECT c FROM t3));\n+------+\n| a |\n+------+\n| 1 |\n| 2 |\n|
3 |\n| 4 |\n| 5 |\n+------+\n\nHere is an example that makes use of
the SEQUENCE storage engine and the\nVALUES statement, to generate a
numeric sequence and remove some arbitrary\nnumbers from it:\n\n(SELECT seq
FROM seq_1_to_10) EXCEPT VALUES (2), (3), (4);\n+-----+\n| seq
|\n+-----+\n| 1 |\n| 5 |\n| 6 |\n| 7 |\n| 8 |\n| 9 |\n| 10
|\n+-----+\n\nURL:
https://mariadb.com/kb/en/except/','','https://mariadb.com/kb/en/except/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(428,27,'INTERSECT','MariaDB starting with
10.3.0\n----------------------------\nINTERSECT was introduced in MariaDB
10.3.0.\n\nThe result of an intersect is the intersection of right and left
SELECT\nresults, i.e. only records that are present in both result sets
will be\nincluded in the result of the
operation.\n\nSyntax\n------\n\nSELECT ...\n(INTERSECT [ALL | DISTINCT] |
EXCEPT [ALL | DISTINCT] | UNION [ALL |\nDISTINCT]) SELECT ...\n[(INTERSECT
[ALL | DISTINCT] | EXCEPT [ALL | DISTINCT] | UNION [ALL |\nDISTINCT])
SELECT ...]\n[ORDER BY [column [, column ...]]]\n[LIMIT {[offset,]
row_count | row_count OFFSET
offset}]\n\nDescription\n-----------\n\nMariaDB has supported INTERSECT (as
well as EXCEPT) in addition to UNION since\nMariaDB 10.3.\n\nAll behavior
for naming columns, ORDER BY and LIMIT is the same as for
UNION.\n\nINTERSECT implicitly supposes a DISTINCT operation.\n\nThe result
of an intersect is the intersection of right and left SELECT\nresults, i.e.
only records that are present in both result sets will be\nincluded in the
result of the operation.\n\nINTERSECT has higher precedence than UNION and
EXCEPT (unless running running\nin Oracle mode, in which case all three
have the same precedence). If possible\nit will be executed linearly but if
not it will be translated to a subquery in\nthe FROM clause:\n\n(select a,b
from t1)\nunion\n(select c,d from t2)\nintersect\n(select e,f from
t3)\nunion\n(select 4,4);\n\nwill be translated to:\n\n(select a,b from
t1)\nunion\nselect c,d from\n ((select c,d from t2)\n intersect\n (select
e,f from t3)) dummy_subselect\nunion\n(select 4,4)\n\nMariaDB starting with
10.4.0\n----------------------------\n\nParentheses\n-----------\n\nFrom
MariaDB 10.4.0, parentheses can be used to specify precedence.
Before\nthis, a syntax error would be returned.\n\nMariaDB starting with
10.5.0\n----------------------------\n\nALL/DISTINCT\n------------\n\nINTERSECT
ALL and INTERSECT DISTINCT were introduced in MariaDB 10.5.0. The\nALL
operator leaves duplicates intact, while the DISTINCT operator
removes\nduplicates. DISTINCT is the default behavior if neither operator
is supplied,\nand the only behavior prior to MariaDB
10.5.\n\nExamples\n--------\n\nShow customers which are
employees:\n\n(SELECT e_name AS name, email FROM
employees)\nINTERSECT\n(SELECT c_name AS name, email FROM
customers);\n\nDifference between UNION, EXCEPT and INTERSECT. INTERSECT
ALL and EXCEPT ALL\nare available from MariaDB 10.5.0.\n\nCREATE TABLE seqs
(i INT);\nINSERT INTO seqs VALUES
(1),(2),(2),(3),(3),(4),(5),(6);\n\nSELECT i FROM seqs WHERE i <= 3
UNION SELECT i FROM seqs WHERE i>=3;\n+------+\n| i |\n+------+\n|
1 |\n| 2 |\n| 3 |\n| 4 |\n| 5 |\n| 6 |\n+------+\n\nSELECT i
FROM seqs WHERE i <= 3 UNION ALL SELECT i FROM seqs WHERE
i>=3;\n+------+\n| i |\n+------+\n| 1 |\n| 2 |\n| 2 |\n|
3 |\n| 3 |\n| 3 |\n| 3 |\n| 4 |\n| 5 |\n| 6
|\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 EXCEPT SELECT i FROM seqs
WHERE i>=3;\n+------+\n| i |\n+------+\n| 1 |\n| 2
|\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 EXCEPT ALL SELECT i FROM
seqs WHERE i>=3;\n+------+\n| i |\n+------+\n| 1 |\n| 2 |\n|
2 |\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 INTERSECT SELECT i FROM
seqs WHERE i>=3;\n+------+\n| i |\n+------+\n| 3
|\n+------+\n\nSELECT i FROM seqs WHERE i <= 3 INTERSECT ALL SELECT i
FROM seqs WHERE i>=3;\n+------+\n| i |\n+------+\n| 3 |\n| 3
|\n+------+\n\nParentheses for specifying precedence, from MariaDB
10.4.0\n\nCREATE OR REPLACE TABLE t1 (a INT);\nCREATE OR REPLACE TABLE t2
(b INT);\nCREATE OR REPLACE TABLE t3 (c INT);\n\nINSERT INTO t1 VALUES
(1),(2),(3),(4);\nINSERT INTO t2 VALUES (5),(6);\nINSERT INTO t3 VALUES
(1),(6);\n\n((SELECT a FROM t1) UNION (SELECT b FROM t2)) INTERSECT (SELECT
c FROM t3);\n+------+\n| a |\n+------+\n| 1 |\n| 6
|\n+------+\n\n(SELECT a FROM t1) UNION ((SELECT b FROM t2) INTERSECT
(SELECT c FROM t3));\n+------+\n| a |\n+------+\n| 1 |\n| 2 |\n|
3 |\n| 4 |\n| 6 |\n+------+\n\nURL:
https://mariadb.com/kb/en/intersect/','','https://mariadb.com/kb/en/intersect/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(429,27,'Precedence Control in Table Operations','MariaDB
starting with 10.4.0\n----------------------------\nBeginning in MariaDB
10.4, you can control the ordering of execution on table\noperations using
parentheses.\n\nSyntax\n------\n\n( expression )\n[ORDER BY [column[,
column...]]]\n[LIMIT {[offset,] row_count | row_count OFFSET
offset}]\n\nDescription\n-----------\n\nUsing parentheses in your SQL
allows you to control the order of execution for\nSELECT statements and
Table Value Constructor, including UNION, EXCEPT, and\nINTERSECT
operations. MariaDB executes the parenthetical expression before the\nrest
of the statement. You can then use ORDER BY and LIMIT clauses the
further\norganize the result-set.\n\nNote: In practice, the Optimizer may
rearrange the exact order in which\nMariaDB executes different parts of the
statement. When it calculates the\nresult-set, however, it returns values
as though the parenthetical expression\nwere executed
first.\n\nExample\n-------\n\nCREATE TABLE test.t1 (num INT);\n\nINSERT
INTO test.t1 VALUES (1),(2),(3);\n\n(SELECT * FROM test.t1 \n UNION \n
VALUES (10)) \nINTERSECT \nVALUES (1),(3),(10),(11);\n+------+\n| num
|\n+------+\n| 1 |\n| 3 |\n| 10 |\n+------+\n\n((SELECT * FROM
test.t1 \n UNION\n VALUES (10))\n INTERSECT \n VALUES (1),(3),(10),(11))
\nORDER BY 1 DESC;\n+------+\n| num |\n+------+\n| 10 |\n| 3 |\n|
1 |\n+------+\n\nURL:
https://mariadb.com/kb/en/precedence-control-in-table-operations/','','https://mariadb.com/kb/en/precedence-control-in-table-operations/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(430,27,'LIMIT','Description\n-----------\n\nUse the LIMIT
clause to restrict the number of returned rows. When you use a\nsingle
integer n with LIMIT, the first n rows will be returned. Use the ORDER\nBY
clause to control which rows come first. You can also select a number
of\nrows after an offset using either of the following:\n\nLIMIT offset,
row_count\nLIMIT row_count OFFSET offset\n\nWhen you provide an offset m
with a limit n, the first m rows will be ignored,\nand the following n rows
will be returned.\n\nExecuting an UPDATE with the LIMIT clause is not safe
for replication. LIMIT 0\nis an exception to this rule (see
MDEV-6170).\n\nThere is a LIMIT ROWS EXAMINED optimization which provides
the means to\nterminate the execution of SELECT statements which examine
too many rows, and\nthus use too many resources. See LIMIT ROWS
EXAMINED.\n\nMulti-Table Updates\n-------------------\n\nMariaDB starting
with 10.3.2\n----------------------------\nUntil MariaDB 10.3.1, it was not
possible to use LIMIT (or ORDER BY) in a\nmulti-table UPDATE statement.
This restriction was lifted in MariaDB
10.3.2.\n\nGROUP_CONCAT\n------------\n\nMariaDB starting with
10.3.2\n----------------------------\nStarting from MariaDB 10.3.3, it is
possible to use LIMIT with GROUP_CONCAT().\n\nExamples\n--------\n\nCREATE
TABLE members (name VARCHAR(20));\nINSERT INTO members
VALUES(\'Jagdish\'),(\'Kenny\'),(\'Rokurou\'),(\'Immaculada\');\n\nSELECT
* FROM members;\n+------------+\n| name |\n+------------+\n| Jagdish
|\n| Kenny |\n| Rokurou |\n| Immaculada
|\n+------------+\n\nSelect the first two names (no ordering
specified):\n\nSELECT * FROM members LIMIT 2;\n+---------+\n| name
|\n+---------+\n| Jagdish |\n| Kenny |\n+---------+\n\nAll the names in
alphabetical order:\n\nSELECT * FROM members ORDER BY
name;\n+------------+\n| name |\n+------------+\n| Immaculada |\n|
Jagdish |\n| Kenny |\n| Rokurou |\n+------------+\n\nThe first
two names, ordered alphabetically:\n\nSELECT * FROM members ORDER BY name
LIMIT 2;\n+------------+\n| name |\n+------------+\n| Immaculada |\n|
Jagdish |\n+------------+\n\nThe third name, ordered alphabetically (the
first name would be offset zero,\nso the third is offset two):\n\nSELECT *
FROM members ORDER BY name LIMIT 2,1;\n+-------+\n| name |\n+-------+\n|
Kenny |\n+-------+\n\nFrom MariaDB 10.3.2, LIMIT can be used in a
multi-table update:\n\nCREATE TABLE warehouse (product_id INT, qty
INT);\nINSERT INTO warehouse VALUES
(1,100),(2,100),(3,100),(4,100);\n\nCREATE TABLE store (product_id INT, qty
INT);\nINSERT INTO store VALUES (1,5),(2,5),(3,5),(4,5);\n\nUPDATE
warehouse,store SET warehouse.qty = warehouse.qty-2, store.qty
=\nstore.qty+2 \n WHERE (warehouse.product_id = store.product_id AND
store.product_id >= 1)\n ORDER BY store.product_id DESC LIMIT
2;\n\nSELECT * FROM warehouse;\n+------------+------+\n| product_id | qty
|\n+------------+------+\n| 1 | 100 |\n| 2 | 100 |\n|
3 | 98 |\n| 4 | 98 |\n+------------+------+\n\nSELECT *
FROM store;\n+------------+------+\n| product_id | qty
|\n+------------+------+\n| 1 | 5 |\n| 2 | 5 |\n|
3 | 7 |\n| 4 | 7 |\n+------------+------+\n\nFrom
MariaDB 10.3.3, LIMIT can be used with GROUP_CONCAT, so, for
example,\ngiven the following table:\n\nCREATE TABLE d (dd DATE, cc
INT);\n\nINSERT INTO d VALUES (\'2017-01-01\',1);\nINSERT INTO d
VALUES (\'2017-01-02\',2);\nINSERT INTO d VALUES
(\'2017-01-04\',3);\n\nthe following query:\n\nSELECT
SUBSTRING_INDEX(GROUP_CONCAT(CONCAT_WS(\":\",dd,cc) ORDER BY
cc\nDESC),\",\",1) FROM
d;\n+----------------------------------------------------------------------------+\n|
SUBSTRING_INDEX(GROUP_CONCAT(CONCAT_WS(\":\",dd,cc) ORDER BY cc
DESC),\",\",1)
|\n+----------------------------------------------------------------------------+\n|
2017-01-04:3
|\n+----------------------------------------------------------------------------+\n\ncan
be more simply rewritten as:\n\nSELECT
GROUP_CONCAT(CONCAT_WS(\":\",dd,cc) ORDER BY cc DESC LIMIT 1)
FROM d;\n+-------------------------------------------------------------+\n|
GROUP_CONCAT(CONCAT_WS(\":\",dd,cc) ORDER BY cc DESC LIMIT 1)
|\n+-------------------------------------------------------------+\n|
2017-01-04:3
|\n+-------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/limit/','','https://mariadb.com/kb/en/limit/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(431,27,'ORDER BY','Description\n-----------\n\nUse the
ORDER BY clause to order a resultset, such as that are returned from
a\nSELECT statement. You can specify just a column or use any expression
with\nfunctions. If you are using the GROUP BY clause, you can use
grouping\nfunctions in ORDER BY. Ordering is done after grouping.\n\nYou
can use multiple ordering expressions, separated by commas. Rows will
be\nsorted by the first expression, then by the second expression if they
have the\nsame value for the first, and so on.\n\nYou can use the keywords
ASC and DESC after each ordering expression to force\nthat ordering to be
ascending or descending, respectively. Ordering is\nascending by
default.\n\nYou can also use a single integer as the ordering expression.
If you use an\ninteger n, the results will be ordered by the nth column in
the select\nexpression.\n\nWhen string values are compared, they are
compared as if by the STRCMP\nfunction. STRCMP ignores trailing whitespace
and may normalize characters and\nignore case, depending on the collation
in use.\n\nDuplicated entries in the ORDER BY clause are removed.\n\nORDER
BY can also be used to order the activities of a DELETE or
UPDATE\nstatement (usually with the LIMIT clause).\n\nMariaDB starting with
10.3.2\n----------------------------\nUntil MariaDB 10.3.1, it was not
possible to use ORDER BY (or LIMIT) in a\nmulti-table UPDATE statement.
This restriction was lifted in MariaDB 10.3.2.\n\nMariaDB starting with
10.5\n--------------------------\nFrom MariaDB 10.5, MariaDB allows packed
sort keys and values of non-sorted\nfields in the sort buffer. This can
make filesort temporary files much smaller\nwhen VARCHAR, CHAR or BLOBs are
used, notably speeding up some ORDER BY
sorts.\n\nExamples\n--------\n\nCREATE TABLE seq (i INT, x
VARCHAR(1));\nINSERT INTO seq VALUES (1,\'a\'),
(2,\'b\'), (3,\'b\'), (4,\'f\'),
(5,\'e\');\n\nSELECT * FROM seq ORDER BY i;\n+------+------+\n| i
| x |\n+------+------+\n| 1 | a |\n| 2 | b |\n| 3 | b
|\n| 4 | f |\n| 5 | e |\n+------+------+\n\nSELECT * FROM seq
ORDER BY i DESC;\n+------+------+\n| i | x |\n+------+------+\n| 5
| e |\n| 4 | f |\n| 3 | b |\n| 2 | b |\n| 1 | a
|\n+------+------+\n\nSELECT * FROM seq ORDER BY x,i;\n+------+------+\n| i
| x |\n+------+------+\n| 1 | a |\n| 2 | b |\n| 3 | b
|\n| 5 | e |\n| 4 | f |\n+------+------+\n\nORDER BY in an
UPDATE statement, in conjunction with LIMIT:\n\nUPDATE seq SET
x=\'z\' WHERE x=\'b\' ORDER BY i DESC LIMIT
1;\n\nSELECT * FROM seq;\n+------+------+\n| i | x
|\n+------+------+\n| 1 | a |\n| 2 | b |\n| 3 | z |\n|
4 | f |\n| 5 | e |\n+------+------+\n\nFrom MariaDB 10.3.2, ORDER
BY can be used in a multi-table update:\n\nCREATE TABLE warehouse
(product_id INT, qty INT);\nINSERT INTO warehouse VALUES
(1,100),(2,100),(3,100),(4,100);\n\nCREATE TABLE store (product_id INT, qty
INT);\nINSERT INTO store VALUES (1,5),(2,5),(3,5),(4,5);\n\nUPDATE
warehouse,store SET warehouse.qty = warehouse.qty-2, store.qty
=\nstore.qty+2 \n WHERE (warehouse.product_id = store.product_id AND
store.product_id >= 1)\n ORDER BY store.product_id DESC LIMIT
2;\n\nSELECT * FROM warehouse;\n+------------+------+\n| product_id | qty
|\n+------------+------+\n| 1 | 100 |\n| 2 | 100 |\n|
3 | 98 |\n| 4 | 98 |\n+------------+------+\n\nSELECT *
FROM store;\n+------------+------+\n| product_id | qty
|\n+------------+------+\n| 1 | 5 |\n| 2 | 5 |\n|
3 | 7 |\n| 4 | 7 |\n+------------+------+\n\nURL:
https://mariadb.com/kb/en/order-by/','','https://mariadb.com/kb/en/order-by/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(432,27,'GROUP BY','Use the GROUP BY clause in a SELECT
statement to group rows together that have\nthe same value in one or more
column, or the same computed value using\nexpressions with any functions
and operators except grouping functions. When\nyou use a GROUP BY clause,
you will get a single result row for each group of\nrows that have the same
value for the expression given in GROUP BY.\n\nWhen grouping rows, grouping
values are compared as if by the = operator. For\nstring values, the =
operator ignores trailing whitespace and may normalize\ncharacters and
ignore case, depending on the collation in use.\n\nYou can use any of the
grouping functions in your select expression. Their\nvalues will be
calculated based on all the rows that have been grouped\ntogether for each
result row. If you select a non-grouped column or a value\ncomputed from a
non-grouped column, it is undefined which row the returned\nvalue is taken
from. This is not permitted if the ONLY_FULL_GROUP_BY SQL_MODE\nis
used.\n\nYou can use multiple expressions in the GROUP BY clause, separated
by commas.\nRows are grouped together if they match on each of the
expressions.\n\nYou can also use a single integer as the grouping
expression. If you use an\ninteger n, the results will be grouped by the
nth column in the select\nexpression.\n\nThe WHERE clause is applied before
the GROUP BY clause. It filters\nnon-aggregated rows before the rows are
grouped together. To filter grouped\nrows based on aggregate values, use
the HAVING clause. The HAVING clause takes\nany expression and evaluates it
as a boolean, just like the WHERE clause. You\ncan use grouping functions
in the HAVING clause. As with the select\nexpression, if you reference
non-grouped columns in the HAVING clause, the\nbehavior is undefined.\n\nBy
default, if a GROUP BY clause is present, the rows in the output will
be\nsorted by the expressions used in the GROUP BY. You can also specify
ASC or\nDESC (ascending, descending) after those expressions, like in ORDER
BY. The\ndefault is ASC.\n\nIf you want the rows to be sorted by another
field, you can add an explicit\nORDER BY. If you don\'t want the
result to be ordered, you can add ORDER BY\nNULL.\n\nWITH
ROLLUP\n-----------\n\nThe WITH ROLLUP modifer adds extra rows to the
resultset that represent\nsuper-aggregate summaries. For a full description
with examples, see SELECT\nWITH ROLLUP.\n\nGROUP BY
Examples\n-----------------\n\nConsider the following table that records
how many times each user has played\nand won a game:\n\nCREATE TABLE plays
(name VARCHAR(16), plays INT, wins INT);\nINSERT INTO plays VALUES \n
(\"John\", 20, 5),\n (\"Robert\", 22, 8),\n
(\"Wanda\", 32, 8),\n (\"Susan\", 17, 3);\n\nGet a list
of win counts along with a count:\n\nSELECT wins, COUNT(*) FROM plays GROUP
BY wins;\n+------+----------+\n| wins | COUNT(*) |\n+------+----------+\n|
3 | 1 |\n| 5 | 1 |\n| 8 | 2
|\n+------+----------+\n3 rows in set (0.00 sec)\n\nThe GROUP BY expression
can be a computed value, and can refer back to an\nidentifer specified with
AS. Get a list of win averages along with a count:\n\nSELECT (wins / plays)
AS winavg, COUNT(*) FROM plays GROUP BY winavg;\n+--------+----------+\n|
winavg | COUNT(*) |\n+--------+----------+\n| 0.1765 | 1 |\n| 0.2500
| 2 |\n| 0.3636 | 1 |\n+--------+----------+\n3 rows in set
(0.00 sec)\n\nYou can use any grouping function in the select expression.
For each win\naverage as above, get a list of the average play count taken
to get that\naverage:\n\nSELECT (wins / plays) AS winavg, AVG(plays) FROM
plays \n GROUP BY winavg;\n+--------+------------+\n| winavg | AVG(plays)
|\n+--------+------------+\n| 0.1765 | 17.0000 |\n| 0.2500 | 26.0000
|\n| 0.3636 | 22.0000 |\n+--------+------------+\n3 rows in set (0.00
sec)\n\nYou can filter on aggregate information using the HAVING clause.
The HAVING\nclause is applied after GROUP BY and allows you to filter on
aggregate data\nthat is not available to the WHERE clause. Restrict the
above example to\nresults that involve an average number of plays over
20:\n\nSELECT (wins / plays) AS winavg, AVG(plays) FROM plays \n GROUP BY
winavg HAVING AVG(plays) > 20;\n+--------+------------+\n| winavg |
AVG(plays) |\n+--------+------------+\n| 0.2500 | 26.0000 |\n| 0.3636 |
22.0000 |\n+--------+------------+\n2 rows in set (0.00 sec)\n\nURL:
https://mariadb.com/kb/en/group-by/','','https://mariadb.com/kb/en/group-by/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(433,27,'WITH','MariaDB starting with
10.2.1\n----------------------------\nCommon Table Expressions were
introduced in MariaDB 10.2.1.\n\nSyntax\n------\n\nWITH [RECURSIVE]
table_reference [(columns_list)] AS (\n SELECT ...\n)\n[CYCLE
cycle_column_list RESTRICT]\nSELECT ...\n\nDescription\n-----------\n\nThe
WITH keyword signifies a Common Table Expression (CTE). It allows you
to\nrefer to a subquery expression many times in a query, as if having a
temporary\ntable that only exists for the duration of a query.\n\nThere are
two kinds of CTEs:\n\n* Non-Recursive\n* Recursive (signified by the
RECURSIVE keyword, supported since MariaDB\n10.2.2)\n\nYou can use
table_reference as any normal table in the external SELECT part.\nYou can
also use WITH in subqueries, as well as with EXPLAIN and
SELECT.\n\nPoorly-formed recursive CTEs can in theory cause infinite loops.
The\nmax_recursive_iterations system variable limits the number of
recursions.\n\nCYCLE ... RESTRICT\n------------------\n\nMariaDB starting
with 10.5.2\n----------------------------\nThe CYCLE clause enables CTE
cycle detection, avoiding excessive or infinite\nloops, MariaDB supports a
relaxed, non-standard grammar.\n\nThe SQL Standard permits a CYCLE clause,
as follows:\n\nWITH RECURSIVE ... (\n ...\n)\nCYCLE <cycle column
list>\nSET <cycle mark column> TO <cycle mark value> DEFAULT
<non-cycle mark value>\nUSING <path column>\n\nwhere all
clauses are mandatory.\n\nMariaDB does not support this, but from 10.5.2
permits a non-standard relaxed\ngrammar, as follows:\n\nWITH RECURSIVE ...
(\n ...\n)\nCYCLE <cycle column list> RESTRICT\n\nWith the use of
CYCLE ... RESTRICT it makes no difference whether the CTE uses\nUNION ALL
or UNION DISTINCT anymore. UNION ALL means \"all rows, but
without\ncycles\", which is exactly what the CYCLE clause enables. And
UNION DISTINCT\nmeans all rows should be different, which, again, is what
will happen — as\nuniqueness is enforced over a subset of columns,
complete rows will\nautomatically all be
different.\n\nExamples\n--------\n\nBelow is an example with the WITH at
the top level:\n\nWITH t AS (SELECT a FROM t1 WHERE b >=
\'c\') \n SELECT * FROM t2, t WHERE t2.c = t.a;\n\nThe example
below uses WITH in a subquery:\n\nSELECT t1.a, t1.b FROM t1, t2\n WHERE
t1.a > t2.c\n AND t2.c IN(WITH t AS (SELECT * FROM t1 WHERE t1.a <
5)\n SELECT t2.c FROM t2, t WHERE t2.c = t.a);\n\nBelow is an
example of a Recursive CTE:\n\nWITH RECURSIVE ancestors AS \n ( SELECT *
FROM folks\n WHERE name=\"Alex\"\n UNION\n SELECT f.*\n FROM
folks AS f, ancestors AS a\n WHERE f.id = a.father OR f.id = a.mother
)\nSELECT * FROM ancestors;\n\nTake the following structure, and
data,\n\nCREATE TABLE t1 (from_ int, to_ int);\nINSERT INTO t1 VALUES
(1,2), (1,100), (2,3), (3,4), (4,1);\nSELECT * FROM
t1;\n+-------+------+\n| from_ | to_ |\n+-------+------+\n| 1 | 2
|\n| 1 | 100 |\n| 2 | 3 |\n| 3 | 4 |\n| 4 | 1
|\n+-------+------+\n\nGiven the above, the following query would
theoretically result in an infinite\nloop due to the last record in t1
(note that max_recursive_iterations is set\nto 10 for the purposes of this
example, to avoid the excessive number of\ncycles):\n\nSET
max_recursive_iterations=10;\n\nWITH RECURSIVE cte (depth, from_, to_) AS (
\n SELECT 0,1,1 UNION DISTINCT SELECT depth+1, t1.from_, t1.to_\n FROM t1,
cte WHERE t1.from_ = cte.to_\n) \nSELECT * FROM
cte;\n+-------+-------+------+\n| depth | from_ | to_
|\n+-------+-------+------+\n| 0 | 1 | 1 |\n| 1 | 1 |
2 |\n| 1 | 1 | 100 |\n| 2 | 2 | 3 |\n| 3 | 3 |
4 |\n| 4 | 4 | 1 |\n| 5 | 1 | 2 |\n| 5 | 1
| 100 |\n| 6 | 2 | 3 |\n| 7 | 3 | 4 |\n| 8 |
4 | 1 |\n| 9 | 1 | 2 |\n| 9 | 1 | 100 |\n| 10 |
2 | 3 |\n+-------+-------+------+\n\nHowever, the CYCLE ... RESTRICT
clause (from MariaDB 10.5.2) can overcome this:\n\nWITH RECURSIVE cte
(depth, from_, to_) AS ( \n SELECT 0,1,1 UNION SELECT depth+1, t1.from_,
t1.to_\n FROM t1, cte WHERE t1.from_ = cte.to_\n) \nCYCLE from_, to_
RESTRICT \nSELECT * FROM cte;\n+-------+-------+------+\n| depth | from_ |
to_ |\n+-------+-------+------+\n| 0 | 1 | 1 |\n| 1 | 1
| 2 |\n| 1 | 1 | 100 |\n| 2 | 2 | 3 |\n| 3 |
3 | 4 |\n| 4 | 4 | 1 |\n+-------+-------+------+\n\nURL:
https://mariadb.com/kb/en/with/','','https://mariadb.com/kb/en/with/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(434,27,'Non-Recursive Common Table Expressions
Overview','Common Table Expressions (CTEs) are a standard SQL
feature, and are\nessentially temporary named result sets. There are two
kinds of CTEs:\nNon-Recursive, which this article covers; and
Recursive.\n\nMariaDB starting with
10.2.1\n----------------------------\nCommon table expressions were
introduced in MariaDB 10.2.1.\n\nNon-Recursive
CTEs\n------------------\n\nThe WITH keyword signifies a CTE. It is given a
name, followed by a body (the\nmain query) as follows:\n\nCTEs are similar
to derived tables. For example\n\nWITH engineers AS \n ( SELECT * FROM
employees\n WHERE dept = \'Engineering\' )\n\nSELECT * FROM
engineers\nWHERE ...\n\nSELECT * FROM\n ( SELECT * FROM employees\n WHERE
dept = \'Engineering\' ) AS engineers\nWHERE\n...\n\nA
non-recursive CTE is basically a query-local VIEW. There are
several\nadvantages and caveats to them. The syntax is more readable than
nested FROM\n(SELECT ...). A CTE can refer to another and it can be
referenced from\nmultiple places.\n\nA CTE referencing Another
CTE\n-----------------------------\n\nUsing this format makes for a more
readable SQL than a nested FROM(SELECT ...)\nclause. Below is an example of
this:\n\nWITH engineers AS (\nSELECT * FROM employees\nWHERE dept
IN(\'Development\',\'Support\') ),\neu_engineers AS (
SELECT * FROM engineers WHERE country IN(\'NL\',...)
)\nSELECT\n...\nFROM eu_engineers;\n\nMultiple Uses of a
CTE\n----------------------\n\nThis can be an \'anti-self join\',
for example:\n\nWITH engineers AS (\nSELECT * FROM employees\nWHERE dept
IN(\'Development\',\'Support\') )\n\nSELECT * FROM
engineers E1\nWHERE NOT EXISTS\n (SELECT 1 FROM engineers E2\n WHERE
E2.country=E1.country\n AND E2.name <> E1.name );\n\nOr, for
year-over-year comparisons, for example:\n\nWITH sales_product_year AS
(\nSELECT product, YEAR(ship_date) AS year,\nSUM(price) AS total_amt\nFROM
item_sales\nGROUP BY product, year )\n\nSELECT *\nFROM sales_product_year
CUR,\nsales_product_year PREV,\nWHERE CUR.product=PREV.product \nAND
CUR.year=PREV.year + 1 \nAND CUR.total_amt > PREV.total_amt\n\nAnother
use is to compare individuals against their group. Below is an example\nof
how this might be executed:\n\nWITH sales_product_year AS (\nSELECT
product,\nYEAR(ship_date) AS year,\nSUM(price) AS total_amt\nFROM
item_sales\nGROUP BY product, year\n)\n\nSELECT * \nFROM sales_product_year
S1\nWHERE\ntotal_amt > \n (SELECT 0.1 * SUM(total_amt)\n FROM
sales_product_year S2\n WHERE S2.year = S1.year)\n\nURL:
https://mariadb.com/kb/en/non-recursive-common-table-expressions-overview/','','https://mariadb.com/kb/en/non-recursive-common-table-expressions-overview/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(435,27,'Recursive Common Table Expressions
Overview','MariaDB starting with
10.2.2\n----------------------------\nRecursive Common Table Expressions
have been supported since MariaDB 10.2.2.\n\nCommon Table Expressions
(CTEs) are a standard SQL feature, and are\nessentially temporary named
result sets. CTEs first appeared in the SQL\nstandard in 1999, and the
first implementations began appearing in 2007.\n\nThere are two kinds of
CTEs:\n\n* Non-recursive\n* Recursive, which this article covers.\n\nSQL is
generally poor at recursive structures.\n\nCTEs permit a query to reference
itself. A recursive CTE will repeatedly\nexecute subsets of the data until
it obtains the complete result set. This\nmakes it particularly useful for
handing hierarchical or tree-structured data.\nmax_recursive_iterations
avoids infinite loops.\n\nSyntax example\n--------------\n\nWITH RECURSIVE
signifies a recursive CTE. It is given a name, followed by a\nbody (the
main query) as follows:\n\nComputation\n-----------\n\nGiven the following
structure:\n\nFirst execute the anchor part of the query:\n\nNext, execute
the recursive part of the query:\n\nSummary so far\n--------------\n\nwith
recursive R as (\n select anchor_data\n union [all]\n select
recursive_part\n from R, ...\n)\nselect ...\n\n* Compute anchor_data\n*
Compute recursive_part to get the new data\n* if (new data is non-empty)
goto 2;\n\nCAST to avoid truncating
data\n-----------------------------\n\nAs currently implemented by MariaDB
and by the SQL Standard, data may be\ntruncated if not correctly cast. It
is necessary to CAST the column to the\ncorrect width if the CTE\'s
recursive part produces wider values for a column\nthan the CTE\'s
nonrecursive part. Some other DBMS give an error in this\nsituation, and
MariaDB\'s behavior may change in future - see MDEV-12325. See\nthe
examples below.\n\nExamples\n--------\n\nTransitive closure - determining
bus
destinations\n-------------------------------------------------\n\nSample
data:\n\nCREATE TABLE bus_routes (origin varchar(50), dst
varchar(50));\nINSERT INTO bus_routes VALUES \n (\'New York\',
\'Boston\'),\n (\'Boston\', \'New York\'),\n
(\'New York\', \'Washington\'),\n
(\'Washington\', \'Boston\'),\n
(\'Washington\', \'Raleigh\');\n\nNow, we want to
return the bus destinations with New York as the origin:\n\nWITH RECURSIVE
bus_dst as ( \n SELECT origin as dst FROM bus_routes WHERE
origin=\'New York\'\n UNION\n SELECT bus_routes.dst FROM
bus_routes JOIN bus_dst ON bus_dst.dst=\nbus_routes.origin \n) \nSELECT *
FROM bus_dst;\n+------------+\n| dst |\n+------------+\n| New York
|\n| Boston |\n| Washington |\n| Raleigh |\n+------------+\n\nThe
above example is computed as follows:\n\nFirst, the anchor data is
calculated:\n\n* Starting from New York\n* Boston and Washington are
added\n\nNext, the recursive part:\n\n* Starting from Boston and then
Washington\n* Raleigh is added\n* UNION excludes nodes that are already
present.\n\nComputing paths - determining bus
routes\n----------------------------------------\n\nThis time, we are
trying to get bus routes such as \"New York -> Washington
->\nRaleigh\".\n\nUsing the same sample data as the previous
example:\n\nWITH RECURSIVE paths (cur_path, cur_dest) AS (\n SELECT
origin, origin FROM bus_routes WHERE origin=\'New York\'\n
UNION\n SELECT CONCAT(paths.cur_path, \',\', bus_routes.dst),
bus_routes.dst\n FROM paths\n JOIN bus_routes\n ON paths.cur_dest =
bus_routes.origin AND\n NOT FIND_IN_SET(bus_routes.dst,
paths.cur_path)\n) \nSELECT * FROM
paths;\n+-----------------------------+------------+\n| cur_path
| cur_dest |\n+-----------------------------+------------+\n| New
York | New York |\n| New York,Boston |
Boston |\n| New York,Washington | Washington |\n| New
York,Washington,Boston | Boston |\n| New York,Washington,Raleigh |
Raleigh |\n+-----------------------------+------------+\n\nCAST to avoid
data truncation\n-----------------------------\n\nIn the following example,
data is truncated because the results are not\nspecifically cast to a wide
enough type:\n\nWITH RECURSIVE tbl AS (\n SELECT NULL AS col\n UNION\n
SELECT \"THIS NEVER SHOWS UP\" AS col FROM tbl\n)\nSELECT col
FROM tbl\n+------+\n| col |\n+------+\n| NULL |\n|
|\n+------+\n\nExplicitly use CAST to overcome this:\n\nWITH RECURSIVE tbl
AS (\n SELECT CAST(NULL AS CHAR(50)) AS col\n UNION SELECT \"THIS
NEVER SHOWS UP\" AS col FROM tbl\n) \nSELECT * FROM
tbl;\n+---------------------+\n| col
|\n+---------------------+\n| NULL |\n| THIS NEVER SHOWS UP
|\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/recursive-common-table-expressions-overview/','','https://mariadb.com/kb/en/recursive-common-table-expressions-overview/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(436,27,'SELECT WITH ROLLUP','Syntax\n------\n\nSee SELECT
for the full syntax.\n\nDescription\n-----------\n\nThe WITH ROLLUP
modifier adds extra rows to the resultset that represent\nsuper-aggregate
summaries. The super-aggregated column is represented by a\nNULL value.
Multiple aggregates over different columns will be added if there\nare
multiple GROUP BY columns.\n\nThe LIMIT clause can be used at the same
time, and is applied after the WITH\nROLLUP rows have been added.\n\nWITH
ROLLUP cannot be used with ORDER BY. Some sorting is still possible
by\nusing ASC or DESC clauses with the GROUP BY column, although
the\nsuper-aggregate rows will always be added
last.\n\nExamples\n--------\n\nThese examples use the following sample
table\n\nCREATE TABLE booksales ( \n country VARCHAR(35), genre
ENUM(\'fiction\',\'non-fiction\'), year YEAR,
sales\nINT);\n\nINSERT INTO booksales VALUES\n
(\'Senegal\',\'fiction\',2014,12234),
(\'Senegal\',\'fiction\',2015,15647),\n
(\'Senegal\',\'non-fiction\',2014,64980),
(\'Senegal\',\'non-fiction\',2015,78901),\n
(\'Paraguay\',\'fiction\',2014,87970),
(\'Paraguay\',\'fiction\',2015,76940),\n
(\'Paraguay\',\'non-fiction\',2014,8760),
(\'Paraguay\',\'non-fiction\',2015,9030);\n\nThe
addition of the WITH ROLLUP modifier in this example adds an extra
row\nthat aggregates both years:\n\nSELECT year, SUM(sales) FROM booksales
GROUP BY year;\n+------+------------+\n| year | SUM(sales)
|\n+------+------------+\n| 2014 | 173944 |\n| 2015 | 180518
|\n+------+------------+\n2 rows in set (0.08 sec)\n\nSELECT year,
SUM(sales) FROM booksales GROUP BY year WITH
ROLLUP;\n+------+------------+\n| year | SUM(sales)
|\n+------+------------+\n| 2014 | 173944 |\n| 2015 | 180518 |\n|
NULL | 354462 |\n+------+------------+\n\nIn the following example,
each time the genre, the year or the country change,\nanother
super-aggregate row is added:\n\nSELECT country, year, genre, SUM(sales) \n
FROM booksales GROUP BY country, year,
genre;\n+----------+------+-------------+------------+\n| country | year |
genre | SUM(sales)
|\n+----------+------+-------------+------------+\n| Paraguay | 2014 |
fiction | 87970 |\n| Paraguay | 2014 | non-fiction | 8760
|\n| Paraguay | 2015 | fiction | 76940 |\n| Paraguay | 2015 |
non-fiction | 9030 |\n| Senegal | 2014 | fiction | 12234
|\n| Senegal | 2014 | non-fiction | 64980 |\n| Senegal | 2015 |
fiction | 15647 |\n| Senegal | 2015 | non-fiction | 78901
|\n+----------+------+-------------+------------+\n\nSELECT country, year,
genre, SUM(sales) \n FROM booksales GROUP BY country, year, genre WITH
ROLLUP;\n+----------+------+-------------+------------+\n| country | year
| genre | SUM(sales)
|\n+----------+------+-------------+------------+\n| Paraguay | 2014 |
fiction | 87970 |\n| Paraguay | 2014 | non-fiction | 8760
|\n| Paraguay | 2014 | NULL | 96730 |\n| Paraguay | 2015 |
fiction | 76940 |\n| Paraguay | 2015 | non-fiction | 9030
|\n| Paraguay | 2015 | NULL | 85970 |\n| Paraguay | NULL | NULL
| 182700 |\n| Senegal | 2014 | fiction | 12234 |\n|
Senegal | 2014 | non-fiction | 64980 |\n| Senegal | 2014 | NULL
| 77214 |\n| Senegal | 2015 | fiction | 15647 |\n| Senegal
| 2015 | non-fiction | 78901 |\n| Senegal | 2015 | NULL |
94548 |\n| Senegal | NULL | NULL | 171762 |\n| NULL | NULL
| NULL | 354462
|\n+----------+------+-------------+------------+\n\nThe LIMIT clause,
applied after WITH ROLLUP:\n\nSELECT country, year, genre, SUM(sales) \n
FROM booksales GROUP BY country, year, genre WITH ROLLUP LIMIT
4;\n+----------+------+-------------+------------+\n| country | year |
genre | SUM(sales)
|\n+----------+------+-------------+------------+\n| Paraguay | 2014 |
fiction | 87970 |\n| Paraguay | 2014 | non-fiction | 8760
|\n| Paraguay | 2014 | NULL | 96730 |\n| Paraguay | 2015 |
fiction | 76940
|\n+----------+------+-------------+------------+\n\nSorting by year
descending:\n\nSELECT country, year, genre, SUM(sales) \n FROM booksales
GROUP BY country, year DESC, genre WITH
ROLLUP;\n+----------+------+-------------+------------+\n| country | year
| genre | SUM(sales)
|\n+----------+------+-------------+------------+\n| Paraguay | 2015 |
fiction | 76940 |\n| Paraguay | 2015 | non-fiction | 9030
|\n| Paraguay | 2015 | NULL | 85970 |\n| Paraguay | 2014 |
fiction | 87970 |\n| Paraguay | 2014 | non-fiction | 8760
|\n| Paraguay | 2014 | NULL | 96730 |\n| Paraguay | NULL | NULL
| 182700 |\n| Senegal | 2015 | fiction | 15647 |\n|
Senegal | 2015 | non-fiction | 78901 |\n| Senegal | 2015 | NULL
| 94548 |\n| Senegal | 2014 | fiction | 12234 |\n| Senegal
| 2014 | non-fiction | 64980 |\n| Senegal | 2014 | NULL |
77214 |\n| Senegal | NULL | NULL | 171762 |\n| NULL | NULL
| NULL | 354462
|\n+----------+------+-------------+------------+\n\nURL:
https://mariadb.com/kb/en/select-with-rollup/','','https://mariadb.com/kb/en/select-with-rollup/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(437,27,'SELECT INTO OUTFILE','Syntax\n------\n\nSELECT ...
INTO OUTFILE \'file_name\'\n [CHARACTER SET charset_name]\n
[export_options]\n\nexport_options:\n [{FIELDS | COLUMNS}\n [TERMINATED
BY \'string\']\n [[OPTIONALLY] ENCLOSED BY
\'char\']\n [ESCAPED BY \'char\']\n ]\n [LINES\n
[STARTING BY \'string\']\n [TERMINATED BY
\'string\']\n ]\n\nDescription\n-----------\n\nSELECT INTO
OUTFILE writes the resulting rows to a file, and allows the use of\ncolumn
and row terminators to specify a particular output format. The default\nis
to terminate fields with tabs (\\t) and lines with newlines (\\n).\n\nThe
file must not exist. It cannot be overwritten. A user needs the
FILE\nprivilege to run this statement. Also, MariaDB needs permission to
write files\nin the specified location. If the secure_file_priv system
variable is set to a\nnon-empty directory name, the file can only be
written to that directory.\n\nThe LOAD DATA INFILE statement complements
SELECT INTO OUTFILE.\n\nCharacter-sets\n--------------\n\nThe CHARACTER SET
clause specifies the character set in which the results are\nto be written.
Without the clause, no conversion takes place (the binary\ncharacter set).
In this case, if there are multiple character sets, the output\nwill
contain these too, and may not easily be able to be reloaded.\n\nIn cases
where you have two servers using different character-sets, using\nSELECT
INTO OUTFILE to transfer data from one to the other can have
unexpected\nresults. To ensure that MariaDB correctly interprets the escape
sequences, use\nthe CHARACTER SET clause on both the SELECT INTO OUTFILE
statement and the\nsubsequent LOAD DATA INFILE
statement.\n\nExample\n-------\n\nThe following example produces a file in
the CSV format:\n\nSELECT customer_id, firstname, surname from customer\n
INTO OUTFILE \'/exportdata/customers.txt\'\n FIELDS TERMINATED BY
\',\' OPTIONALLY ENCLOSED BY \'\"\'\n LINES
TERMINATED BY \'\\n\';\n\nThe following ANSI syntax is also
supported for simple SELECT without UNION\n\nSELECT customer_id, firstname,
surname INTO OUTFILE \'/exportdata/customers.txt\'\n FIELDS
TERMINATED BY \',\' OPTIONALLY ENCLOSED BY
\'\"\'\n LINES TERMINATED BY \'\\n\'\n FROM
customers;\n\nIf you want to use the ANSI syntax with UNION or similar
construct you have to\nuse the syntax:\n\nSELECT * INTO OUTFILE
\"/tmp/skr3\" FROM (SELECT * FROM t1 UNION SELECT *
FROM\nt1);\n\nURL:
https://mariadb.com/kb/en/select-into-outfile/','','https://mariadb.com/kb/en/select-into-outfile/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(438,27,'SELECT INTO DUMPFILE','Syntax\n------\n\nSELECT ...
INTO DUMPFILE \'file_path\'\n\nDescription\n-----------\n\nSELECT
... INTO DUMPFILE is a SELECT clause which writes the resultset into
a\nsingle unformatted row, without any separators, in a file. The results
will\nnot be returned to the client.\n\nfile_path can be an absolute path,
or a relative path starting from the data\ndirectory. It can only be
specified as a string literal, not as a variable.\nHowever, the statement
can be dynamically composed and executed as a prepared\nstatement to work
around this limitation.\n\nThis statement is binary-safe and so is
particularly useful for writing BLOB\nvalues to file. It can be used, for
example, to copy an image or an audio\ndocument from the database to a
file. SELECT ... INTO FILE can be used to save\na text file.\n\nThe file
must not exist. It cannot be overwritten. A user needs the FILE\nprivilege
to run this statement. Also, MariaDB needs permission to write files\nin
the specified location. If the secure_file_priv system variable is set to
a\nnon-empty directory name, the file can only be written to that
directory.\n\nSince MariaDB 5.1, the character_set_filesystem system
variable has controlled\ninterpretation of file names that are given as
literal strings.\n\nExample\n-------\n\nSELECT _utf8\'Hello
world!\' INTO DUMPFILE \'/tmp/world\';\n\nSELECT
LOAD_FILE(\'/tmp/world\') AS world;\n+--------------+\n| world
|\n+--------------+\n| Hello world! |\n+--------------+\n\nURL:
https://mariadb.com/kb/en/select-into-dumpfile/','','https://mariadb.com/kb/en/select-into-dumpfile/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(439,27,'FOR UPDATE','InnoDB supports row-level locking.
Selected rows can be locked using LOCK IN\nSHARE MODE or FOR UPDATE. In
both cases, a lock is acquired on the rows read\nby the query, and it will
be released when the current transaction is\ncommitted.\n\nThe FOR UPDATE
clause of SELECT applies only when autocommit is set to 0 or\nthe SELECT is
enclosed in a transaction. A lock is acquired on the rows, and\nother
transactions are prevented from writing the rows, acquire locks, and\nfrom
reading them (unless their isolation level is READ UNCOMMITTED).\n\nIf
autocommit is set to 1, the LOCK IN SHARE MODE and FOR UPDATE clauses
have\nno effect.\n\nIf the isolation level is set to SERIALIZABLE, all
plain SELECT statements are\nconverted to SELECT ... LOCK IN SHARE
MODE.\n\nExample\n-------\n\nSELECT * FROM trans WHERE period=2001 FOR
UPDATE;\n\nURL:
https://mariadb.com/kb/en/for-update/','','https://mariadb.com/kb/en/for-update/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(440,27,'LOCK IN SHARE MODE','InnoDB supports row-level
locking. Selected rows can be locked using LOCK IN\nSHARE MODE or FOR
UPDATE. In both cases, a lock is acquired on the rows read\nby the query,
and it will be released when the current transaction is\ncommitted.\n\nWhen
LOCK IN SHARE MODE is specified in a SELECT statement, MariaDB will
wait\nuntil all transactions that have modified the rows are committed.
Then, a\nwrite lock is acquired. All transactions can read the rows, but if
they want\nto modify them, they have to wait until your transaction is
committed.\n\nIf autocommit is set to 1, the LOCK IN SHARE MODE and FOR
UPDATE clauses have\nno effect.\n\nURL:
https://mariadb.com/kb/en/lock-in-share-mode/','','https://mariadb.com/kb/en/lock-in-share-mode/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(441,27,'Optimizer Hints','Optimizer
hints\n---------------\n\nThere are some options available in SELECT to
affect the execution plan. These\nare known as optimizer hints.\n\nHIGH
PRIORITY\n-------------\n\nHIGH_PRIORITY gives the statement a higher
priority. If the table is locked,\nhigh priority SELECTs will be executed
as soon as the lock is released, even\nif other statements are queued.
HIGH_PRIORITY applies only if the storage\nengine only supports table-level
locking (MyISAM, MEMORY, MERGE). See\nHIGH_PRIORITY and LOW_PRIORITY
clauses for details.\n\nSQL_CACHE /
SQL_NO_CACHE\n------------------------\n\nIf the query_cache_type system
variable is set to 2 or DEMAND, and the current\nstatement is cacheable,
SQL_CACHE causes the query to be cached and\nSQL_NO_CACHE causes the query
not to be cached. For UNIONs, SQL_CACHE or\nSQL_NO_CACHE should be
specified for the first query. See also The Query Cache\nfor more detail
and a list of the types of statements that aren\'t
cacheable.\n\nSQL_BUFFER_RESULT\n-----------------\n\nSQL_BUFFER_RESULT
forces the optimizer to use a temporary table to process the\nresult. This
is useful to free locks as soon as possible.\n\nSQL_SMALL_RESULT /
SQL_BIG_RESULT\n---------------------------------\n\nSQL_SMALL_RESULT and
SQL_BIG_RESULT tell the optimizer whether the result is\nvery big or not.
Usually, GROUP BY and DISTINCT operations are performed using\na temporary
table. Only if the result is very big, using a temporary table is\nnot
convenient. The optimizer automatically knows if the result is too
big,\nbut you can force the optimizer to use a temporary table
with\nSQL_SMALL_RESULT, or avoid the temporary table using
SQL_BIG_RESULT.\n\nSTRAIGHT_JOIN\n-------------\n\nSTRAIGHT_JOIN applies to
the JOIN queries, and tells the optimizer that the\ntables must be read in
the order they appear in the SELECT. For const and\nsystem table this
options is sometimes
ignored.\n\nSQL_CALC_FOUND_ROWS\n-------------------\n\nSQL_CALC_FOUND_ROWS
is only applied when using the LIMIT clause. If this\noption is used,
MariaDB will count how many rows would match the query,\nwithout the LIMIT
clause. That number can be retrieved in the next query,\nusing
FOUND_ROWS().\n\nUSE/FORCE/IGNORE INDEX\n----------------------\n\nUSE
INDEX, FORCE INDEX and IGNORE INDEX constrain the query planning to
a\nspecific index.\n\nFor further information about some of these options,
see How to force query\nplans.\n\nURL:
https://mariadb.com/kb/en/optimizer-hints/','','https://mariadb.com/kb/en/optimizer-hints/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(442,27,'PROCEDURE','The PROCEDURE clause of SELECT passes
the whole result set to a Procedure\nwhich will process it. These
Procedures are not Stored Procedures, and can\nonly be written in the C
language, so it is necessary to recompile the server.\n\nCurrently, the
only available procedure is ANALYSE, which examines the\nresultset and
suggests the optimal datatypes for each column. It is defined in\nthe
sql/sql_analyse.cc file, and can be used as an example to create
more\nProcedures.\n\nThis clause cannot be used in a view\'s
definition.\n\nURL:
https://mariadb.com/kb/en/procedure/','','https://mariadb.com/kb/en/procedure/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(443,27,'DUAL','Description\n-----------\n\nYou are allowed
to specify DUAL as a dummy table name in situations where no\ntables are
referenced, such as the following SELECT statement:\n\nSELECT 1 + 1 FROM
DUAL;\n+-------+\n| 1 + 1 |\n+-------+\n| 2 |\n+-------+\n\nDUAL is
purely for the convenience of people who require that all
SELECT\nstatements should have FROM and possibly other clauses. MariaDB
ignores the\nclauses. MariaDB does not require FROM DUAL if no tables are
referenced.\n\nFROM DUAL could be used when you only SELECT computed
values, but require a\nWHERE clause, perhaps to test that a script
correctly handles empty resultsets:\n\nSELECT 1 FROM DUAL WHERE
FALSE;\nEmpty set (0.00 sec)\n\nURL:
https://mariadb.com/kb/en/dual/','','https://mariadb.com/kb/en/dual/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(444,27,'SELECT ... OFFSET ... FETCH','MariaDB starting with
10.6.0\n----------------------------\nSELECT ... OFFSET ... FETCH was
introduced in MariaDB 10.6.\n\nSyntax\n------\n\nOFFSET start { ROW | ROWS
}\nFETCH { FIRST | NEXT } [ count ] { ROW | ROWS } { ONLY | WITH TIES
}\n\nDescription\n-----------\n\nThe OFFSET clause allows one to return
only those elements of a resultset that\ncome after a specified offset. The
FETCH clause specifies the number of rows\nto return, while ONLY or WITH
TIES specifies whether or not to also return any\nfurther results that tie
for last place according to the ordered resultset.\n\nEither the singular
ROW or the plural ROWS can be used after the OFFSET and\nFETCH clauses; the
choice has no impact on the results.\n\nIn the case of WITH TIES, an ORDER
BY clause is required, otherwise an ERROR\nwill be returned.\n\nSELECT i
FROM t1 FETCH FIRST 2 ROWS WITH TIES;\nERROR 4180 (HY000): FETCH ... WITH
TIES requires ORDER BY clause to be present\n\nExamples\n--------\n\nGiven
a table with 6 rows:\n\nCREATE OR REPLACE TABLE t1 (i INT);\nINSERT INTO t1
VALUES (1),(2),(3),(4), (4), (5);\nSELECT i FROM t1 ORDER BY i
ASC;\n+------+\n| i |\n+------+\n| 1 |\n| 2 |\n| 3 |\n| 4
|\n| 4 |\n| 5 |\n+------+\n\nOFFSET 2 allows one to skip the first
two results.\n\nSELECT i FROM t1 ORDER BY i ASC OFFSET 2 ROWS;\n+------+\n|
i |\n+------+\n| 3 |\n| 4 |\n| 4 |\n| 5 |\n+------+\n\nFETCH
FIRST 3 ROWS ONLY limits the results to three rows only\n\nSELECT i FROM t1
ORDER BY i ASC OFFSET 1 ROWS FETCH FIRST 3 ROWS ONLY;\n+------+\n| i
|\n+------+\n| 2 |\n| 3 |\n| 4 |\n+------+\n\nThe same outcome can
also be achieved with the LIMIT clause:\n\nSELECT i FROM t1 ORDER BY i ASC
LIMIT 3 OFFSET 1;\n+------+\n| i |\n+------+\n| 2 |\n| 3 |\n| 4
|\n+------+\n\nWITH TIES ensures the tied result 4 is also
returned.\n\nSELECT i FROM t1 ORDER BY i ASC OFFSET 1 ROWS FETCH FIRST 3
ROWS WITH TIES;\n+------+\n| i |\n+------+\n| 2 |\n| 3 |\n| 4
|\n| 4 |\n+------+\n\nURL:
https://mariadb.com/kb/en/select-offset-fetch/','','https://mariadb.com/kb/en/select-offset-fetch/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(445,27,'INSERT','Syntax\n------\n\nINSERT [LOW_PRIORITY |
DELAYED | HIGH_PRIORITY] [IGNORE]\n [INTO] tbl_name [PARTITION
(partition_list)] [(col,...)]\n {VALUES | VALUE} ({expr |
DEFAULT},...),(...),...\n [ ON DUPLICATE KEY UPDATE\n col=expr\n [,
col=expr] ... ] [RETURNING select_expr\n [, select_expr
...]]\n\nOr:\n\nINSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE]\n
[INTO] tbl_name [PARTITION (partition_list)]\n SET col={expr | DEFAULT},
...\n [ ON DUPLICATE KEY UPDATE\n col=expr\n [, col=expr] ... ]
[RETURNING select_expr\n [, select_expr ...]]\n\nOr:\n\nINSERT
[LOW_PRIORITY | HIGH_PRIORITY] [IGNORE]\n [INTO] tbl_name [PARTITION
(partition_list)] [(col,...)]\n SELECT ...\n [ ON DUPLICATE KEY UPDATE\n
col=expr\n [, col=expr] ... ] [RETURNING select_expr\n [, select_expr
...]]\n\nThe INSERT statement is used to insert new rows into an existing
table. The\nINSERT ... VALUES and INSERT ... SET forms of the statement
insert rows based\non explicitly specified values. The INSERT ... SELECT
form inserts rows\nselected from another table or tables. INSERT ... SELECT
is discussed further\nin the INSERT ... SELECT article.\n\nThe table name
can be specified in the form db_name.tbl_name or, if a default\ndatabase is
selected, in the form tbl_name (see Identifier Qualifiers). This\nallows to
use INSERT ... SELECT to copy rows between different databases.\n\nThe
PARTITION clause can be used in both the INSERT and the SELECT part.
See\nPartition Pruning and Selection for details.\n\nMariaDB starting with
10.5\n--------------------------\nThe RETURNING clause was introduced in
MariaDB 10.5.\n\nThe columns list is optional. It specifies which values
are explicitly\ninserted, and in which order. If this clause is not
specified, all values must\nbe explicitly specified, in the same order they
are listed in the table\ndefinition.\n\nThe list of value follow the VALUES
or VALUE keyword (which are\ninterchangeable, regardless how much values
you want to insert), and is\nwrapped by parenthesis. The values must be
listed in the same order as the\ncolumns list. It is possible to specify
more than one list to insert more than\none rows with a single statement.
If many rows are inserted, this is a speed\noptimization.\n\nFor one-row
statements, the SET clause may be more simple, because you
don\'t\nneed to remember the columns order. All values are specified
in the form col =\nexpr.\n\nValues can also be specified in the form of a
SQL expression or subquery.\nHowever, the subquery cannot access the same
table that is named in the INTO\nclause.\n\nIf you use the LOW_PRIORITY
keyword, execution of the INSERT is delayed until\nno other clients are
reading from the table. If you use the HIGH_PRIORITY\nkeyword, the
statement has the same priority as SELECTs. This affects only\nstorage
engines that use only table-level locking (MyISAM, MEMORY,
MERGE).\nHowever, if one of these keywords is specified, concurrent inserts
cannot be\nused. See HIGH_PRIORITY and LOW_PRIORITY clauses for
details.\n\nINSERT DELAYED\n--------------\n\nFor more details on the
DELAYED option, see INSERT DELAYED.\n\nHIGH PRIORITY and LOW
PRIORITY\n------------------------------\n\nSee HIGH_PRIORITY and
LOW_PRIORITY.\n\nDefaults and Duplicate
Values\n-----------------------------\n\nSee INSERT - Default &
Duplicate Values for details..\n\nINSERT IGNORE\n-------------\n\nSee
INSERT IGNORE.\n\nINSERT ON DUPLICATE KEY
UPDATE\n------------------------------\n\nSee INSERT ON DUPLICATE KEY
UPDATE.\n\nExamples\n--------\n\nSpecifying the column names:\n\nINSERT
INTO person (first_name, last_name) VALUES (\'John\',
\'Doe\');\n\nInserting more than 1 row at a time:\n\nINSERT INTO
tbl_name VALUES (1, \"row 1\"), (2, \"row
2\");\n\nUsing the SET clause:\n\nINSERT INTO person SET first_name =
\'John\', last_name = \'Doe\';\n\nSELECTing from
another table:\n\nINSERT INTO contractor SELECT * FROM person WHERE status
= \'c\';\n\nSee INSERT ON DUPLICATE KEY UPDATE and INSERT IGNORE
for further examples.\n\nINSERT ...
RETURNING\n--------------------\n\nINSERT ... RETURNING returns a resultset
of the inserted rows.\n\nThis returns the listed columns for all the rows
that are inserted, or\nalternatively, the specified SELECT expression. Any
SQL expressions which can\nbe calculated can be used in the select
expression for the RETURNING clause,\nincluding virtual columns and
aliases, expressions which use various operators\nsuch as bitwise, logical
and arithmetic operators, string functions, date-time\nfunctions, numeric
functions, control flow functions, secondary functions and\nstored
functions. Along with this, statements which have subqueries and\nprepared
statements can also be used.\n\nExamples\n--------\n\nSimple INSERT
statement\n\nINSERT INTO t2 VALUES
(1,\'Dog\'),(2,\'Lion\'),(3,\'Tiger\'),(4,\'Leopard\')
\nRETURNING
id2,id2+id2,id2&id2,id2||id2;\n+-----+---------+---------+----------+\n|
id2 | id2+id2 | id2&id2 | id2||id2
|\n+-----+---------+---------+----------+\n| 1 | 2 | 1 |
1 |\n| 2 | 4 | 2 | 1 |\n| 3 | 6 | 3 |
1 |\n| 4 | 8 | 4 | 1
|\n+-----+---------+---------+----------+\n\nUsing stored functions in
RETURNING\n\nDELIMITER |\nCREATE FUNCTION f(arg INT) RETURNS INT\n BEGIN\n
RETURN (SELECT arg+arg);\n END|\n\nDELIMITER ;\n\nPREPARE stmt FROM
\"INSERT INTO t1 SET id1=1, animal1=\'Bear\' RETURNING
f(id1),\nUPPER(animal1)\";\n\nEXECUTE
stmt;\n+---------+----------------+\n| f(id1) | UPPER(animal1)
|\n+---------+----------------+\n| 2 | BEAR
|\n+---------+----------------+\n\nSubqueries in the RETURNING clause that
return more than one row or column\ncannot be used.\n\nAggregate functions
cannot be used in the RETURNING clause. Since aggregate\nfunctions work on
a set of values, and if the purpose is to get the row count,\nROW_COUNT()
with SELECT can be used or it can be used in\nINSERT...SELECT...RETURNING
if the table in the RETURNING clause is not the\nsame as the INSERT
table.\n\nURL:
https://mariadb.com/kb/en/insert/','','https://mariadb.com/kb/en/insert/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(446,27,'INSERT DELAYED','Syntax\n------\n\nINSERT DELAYED
...\n\nDescription\n-----------\n\nThe DELAYED option for the INSERT
statement is a MariaDB/MySQL extension to\nstandard SQL that is very useful
if you have clients that cannot or need not\nwait for the INSERT to
complete. This is a common situation when you use\nMariaDB for logging and
you also periodically run SELECT and UPDATE statements\nthat take a long
time to complete.\n\nWhen a client uses INSERT DELAYED, it gets an okay
from the server at once,\nand the row is queued to be inserted when the
table is not in use by any other\nthread.\n\nAnother major benefit of using
INSERT DELAYED is that inserts from many\nclients are bundled together and
written in one block. This is much faster\nthan performing many separate
inserts.\n\nNote that INSERT DELAYED is slower than a normal INSERT if the
table is not\notherwise in use. There is also the additional overhead for
the server to\nhandle a separate thread for each table for which there are
delayed rows. This\nmeans that you should use INSERT DELAYED only when you
are really sure that\nyou need it.\n\nThe queued rows are held only in
memory until they are inserted into the\ntable. This means that if you
terminate mysqld forcibly (for example, with\nkill -9) or if mysqld dies
unexpectedly, any queued rows that have not been\nwritten to disk are
lost.\n\nThe number of concurrent INSERT DELAYED threads is limited by
the\nmax_delayed_threads server system variables. If it is set to 0, INSERT
DELAYED\nis disabled. The session value can be equal to the global value,
or 0 to\ndisable this statement for the current session. If this limit has
been\nreached, the DELAYED clause will be silently ignore for subsequent
statements\n(no error will be
produced).\n\nLimitations\n-----------\n\nThere are some limitations on the
use of DELAYED:\n\n* INSERT DELAYED works only with MyISAM, MEMORY,
ARCHIVE,\n and BLACKHOLE tables. If you execute INSERT DELAYED with another
storage\nengine, you will get an error like this: ERROR 1616 (HY000):
DELAYED option\nnot supported for table \'tab_name\'\n* For
MyISAM tables, if there are no free blocks in the middle of the data\n
file, concurrent SELECT and INSERT statements are supported. Under these\n
circumstances, you very seldom need to use INSERT DELAYED\n with MyISAM.\n*
INSERT DELAYED should be used only for\n INSERT statements that specify
value lists. The server\n ignores DELAYED for INSERT ... SELECT\n or INSERT
... ON DUPLICATE KEY UPDATE statements.\n* Because the INSERT DELAYED
statement returns immediately,\n before the rows are inserted, you cannot
use\n LAST_INSERT_ID() to get the\n AUTO_INCREMENT value that the statement
might generate.\n* DELAYED rows are not visible to SELECT\n statements
until they actually have been inserted.\n* After INSERT DELAYED,
ROW_COUNT() returns the number of the rows you tried\nto insert, not the
number of the successful writes.\n* DELAYED is ignored on slave replication
servers, so that \n INSERT DELAYED is treated as a normal\n INSERT on
slaves. This is because\n DELAYED could cause the slave to have different
data than\n the master. INSERT DELAYED statements are not safe for
replication.\n* Pending INSERT DELAYED statements are lost if a table is\n
write locked and ALTER TABLE is used to modify the table structure.\n*
INSERT DELAYED is not supported for views. If you try, you will get an
error\nlike this: ERROR 1347 (HY000): \'view_name\' is not BASE
TABLE\n* INSERT DELAYED is not supported for partitioned tables.\n* INSERT
DELAYED is not supported within stored programs.\n* INSERT DELAYED does not
work with triggers.\n* INSERT DELAYED does not work if there is a check
constraint in place.\n* INSERT DELAYED does not work if skip-new mode is
active.\n\nURL:
https://mariadb.com/kb/en/insert-delayed/','','https://mariadb.com/kb/en/insert-delayed/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(447,27,'INSERT SELECT','Syntax\n------\n\nINSERT
[LOW_PRIORITY | HIGH_PRIORITY] [IGNORE]\n [INTO] tbl_name
[(col_name,...)]\n SELECT ...\n [ ON DUPLICATE KEY UPDATE col_name=expr,
... ]\n\nDescription\n-----------\n\nWith INSERT ... SELECT, you can
quickly insert many rows into a table from one\nor more other tables. For
example:\n\nINSERT INTO tbl_temp2 (fld_id)\n SELECT
tbl_temp1.fld_order_id\n FROM tbl_temp1 WHERE tbl_temp1.fld_order_id >
100;\n\ntbl_name can also be specified in the form db_name.tbl_name (see
Identifier\nQualifiers). This allows to copy rows between different
databases.\n\nIf the new table has a primary key or UNIQUE indexes, you can
use IGNORE to\nhandle duplicate key errors during the query. The newer
values will not be\ninserted if an identical value already
exists.\n\nREPLACE can be used instead of INSERT to prevent duplicates on
UNIQUE indexes\nby deleting old values. In that case, ON DUPLICATE KEY
UPDATE cannot be used.\n\nINSERT ... SELECT works for tables which already
exist. To create a table for\na given resultset, you can use CREATE TABLE
... SELECT.\n\nURL:
https://mariadb.com/kb/en/insert-select/','','https://mariadb.com/kb/en/insert-select/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(448,27,'LOAD DATA INFILE','Syntax\n------\n\nLOAD DATA
[LOW_PRIORITY | CONCURRENT] [LOCAL] INFILE \'file_name\'\n
[REPLACE | IGNORE]\n INTO TABLE tbl_name\n [CHARACTER SET charset_name]\n
[{FIELDS | COLUMNS}\n [TERMINATED BY \'string\']\n
[[OPTIONALLY] ENCLOSED BY \'char\']\n [ESCAPED BY
\'char\']\n ]\n [LINES\n [STARTING BY
\'string\']\n [TERMINATED BY \'string\']\n ]\n
[IGNORE number LINES]\n [(col_name_or_user_var,...)]\n [SET col_name =
expr,...]\n\nDescription\n-----------\n\nLOAD DATA INFILE is unsafe for
statement-based replication.\n\nReads rows from a text file into the
designated table on the database at a\nvery high speed. The file name must
be given as a literal string.\n\nFiles are written to disk using the SELECT
INTO OUTFILE statement. You can\nthen read the files back into a table
using the LOAD DATA INFILE statement.\nThe FIELDS and LINES clauses are the
same in both statements. These clauses\nare optional, but if both are
specified then the FIELDS clause must precede\nLINES.\n\nExecuting this
statement activates INSERT triggers.\n\nOne must have the FILE privilege to
be able to execute LOAD DATA INFILE. This\nis to ensure normal users cannot
read system files. LOAD DATA LOCAL INFILE\ndoes not have this
requirement.\n\nIf the secure_file_priv system variable is set (by default
it is not), the\nloaded file must be present in the specified
directory.\n\nNote that MariaDB\'s systemd unit file restricts access
to /home, /root, and\n/run/user by default. See Configuring access to home
directories.\n\nLOAD DATA LOCAL INFILE\n----------------------\n\nWhen you
execute the LOAD DATA INFILE statement, MariaDB Server attempts to\nread
the input file from its own file system. By contrast, when you execute\nthe
LOAD DATA LOCAL INFILE statement, the client attempts to read the
input\nfile from its file system, and it sends the contents of the input
file to the\nMariaDB Server. This allows you to load files from the
client\'s local file\nsystem into the database.\n\nIf you don\'t
want to permit this operation (perhaps for security reasons), you\ncan
disable the LOAD DATA LOCAL INFILE statement on either the server or
the\nclient.\n\n* The LOAD DATA LOCAL INFILE statement can be disabled on
the server by\nsetting the local_infile system variable to 0.\n* The LOAD
DATA LOCAL INFILE statement can be disabled on the client. If you\nare
using MariaDB Connector/C, this can be done by unsetting
the\nCLIENT_LOCAL_FILES capability flag with the mysql_real_connect
function or by\nunsetting the MYSQL_OPT_LOCAL_INFILE option with
mysql_optionsv function. If\nyou are using a different client or client
library, then see the documentation\nfor your specific client or client
library to determine how it handles the\nLOAD DATA LOCAL INFILE
statement.\n\nIf the LOAD DATA LOCAL INFILE statement is disabled by either
the server or\nthe client and if the user attempts to execute it, then the
server will cause\nthe statement to fail with the following error
message:\n\nThe used command is not allowed with this MariaDB
version\n\nNote that it is not entirely accurate to say that the MariaDB
version does not\nsupport the command. It would be more accurate to say
that the MariaDB\nconfiguration does not support the command. See
MDEV-20500 for more\ninformation.\n\nFrom MariaDB 10.5.2, the error message
is more accurate:\n\nThe used command is not allowed because the MariaDB
server or client \n has disabled the local infile capability\n\nREPLACE and
IGNORE\n------------------\n\nIf you load data from a file into a table
that already contains data and has a\nprimary key, you may encounter issues
where the statement attempts to insert a\nrow with a primary key that
already exists. When this happens, the statement\nfails with Error 1064,
protecting the data already on the table. If you want\nMariaDB to overwrite
duplicates, use the REPLACE keyword.\n\nThe REPLACE keyword works like the
REPLACE statement. Here, the statement\nattempts to load the data from the
file. If the row does not exist, it adds it\nto the table. If the row
contains an existing primary key, it replaces the\ntable data. That is, in
the event of a conflict, it assumes the file contains\nthe desired
row.\n\nThis operation can cause a degradation in load speed by a factor of
20 or more\nif the part that has already been loaded is larger than the
capacity of the\nInnoDB Buffer Pool. This happens because it causes a lot
of turnaround in the\nbuffer pool.\n\nUse the IGNORE keyword when you want
to skip any rows that contain a\nconflicting primary key. Here, the
statement attempts to load the data from\nthe file. If the row does not
exist, it adds it to the table. If the row\ncontains an existing primary
key, it ignores the addition request and moves on\nto the next. That is, in
the event of a conflict, it assumes the table\ncontains the desired
row.\n\nCharacter-sets\n--------------\n\nWhen the statement opens the
file, it attempts to read the contents using the\ndefault character-set, as
defined by the character_set_database system\nvariable.\n\nIn the cases
where the file was written using a character-set other than the\ndefault,
you can specify the character-set to use with the CHARACTER SET\nclause in
the statement. It ignores character-sets specified by the SET
NAMES\nstatement and by the character_set_client system variable. Setting
the\nCHARACTER SET clause to a value of binary indicates \"no
conversion.\"\n\nThe statement interprets all fields in the file as
having the same\ncharacter-set, regardless of the column data type. To
properly interpret file\ncontents, you must ensure that it was written with
the correct character-set.\nIf you write a data file with mysqldump -T or
with the SELECT INTO OUTFILE\nstatement with the mysql client, be sure to
use the --default-character-set\noption, so that the output is written with
the desired character-set.\n\nWhen using mixed character sets, use the
CHARACTER SET clause in both SELECT\nINTO OUTFILE and LOAD DATA INFILE to
ensure that MariaDB correctly interprets\nthe escape sequences.\n\nThe
character_set_filesystem system variable controls the interpretation
of\nthe filename.\n\nIt is currently not possible to load data files that
use the ucs2 character\nset.\n\nPreprocessing
Inputs\n--------------------\n\ncol_name_or_user_var can be a column name,
or a user variable. In the case of\na variable, the SET statement can be
used to preprocess the value before\nloading into the table.\n\nPriority
and Concurrency\n------------------------\n\nIn storage engines that
perform table-level locking (MyISAM, MEMORY and\nMERGE), using the
LOW_PRIORITY keyword, MariaDB delays insertions until no\nother clients are
reading from the table. Alternatively, when using the MyISAM\nstorage
engine, you can use the CONCURRENT keyword to perform
concurrent\ninsertion.\n\nThe LOW_PRIORITY and CONCURRENT keywords are
mutually exclusive. They cannot\nbe used in the same statement.\n\nProgress
Reporting\n------------------\n\nThe LOAD DATA INFILE statement supports
progress reporting. You may find this\nuseful when dealing with
long-running operations. Using another client you can\nissue a SHOW
PROCESSLIST query to check the progress of the data load.\n\nUsing
mariadb-import/mysqlimport\n--------------------------------\n\nMariaDB
ships with a separate utility for loading data from files:\nmariadb-import
(or mysqlimport before MariaDB 10.5). It operates by sending\nLOAD DATA
INFILE statements to the server.\n\nUsing mariadb-import/mysqlimport you
can compress the file using the\n--compress option, to get better
performance over slow networks, providing\nboth the client and server
support the compressed protocol. Use the --local\noption to load from the
local file system.\n\nIndexing\n--------\n\nIn cases where the storage
engine supports ALTER TABLE... DISABLE KEYS\nstatements (MyISAM and Aria),
the LOAD DATA INFILE statement automatically\ndisables indexes during the
execution.\n\nExamples\n--------\n\nYou have a file with this content (note
the the separator is \',\', not tab,\nwhich is the
default):\n\n2,2\n3,3\n4,4\n5,5\n6,8\n\nCREATE TABLE t1 (a int, b int, c
int, d int, PRIMARY KEY (a));\nLOAD DATA LOCAL INFILE \n
\'/tmp/loaddata7.dat\' INTO TABLE t1 FIELDS TERMINATED BY
\',\' (a,b) SET c=a+b;\nSELECT * FROM
t1;\n+------+------+------+\n| a | b | c
|\n+------+------+------+\n| 2 | 2 | 4 |\n| 3 | 3 | 6
|\n| 4 | 4 | 8 |\n| 5 | 5 | 10 |\n| 6 | 8 | 14
|\n+------+------+------+\n\nAnother example, given the following data (the
separator is a tab):\n\n1 a\n2 b\n\nThe value of the first
column is doubled before loading:\n\nLOAD DATA INFILE \'ld.txt\'
INTO TABLE ld (@i,v) SET i=@i*2;\n\nSELECT * FROM ld;\n+------+------+\n| i
| v |\n+------+------+\n| 2 | a |\n| 4 | b
|\n+------+------+\n\nURL:
https://mariadb.com/kb/en/load-data-infile/','','https://mariadb.com/kb/en/load-data-infile/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(449,27,'LOAD XML','Syntax\n------\n\nLOAD XML [LOW_PRIORITY
| CONCURRENT] [LOCAL] INFILE \'file_name\'\n [REPLACE |
IGNORE]\n INTO TABLE [db_name.]tbl_name\n [CHARACTER SET charset_name]\n
[ROWS IDENTIFIED BY \'<tagname>\']\n [IGNORE number {LINES
| ROWS}]\n [(column_or_user_var,...)]\n [SET col_name =
expr,...]\n\nDescription\n-----------\n\nThe LOAD XML statement reads data
from an XML file into a table. The file_name\nmust be given as a literal
string. The tagname in the optional ROWS IDENTIFIED\nBY clause must also be
given as a literal string, and must be surrounded by\nangle brackets (<
and >).\n\nLOAD XML acts as the complement of running the mysql client
in XML output mode\n(that is, starting the client with the --xml option).
To write data from a\ntable to an XML file, use a command such as the
following one from the system\nshell:\n\nshell> mysql --xml -e
\'SELECT * FROM mytable\' > file.xml\n\nTo read the file back
into a table, use LOAD XML INFILE. By default, the <row>\nelement is
considered to be the equivalent of a database table row; this can\nbe
changed using the ROWS IDENTIFIED BY clause.\n\nThis statement supports
three different XML formats:\n\n* Column names as attributes and column
values as attribute values:\n\n<row column1=\"value1\"
column2=\"value2\" .../>\n\n* Column names as tags and column
values as the content of these tags:\n\n<row>\n
<column1>value1</column1>\n
<column2>value2</column2>\n</row>\n\n* Column names are
the name attributes of <field> tags, and values are\n the contents of
these tags:\n\n<row>\n <field
name=\'column1\'>value1</field>\n <field
name=\'column2\'>value2</field>\n</row>\n\nThis is
the format used by other tools, such as mysqldump.\n\nAll 3 formats can be
used in the same XML file; the import routine\nautomatically detects the
format for each row and interprets it correctly.\nTags are matched based on
the tag or attribute name and the column name.\n\nThe following clauses
work essentially the same way for LOAD XML as they do\nfor LOAD DATA:\n\n*
LOW_PRIORITY or CONCURRENT\n* LOCAL\n* REPLACE or IGNORE\n* CHARACTER
SET\n* (column_or_user_var,...)\n* SET\n\nSee LOAD DATA for more
information about these clauses.\n\nThe IGNORE number LINES or IGNORE
number ROWS clause causes the first number\nrows in the XML file to be
skipped. It is analogous to the LOAD DATA\nstatement\'s IGNORE ...
LINES clause.\n\nIf the LOW_PRIORITY keyword is used, insertions are
delayed until no other\nclients are reading from the table. The CONCURRENT
keyword allowes the use of\nconcurrent inserts. These clauses cannot be
specified together.\n\nThis statement activates INSERT triggers.\n\nURL:
https://mariadb.com/kb/en/load-xml/','','https://mariadb.com/kb/en/load-xml/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(450,27,'Concurrent Inserts','The MyISAM storage engine
supports concurrent inserts. This feature allows\nSELECT statements to be
executed during INSERT operations, reducing contention.\n\nWhether
concurrent inserts can be used or not depends on the value of
the\nconcurrent_insert server system variable:\n\n* NEVER (0) disables
concurrent inserts.\n* AUTO (1) allows concurrent inserts only when the
target table has no free\nblocks (no data in the middle of the table has
been deleted after the last\nOPTIMIZE TABLE). This is the default.\n*
ALWAYS (2) always enables concurrent inserts, in which case new rows
are\nadded at the end of a table if the table is being used by another
thread.\n\nIf the binary log is used, CREATE TABLE ... SELECT and INSERT
... SELECT\nstatements cannot use concurrent inserts. These statements
acquire a read lock\non the table, so concurrent inserts will need to wait.
This way the log can be\nsafely used to restore data.\n\nConcurrent inserts
are not used by replicas with the row based replication\n(see binary log
formats).\n\nIf an INSERT statement contain the HIGH_PRIORITY clause,
concurrent inserts\ncannot be used. INSERT ... DELAYED is usually unneeded
if concurrent inserts\nare enabled.\n\nLOAD DATA INFILE uses concurrent
inserts if the CONCURRENT keyword is\nspecified and concurrent_insert is
not NEVER. This makes the statement slower\n(even if no other sessions
access the table) but reduces contention.\n\nLOCK TABLES allows
non-conflicting concurrent inserts if a READ LOCAL lock is\nused.
Concurrent inserts are not allowed if the LOCAL keyword is
omitted.\n\nNotes\n-----\n\nThe decision to enable concurrent insert for a
table is done when the table is\nopened. If you change the value of
concurrent_insert it will only affect new\nopened tables. If you want it to
work for also for tables in use or cached,\nyou should do FLUSH TABLES
after setting the variable.\n\nURL:
https://mariadb.com/kb/en/concurrent-inserts/','','https://mariadb.com/kb/en/concurrent-inserts/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(451,27,'HIGH_PRIORITY and LOW_PRIORITY','The InnoDB storage
engine uses row-level locking to ensure data integrity.\nHowever some
storage engines (such as MEMORY, MyISAM, Aria and MERGE) lock the\nwhole
table to prevent conflicts. These storage engines use two separate\nqueues
to remember pending statements; one is for SELECTs and the other one
is\nfor write statements (INSERT, DELETE, UPDATE). By default, the latter
has a\nhigher priority.\n\nTo give write operations a lower priority, the
low_priority_updates server\nsystem variable can be set to ON. The option
is available on both the global\nand session levels, and it can be set at
startup or via the SET statement.\n\nWhen too many table locks have been
set by write statements, some pending\nSELECTs are executed. The maximum
number of write locks that can be acquired\nbefore this happens is
determined by the max_write_lock_count server system\nvariable, which is
dynamic.\n\nIf write statements have a higher priority (default), the
priority of\nindividual write statements (INSERT, REPLACE, UPDATE, DELETE)
can be changed\nvia the LOW_PRIORITY attribute, and the priority of a
SELECT statement can be\nraised via the HIGH_PRIORITY attribute. Also, LOCK
TABLES supports a\nLOW_PRIORITY attribute for WRITE locks.\n\nIf read
statements have a higher priority, the priority of an INSERT can
be\nchanged via the HIGH_PRIORITY attribute. However, the priority of other
write\nstatements cannot be raised individually.\n\nThe use of LOW_PRIORITY
or HIGH_PRIORITY for an INSERT prevents Concurrent\nInserts from being
used.\n\nURL:
https://mariadb.com/kb/en/high_priority-and-low_priority/','','https://mariadb.com/kb/en/high_priority-and-low_priority/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(452,27,'INSERT - Default & Duplicate Values','Default
Values\n--------------\n\nIf the SQL_MODE contains STRICT_TRANS_TABLES and
you are inserting into a\ntransactional table (like InnoDB), or if the
SQL_MODE contains\nSTRICT_ALL_TABLES, all NOT NULL columns which do not
have a DEFAULT value (and\nare not AUTO_INCREMENT) must be explicitly
referenced in INSERT statements. If\nnot, an error like this is
produced:\n\nERROR 1364 (HY000): Field \'col\' doesn\'t have
a default value\n\nIn all other cases, if a NOT NULL column without a
DEFAULT value is not\nreferenced, an empty value will be inserted (for
example, 0 for INTEGER\ncolumns and \'\' for CHAR columns). See
NULL Values in MariaDB:Inserting for\nexamples.\n\nIf a NOT NULL column
having a DEFAULT value is not referenced, NULL will be\ninserted.\n\nIf a
NULL column having a DEFAULT value is not referenced, its default
value\nwill be inserted. It is also possible to explicitly assign the
default value\nusing the DEFAULT keyword or the DEFAULT() function.\n\nIf
the DEFAULT keyword is used but the column does not have a DEFAULT
value,\nan error like this is produced:\n\nERROR 1364 (HY000): Field
\'col\' doesn\'t have a default value\n\nDuplicate
Values\n----------------\n\nBy default, if you try to insert a duplicate
row and there is a UNIQUE index,\nINSERT stops and an error like this is
produced:\n\nERROR 1062 (23000): Duplicate entry \'dup_value\'
for key \'col\'\n\nTo handle duplicates you can use the IGNORE
clause, INSERT ON DUPLICATE KEY\nUPDATE or the REPLACE statement. Note that
the IGNORE and DELAYED options are\nignored when you use ON DUPLICATE KEY
UPDATE.\n\nURL:
https://mariadb.com/kb/en/insert-default-duplicate-values/','','https://mariadb.com/kb/en/insert-default-duplicate-values/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(453,27,'INSERT IGNORE','Ignoring
Errors\n---------------\n\nNormally INSERT stops and rolls back when it
encounters an error.\n\nBy using the IGNORE keyword all errors are
converted to warnings, which will\nnot stop inserts of additional
rows.\n\nThe IGNORE and DELAYED options are ignored when you use ON
DUPLICATE KEY\nUPDATE.\n\nPrior to MySQL and MariaDB 5.5.28, no warnings
were issued for duplicate key\nerrors when using IGNORE. You can get the
old behavior if you set OLD_MODE
to\nNO_DUP_KEY_WARNINGS_WITH_IGNORE.\n\nExamples\n--------\n\nCREATE TABLE
t1 (x INT UNIQUE);\n\nINSERT INTO t1 VALUES(1),(2);\n\nINSERT INTO t1
VALUES(2),(3);\nERROR 1062 (23000): Duplicate entry \'2\' for key
\'x\'\nSELECT * FROM t1;\n+------+\n| x |\n+------+\n| 1
|\n| 2 |\n+------+\n2 rows in set (0.00 sec)\n\nINSERT IGNORE INTO t1
VALUES(2),(3);\nQuery OK, 1 row affected, 1 warning (0.04 sec)\n\nSHOW
WARNINGS;\n+---------+------+---------------------------------+\n| Level
| Code | Message
|\n+---------+------+---------------------------------+\n| Warning | 1062 |
Duplicate entry \'2\' for key \'x\'
|\n+---------+------+---------------------------------+\n\nSELECT * FROM
t1;\n+------+\n| x |\n+------+\n| 1 |\n| 2 |\n| 3
|\n+------+\n\nSee INSERT ON DUPLICATE KEY UPDATE for further examples
using that syntax.\n\nURL:
https://mariadb.com/kb/en/insert-ignore/','','https://mariadb.com/kb/en/insert-ignore/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(454,27,'INSERT ON DUPLICATE KEY
UPDATE','Syntax\n------\n\nINSERT [LOW_PRIORITY | DELAYED |
HIGH_PRIORITY] [IGNORE]\n [INTO] tbl_name [PARTITION (partition_list)]
[(col,...)]\n {VALUES | VALUE} ({expr | DEFAULT},...),(...),...\n [ ON
DUPLICATE KEY UPDATE\n col=expr\n [, col=expr] ... ]\n\nOr:\n\nINSERT
[LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE]\n [INTO] tbl_name
[PARTITION (partition_list)]\n SET col={expr | DEFAULT}, ...\n [ ON
DUPLICATE KEY UPDATE\n col=expr\n [, col=expr] ... ]\n\nOr:\n\nINSERT
[LOW_PRIORITY | HIGH_PRIORITY] [IGNORE]\n [INTO] tbl_name [PARTITION
(partition_list)] [(col,...)]\n SELECT ...\n [ ON DUPLICATE KEY UPDATE\n
col=expr\n [, col=expr] ... ]\n\nDescription\n-----------\n\nINSERT ...
ON DUPLICATE KEY UPDATE is a MariaDB/MySQL extension to the
INSERT\nstatement that, if it finds a duplicate unique or primary key, will
instead\nperform an UPDATE.\n\nThe row/s affected value is reported as 1 if
a row is inserted, and 2 if a row\nis updated, unless the API\'s
CLIENT_FOUND_ROWS flag is set.\n\nIf more than one unique index is matched,
only the first is updated. It is not\nrecommended to use this statement on
tables with more than one unique index.\n\nIf the table has an
AUTO_INCREMENT primary key and the statement inserts or\nupdates a row, the
LAST_INSERT_ID() function returns its AUTO_INCREMENT value.\n\nThe VALUES()
function can only be used in a ON DUPLICATE KEY UPDATE clause and\nhas no
meaning in any other context. It returns the column values from the\nINSERT
portion of the statement. This function is particularly useful
for\nmulti-rows inserts.\n\nThe IGNORE and DELAYED options are ignored when
you use ON DUPLICATE KEY\nUPDATE.\n\nSee Partition Pruning and Selection
for details on the PARTITION clause.\n\nThis statement activates INSERT and
UPDATE triggers. See Trigger Overview for\ndetails.\n\nSee also a similar
statement, REPLACE.\n\nExamples\n--------\n\nCREATE TABLE ins_duplicate (id
INT PRIMARY KEY, animal VARCHAR(30));\nINSERT INTO ins_duplicate VALUES
(1,\'Aardvark\'), (2,\'Cheetah\'),
(3,\'Zebra\');\n\nIf there is no existing key, the statement runs
as a regular INSERT:\n\nINSERT INTO ins_duplicate VALUES
(4,\'Gorilla\') \n ON DUPLICATE KEY UPDATE
animal=\'Gorilla\';\nQuery OK, 1 row affected (0.07
sec)\n\nSELECT * FROM ins_duplicate;\n+----+----------+\n| id | animal
|\n+----+----------+\n| 1 | Aardvark |\n| 2 | Cheetah |\n| 3 | Zebra
|\n| 4 | Gorilla |\n+----+----------+\n\nA regular INSERT with a primary
key value of 1 will fail, due to the existing\nkey:\n\nINSERT INTO
ins_duplicate VALUES (1,\'Antelope\');\nERROR 1062 (23000):
Duplicate entry \'1\' for key \'PRIMARY\'\n\nHowever,
we can use an INSERT ON DUPLICATE KEY UPDATE instead:\n\nINSERT INTO
ins_duplicate VALUES (1,\'Antelope\') \n ON DUPLICATE KEY UPDATE
animal=\'Antelope\';\nQuery OK, 2 rows affected (0.09
sec)\n\nNote that there are two rows reported as affected, but this refers
only to the\nUPDATE.\n\nSELECT * FROM ins_duplicate;\n+----+----------+\n|
id | animal |\n+----+----------+\n| 1 | Antelope |\n| 2 | Cheetah |\n|
3 | Zebra |\n| 4 | Gorilla |\n+----+----------+\n\nAdding a second
unique column:\n\nALTER TABLE ins_duplicate ADD id2 INT;\nUPDATE
ins_duplicate SET id2=id+10;\nALTER TABLE ins_duplicate ADD UNIQUE
KEY(id2);\n\nWhere two rows match the unique keys match, only the first is
updated. This\ncan be unsafe and is not recommended unless you are certain
what you are doing.\n\nINSERT INTO ins_duplicate VALUES
(2,\'Lion\',13) \n ON DUPLICATE KEY UPDATE
animal=\'Lion\';\nQuery OK, 2 rows affected (0.004 sec)\n\nSELECT
* FROM ins_duplicate;\n+----+----------+------+\n| id | animal | id2
|\n+----+----------+------+\n| 1 | Antelope | 11 |\n| 2 | Lion |
12 |\n| 3 | Zebra | 13 |\n| 4 | Gorilla | 14
|\n+----+----------+------+\n\nAlthough the third row with an id of 3 has
an id2 of 13, which also matched,\nit was not updated.\n\nChanging id to an
auto_increment field. If a new row is added, the\nauto_increment is moved
forward. If the row is updated, it remains the same.\n\nALTER TABLE
`ins_duplicate` CHANGE `id` `id` INT( 11 ) NOT NULL AUTO_INCREMENT;\nALTER
TABLE ins_duplicate DROP id2;\nSELECT Auto_increment FROM
INFORMATION_SCHEMA.TABLES \n WHERE
TABLE_NAME=\'ins_duplicate\';\n+----------------+\n|
Auto_increment |\n+----------------+\n| 5
|\n+----------------+\n\nINSERT INTO ins_duplicate VALUES
(2,\'Leopard\') \n ON DUPLICATE KEY UPDATE
animal=\'Leopard\';\nQuery OK, 2 rows affected (0.00
sec)\n\nSELECT Auto_increment FROM INFORMATION_SCHEMA.TABLES \n WHERE
TABLE_NAME=\'ins_duplicate\';\n+----------------+\n|
Auto_increment |\n+----------------+\n| 5
|\n+----------------+\n\nINSERT INTO ins_duplicate VALUES (5,\'Wild
Dog\') \n ON DUPLICATE KEY UPDATE animal=\'Wild
Dog\';\nQuery OK, 1 row affected (0.09 sec)\n\nSELECT * FROM
ins_duplicate;\n+----+----------+\n| id | animal |\n+----+----------+\n|
1 | Antelope |\n| 2 | Leopard |\n| 3 | Zebra |\n| 4 | Gorilla |\n|
5 | Wild Dog |\n+----+----------+\n\nSELECT Auto_increment FROM
INFORMATION_SCHEMA.TABLES \n WHERE
TABLE_NAME=\'ins_duplicate\';\n+----------------+\n|
Auto_increment |\n+----------------+\n| 6
|\n+----------------+\n\nRefering to column values from the INSERT portion
of the statement:\n\nINSERT INTO table (a,b,c) VALUES (1,2,3),(4,5,6)\n ON
DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b);\n\nSee the VALUES() function
for more.\n\nURL:
https://mariadb.com/kb/en/insert-on-duplicate-key-update/','','https://mariadb.com/kb/en/insert-on-duplicate-key-update/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(455,27,'INSERT...RETURNING','MariaDB starting with
10.5.0\n----------------------------\nINSERT ... RETURNING was added in
MariaDB 10.5.0, and returns a resultset of\nthe inserted
rows.\n\nSyntax\n------\n\nINSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY]
[IGNORE]\n [INTO] tbl_name [PARTITION (partition_list)] [(col,...)]\n
{VALUES | VALUE} ({expr | DEFAULT},...),(...),...\n [ ON DUPLICATE KEY
UPDATE\n col=expr\n [, col=expr] ... ] [RETURNING select_expr\n [,
select_expr ...]]\n\nOr:\n\nINSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY]
[IGNORE]\n [INTO] tbl_name [PARTITION (partition_list)]\n SET col={expr |
DEFAULT}, ...\n [ ON DUPLICATE KEY UPDATE\n col=expr\n [, col=expr]
... ] [RETURNING select_expr\n [, select_expr ...]]\n\nOr:\n\nINSERT
[LOW_PRIORITY | HIGH_PRIORITY] [IGNORE]\n [INTO] tbl_name [PARTITION
(partition_list)] [(col,...)]\n SELECT ...\n [ ON DUPLICATE KEY UPDATE\n
col=expr\n [, col=expr] ... ] [RETURNING select_expr\n [, select_expr
...]]\n\nDescription\n-----------\n\nINSERT ... RETURNING returns a
resultset of the inserted rows.\n\nThis returns the listed columns for all
the rows that are inserted, or\nalternatively, the specified SELECT
expression. Any SQL expressions which can\nbe calculated can be used in the
select expression for the RETURNING clause,\nincluding virtual columns and
aliases, expressions which use various operators\nsuch as bitwise, logical
and arithmetic operators, string functions, date-time\nfunctions, numeric
functions, control flow functions, secondary functions and\nstored
functions. Along with this, statements which have subqueries and\nprepared
statements can also be used.\n\nExamples\n--------\n\nSimple INSERT
statements:\n\nCREATE OR REPLACE TABLE t2 (id INT, animal VARCHAR(20), t
TIMESTAMP);\n\nINSERT INTO t2 (id) VALUES (2),(3) RETURNING
id,t;\n+------+---------------------+\n| id | t
|\n+------+---------------------+\n| 2 | 2021-04-28 00:59:32 |\n| 3 |
2021-04-28 00:59:32 |\n+------+---------------------+\n\nINSERT INTO
t2(id,animal)
VALUES\n(1,\'Dog\'),(2,\'Lion\'),(3,\'Tiger\'),(4,\'Leopard\')
\n RETURNING
id,id+id,id&id,id||id;\n+------+-------+-------+--------+\n| id |
id+id | id&id | id||id |\n+------+-------+-------+--------+\n| 1 |
2 | 1 | 1 |\n| 2 | 4 | 2 | 1 |\n| 3 | 6 |
3 | 1 |\n| 4 | 8 | 4 | 1
|\n+------+-------+-------+--------+\n\nUsing stored functions in
RETURNING\n\nDELIMITER |\nCREATE FUNCTION f(arg INT) RETURNS INT\n BEGIN\n
RETURN (SELECT arg+arg);\n END|\n\nDELIMITER ;\n\nPREPARE stmt FROM
\"INSERT INTO t1 SET id1=1, animal1=\'Bear\' RETURNING
f(id1),\nUPPER(animal1)\";\n\nEXECUTE
stmt;\n+---------+----------------+\n| f(id1) | UPPER(animal1)
|\n+---------+----------------+\n| 2 | BEAR
|\n+---------+----------------+\n\nSubqueries in the RETURNING clause that
return more than one row or column\ncannot be used.\n\nAggregate functions
cannot be used in the RETURNING clause. Since aggregate\nfunctions work on
a set of values, and if the purpose is to get the row count,\nROW_COUNT()
with SELECT can be used or it can be used in\nINSERT...SELECT...RETURNING
if the table in the RETURNING clause is not the\nsame as the INSERT
table.\n\nURL:
https://mariadb.com/kb/en/insertreturning/','','https://mariadb.com/kb/en/insertreturning/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(456,27,'REPLACE...RETURNING','MariaDB starting with
10.5.0\n----------------------------\nREPLACE ... RETURNING was added in
MariaDB 10.5.0, and returns a resultset of\nthe replaced
rows.\n\nSyntax\n------\n\nREPLACE [LOW_PRIORITY | DELAYED]\n [INTO]
tbl_name [PARTITION (partition_list)] [(col,...)]\n {VALUES | VALUE} ({expr
| DEFAULT},...),(...),...\n[RETURNING select_expr \n [, select_expr
...]]\n\nOr:\n\nREPLACE [LOW_PRIORITY | DELAYED]\n [INTO] tbl_name
[PARTITION (partition_list)]\n SET col={expr | DEFAULT}, ...\n[RETURNING
select_expr \n [, select_expr ...]]\n\nOr:\n\nREPLACE [LOW_PRIORITY |
DELAYED]\n [INTO] tbl_name [PARTITION (partition_list)] [(col,...)]\n
SELECT ...\n[RETURNING select_expr \n [, select_expr
...]]\n\nDescription\n-----------\n\nREPLACE ... RETURNING returns a
resultset of the replaced rows.\n\nThis returns the listed columns for all
the rows that are replaced, or\nalternatively, the specified SELECT
expression. Any SQL expressions which can\nbe calculated can be used in the
select expression for the RETURNING clause,\nincluding virtual columns and
aliases, expressions which use various operators\nsuch as bitwise, logical
and arithmetic operators, string functions, date-time\nfunctions, numeric
functions, control flow functions, secondary functions and\nstored
functions. Along with this, statements which have subqueries and\nprepared
statements can also be used.\n\nExamples\n--------\n\nSimple REPLACE
statement\n\nREPLACE INTO t2 VALUES
(1,\'Leopard\'),(2,\'Dog\') RETURNING id2, id2+id2 \nas
Total ,id2|id2, id2&&id2;\n+-----+-------+---------+----------+\n|
id2 | Total | id2|id2 | id2&&id2
|\n+-----+-------+---------+----------+\n| 1 | 2 | 1 | 1
|\n| 2 | 4 | 2 | 1
|\n+-----+-------+---------+----------+\n\nUsing stored functions in
RETURNING\n\nDELIMITER |\nCREATE FUNCTION f(arg INT) RETURNS INT\n BEGIN\n
RETURN (SELECT arg+arg);\n END|\n\nDELIMITER ;\nPREPARE stmt FROM
\"REPLACE INTO t2 SET id2=3, animal2=\'Fox\' RETURNING
f2(id2),\nUPPER(animal2)\";\n\nEXECUTE
stmt;\n+---------+----------------+\n| f2(id2) | UPPER(animal2)
|\n+---------+----------------+\n| 6 | FOX
|\n+---------+----------------+\n\nSubqueries in the statement\n\nREPLACE
INTO t1 SELECT * FROM t2 RETURNING (SELECT id2 FROM t2 WHERE \nid2 IN
(SELECT id2 FROM t2 WHERE id2=1)) AS new_id;\n+--------+\n| new_id
|\n+--------+\n| 1 |\n| 1 |\n| 1 |\n| 1
|\n+--------+\n\nSubqueries in the RETURNING clause that return more than
one row or column\ncannot be used..\n\nAggregate functions cannot be used
in the RETURNING clause. Since aggregate\nfunctions work on a set of values
and if the purpose is to get the row count,\nROW_COUNT() with SELECT can be
used, or it can be used in\nREPLACE...SELECT...RETURNING if the table in
the RETURNING clause is not the\nsame as the REPLACE table.\n\nURL:
https://mariadb.com/kb/en/replacereturning/','','https://mariadb.com/kb/en/replacereturning/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(457,27,'CALL','Syntax\n------\n\nCALL
sp_name([parameter[,...]])\nCALL
sp_name[()]\n\nDescription\n-----------\n\nThe CALL statement invokes a
stored procedure that was defined previously with\nCREATE
PROCEDURE.\n\nStored procedure names can be specified as
database_name.procedure_name.\nProcedure names and database names can be
quoted with backticks (). This is\nnecessary if they are reserved words, or
contain special characters. See\nidentifier qualifiers for details.\n\nCALL
p() and CALL p are equivalent.\n\nIf parentheses are used, any number of
spaces, tab characters and newline\ncharacters are allowed between the
procedure\'s name and the open parenthesis.\n\nCALL can pass back
values to its caller using parameters that are declared as\nOUT or INOUT
parameters. If no value is assigned to an OUT parameter, NULL is\nassigned
(and its former value is lost). To pass such values from another\nstored
program you can use user-defined variables, local variables
or\nroutine\'s parameters; in other contexts, you can only use
user-defined\nvariables.\n\nCALL can also be executed as a prepared
statement. Placeholders can be used\nfor IN parameters in all versions of
MariaDB; for OUT and INOUT parameters,\nplaceholders can be used since
MariaDB 5.5.\n\nWhen the procedure returns, a client program can also
obtain the number of\nrows affected for the final statement executed within
the routine: At the SQL\nlevel, call the ROW_COUNT() function; from the C
API, call the\nmysql_affected_rows() function.\n\nIf the
CLIENT_MULTI_RESULTS API flag is set, CALL can return any number
of\nresultsets and the called stored procedure can execute prepared
statements. If\nit is not set, at most one resultset can be returned and
prepared statements\ncannot be used within procedures.\n\nURL:
https://mariadb.com/kb/en/call/','','https://mariadb.com/kb/en/call/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(458,27,'DO','Syntax\n------\n\nDO expr [, expr]
...\n\nDescription\n-----------\n\nDO executes the expressions but does not
return any results. In most respects,\nDO is shorthand for SELECT expr,
..., but has the advantage that it is\nslightly faster when you do not care
about the result.\n\nDO is useful primarily with functions that have side
effects, such as\nRELEASE_LOCK().\n\nURL:
https://mariadb.com/kb/en/do/','','https://mariadb.com/kb/en/do/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(459,27,'Comment Syntax','There are three supported comment
styles in MariaDB:\n\n* From a \'#\' to the end of a line:SELECT
* FROM users; # This is a comment\n\n* From a \'-- \' to the end
of a line. The space after the two dashes is\nrequired (as in MySQL).SELECT
* FROM users; -- This is a comment\n\n* C style comments from an opening
\'/*\' to a closing \'*/\'. Comments of this\nform can
span multiple lines:SELECT * FROM users; /* This is a\nmulti-line\ncomment
*/\n\nNested comments are possible in some situations, but they are not
supported or\nrecommended.\n\nExecutable
Comments\n-------------------\n\nAs an aid to portability between different
databases, MariaDB supports\nexecutable comments. These special comments
allow you to embed SQL code which\nwill not execute when run on other
databases, but will execute when run on\nMariaDB.\n\nMariaDB supports both
MySQL\'s executable comment format, and a slightly\nmodified version
specific to MariaDB. This way, if you have SQL code that\nworks on MySQL
and MariaDB, but not other databases, you can wrap it in a\nMySQL
executable comment, and if you have code that specifically takes\nadvantage
of features only available in MariaDB you can use the MariaDB\nspecific
format to hide the code from MySQL.\n\nExecutable Comment
Syntax\n-------------------------\n\nMySQL and MariaDB executable comment
syntax:\n\n/*! MySQL or MariaDB-specific code */\n\nCode that should be
executed only starting from a specific MySQL or
MariaDB\nversion:\n\n/*!##### MySQL or MariaDB-specific code */\n\nThe
numbers, represented by \'######\' in the syntax examples above
specify the\nspecific the minimum versions of MySQL and MariaDB that should
execute the\ncomment. The first number is the major version, the second 2
numbers are the\nminor version and the last 2 is the patch level.\n\nFor
example, if you want to embed some code that should only execute on
MySQL\nor MariaDB starting from 5.1.0, you would do the
following:\n\n/*!50100 MySQL and MariaDB 5.1.0 (and above) code goes here.
*/\n\nMariaDB-only executable comment syntax (starting from MariaDB
5.3.1):\n\n/*M! MariaDB-specific code */\n/*M!###### MariaDB-specific code
*/\n\nMariaDB ignores MySQL-style executable comments that have a version
number in\nthe range 50700..99999. This is needed to skip features
introduced in\nMySQL-5.7 that are not ported to MariaDB 10.x
yet.\n\n/*!50701 MariaDB-10.x ignores MySQL-5.7 specific code */\n\nNote:
comments which have a version number in the range 50700..99999 that
use\nMariaDB-style executable comment syntax are still
executed.\n\n/*M!50701 MariaDB-10.x does not ignore this */\n\nStatement
delimiters cannot be used within executable
comments.\n\nExamples\n--------\n\nIn MySQL all the following will return
2: In MariaDB, the last 2 queries would\nreturn 3.\n\nSELECT 2 /* +1
*/;\nSELECT 1 /*! +1 */;\nSELECT 1 /*!50101 +1 */;\nSELECT 2 /*M! +1
*/;\nSELECT 2 /*M!50301 +1 */;\n\nThe following executable statement will
not work due to the delimiter inside\nthe executable portion:\n\n/*M!100100
select 1 ; */\nERROR 1064 (42000): You have an error in your SQL syntax;
check the manual\nthat corresponds to your MariaDB server version for the
right syntax to use\nnear \'\' at line 1\n\nInstead, the
delimiter should be placed outside the executable portion:\n\n/*M!100100
select 1 */;\n+---+\n| 1 |\n+---+\n| 1 |\n+---+\n\nURL:
https://mariadb.com/kb/en/comment-syntax/','','https://mariadb.com/kb/en/comment-syntax/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(460,27,'HANDLER Commands','Syntax\n------\n\nHANDLER
tbl_name OPEN [ [AS] alias]\nHANDLER tbl_name READ index_name { = | >= |
<= | < } (value1,value2,...)\n [ WHERE where_condition ] [LIMIT ...
]\nHANDLER tbl_name READ index_name { FIRST | NEXT | PREV | LAST }\n [
WHERE where_condition ] [LIMIT ... ]\nHANDLER tbl_name READ { FIRST | NEXT
}\n [ WHERE where_condition ] [LIMIT ... ]\nHANDLER tbl_name
CLOSE\n\nDescription\n-----------\n\nThe HANDLER statement provides direct
access to table storage engine\ninterfaces for key lookups and key or table
scans. It is available for at\nleast Aria, Memory, MyISAM and InnoDB tables
(and should work with most\n\'normal\' storage engines, but not
with system tables, MERGE or views).\n\nHANDLER ... OPEN opens a table,
allowing it to be accessible to subsequent\nHANDLER ... READ statements.
The table can either be opened using an alias\n(which must then be used by
HANDLER ... READ, or a table name.\n\nThe table object is only closed when
HANDLER ... CLOSE is called by the\nsession, and is not shared by other
sessions.\n\nPrepared statements work with HANDLER READ, which gives a much
higher\nperformance (50% speedup) as there is no parsing and all data is
transformed\nin binary (without conversions to text, as with the normal
protocol).\n\nThe HANDLER command does not work with partitioned
tables.\n\nKey Lookup\n----------\n\nA key lookup is started
with:\n\nHANDLER tbl_name READ index_name { = | >= | <= | < }
(value,value) [LIMIT...]\n\nThe values stands for the value of each of the
key columns. For most key types\n(except for HASH keys in MEMORY storage
engine) you can use a prefix subset of\nit\'s columns.\n\nIf you are
using LIMIT, then in case of >= or > then there is an implicit
NEXT\nimplied, while if you are using <= or < then there is an
implicit PREV implied.\n\nAfter the initial read, you can use\n\nHANDLER
tbl_name READ index_name NEXT [ LIMIT ... ]\nor\nHANDLER tbl_name READ
index_name PREV [ LIMIT ... ]\n\nto scan the rows in key order.\n\nNote
that the row order is not defined for keys with duplicated values and\nwill
vary from engine to engine.\n\nKey Scans\n---------\n\nYou can scan a table
in key order by doing:\n\nHANDLER tbl_name READ index_name FIRST [ LIMIT
... ]\nHANDLER tbl_name READ index_name NEXT [ LIMIT ... ]\n\nor, if the
handler supports backwards key scans (most do):\n\nHANDLER tbl_name READ
index_name LAST [ LIMIT ... ]\nHANDLER tbl_name READ index_name PREV [
LIMIT ... ]\n\nTable Scans\n-----------\n\nYou can scan a table in row
order by doing:\n\nHANDLER tbl_name READ FIRST [ LIMIT ... ]\nHANDLER
tbl_name READ NEXT [ LIMIT ... ]\n\nLimitations\n-----------\n\nAs this is
a direct interface to the storage engine, some limitations may\napply for
what you can do and what happens if the table changes. Here follows\nsome
of the common limitations:\n\nFinding \'Old
Rows\'\n------------------\n\nHANDLER READ is not transaction safe,
consistent or atomic. It\'s ok for the\nstorage engine to returns rows
that existed when you started the scan but that\nwere later deleted. This
can happen as the storage engine may cache rows as\npart of the scan from a
previous read.\n\nYou may also find rows committed since the scan
originally started.\n\nInvisible Columns\n-----------------\n\nHANDLER ...
READ also reads the data of invisible-columns.\n\nSystem-Versioned
Tables\n-----------------------\n\nHANDLER ... READ reads everything from
system-versioned tables, and so\nincludes row_start and row_end fields, as
well as all rows that have since\nbeen deleted or changed, including when
history partitions are used.\n\nOther Limitations\n-----------------\n\n*
If you do an ALTER TABLE, all your HANDLERs for that table are
automatically\nclosed.\n* If you do an ALTER TABLE for a table that is used
by some other connection\nwith HANDLER, the ALTER TABLE will wait for the
HANDLER to be closed.\n* For HASH keys, you must use all key parts when
searching for a row.\n* For HASH keys, you can\'t do a key scan of all
values. You can only find all\nrows with the same key value.\n* While each
HANDLER READ command is atomic, if you do a scan in many steps,\nthen some
engines may give you error 1020 if the table changed between the\ncommands.
Please refer to the specific engine handler page if this happens.\n\nError
Codes\n-----------\n\n* Error 1031 (ER_ILLEGAL_HA) Table storage engine for
\'t1\' doesn\'t have this\noption\nIf you get this for
HANDLER OPEN it means the storage engine doesn\'t support\nHANDLER
calls.\nIf you get this for HANDLER READ it means you are trying to use an
incomplete\nHASH key.\n\n* Error 1020 (ER_CHECKREAD) Record has changed
since last read in table \'...\'\nThis means that the table
changed between two reads and the handler can\'t\nhandle this case for
the given scan.\n\nURL:
https://mariadb.com/kb/en/handler-commands/','','https://mariadb.com/kb/en/handler-commands/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(461,27,'HANDLER for MEMORY Tables','This article explains
how to use HANDLER commands efficiently with MEMORY/HEAP\ntables.\n\nIf you
want to scan a table for over different key values, not just search
for\nexact key values, you should create your keys with \'USING
BTREE\':\n\nCREATE TABLE t1 (a INT, b INT, KEY(a), KEY b USING BTREE
(b)) engine=memory;\n\nIn the above table, a is a HASH key that only
supports exact matches (=) while\nb is a BTREE key that you can use to scan
the table in key order, starting\nfrom start or from a given key
value.\n\nThe limitations for HANDLER READ with Memory|HEAP tables
are:\n\nLimitations for HASH keys\n-------------------------\n\n* You must
use all key parts when searching for a row.\n* You can\'t do a key
scan of all values. You can only find all rows with the\nsame key value.\n*
READ NEXT gives error 1031 if the tables changed since last
read.\n\nLimitations for BTREE keys\n--------------------------\n\n* READ
NEXT gives error 1031 if the tables changed since last read.
This\nlimitation can be lifted in the future.\n\nLimitations for table
scans\n---------------------------\n\n* READ NEXT gives error 1031 if the
table was truncated since last READ call.\n\nURL:
https://mariadb.com/kb/en/handler-for-memory-tables/','','https://mariadb.com/kb/en/handler-for-memory-tables/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(462,27,'Useful MariaDB Queries','This page is intended to
be a quick reference of commonly-used and/or useful\nqueries in
MariaDB.\n\nCreating a Table\n----------------\n\nCREATE TABLE t1 ( a INT
);\nCREATE TABLE t2 ( b INT );\nCREATE TABLE student_tests (\n name
CHAR(10), test CHAR(10), \n score TINYINT, test_date DATE\n);\n\nSee CREATE
TABLE for more.\n\nInserting Records\n-----------------\n\nINSERT INTO t1
VALUES (1), (2), (3);\nINSERT INTO t2 VALUES (2), (4);\n\nINSERT INTO
student_tests \n (name, test, score, test_date) VALUES\n
(\'Chun\', \'SQL\', 75, \'2012-11-05\'), \n
(\'Chun\', \'Tuning\', 73, \'2013-06-14\'),\n
(\'Esben\', \'SQL\', 43, \'2014-02-11\'), \n
(\'Esben\', \'Tuning\', 31, \'2014-02-09\'),
\n (\'Kaolin\', \'SQL\', 56,
\'2014-01-01\'),\n (\'Kaolin\', \'Tuning\',
88, \'2013-12-29\'), \n (\'Tatiana\',
\'SQL\', 87, \'2012-04-28\'), \n
(\'Tatiana\', \'Tuning\', 83,
\'2013-09-30\');\n\nSee INSERT for more.\n\nUsing
AUTO_INCREMENT\n--------------------\n\nThe AUTO_INCREMENT attribute is
used to automatically generate a unique\nidentity for new rows.\n\nCREATE
TABLE student_details (\n id INT NOT NULL AUTO_INCREMENT, name CHAR(10), \n
date_of_birth DATE, PRIMARY KEY (id)\n);\n\nWhen inserting, the id field
can be omitted, and is automatically created.\n\nINSERT INTO
student_details (name,date_of_birth) VALUES \n (\'Chun\',
\'1993-12-31\'), \n
(\'Esben\',\'1946-01-01\'),\n
(\'Kaolin\',\'1996-07-16\'),\n (\'Tatiana\',
\'1988-04-13\');\n\nSELECT * FROM
student_details;\n+----+---------+---------------+\n| id | name |
date_of_birth |\n+----+---------+---------------+\n| 1 | Chun |
1993-12-31 |\n| 2 | Esben | 1946-01-01 |\n| 3 | Kaolin |
1996-07-16 |\n| 4 | Tatiana | 1988-04-13
|\n+----+---------+---------------+\n\nSee AUTO_INCREMENT for
more.\n\nQuerying from two tables on a common
value\n------------------------------------------\n\nSELECT * FROM t1 INNER
JOIN t2 ON t1.a = t2.b;\n\nThis kind of query is called a join - see JOINS
for more.\n\nFinding the Maximum Value\n-------------------------\n\nSELECT
MAX(a) FROM t1;\n+--------+\n| MAX(a) |\n+--------+\n| 3
|\n+--------+\n\nSee the MAX() function for more, as well as Finding the
maximum value and\ngrouping the results below for a more practical
example.\n\nFinding the Minimum Value\n-------------------------\n\nSELECT
MIN(a) FROM t1;\n+--------+\n| MIN(a) |\n+--------+\n| 1
|\n+--------+\n\nSee the MIN() function for more.\n\nFinding the Average
Value\n-------------------------\n\nSELECT AVG(a) FROM t1;\n+--------+\n|
AVG(a) |\n+--------+\n| 2.0000 |\n+--------+\n\nSee the AVG() function for
more.\n\nFinding the Maximum Value and Grouping the
Results\n--------------------------------------------------\n\nSELECT name,
MAX(score) FROM student_tests GROUP BY name;\n+---------+------------+\n|
name | MAX(score) |\n+---------+------------+\n| Chun | 75
|\n| Esben | 43 |\n| Kaolin | 88 |\n| Tatiana |
87 |\n+---------+------------+\n\nSee the MAX() function for
more.\n\nOrdering Results\n----------------\n\nSELECT name, test, score
FROM student_tests ORDER BY score DESC;\n+---------+--------+-------+\n|
name | test | score |\n+---------+--------+-------+\n| Kaolin |
Tuning | 88 |\n| Tatiana | SQL | 87 |\n| Tatiana | Tuning | 83
|\n| Chun | SQL | 75 |\n| Chun | Tuning | 73 |\n| Kaolin |
SQL | 56 |\n| Esben | SQL | 43 |\n| Esben | Tuning | 31
|\n+---------+--------+-------+\n\nSee ORDER BY for more.\n\nFinding the
Row with the Minimum of a Particular
Column\n-------------------------------------------------------\n\nIn this
example, we want to find the lowest test score for any student.\n\nSELECT
name,test, score FROM student_tests WHERE score=(SELECT MIN(score)
FROM\nstudent);\n+-------+--------+-------+\n| name | test | score
|\n+-------+--------+-------+\n| Esben | Tuning | 31
|\n+-------+--------+-------+\n\nFinding Rows with the Maximum Value of a
Column by
Group\n--------------------------------------------------------\n\nThis
example returns the best test results of each student:\n\nSELECT name,
test, score FROM student_tests st1 WHERE score = (\n SELECT MAX(score) FROM
student st2 WHERE st1.name = st2.name\n); \n+---------+--------+-------+\n|
name | test | score |\n+---------+--------+-------+\n| Chun | SQL
| 75 |\n| Esben | SQL | 43 |\n| Kaolin | Tuning | 88 |\n|
Tatiana | SQL | 87 |\n+---------+--------+-------+\n\nCalculating
Age\n---------------\n\nThe TIMESTAMPDIFF function can be used to calculate
someone\'s age:\n\nSELECT CURDATE() AS today;\n+------------+\n| today
|\n+------------+\n| 2014-02-17 |\n+------------+\n\nSELECT name,
date_of_birth, TIMESTAMPDIFF(YEAR,date_of_birth,\'2014-08-02\')
AS\nage \n FROM student_details;\n+---------+---------------+------+\n|
name | date_of_birth | age |\n+---------+---------------+------+\n|
Chun | 1993-12-31 | 20 |\n| Esben | 1946-01-01 | 68 |\n|
Kaolin | 1996-07-16 | 18 |\n| Tatiana | 1988-04-13 | 26
|\n+---------+---------------+------+\n\nSee TIMESTAMPDIFF() for
more.\n\nUsing User-defined Variables\n----------------------------\n\nThis
example sets a user-defined variable with the average test score, and\nthen
uses it in a later query to return all results above the average.\n\nSELECT
@avg_score:= AVG(score) FROM student_tests;\n+-------------------------+\n|
@avg_score:= AVG(score) |\n+-------------------------+\n|
67.000000000 |\n+-------------------------+\n\nSELECT * FROM student_tests
WHERE score > @avg_score;\n+---------+--------+-------+------------+\n|
name | test | score | test_date
|\n+---------+--------+-------+------------+\n| Chun | SQL | 75 |
2012-11-05 |\n| Chun | Tuning | 73 | 2013-06-14 |\n| Kaolin | Tuning
| 88 | 2013-12-29 |\n| Tatiana | SQL | 87 | 2012-04-28 |\n|
Tatiana | Tuning | 83 | 2013-09-30
|\n+---------+--------+-------+------------+\n\nUser-defined variables can
also be used to add an incremental counter to a\nresultset:\n\nSET @count =
0;\n\nSELECT @count := @count + 1 AS counter, name, date_of_birth
FROM\nstudent_details;\n+---------+---------+---------------+\n| counter |
name | date_of_birth |\n+---------+---------+---------------+\n| 1
| Chun | 1993-12-31 |\n| 2 | Esben | 1946-01-01 |\n|
3 | Kaolin | 1996-07-16 |\n| 4 | Tatiana | 1988-04-13
|\n+---------+---------+---------------+\n\nSee User-defined Variables for
more.\n\nView Tables in Order of
Size\n----------------------------\n\nReturns a list of all tables in the
database, ordered by size:\n\nSELECT table_schema as `DB`, table_name AS
`Table`, \n ROUND(((data_length + index_length) / 1024 / 1024), 2) `Size
(MB)`\n FROM information_schema.TABLES\n ORDER BY (data_length +
index_length)
DESC;\n\n+--------------------+---------------------------------------+-----------+\n|
DB | Table | Size (MB)
|\n+--------------------+---------------------------------------+-----------+\n|
wordpress | wp_simple_history_contexts | 7.05 |\n|
wordpress | wp_posts | 6.59 |\n|
wordpress | wp_simple_history | 3.05 |\n|
wordpress | wp_comments | 2.73 |\n|
wordpress | wp_commentmeta | 2.47 |\n|
wordpress | wp_simple_login_log | 2.03
|\n...\n\nRemoving Duplicates\n-------------------\n\nMariaDB starting with
10.3\n--------------------------\nThe following syntax is only valid
MariaDB 10.3 and beyond:\n\nThis example assumes there\'s a unique ID,
but that all other fields are\nidentical. In the example below, there are 4
records, 3 of which are\nduplicates, so two of the three duplicates need to
be removed. The\nintermediate SELECT is not necessary, but demonstrates
what is being returned.\n\nCREATE TABLE t (id INT, f1
VARCHAR(2));\n\nINSERT INTO t VALUES (1,\'a\'),
(2,\'a\'), (3,\'b\'), (4,\'a\');\n\nSELECT *
FROM t t1, t t2 WHERE t1.f1=t2.f1 AND t1.id<>t2.id AND t1.id=(\n
SELECT MAX(id) FROM t tab WHERE
tab.f1=t1.f1\n);\n+------+------+------+------+\n| id | f1 | id | f1
|\n+------+------+------+------+\n| 4 | a | 1 | a |\n| 4 |
a | 2 | a |\n+------+------+------+------+\n\nDELETE FROM t WHERE
id IN (\n SELECT t2.id FROM t t1, t t2 WHERE t1.f1=t2.f1 AND
t1.id<>t2.id AND t1.id=(\n SELECT MAX(id) FROM t tab WHERE
tab.f1=t1.f1\n )\n);\nQuery OK, 2 rows affected (0.120 sec)\n\nSELECT *
FROM t;\n+------+------+\n| id | f1 |\n+------+------+\n| 3 | b
|\n| 4 | a |\n+------+------\n\nURL:
https://mariadb.com/kb/en/useful-mariadb-queries/','','https://mariadb.com/kb/en/useful-mariadb-queries/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(463,28,'ANALYZE FORMAT=JSON','ANALYZE FORMAT=JSON is a mix
of the EXPLAIN FORMAT=JSON and ANALYZE statement\nfeatures. The ANALYZE
FORMAT=JSON $statement will execute $statement, and then\nprint the output
of EXPLAIN FORMAT=JSON, amended with data from the
query\nexecution.\n\nBasic Execution Data\n--------------------\n\nYou can
get the following also from tabular ANALYZE statement form:\n\n* r_rows is
provided for any node that reads rows. It shows how many rows\nwere read,
on average \n* r_filtered is provided whenever there is a condition that is
checked. It\nshows the percentage of rows left after checking the
condition.\n\nAdvanced Execution Data\n-----------------------\n\nThe most
important data not available in the regular tabula ANALYZE
statement\nare:\n\n* r_loops field. This shows how many times the node was
executed. Most query\nplan elements have this field.\n* r_total_time_ms
field. It shows how much time in total was spent executing\nthis node. If
the node has subnodes, their execution time is included.\n* r_buffer_size
field. Query plan nodes that make use of buffers report the\nsize of buffer
that was was used.\n\nSHOW ANALYZE
FORMAT=JSON\n------------------------\n\nMariaDB starting with
10.9\n--------------------------\nSHOW ANALYZE FORMAT=JSON for
<connection_id> extends ANALYZE [FORMAT=JSON]\n<select> to
allow one to analyze a query currently running in
another\nconnection.\n\nData About Individual Query Plan
Nodes\n--------------------------------------\n\n* filesort node reports
whether sorting was done with LIMIT n parameter, and\nhow many rows were in
the sort result. \n* block-nl-join node has r_loops field, which allows to
tell whether Using\njoin buffer was efficient \n*
range-checked-for-each-record reports counters that show the result of
the\ncheck. \n* expression-cache is used for subqueries, and it reports how
many times the\ncache was used, and what cache hit ratio was.\n*
union_result node has r_rows so one can see how many rows were
produced\nafter UNION operation\n* and so forth\n\nUse
Cases\n---------\n\nSee Examples of ANALYZE FORMAT=JSON.\n\nURL:
https://mariadb.com/kb/en/analyze-format-json/','','https://mariadb.com/kb/en/analyze-format-json/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(464,28,'ANALYZE FORMAT=JSON Examples','Example
#1\n----------\n\nCustomers who have ordered more than 1M goods.\n\nANALYZE
FORMAT=JSON\nSELECT COUNT(*)\nFROM customer\nWHERE\n (SELECT
SUM(o_totalprice) FROM orders WHERE o_custkey=c_custkey) >
1000*1000;\n\nThe query takes 40 seconds over cold cache\n\nEXPLAIN: {\n
\"query_block\": {\n \"select_id\": 1,\n
\"r_loops\": 1,\n \"r_total_time_ms\": 39872,\n
\"table\": {\n \"table_name\":
\"customer\",\n \"access_type\":
\"index\",\n \"key\": \"i_c_nationkey\",\n
\"key_length\": \"5\",\n
\"used_key_parts\": [\"c_nationkey\"],\n
\"r_loops\": 1,\n \"rows\": 150303,\n
\"r_rows\": 150000,\n \"r_total_time_ms\": 270.3,\n
\"filtered\": 100,\n \"r_filtered\": 60.691,\n
\"attached_condition\": \"((subquery#2) >
<cache>((1000 * 1000)))\",\n \"using_index\": true\n
},\n \"subqueries\": [\n {\n \"query_block\":
{\n \"select_id\": 2,\n \"r_loops\": 150000,\n
\"r_total_time_ms\": 39531,\n \"table\": {\n
\"table_name\": \"orders\",\n
\"access_type\": \"ref\",\n
\"possible_keys\": [\"i_o_custkey\"],\n
\"key\": \"i_o_custkey\",\n
\"key_length\": \"5\",\n
\"used_key_parts\": [\"o_custkey\"],\n
\"ref\": [\"dbt3sf1.customer.c_custkey\"],\n
\"r_loops\": 150000,\n \"rows\": 7,\n
\"r_rows\": 10,\n \"r_total_time_ms\": 39208,\n
\"filtered\": 100,\n \"r_filtered\": 100\n
}\n }\n }\n ]\n }\n}\nANALYZE shows that 39.2 seconds were spent in
the subquery, which was executed\n150K times (for every row of outer
table).\n\nURL:
https://mariadb.com/kb/en/analyze-formatjson-examples/','','https://mariadb.com/kb/en/analyze-formatjson-examples/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(465,28,'ANALYZE Statement','Description\n-----------\n\nThe
ANALYZE statement is similar to the EXPLAIN statement. ANALYZE
statement\nwill invoke the optimizer, execute the statement, and then
produce EXPLAIN\noutput instead of the result set. The EXPLAIN output will
be annotated with\nstatistics from statement execution.\n\nThis lets one
check how close the optimizer\'s estimates about the query plan\nare
to the reality. ANALYZE produces an overview, while the
ANALYZE\nFORMAT=JSON command provides a more detailed view of the query
plan and the\nquery execution.\n\nThe syntax is\n\nANALYZE
explainable_statement;\n\nwhere the statement is any statement for which
one can run EXPLAIN.\n\nCommand Output\n--------------\n\nConsider an
example:\n\nANALYZE SELECT * FROM tbl1 \nWHERE key1 \n BETWEEN 10 AND 200
AND\n col1 LIKE \'foo%\'\\G\n\n*************************** 1. row
***************************\n id: 1\n select_type: SIMPLE\n table:
tbl1\n type: range\npossible_keys: key1\n key: key1\n key_len: 5\n
ref: NULL\n rows: 181\n r_rows: 181\n filtered: 100.00\n
r_filtered: 10.50\n Extra: Using index condition; Using
where\n\nCompared to EXPLAIN, ANALYZE produces two extra columns:\n\n*
r_rows is an observation-based counterpart of the rows column. It shows
how\nmany rows were actually read from the table. \n* r_filtered is an
observation-based counterpart of the filtered column. It\nshows which
fraction of rows was left after applying the WHERE
condition.\n\nInterpreting the
Output\n-----------------------\n\nJoins\n-----\n\nLet\'s consider a
more complicated example.\n\nANALYZE SELECT *\nFROM orders, customer
\nWHERE\n customer.c_custkey=orders.o_custkey AND\n customer.c_acctbal <
0 AND\n orders.o_totalprice >
200*1000\n\n+----+-------------+----------+------+---------------+-------------+---------+-\n------------------+--------+--------+----------+------------+-------------+\n|
id | select_type | table | type | possible_keys | key | key_len
|\nref | rows | r_rows | filtered | r_filtered | Extra
|\n+----+-------------+----------+------+---------------+-------------+---------+-\n------------------+--------+--------+----------+------------+-------------+\n|
1 | SIMPLE | customer | ALL | PRIMARY,... | NULL | NULL
|\nNULL | 149095 | 150000 | 18.08 | 9.13 | Using
where |\n| 1 | SIMPLE | orders | ref | i_o_custkey | i_o_custkey
| 5 |\ncustomer.c_custkey | 7 | 10 | 100.00 | 30.03 |
Using where
|\n+----+-------------+----------+------+---------------+-------------+---------+-\n------------------+--------+--------+----------+------------+-------------+\n\nHere,
one can see that\n\n* For table customer, customer.rows=149095,
customer.r_rows=150000. The\nestimate for number of rows we will read was
fairly precise\n* customer.filtered=18.08, customer.r_filtered=9.13. The
optimizer somewhat\noverestimated the number of records that will match
selectivity of condition\nattached to `customer` table (in general, when
you have a full scan and\nr_filtered is less than 15%, it\'s time to
consider adding an appropriate\nindex).\n* For table orders,
orders.rows=7, orders.r_rows=10. This means that on\naverage, there are 7
orders for a given c_custkey, but in our case there were\n10, which is
close to the expectation (when this number is consistently far\nfrom the
expectation, it may be time to run ANALYZE TABLE, or even edit the\ntable
statistics manually to get better query plans).\n* orders.filtered=100,
orders.r_filtered=30.03. The optimizer didn\'t have any\nway to
estimate which fraction of records will be left after it checks
the\ncondition that is attached to table orders (it\'s
orders.o_totalprice >\n200*1000). So, it used 100%. In reality, it is
30%. 30% is typically not\nselective enough to warrant adding new indexes.
For joins with many tables, it\nmight be worth to collect and use column
statistics for columns in question,\nthis may help the optimizer to pick a
better query plan.\n\nMeaning of NULL in r_rows and
r_filtered\n----------------------------------------\n\nLet\'s modify
the previous example slightly\n\nANALYZE SELECT * \nFROM orders, customer
\nWHERE\n customer.c_custkey=orders.o_custkey AND\n customer.c_acctbal <
-0 AND\n customer.c_comment LIKE \'%foo%\' AND\n
orders.o_totalprice >
200*1000;\n\n+----+-------------+----------+------+---------------+-------------+---------+-\n------------------+--------+--------+----------+------------+-------------+\n|
id | select_type | table | type | possible_keys | key | key_len
|\nref | rows | r_rows | filtered | r_filtered | Extra
|\n+----+-------------+----------+------+---------------+-------------+---------+-\n------------------+--------+--------+----------+------------+-------------+\n|
1 | SIMPLE | customer | ALL | PRIMARY,... | NULL | NULL
|\nNULL | 149095 | 150000 | 18.08 | 0.00 | Using
where |\n| 1 | SIMPLE | orders | ref | i_o_custkey | i_o_custkey
| 5 |\ncustomer.c_custkey | 7 | NULL | 100.00 | NULL |
Using where
|\n+----+-------------+----------+------+---------------+-------------+---------+-\n------------------+--------+--------+----------+------------+-------------+\n\nHere,
one can see that orders.r_rows=NULL and orders.r_filtered=NULL. This\nmeans
that table orders was not scanned even once. Indeed, we can also
see\ncustomer.r_filtered=0.00. This shows that a part of WHERE attached to
table\n`customer` was never satisfied (or, satisfied in less than 0.01% of
cases).\n\nANALYZE FORMAT=JSON\n-------------------\n\nANALYZE FORMAT=JSON
produces JSON output. It produces much more information\nthan tabular
ANALYZE.\n\nNotes\n-----\n\n* ANALYZE UPDATE or ANALYZE DELETE will
actually make updates/deletes (ANALYZE\nSELECT will perform the select
operation and then discard the resultset).\n* PostgreSQL has a similar
command, EXPLAIN ANALYZE.\n* The EXPLAIN in the slow query log feature
allows MariaDB to have ANALYZE\noutput of slow queries printed into the
slow query log (see MDEV-6388).\n\nURL:
https://mariadb.com/kb/en/analyze-statement/','','https://mariadb.com/kb/en/analyze-statement/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(466,28,'EXPLAIN','Syntax\n------\n\nEXPLAIN tbl_name
[col_name | wild]\n\nOr\n\nEXPLAIN [EXTENDED | PARTITIONS | FORMAT=JSON] \n
{SELECT select_options | UPDATE update_options | DELETE
delete_options}\n\nDescription\n-----------\n\nThe EXPLAIN statement can be
used either as a synonym for DESCRIBE or as a way\nto obtain information
about how MariaDB executes a SELECT, UPDATE or DELETE\nstatement:\n\n*
\'EXPLAIN tbl_name\' is synonymous with \n \'DESCRIBE
tbl_name\' or\n \'SHOW COLUMNS FROM tbl_name\'.\n* When you
precede a SELECT, UPDATE or a DELETE statement with the keyword \n EXPLAIN,
MariaDB displays information from the optimizer\n about the query execution
plan. That is, MariaDB explains how it would\n process the SELECT, UPDATE
or DELETE, including information about how tables\n are joined and in which
order. EXPLAIN EXTENDED can be\n used to provide additional information.\n*
EXPLAIN PARTITIONS is useful only when examining queries
involving\npartitioned tables. For details, see Partition pruning and
selection.\n* ANALYZE statement performs the query as well as producing
EXPLAIN output,\nand provides actual as well as estimated statistics.\n*
EXPLAIN output can be printed in the slow query log. See EXPLAIN in the
Slow\nQuery Log for details.\n\nSHOW EXPLAIN shows the output of a running
statement. In some cases, its\noutput can be closer to reality than
EXPLAIN.\n\nThe ANALYZE statement runs a statement and returns information
about its\nexecution plan. It also shows additional columns, to check how
much the\noptimizer\'s estimation about filtering and found rows are
close to reality.\n\nThere is an online EXPLAIN Analyzer that you can use
to share EXPLAIN and\nEXPLAIN EXTENDED output with others.\n\nEXPLAIN can
acquire metadata locks in the same way that SELECT does, as it\nneeds to
know table metadata and, sometimes, data as well.\n\nColumns in EXPLAIN ...
SELECT\n-----------------------------\n\n+--------------------------------------+--------------------------------------+\n|
Column name | Description
|\n+--------------------------------------+--------------------------------------+\n|
id | Sequence number that shows in which
|\n| | order tables are joined.
|\n+--------------------------------------+--------------------------------------+\n|
select_type | What kind of SELECT the table comes
|\n| | from.
|\n+--------------------------------------+--------------------------------------+\n|
table | Alias name of table. Materialized
|\n| | temporary tables for sub
queries |\n| | are named
<subquery#>
|\n+--------------------------------------+--------------------------------------+\n|
type | How rows are found from the table
|\n| | (join type).
|\n+--------------------------------------+--------------------------------------+\n|
possible_keys | keys in table that could be used to
|\n| | find rows in the table
|\n+--------------------------------------+--------------------------------------+\n|
key | The name of the key that is used to
|\n| | retrieve rows. NULL is no key
was |\n| | used.
|\n+--------------------------------------+--------------------------------------+\n|
key_len | How many bytes of the key that was
|\n| | used (shows if we are using
only |\n| | parts of the
multi-column key).
|\n+--------------------------------------+--------------------------------------+\n|
ref | The reference that is used as the
|\n| | key value.
|\n+--------------------------------------+--------------------------------------+\n|
rows | An estimate of how many rows we
|\n| | will find in the table for each
key |\n| | lookup.
|\n+--------------------------------------+--------------------------------------+\n|
Extra | Extra information about this join.
|\n+--------------------------------------+--------------------------------------+\n\nHere
are descriptions of the values for some of the more complex columns
in\nEXPLAIN ... SELECT:\n\n\"Select_type\"
Column\n--------------------\n\nThe select_type column can have the
following
values:\n\n+-----------------+-----------------------------------+-----------------------+\n|
Value | Description | Comment
|\n+-----------------+-----------------------------------+-----------------------+\n|
DEPENDENT | The SUBQUERY is DEPENDENT. |
|\n| SUBQUERY | |
|\n+-----------------+-----------------------------------+-----------------------+\n|
DEPENDENT UNION | The UNION is DEPENDENT. |
|\n+-----------------+-----------------------------------+-----------------------+\n|
DERIVED | The SELECT is DERIVED from the |
|\n| | PRIMARY. |
|\n+-----------------+-----------------------------------+-----------------------+\n|
MATERIALIZED | The SUBQUERY is MATERIALIZED. | Materialized tables
|\n| | | will be
populated at |\n| | |
first access and |\n| |
| will be accessed by |\n| |
| the primary key (= |\n| |
| one key lookup). |\n| |
| Number of rows in |\n| |
| EXPLAIN shows the |\n| |
| cost of populating |\n| |
| the table
|\n+-----------------+-----------------------------------+-----------------------+\n|
PRIMARY | The SELECT is in the outermost |
|\n| | query, but there is also a |
|\n| | SUBQUERY within it. |
|\n+-----------------+-----------------------------------+-----------------------+\n|
SIMPLE | It is a simple SELECT query |
|\n| | without any SUBQUERY or UNION. |
|\n+-----------------+-----------------------------------+-----------------------+\n|
SUBQUERY | The SELECT is a SUBQUERY of the |
|\n| | PRIMARY. |
|\n+-----------------+-----------------------------------+-----------------------+\n|
UNCACHEABLE | The SUBQUERY is UNCACHEABLE. |
|\n| SUBQUERY | |
|\n+-----------------+-----------------------------------+-----------------------+\n|
UNCACHEABLE | The UNION is UNCACHEABLE. |
|\n| UNION | |
|\n+-----------------+-----------------------------------+-----------------------+\n|
UNION | The SELECT is a UNION of the |
|\n| | PRIMARY. |
|\n+-----------------+-----------------------------------+-----------------------+\n|
UNION RESULT | The result of the UNION. |
|\n+-----------------+-----------------------------------+-----------------------+\n|
LATERAL DERIVED | The SELECT uses a Lateral |
|\n| | Derived optimization |
|\n+-----------------+-----------------------------------+-----------------------+\n\n\"Type\"
Column\n-------------\n\nThis column contains information on how the table
is
accessed.\n\n+------------------------+---------------------------------------------------+\n|
Value | Description
|\n+------------------------+---------------------------------------------------+\n|
ALL | A full table scan is done for the table (all
|\n| | rows are read). This is bad if the table is
|\n| | large and the table is joined against a
previous |\n| | table! This happens when the
optimizer could |\n| | not find any usable index
to access rows.
|\n+------------------------+---------------------------------------------------+\n|
const | There is only one possibly matching row in the
|\n| | table. The row is read before the
optimization |\n| | phase and all columns in the
table are treated |\n| | as constants.
|\n+------------------------+---------------------------------------------------+\n|
eq_ref | A unique index is used to find the rows. This is
|\n| | the best possible plan to find the row.
|\n+------------------------+---------------------------------------------------+\n|
fulltext | A fulltext index is used to access the rows.
|\n+------------------------+---------------------------------------------------+\n|
index_merge | A \'range\' access is done for for
several index |\n| | and the found rows are
merged. The key column |\n| | shows which keys
are used.
|\n+------------------------+---------------------------------------------------+\n|
index_subquery | This is similar as ref, but used for sub queries
|\n| | that are transformed to key lookups.
|\n+------------------------+---------------------------------------------------+\n|
index | A full scan over the used index. Better than
|\n| | ALL but still bad if index is large and the
|\n| | table is joined against a previous table.
|\n+------------------------+---------------------------------------------------+\n|
range | The table will be accessed with a key over one
|\n| | or more value ranges.
|\n+------------------------+---------------------------------------------------+\n|
ref_or_null | Like \'ref\' but in addition another
search for |\n| | the \'null\' value
is done if the first value was |\n| | not found.
This happens usually with sub queries.
|\n+------------------------+---------------------------------------------------+\n|
ref | A non unique index or prefix of an unique index
|\n| | is used to find the rows. Good if the prefix
|\n| | doesn\'t match many rows.
|\n+------------------------+---------------------------------------------------+\n|
system | The table has 0 or 1 rows.
|\n+------------------------+---------------------------------------------------+\n|
unique_subquery | This is similar as eq_ref, but used for sub
|\n| | queries that are transformed to key lookups
|\n+------------------------+---------------------------------------------------+\n\n\"Extra\"
Column\n--------------\n\nThis column consists of one or more of the
following values, separated by \';\'\n\nNote that some of these
values are detected after the optimization phase.\n\nThe optimization phase
can do the following changes to the WHERE clause:\n\n* Add the expressions
from the ON and USING clauses to the WHERE\n clause.\n* Constant
propagation: If there is column=constant, replace all column\n instances
with this constant.\n* Replace all columns from \'const\' tables
with their values.\n* Remove the used key columns from the WHERE (as this
will be tested as\n part of the key lookup).\n* Remove impossible constant
sub expressions.\n For example WHERE \'(a=1 and a=2) OR b=1\'
becomes \'b=1\'.\n* Replace columns with other columns that has
identical values:\n Example: WHERE a=b and a=c may be treated\n as
\'WHERE a=b and a=c and b=c\'.\n* Add extra conditions to detect
impossible row conditions earlier. This\n happens mainly with OUTER JOIN
where we in some cases add detection\n of NULL values in the WHERE (Part of
\'Not exists\' optimization).\n This can cause an unexpected
\'Using where\' in the Extra column.\n* For each table level we
remove expressions that have already been tested when\n we read the
previous row. Example: When joining tables t1 with t2\n using the following
WHERE \'t1.a=1 and t1.a=t2.b\', we don\'t have to\n test
\'t1.a=1\' when checking rows in t2 as we already know that
this\n expression is
true.\n\n+------------------------+---------------------------------------------------+\n|
Value | Description
|\n+------------------------+---------------------------------------------------+\n|
const row not found | The table was a system table (a table with
|\n| | should exactly one row), but no row was
found.
|\n+------------------------+---------------------------------------------------+\n|
Distinct | If distinct optimization (remove duplicates) was
|','','https://mariadb.com/kb/en/explain/');
update help_topic set description = CONCAT(description, '\n|
| used. This is marked only for the last table in |\n|
| the SELECT.
|\n+------------------------+---------------------------------------------------+\n|
Full scan on NULL key | The table is a part of the sub query and if the
|\n| | value that is used to match the sub query
will |\n| | be NULL, we will do a full table
scan.
|\n+------------------------+---------------------------------------------------+\n|
Impossible HAVING | The used HAVING clause is always false so the
|\n| | SELECT will return no rows.
|\n+------------------------+---------------------------------------------------+\n|
Impossible WHERE | The used WHERE clause is always false so the
|\n| noticed after reading | SELECT will return no rows. This case was
|\n| const tables. | detected after we had read all
\'const\' tables |\n| | and used the
column values as constant in the |\n| | WHERE
clause. For example: WHERE const_column=5 |\n| |
and const_column had a value of 4.
|\n+------------------------+---------------------------------------------------+\n|
Impossible WHERE | The used WHERE clause is always false so the
|\n| | SELECT will return no rows. For example:
WHERE |\n| | 1=2
|\n+------------------------+---------------------------------------------------+\n|
No matching min/max | During early optimization of MIN()/MAX() values
|\n| row | it was detected that no row could match the
|\n| | WHERE clause. The MIN()/MAX() function
will |\n| | return NULL.
|\n+------------------------+---------------------------------------------------+\n|
no matching row in | The table was a const table (a table with only
|\n| const table | one possible matching row), but no row was
found.
|\n+------------------------+---------------------------------------------------+\n|
No tables used | The SELECT was a sub query that did not use any
|\n| | tables. For example a there was no FROM
clause |\n| | or a FROM DUAL clause.
|\n+------------------------+---------------------------------------------------+\n|
Not exists | Stop searching after more row if we find one
|\n| | single matching row. This optimization is
used |\n| | with LEFT JOIN where one is
explicitly searching |\n| | for rows that
doesn\'t exists in the LEFT JOIN |\n| |
TABLE. Example: SELECT * FROM t1 LEFT JOIN t2 on |\n|
| (...) WHERE t2.not_null_column IS NULL. As |\n|
| t2.not_null_column can only be NULL if there was |\n|
| no matching row for on condition, we can stop |\n|
| searching if we find a single matching row.
|\n+------------------------+---------------------------------------------------+\n|
Open_frm_only | For information_schema tables. Only the frm
|\n| | (table definition file was opened) was opened
|\n| | for each matching row.
|\n+------------------------+---------------------------------------------------+\n|
Open_full_table | For information_schema tables. A full table open
|\n| | for each matching row is done to retrieve the
|\n| | requested information. (Slow)
|\n+------------------------+---------------------------------------------------+\n|
Open_trigger_only | For information_schema tables. Only the trigger
|\n| | file definition was opened for each matching
row.
|\n+------------------------+---------------------------------------------------+\n|
Range checked for | This only happens when there was no good default
|\n| each record (index | index to use but there may some index that
could |\n| map: ...) | be used when we can treat all columns
from |\n| | previous table as constants. For
each row |\n| | combination the optimizer
will decide which |\n| | index to use (if any)
to fetch a row from this |\n| | table. This is
not fast, but faster than a full |\n| | table scan
that is the only other choice. The |\n| | index
map is a bitmask that shows which index |\n| |
are considered for each row condition.
|\n+------------------------+---------------------------------------------------+\n|
Scanned 0/1/all | For information_schema tables. Shows how many
|\n| databases | times we had to do a directory scan.
|\n+------------------------+---------------------------------------------------+\n|
Select tables | All tables in the join was optimized away. This
|\n| optimized away | happens when we are only using COUNT(*),
MIN() |\n| | and MAX() functions in the SELECT
and we where |\n| | able to replace all of these
with constants.
|\n+------------------------+---------------------------------------------------+\n|
Skip_open_table | For information_schema tables. The queried table
|\n| | didn\'t need to be opened.
|\n+------------------------+---------------------------------------------------+\n|
unique row not found | The table was detected to be a const table (a
|\n| | table with only one possible matching row)
|\n| | during the early optimization phase, but
no row |\n| | was found.
|\n+------------------------+---------------------------------------------------+\n|
Using filesort | Filesort is needed to resolve the query. This
|\n| | means an extra phase where we first collect
all |\n| | columns to sort, sort them with a disk
based |\n| | merge sort and then use the sorted
set to |\n| | retrieve the rows in sorted
order. If the column |\n| | set is small, we store
all the columns in the |\n| | sort file to not
have to go to the database to |\n| | retrieve
them again.
|\n+------------------------+---------------------------------------------------+\n|
Using index | Only the index is used to retrieve the needed
|\n| | information from the table. There is no need
to |\n| | perform an extra seek to retrieve the
actual |\n| | record.
|\n+------------------------+---------------------------------------------------+\n|
Using index condition | Like \'Using where\' but the where
condition is |\n| | pushed down to the table
engine for internal |\n| | optimization at the
index level.
|\n+------------------------+---------------------------------------------------+\n|
Using index | Like \'Using index condition\' but in
addition we |\n| condition(BKA) | use batch key access to
retrieve rows.
|\n+------------------------+---------------------------------------------------+\n|
Using index for | The index is being used to resolve a GROUP BY or
|\n| group-by | DISTINCT query. The rows are not read. This
is |\n| | very efficient if the table has a lot of
|\n| | identical index entries as
duplicates are |\n| | quickly jumped over.
|\n+------------------------+---------------------------------------------------+\n|
Using intersect(...) | For index_merge joins. Shows which index are
|\n| | part of the intersect.
|\n+------------------------+---------------------------------------------------+\n|
Using join buffer | We store previous row combinations in a row
|\n| | buffer to be able to match each row against
all |\n| | of the rows combinations in the join
buffer at |\n| | one go.
|\n+------------------------+---------------------------------------------------+\n|
Using sort_union(...) | For index_merge joins. Shows which index are
|\n| | part of the union.
|\n+------------------------+---------------------------------------------------+\n|
Using temporary | A temporary table is created to hold the result.
|\n| | This typically happens if you are using GROUP
|\n| | BY, DISTINCT or ORDER BY.
|\n+------------------------+---------------------------------------------------+\n|
Using where | A WHERE expression (in additional to the
|\n| | possible key lookup) is used to check if the
row |\n| | should be accepted. If you don\'t
have \'Using |\n| | where\' together
with a join type of ALL, you are |\n| | probably
doing something wrong!
|\n+------------------------+---------------------------------------------------+\n|
Using where with | Like \'Using where\' but the where
condition is |\n| pushed condition | pushed down to the table
engine for internal |\n| | optimization at the
row level.
|\n+------------------------+---------------------------------------------------+\n|
Using buffer | The UPDATE statement will first buffer the rows,
|\n| | and then run the updates, rather than do
updates |\n| | on the fly. See Using Buffer UPDATE
Algorithm |\n| | for a detailed explanation.
|\n+------------------------+---------------------------------------------------+\n\nEXPLAIN
EXTENDED\n----------------\n\nThe EXTENDED keyword adds another column,
filtered, to the output. This is a\npercentage estimate of the table rows
that will be filtered by the condition.\n\nAn EXPLAIN EXTENDED will always
throw a warning, as it adds extra Message\ninformation to a subsequent SHOW
WARNINGS statement. This includes what the\nSELECT query would look like
after optimizing and rewriting rules are applied\nand how the optimizer
qualifies columns and tables.\n\nExamples\n--------\n\nAs synonym for
DESCRIBE or SHOW COLUMNS FROM:\n\nDESCRIBE
city;\n+------------+----------+------+-----+---------+----------------+\n|
Field | Type | Null | Key | Default | Extra
|\n+------------+----------+------+-----+---------+----------------+\n| Id
| int(11) | NO | PRI | NULL | auto_increment |\n| Name |
char(35) | YES | | NULL | |\n| Country | char(3)
| NO | UNI | | |\n| District | char(20) | YES |
MUL | | |\n| Population | int(11) | YES | |
NULL |
|\n+------------+----------+------+-----+---------+----------------+\n\nA
simple set of examples to see how EXPLAIN can identify poor index
usage:\n\nCREATE TABLE IF NOT EXISTS `employees_example` (\n `id` int(11)
NOT NULL AUTO_INCREMENT,\n `first_name` varchar(30) NOT NULL,\n `last_name`
varchar(40) NOT NULL,\n `position` varchar(25) NOT NULL,\n `home_address`
varchar(50) NOT NULL,\n `home_phone` varchar(12) NOT NULL,\n
`employee_code` varchar(25) NOT NULL,\n PRIMARY KEY (`id`),\n UNIQUE KEY
`employee_code` (`employee_code`),\n KEY `first_name`
(`first_name`,`last_name`)\n) ENGINE=Aria;\n\nINSERT INTO
`employees_example` (`first_name`, `last_name`,
`position`,\n`home_address`, `home_phone`, `employee_code`)\n VALUES\n
(\'Mustapha\', \'Mond\', \'Chief Executive
Officer\', \'692 Promiscuous
Plaza\',\n\'326-555-3492\', \'MM1\'),\n
(\'Henry\', \'Foster\', \'Store Manager\',
\'314 Savage Circle\',
\'326-555-3847\',\n\'HF1\'),\n (\'Bernard\',
\'Marx\', \'Cashier\', \'1240 Ambient
Avenue\', \'326-555-8456\', \'BM1\'),\n
(\'Lenina\', \'Crowne\', \'Cashier\',
\'281 Bumblepuppy Boulevard\',
\'328-555-2349\',\n\'LC1\'),\n (\'Fanny\',
\'Crowne\', \'Restocker\', \'1023 Bokanovsky
Lane\', \'326-555-6329\',\n\'FC1\'),\n
(\'Helmholtz\', \'Watson\', \'Janitor\',
\'944 Soma Court\', \'329-555-2478\',
\'HW1\');\n\nSHOW INDEXES FROM
employees_example;\n+-------------------+------------+---------------+--------------+--------------\n+-----------+-------------+----------+--------+------+------------+---------+--\n------------+\n|
Table | Non_unique | Key_name | Seq_in_index | Column_name
\n | Collation | Cardinality | Sub_part | Packed | Null | Index_type |
Comment |\nIndex_comment
|\n+-------------------+------------+---------------+--------------+--------------\n+-----------+-------------+----------+--------+------+------------+---------+--\n------------+\n|
employees_example | 0 | PRIMARY | 1 | id
\n | A | 7 | NULL | NULL | | BTREE |
|\n |\n| employees_example | 0 | employee_code |
1 |\nemployee_code | A | 7 | NULL | NULL | |
BTREE \n | | |\n| employees_example | 1 |
first_name | 1 | first_name \n | A | NULL |
NULL | NULL | | BTREE | |\n |') WHERE
help_topic_id = 466;
update help_topic set description = CONCAT(description, '\n|
employees_example | 1 | first_name | 2 | last_name
\n | A | NULL | NULL | NULL | | BTREE |
|\n
|\n+-------------------+------------+---------------+--------------+--------------\n+-----------+-------------+----------+--------+------+------------+---------+--\n------------+\n\nSELECT
on a primary key:\n\nEXPLAIN SELECT * FROM employees_example WHERE
id=1;\n+------+-------------+-------------------+-------+---------------+---------+---\n-----+-------+------+-------+\n|
id | select_type | table | type | possible_keys | key
|\nkey_len | ref | rows | Extra
|\n+------+-------------+-------------------+-------+---------------+---------+---\n-----+-------+------+-------+\n|
1 | SIMPLE | employees_example | const | PRIMARY | PRIMARY |
4\n | const | 1 |
|\n+------+-------------+-------------------+-------+---------------+---------+---\n-----+-------+------+-------+\n\nThe
type is const, which means that only one possible result could
be\nreturned. Now, returning the same record but searching by their phone
number:\n\nEXPLAIN SELECT * FROM employees_example WHERE
home_phone=\'326-555-3492\';\n+------+-------------+-------------------+------+---------------+------+-------\n-+------+------+-------------+\n|
id | select_type | table | type | possible_keys | key
|\nkey_len | ref | rows | Extra
|\n+------+-------------+-------------------+------+---------------+------+-------\n-+------+------+-------------+\n|
1 | SIMPLE | employees_example | ALL | NULL | NULL | NULL
\n | NULL | 6 | Using where
|\n+------+-------------+-------------------+------+---------------+------+-------\n-+------+------+-------------+\n\nHere,
the type is All, which means no index could be used. Looking at the
rows\ncount, a full table scan (all six rows) had to be performed in order
to\nretrieve the record. If it\'s a requirement to search by phone
number, an index\nwill have to be created.\n\nSHOW EXPLAIN example:\n\nSHOW
EXPLAIN FOR
1;\n+------+-------------+-------+-------+---------------+------+---------+------+-\n-------+-------------+\n|
id | select_type | table | type | possible_keys | key | key_len | ref
|\nrows | Extra
|\n+------+-------------+-------+-------+---------------+------+---------+------+-\n-------+-------------+\n|
1 | SIMPLE | tbl | index | NULL | a | 5 | NULL
|\n1000107 | Using index
|\n+------+-------------+-------+-------+---------------+------+---------+------+-\n-------+-------------+\n1
row in set, 1 warning (0.00 sec)\n\nExample of ref_or_null
Optimization\n-----------------------------------\n\nSELECT * FROM
table_name\n WHERE key_column=expr OR key_column IS NULL;\n\nref_or_null is
something that often happens when you use subqueries with NOT\nIN as then
one has to do an extra check for NULL values if the first
value\ndidn\'t have a matching row.\n\nURL:
https://mariadb.com/kb/en/explain/') WHERE help_topic_id = 466;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(467,28,'EXPLAIN ANALYZE','The syntax for the EXPLAIN
ANALYZE feature was changed to ANALYZE statement,\navailable since MariaDB
10.1.0. See ANALYZE statement.\n\nURL:
https://mariadb.com/kb/en/explain-analyze/','','https://mariadb.com/kb/en/explain-analyze/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(468,28,'EXPLAIN FORMAT=JSON','Synopsis\n--------\n\nEXPLAIN
FORMAT=JSON is a variant of EXPLAIN command that produces output in\nJSON
form. The output always has one row which has only one column
titled\n\"JSON\". The contents are a JSON representation of the
query plan, formatted\nfor readability:\n\nEXPLAIN FORMAT=JSON SELECT *
FROM t1 WHERE col1=1\\G\n\n*************************** 1. row
***************************\nEXPLAIN: {\n \"query_block\": {\n
\"select_id\": 1,\n \"table\": {\n
\"table_name\": \"t1\",\n \"access_type\":
\"ALL\",\n \"rows\": 1000,\n
\"filtered\": 100,\n \"attached_condition\":
\"(t1.col1 = 1)\"\n }\n }\n}\n\nOutput is different from
MySQL\n------------------------------\n\nThe output of MariaDB\'s
EXPLAIN FORMAT=JSON is different from EXPLAIN\nFORMAT=JSON in MySQL.The
reasons for that are:\n\n* MySQL\'s output has deficiencies. Some are
listed here: EXPLAIN FORMAT=JSON\nin MySQL\n* The output of MySQL\'s
EXPLAIN FORMAT=JSON is not defined. Even MySQL\nWorkbench has trouble
parsing it (see this blog post).\n* MariaDB has query optimizations that
MySQL does not have. Ergo, MariaDB\ngenerates query plans that MySQL does
not generate.\n\nA (as yet incomplete) list of how MariaDB\'s output
is different from MySQL can\nbe found here: EXPLAIN FORMAT=JSON differences
from MySQL.\n\nOutput Format\n-------------\n\nTODO: MariaDB\'s output
format description.\n\nURL:
https://mariadb.com/kb/en/explain-format-json/','','https://mariadb.com/kb/en/explain-format-json/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(469,28,'DESCRIBE','Syntax\n------\n\n{DESCRIBE | DESC}
tbl_name [col_name | wild]\n\nDescription\n-----------\n\nDESCRIBE provides
information about the columns in a table. It is a shortcut\nfor SHOW
COLUMNS FROM. These statements also display information for
views.\n\ncol_name can be a column name, or a string containing the SQL
\"%\" and \"_\"\nwildcard characters to obtain output
only for the columns with names matching\nthe string. There is no need to
enclose the string within quotes unless it\ncontains spaces or other
special characters.\n\nDESCRIBE
city;\n+------------+----------+------+-----+---------+----------------+\n|
Field | Type | Null | Key | Default | Extra
|\n+------------+----------+------+-----+---------+----------------+\n| Id
| int(11) | NO | PRI | NULL | auto_increment |\n| Name |
char(35) | YES | | NULL | |\n| Country | char(3)
| NO | UNI | | |\n| District | char(20) | YES |
MUL | | |\n| Population | int(11) | YES | |
NULL |
|\n+------------+----------+------+-----+---------+----------------+\n\nThe
description for SHOW COLUMNS provides more information about the
output\ncolumns.\n\nURL:
https://mariadb.com/kb/en/describe/','','https://mariadb.com/kb/en/describe/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(470,29,'Identifier Names','Databases, tables, indexes,
columns, aliases, views, stored routines,\ntriggers, events, variables,
partitions, tablespaces, savepoints, labels,\nusers, roles, are
collectively known as identifiers, and have certain rules\nfor
naming.\n\nIdentifiers may be quoted using the backtick character - `.
Quoting is\noptional for identifiers that don\'t contain special
characters, or for\nidentifiers that are not reserved words. If the
ANSI_QUOTES SQL_MODE flag is\nset, double quotes (\") can also be used
to quote identifiers. If the MSSQL\nflag is set, square brackets ([ and ])
can be used for quoting.\n\nEven when using reserved words as names, fully
qualified names do not need to\nbe quoted. For example, test.select has
only one possible meaning, so it is\ncorrectly parsed even without
quotes.\n\nUnquoted\n--------\n\nThe following characters are valid, and
allow identifiers to be unquoted:\n\n* ASCII: [0-9,a-z,A-Z$_] (numerals
0-9, basic Latin letters, both lowercase\nand uppercase, dollar sign,
underscore)\n* Extended: U+0080 .. U+FFFF\n\nQuoted\n------\n\nThe
following characters are valid, but identifiers using them must be
quoted:\n\n* ASCII: U+0001 .. U+007F (full Unicode Basic Multilingual Plane
(BMP) except\nfor U+0000)\n* Extended: U+0080 .. U+FFFF \n* Identifier
quotes can themselves be used as part of an identifier, as long\nas they
are quoted.\n\nFurther Rules\n-------------\n\nThere are a number of other
rules for identifiers:\n\n* Identifiers are stored as Unicode (UTF-8)\n*
Identifiers may or may not be case-sensitive. See
Indentifier\nCase-sensitivity.\n* Database, table and column names
can\'t end with space characters\n* Identifier names may begin with a
numeral, but can\'t only contain numerals\nunless quoted.\n* An
identifier starting with a numeral, followed by an \'e\', may be
parsed as\na floating point number, and needs to be quoted.\n* Identifiers
are not permitted to contain the ASCII NUL character (U+0000)\nand
supplementary characters (U+10000 and higher).\n* Names such as 5e6, 9e are
not prohibited, but it\'s strongly recommended not\nto use them, as
they could lead to ambiguity in certain contexts, being\ntreated as a
number or expression.\n* User variables cannot be used as part of an
identifier, or as an identifier\nin an SQL statement.\n\nQuote
Character\n---------------\n\nThe regular quote character is the backtick
character - `, but if the\nANSI_QUOTES SQL_MODE option is specified, a
regular double quote - \" may be\nused as well.\n\nThe backtick
character can be used as part of an identifier. In that case
the\nidentifier needs to be quoted. The quote character can be the
backtick, but in\nthat case, the backtick in the name must be escaped with
another backtick.\n\nMaximum Length\n--------------\n\n* Databases, tables,
columns, indexes, constraints, stored routines, triggers,\nevents, views,
tablespaces, servers and log file groups have a maximum length\nof 64
characters.\n* Compound statement labels have a maximum length of 16
characters\n* Aliases have a maximum length of 256 characters, except for
column aliases\nin CREATE VIEW statements, which are checked against the
maximum column length\nof 64 characters (not the maximum alias length of
256 characters).\n* Users have a maximum length of 80 characters.\n* Roles
have a maximum length of 128 characters.\n* Multi-byte characters do not
count extra towards towards the character limit.\n\nMultiple
Identifiers\n--------------------\n\nMariaDB allows the column name to be
used on its own if the reference will be\nunambiguous, or the table name to
be used with the column name, or all three\nof the database, table and
column names. A period is used to separate the\nidentifiers, and the period
can be surrounded by spaces.\n\nExamples\n--------\n\nUsing the period to
separate identifiers:\n\nCREATE TABLE t1 (i int);\n\nINSERT INTO t1(i)
VALUES (10);\n\nSELECT i FROM t1;\n+------+\n| i |\n+------+\n| 10
|\n+------+\n\nSELECT t1.i FROM t1;\n+------+\n| i |\n+------+\n| 10
|\n+------+\n\nSELECT test.t1.i FROM t1;\n+------+\n| i |\n+------+\n|
10 |\n+------+\n\nThe period can be separated by spaces:\n\nSELECT test .
t1 . i FROM t1;\n+------+\n| i |\n+------+\n| 10
|\n+------+\n\nResolving ambiguity:\n\nCREATE TABLE t2 (i int);\n\nSELECT i
FROM t1 LEFT JOIN t2 ON t1.i=t2.i;\nERROR 1052 (23000): Column
\'i\' in field list is ambiguous\n\nSELECT t1.i FROM t1 LEFT JOIN
t2 ON t1.i=t2.i;\n+------+\n| i |\n+------+\n| 10
|\n+------+\n\nCreating a table with characters that require
quoting:\n\nCREATE TABLE 123% (i int);\nERROR 1064 (42000): You have an
error in your SQL syntax; \n check the manual that corresponds to your
MariaDB server version for the\nright syntax \n to use near \'123% (i
int)\' at line 1\n\nCREATE TABLE `123%` (i int);\nQuery OK, 0 rows
affected (0.85 sec)\n\nCREATE TABLE `TABLE` (i int);\nQuery OK, 0 rows
affected (0.36 sec)\n\nUsing double quotes as a quoting
character:\n\nCREATE TABLE \"SELECT\" (i int);\nERROR 1064
(42000): You have an error in your SQL syntax; \n check the manual that
corresponds to your MariaDB server version for the\nright syntax \n to use
near \'\"SELECT\" (i int)\' at line 1\n\nSET
sql_mode=\'ANSI_QUOTES\';\nQuery OK, 0 rows affected (0.03
sec)\n\nCREATE TABLE \"SELECT\" (i int);\nQuery OK, 0 rows
affected (0.46 sec)\n\nUsing an identifier quote as part of an identifier
name:\n\nSHOW VARIABLES LIKE
\'sql_mode\';\n+---------------+-------------+\n| Variable_name |
Value |\n+---------------+-------------+\n| sql_mode |
ANSI_QUOTES |\n+---------------+-------------+\n\nCREATE TABLE
\"fg`d\" (i int);\nQuery OK, 0 rows affected (0.34
sec)\n\nCreating the table named * (Unicode number: U+002A) requires
quoting.\n\nCREATE TABLE `*` (a INT);\n\nFloating point
ambiguity:\n\nCREATE TABLE 8984444cce5d (x INT);\nQuery OK, 0 rows affected
(0.38 sec)\n\nCREATE TABLE 8981e56cce5d (x INT);\nERROR 1064 (42000): You
have an error in your SQL syntax; \n check the manual that corresponds to
your MariaDB server version for the\nright syntax \n to use near
\'8981e56cce5d (x INT)\' at line 1\n\nCREATE TABLE `8981e56cce5d`
(x INT);\nQuery OK, 0 rows affected (0.39 sec)\n\nURL:
https://mariadb.com/kb/en/identifier-names/','','https://mariadb.com/kb/en/identifier-names/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(471,29,'Identifier Case-sensitivity','Whether objects are
case-sensitive or not is partly determined by the\nunderlying operating
system. Unix-based systems are case-sensitive, Windows is\nnot, while Mac
OS X is usually case-insensitive by default, but devices can be\nconfigured
as case-sensitive using Disk Utility.\n\nDatabase, table, table aliases and
trigger names are affected by the systems\ncase-sensitivity, while index,
column, column aliases, stored routine and\nevent names are never case
sensitive.\n\nLog file group name are case sensitive.\n\nThe
lower_case_table_names server system variable plays a key role.
It\ndetermines whether table names, aliases and database names are compared
in a\ncase-sensitive manner. If set to 0 (the default on Unix-based
systems), table\nnames and aliases and database names are compared in a
case-sensitive manner.\nIf set to 1 (the default on Windows), names are
stored in lowercase and not\ncompared in a case-sensitive manner. If set to
2 (the default on Mac OS X),\nnames are stored as declared, but compared in
lowercase.\n\nIt is thus possible to make Unix-based systems behave like
Windows and ignore\ncase-sensitivity, but the reverse is not true, as the
underlying Windows\nfilesystem can not support this.\n\nEven on
case-insensitive systems, you are required to use the same
case\nconsistently within the same statement. The following statement
fails, as it\nrefers to the table name in a different case.\n\nSELECT *
FROM a_table WHERE A_table.id>10;\n\nFor a full list of identifier
naming rules, see Identifier Names.\n\nPlease note that
lower_case_table_names is a database initialization\nparameter. This means
that, along with innodb_page_size, this variable must be\nset before
running mysql_install_db, and will not change the behavior of\nservers
unless applied before the creation of core system databases.\n\nURL:
https://mariadb.com/kb/en/identifier-case-sensitivity/','','https://mariadb.com/kb/en/identifier-case-sensitivity/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(472,29,'Binary Literals','Binary literals can be written in
one of the following formats: b\'value\',\nB\'value\'
or 0bvalue, where value is a string composed by 0 and 1 digits.\n\nBinary
literals are interpreted as binary strings, and are convenient
to\nrepresent VARBINARY, BINARY or BIT values.\n\nTo convert a binary
literal into an integer, just add 0.\n\nExamples\n--------\n\nPrinting the
value as a binary string:\n\nSELECT 0b1000001;\n+-----------+\n| 0b1000001
|\n+-----------+\n| A |\n+-----------+\n\nConverting the same value
into a number:\n\nSELECT 0b1000001+0;\n+-------------+\n| 0b1000001+0
|\n+-------------+\n| 65 |\n+-------------+\n\nURL:
https://mariadb.com/kb/en/binary-literals/','','https://mariadb.com/kb/en/binary-literals/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(473,29,'Boolean Literals','In MariaDB, FALSE is a synonym
of 0 and TRUE is a synonym of 1. These\nconstants are case insensitive, so
TRUE, True, and true are equivalent.\n\nThese terms are not synonyms of 0
and 1 when used with the IS operator. So,\nfor example, 10 IS TRUE returns
1, while 10 = TRUE returns 0 (because 1 != 10).\n\nThe IS operator accepts
a third constant exists: UNKNOWN. It is always a\nsynonym of NULL.\n\nTRUE
and FALSE are reserved words, while UNKNOWN is not.\n\nURL:
https://mariadb.com/kb/en/sql-language-structure-boolean-literals/','','https://mariadb.com/kb/en/sql-language-structure-boolean-literals/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(474,29,'Date and Time Literals','Standard
syntaxes\n-----------------\n\nMariaDB supports the SQL standard and ODBC
syntaxes for DATE, TIME and\nTIMESTAMP literals.\n\nSQL standard
syntax:\n\n* DATE \'string\'\n* TIME \'string\'\n*
TIMESTAMP \'string\'\n\nODBC syntax:\n\n* {d
\'string\'}\n* {t \'string\'}\n* {ts
\'string\'}\n\nThe timestamp literals are treated as DATETIME
literals, because in MariaDB\nthe range of DATETIME is closer to the
TIMESTAMP range in the SQL standard.\n\nstring is a string in a proper
format, as explained below.\n\nDATE literals\n-------------\n\nA DATE
string is a string in one of the following formats:
\'YYYY-MM-DD\' or\n\'YY-MM-DD\'. Note that any
punctuation character can be used as delimiter. All\ndelimiters must
consist of 1 character. Different delimiters can be used in\nthe same
string. Delimiters are optional (but if one delimiter is used,
all\ndelimiters must be used).\n\nA DATE literal can also be an integer, in
one of the following formats:\nYYYYMMDD or YYMMDD.\n\nAll the following
DATE literals are valid, and they all represent the
same\nvalue:\n\n\'19940101\'\n\'940101\'\n\'1994-01-01\'\n\'94/01/01\'\n\'1994-01/01\'\n\'94:01!01\'\n19940101\n940101\n\nDATETIME
literals\n-----------------\n\nA DATETIME string is a string in one of the
following formats: \'YYYY-MM-DD\nHH:MM:SS\' or \'YY-MM-DD
HH:MM:SS\'. Note that any punctuation character can be\nused as
delimiter for the date part and for the time part. All delimiters
must\nconsist of 1 character. Different delimiters can be used in the same
string.\nThe hours, minutes and seconds parts can consist of one character.
For this\nreason, delimiters are mandatory for DATETIME literals.\n\nThe
delimiter between the date part and the time part can be a T or
any\nsequence of space characters (including tabs, new lines and carriage
returns).\n\nA DATETIME literal can also be a number, in one of the
following formats:\nYYYYMMDDHHMMSS, YYMMDDHHMMSS, YYYYMMDD or YYMMDD. In
this case, all the time\nsubparts must consist of 2 digits.\n\nAll the
following DATE literals are valid, and they all represent the
same\nvalue:\n\n\'1994-01-01T12:30:03\'\n\'1994/01/01\\n\\t
12+30+03\'\n\'1994/01\\\\01\\n\\t
12+30-03\'\n\'1994-01-01 12:30:3\'\n\nTIME
literals\n-------------\n\nA TIME string is a string in one of the
following formats: \'D HH:MM:SS\',\n\'HH:MM:SS, \'D
HH:MM\', \'HH:MM\', \'D HH\', or \'SS\'.
D is a value from 0 to 34\nwhich represents days. : is the only allowed
delimiter for TIME literals.\nDelimiters are mandatory, with an exception:
the \'HHMMSS\' format is allowed.\nWhen delimiters are used, each
part of the literal can consist of one\ncharacter.\n\nA TIME literal can
also be a number in one of the following formats: HHMMSS,\nMMSS, or
SS.\n\nThe following literals are
equivalent:\n\n\'09:05:00\'\n\'9:05:0\'\n\'9:5:0\'\n\'090500\'\n\n2-digit
years\n-------------\n\nThe year part in DATE and DATETIME literals is
determined as follows:\n\n* 70 - 99 = 1970 - 1999\n* 00 - 69 = 2000 -
2069\n\nMicroseconds\n------------\n\nDATETIME and TIME literals can have
an optional microseconds part. For both\nstring and numeric forms, it is
expressed as a decimal part. Up to 6 decimal\ndigits are allowed.
Examples:\n\n\'12:30:00.123456\'\n123000.123456\n\nSee
Microseconds in MariaDB for details.\n\nDate and time literals and the
SQL_MODE\n---------------------------------------\n\nUnless the SQL_MODE
NO_ZERO_DATE flag is set, some special values are allowed:\nthe
\'0000-00-00\' DATE, the \'00:00:00\' TIME, and the
0000-00-00 00:00:00\nDATETIME.\n\nIf the ALLOW_INVALID_DATES flag is set,
the invalid dates (for example, 30th\nFebruary) are allowed. If not, if the
NO_ZERO_DATE is set, an error is\nproduced; otherwise, a zero-date is
returned.\n\nUnless the NO_ZERO_IN_DATE flag is set, each subpart of a date
or time value\n(years, hours...) can be set to 0.\n\nURL:
https://mariadb.com/kb/en/date-and-time-literals/','','https://mariadb.com/kb/en/date-and-time-literals/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(475,29,'Hexadecimal Literals','Hexadecimal literals can be
written using any of the following syntaxes:\n\n* x\'value\'\n*
X\'value\' (SQL standard)\n* 0xvalue (ODBC)\n\nvalue is a
sequence of hexadecimal digits (from 0 to 9 and from A to F). The\ncase of
the digits does not matter. With the first two syntaxes, value
must\nconsist of an even number of digits. With the last syntax, digits can
be even,\nand they are treated as if they had an extra 0 at the
beginning.\n\nNormally, hexadecimal literals are interpreted as binary
string, where each\npair of digits represents a character. When used in a
numeric context, they\nare interpreted as integers. (See the example
below). In no case can a\nhexadecimal literal be a decimal number.\n\nThe
first two syntaxes; X\'value\' and x\'value, follow the SQL
standard, and\nbehave as a string in all contexts in MariaDB since MariaDB
10.0.3 and MariaDB\n5.5.31 (fixing MDEV-4489). The latter syntax, 0xvalue,
is a MySQL/MariaDB\nextension for hex hybrids and behaves as a string or as
a number depending on\ncontext. MySQL treats all syntaxes the same, so
there may be different results\nin MariaDB and MySQL (see
below).\n\nExamples\n--------\n\nRepresenting the a character with the
three syntaxes explained above:\n\nSELECT x\'61\',
X\'61\', 0x61;\n+-------+-------+------+\n| x\'61\' |
X\'61\' | 0x61 |\n+-------+-------+------+\n| a | a | a
|\n+-------+-------+------+\n\nHexadecimal literals in a numeric
context:\n\nSELECT 0 + 0xF, -0xF;\n+---------+------+\n| 0 + 0xF | -0xF
|\n+---------+------+\n| 15 | -15 |\n+---------+------+\n\nFun with
Types\n--------------\n\nCREATE TABLE t1 (a INT, b VARCHAR(10));\nINSERT
INTO t1 VALUES (0x31, 0x61),(COALESCE(0x31), COALESCE(0x61));\n\nSELECT *
FROM t1;\n+------+------+\n| a | b |\n+------+------+\n| 49 | a
|\n| 1 | a |\n+------+------+\n\nThe reason for the differing results
above is that when 0x31 is inserted\ndirectly to the column, it\'s
treated as a number, while when 0x31 is passed to\nCOALESCE(), it\'s
treated as a string, because:\n\n* HEX values have a string data type by
default.\n* COALESCE() has the same data type as the
argument.\n\nDifferences Between MariaDB and
MySQL\n-------------------------------------\n\nSELECT
x\'0a\'+0;\n+---------+\n| x\'0a\'+0 |\n+---------+\n|
0 |\n+---------+\n1 row in set, 1 warning (0.00 sec)\n\nWarning (Code
1292): Truncated incorrect DOUBLE value: \'\\x0A\'\n\nSELECT
X\'0a\'+0;\n+---------+\n| X\'0a\'+0 |\n+---------+\n|
0 |\n+---------+\n1 row in set, 1 warning (0.00 sec)\n\nWarning (Code
1292): Truncated incorrect DOUBLE value: \'\\x0A\'\n\nSELECT
0x0a+0;\n+--------+\n| 0x0a+0 |\n+--------+\n| 10 |\n+--------+\n\nIn
MySQL (up until at least MySQL 8.0.26):\n\nSELECT
x\'0a\'+0;\n+---------+\n| x\'0a\'+0 |\n+---------+\n|
10 |\n+---------+\n\nSELECT X\'0a\'+0;\n+---------+\n|
X\'0a\'+0 |\n+---------+\n| 10 |\n+---------+\n\nSELECT
0x0a+0;\n+--------+\n| 0x0a+0 |\n+--------+\n| 10 |\n+--------+\n\nURL:
https://mariadb.com/kb/en/hexadecimal-literals/','','https://mariadb.com/kb/en/hexadecimal-literals/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(476,29,'Identifier Qualifiers','Qualifiers are used within
SQL statements to reference data structures, such\nas databases, tables, or
columns. For example, typically a SELECT query\ncontains references to some
columns and at least one table.\n\nQualifiers can be composed by one or
more identifiers, where the initial parts\naffect the context within which
the final identifier is interpreted:\n\n* For a database, only the database
identifier needs to be specified.\n* For objects which are contained in a
database (like tables, views,\nfunctions, etc) the database identifier can
be specified. If no database is\nspecified, the current database is assumed
(see USE and DATABASE() for more\ndetails). If there is no default database
and no database is specified, an\nerror is issued.\n* For column names, the
table and the database are generally obvious from the\ncontext of the
statement. It is however possible to specify the table\nidentifier, or the
database identifier plus the table identifier.\n* An identifier is
fully-qualified if it contains all possible qualifiers, for\nexample, the
following column is fully qualified: db_name.tbl_name.col_name.\n\nIf a
qualifier is composed by more than one identifier, a dot (.) must be
used\nas a separator. All identifiers can be quoted individually. Extra
spacing\n(including new lines and tabs) is allowed.\n\nAll the following
examples are valid:\n\n* db_name.tbl_name.col_name\n* tbl_name\n*
`db_name`.`tbl_name`.`col_name`\n* `db_name` . `tbl_name`\n* db_name.
tbl_name\n\nIf a table identifier is prefixed with a dot (.), the default
database is\nassumed. This syntax is supported for ODBC compliance, but has
no practical\neffect on MariaDB. These qualifiers are equivalent:\n\n*
tbl_name\n* . tbl_name\n* .`tbl_name`\n* . `tbl_name`\n\nFor DML
statements, it is possible to specify a list of the partitions using\nthe
PARTITION clause. See Partition Pruning and Selection for details.\n\nURL:
https://mariadb.com/kb/en/identifier-qualifiers/','','https://mariadb.com/kb/en/identifier-qualifiers/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(477,29,'Identifier to File Name Mapping','Some identifiers
map to a file name on the filesystem. Databases each have\ntheir own
directory, while, depending on the storage engine, table names and\nindex
names may map to a file name.\n\nNot all characters that are allowed in
table names can be used in file names.\nEvery filesystem has its own rules
of what characters can be used in file\nnames. To let the user create
tables using all characters allowed in the SQL\nStandard and to not depend
on whatever particular filesystem a particular\ndatabase resides, MariaDB
encodes \"potentially unsafe\" characters in the table\nname to
derive the corresponding file name.\n\nThis is implemented using a special
character set. MariaDB converts a table\nname to the \"filename\"
character set to get the file name for this table. And\nit converts the
file name from the \"filename\" character set to, for
example,\nutf8 to get the table name for this file name.\n\nThe conversion
rules are as follows: if the identifier is made up only of\nbasic Latin
numbers, letters and/or the underscore character, the encoding\nmatches the
name (see however Identifier Case Sensitivity). Otherwise they are\nencoded
according to the following
table:\n\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
Code Range | Pattern | Number | Used | Unused | Blocks
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
00C0..017F | [@][0..4][ | 5*20= 100 | 97 | 3 | Latin-1
|\n| | ..z] | | | |
Supplemen |\n| | | | |
| + Latin |\n| | | | |
| Extended- |\n| | | | |
|
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
0370..03FF | [@][5..9][ | 5*20= 100 | 88 | 12 | Greek
|\n| | ..z] | | | | and
|\n| | | | | |
Coptic
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
0400..052F | [@][g..z][ | 20*7= 140 | 137 | 3 | Cyrillic
|\n| | ..6] | | | | +
|\n| | | | | |
Cyrillic |\n| | | | |
| Supplemen |\n| | | | |
|
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
0530..058F | [@][g..z][ | 20*2= 40 | 38 | 2 | Armenian
|\n| | ..8] | | | |
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
2160..217F | [@][g..z][ | 20*1= 20 | 16 | 4 | Number
|\n| | ] | | | | Forms
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
0180..02AF | [@][g..z][ | 20*11=220 | 203 | 17 | Latin
|\n| | ..k] | | | |
Extended- |\n| | | | |
| + IPA |\n| | | | |
| Extension |\n| | | | |
|
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
1E00..1EFF | [@][g..z][ | 20*7= 140 | 136 | 4 | Latin
|\n| | ..r] | | | |
Extended |\n| | | | |
| Additiona |\n| | | | |
|
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
1F00..1FFF | [@][g..z][ | 20*8= 160 | 144 | 16 | Greek
|\n| | ..z] | | | |
Extended
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
.... .... | [@][a..f][ | 6*20= 120 | 0 | 120 | RESERVED
|\n| | ..z] | | | |
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
24B6..24E9 | [@][@][a.. | 26 | 26 | 0 | Enclosed
|\n| | ] | | | |
Alphanume |\n| | | | |
| ics
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n|
FF21..FF5A | [@][a..z][ | 26 | 26 | 0 | Halfwidth
|\n| | ] | | | | and
|\n| | | | | |
Fullwidth |\n| | | | |
| forms
|\n+-----------------+------------+-----------+--------+-----------+-----------+\n\nCode
Range values are UCS-2.\n\nAll of this encoding happens transparently at
the filesystem level with one\nexception. Until MySQL 5.1.6, an old
encoding was used. Identifiers created in\na version before MySQL 5.1.6,
and which haven\'t been updated to the new\nencoding, the server
prefixes mysql50 to their name.\n\nExamples\n--------\n\nFind the file name
for a table with a non-Latin1 name:\n\nselect
cast(convert(\"this_is_таблица\" USING filename) as
binary);\n+------------------------------------------------------------------+\n|
cast(convert(\"this_is_таблица\" USING filename) as
binary)
|\n+------------------------------------------------------------------+\n|
this_is_@y0@g0@h0@r0@o0@i1@g0
|\n+------------------------------------------------------------------+\n\nFind
the table name for a file name:\n\nselect convert(_filename
\"this_is_@y0@g0@h0@r0@o0@i1@g0\" USING
utf8);\n+---------------------------------------------------------------+\n|
convert(_filename \"this_is_@y0@g0@h0@r0@o0@i1@g0\" USING utf8)
|\n+---------------------------------------------------------------+\n|
this_is_таблица
|\n+---------------------------------------------------------------+\n\nAn
old table created before MySQL 5.1.6, with the old encoding:\n\nSHOW
TABLES;\n+--------------------+\n| Tables_in_test
|\n+--------------------+\n| #mysql50#table@1
|\n+--------------------+\n\nThe prefix needs to be supplied to reference
this table:\n\nSHOW COLUMNS FROM `table@1`;\nERROR 1146 (42S02): Table
\'test.table@1\' doesn\'t exist\n\nSHOW COLUMNS FROM
`#mysql50#table@1`;\n+-------+---------+------+-----+---------+-------+\n|
Field | Type | Null | Key | Default | Extra
|\n+-------+---------+------+-----+---------+-------+\n| i | int(11) |
YES | | NULL |
|\n+-------+---------+------+-----+---------+-------+\n\nURL:
https://mariadb.com/kb/en/identifier-to-file-name-mapping/','','https://mariadb.com/kb/en/identifier-to-file-name-mapping/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(478,29,'Numeric Literals','Numeric literals are written as
a sequence of digits from 0 to 9. Initial\nzeros are ignored. A sign can
always precede the digits, but it is optional\nfor positive numbers. In
decimal numbers, the integer part and the decimal\npart are divided with a
dot (.).\n\nIf the integer part is zero, it can be omitted, but the literal
must begin\nwith a dot.\n\nThe notation with exponent can be used. The
exponent is preceded by an E or e\ncharacter. The exponent can be preceded
by a sign and must be an integer. A\nnumber N with an exponent part X, is
calculated as N * POW(10, X).\n\nIn some cases, adding zeroes at the end of
a decimal number can increment the\nprecision of the expression where the
number is used. For example, PI() by\ndefault returns a number with 6
decimal digits. But the PI()+0.0000000000\nexpression (with 10 zeroes)
returns a number with 10 decimal digits.\n\nHexadecimal literals are
interpreted as numbers when used in numeric
contexts.\n\nExamples\n--------\n\n10\n+10\n-10\n\nAll these literals are
equivalent:\n\n0.1\n.1\n+0.1\n+.1\n\nWith exponents:\n\n0.2E3 -- 0.2 *
POW(10, 3) = 200\n.2e3\n.2e+2\n1.1e-10 -- 0.00000000011\n-1.1e10 --
-11000000000\n\nURL:
https://mariadb.com/kb/en/numeric-iterals/','','https://mariadb.com/kb/en/numeric-iterals/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(479,29,'Reserved Words','The following is a list of all
reserved words in MariaDB.\n\nReserved words cannot be used as Identifiers,
unless they are quoted.\n\nThe definitive list of reserved words for each
version can be found by\nexamining the sql/lex.h and sql/sql_yacc.yy
files.\n\nReserved
Words\n--------------\n\n+--------------------------------------------+--------------------------------+\n|
Keyword | Notes
|\n+--------------------------------------------+--------------------------------+\n|
ACCESSIBLE |
|\n+--------------------------------------------+--------------------------------+\n|
ADD |
|\n+--------------------------------------------+--------------------------------+\n|
ALL |
|\n+--------------------------------------------+--------------------------------+\n|
ALTER |
|\n+--------------------------------------------+--------------------------------+\n|
ANALYZE |
|\n+--------------------------------------------+--------------------------------+\n|
AND |
|\n+--------------------------------------------+--------------------------------+\n|
AS |
|\n+--------------------------------------------+--------------------------------+\n|
ASC |
|\n+--------------------------------------------+--------------------------------+\n|
ASENSITIVE |
|\n+--------------------------------------------+--------------------------------+\n|
BEFORE |
|\n+--------------------------------------------+--------------------------------+\n|
BETWEEN |
|\n+--------------------------------------------+--------------------------------+\n|
BIGINT |
|\n+--------------------------------------------+--------------------------------+\n|
BINARY |
|\n+--------------------------------------------+--------------------------------+\n|
BLOB |
|\n+--------------------------------------------+--------------------------------+\n|
BOTH |
|\n+--------------------------------------------+--------------------------------+\n|
BY |
|\n+--------------------------------------------+--------------------------------+\n|
CALL |
|\n+--------------------------------------------+--------------------------------+\n|
CASCADE |
|\n+--------------------------------------------+--------------------------------+\n|
CASE |
|\n+--------------------------------------------+--------------------------------+\n|
CHANGE |
|\n+--------------------------------------------+--------------------------------+\n|
CHAR |
|\n+--------------------------------------------+--------------------------------+\n|
CHARACTER |
|\n+--------------------------------------------+--------------------------------+\n|
CHECK |
|\n+--------------------------------------------+--------------------------------+\n|
COLLATE |
|\n+--------------------------------------------+--------------------------------+\n|
COLUMN |
|\n+--------------------------------------------+--------------------------------+\n|
CONDITION |
|\n+--------------------------------------------+--------------------------------+\n|
CONSTRAINT |
|\n+--------------------------------------------+--------------------------------+\n|
CONTINUE |
|\n+--------------------------------------------+--------------------------------+\n|
CONVERT |
|\n+--------------------------------------------+--------------------------------+\n|
CREATE |
|\n+--------------------------------------------+--------------------------------+\n|
CROSS |
|\n+--------------------------------------------+--------------------------------+\n|
CURRENT_DATE |
|\n+--------------------------------------------+--------------------------------+\n|
CURRENT_ROLE |
|\n+--------------------------------------------+--------------------------------+\n|
CURRENT_TIME |
|\n+--------------------------------------------+--------------------------------+\n|
CURRENT_TIMESTAMP |
|\n+--------------------------------------------+--------------------------------+\n|
CURRENT_USER |
|\n+--------------------------------------------+--------------------------------+\n|
CURSOR |
|\n+--------------------------------------------+--------------------------------+\n|
DATABASE |
|\n+--------------------------------------------+--------------------------------+\n|
DATABASES |
|\n+--------------------------------------------+--------------------------------+\n|
DAY_HOUR |
|\n+--------------------------------------------+--------------------------------+\n|
DAY_MICROSECOND |
|\n+--------------------------------------------+--------------------------------+\n|
DAY_MINUTE |
|\n+--------------------------------------------+--------------------------------+\n|
DAY_SECOND |
|\n+--------------------------------------------+--------------------------------+\n|
DEC |
|\n+--------------------------------------------+--------------------------------+\n|
DECIMAL |
|\n+--------------------------------------------+--------------------------------+\n|
DECLARE |
|\n+--------------------------------------------+--------------------------------+\n|
DEFAULT |
|\n+--------------------------------------------+--------------------------------+\n|
DELAYED |
|\n+--------------------------------------------+--------------------------------+\n|
DELETE |
|\n+--------------------------------------------+--------------------------------+\n|
DELETE_DOMAIN_ID |
|\n+--------------------------------------------+--------------------------------+\n|
DESC |
|\n+--------------------------------------------+--------------------------------+\n|
DESCRIBE |
|\n+--------------------------------------------+--------------------------------+\n|
DETERMINISTIC |
|\n+--------------------------------------------+--------------------------------+\n|
DISTINCT |
|\n+--------------------------------------------+--------------------------------+\n|
DISTINCTROW |
|\n+--------------------------------------------+--------------------------------+\n|
DIV |
|\n+--------------------------------------------+--------------------------------+\n|
DO_DOMAIN_IDS |
|\n+--------------------------------------------+--------------------------------+\n|
DOUBLE |
|\n+--------------------------------------------+--------------------------------+\n|
DROP |
|\n+--------------------------------------------+--------------------------------+\n|
DUAL |
|\n+--------------------------------------------+--------------------------------+\n|
EACH |
|\n+--------------------------------------------+--------------------------------+\n|
ELSE |
|\n+--------------------------------------------+--------------------------------+\n|
ELSEIF |
|\n+--------------------------------------------+--------------------------------+\n|
ENCLOSED |
|\n+--------------------------------------------+--------------------------------+\n|
ESCAPED |
|\n+--------------------------------------------+--------------------------------+\n|
EXCEPT | Added in MariaDB 10.3.0
|\n+--------------------------------------------+--------------------------------+\n|
EXISTS |
|\n+--------------------------------------------+--------------------------------+\n|
EXIT |
|\n+--------------------------------------------+--------------------------------+\n|
EXPLAIN |
|\n+--------------------------------------------+--------------------------------+\n|
FALSE |
|\n+--------------------------------------------+--------------------------------+\n|
FETCH |
|\n+--------------------------------------------+--------------------------------+\n|
FLOAT |
|\n+--------------------------------------------+--------------------------------+\n|
FLOAT4 |
|\n+--------------------------------------------+--------------------------------+\n|
FLOAT8 |
|\n+--------------------------------------------+--------------------------------+\n|
FOR |
|\n+--------------------------------------------+--------------------------------+\n|
FORCE |
|\n+--------------------------------------------+--------------------------------+\n|
FOREIGN |
|\n+--------------------------------------------+--------------------------------+\n|
FROM |
|\n+--------------------------------------------+--------------------------------+\n|
FULLTEXT |
|\n+--------------------------------------------+--------------------------------+\n|
GENERAL |
|\n+--------------------------------------------+--------------------------------+\n|
GRANT |
|\n+--------------------------------------------+--------------------------------+\n|
GROUP |
|\n+--------------------------------------------+--------------------------------+\n|
HAVING |
|\n+--------------------------------------------+--------------------------------+\n|
HIGH_PRIORITY |
|\n+--------------------------------------------+--------------------------------+\n|
HOUR_MICROSECOND |
|\n+--------------------------------------------+--------------------------------+\n|
HOUR_MINUTE |
|\n+--------------------------------------------+--------------------------------+\n|
HOUR_SECOND |
|','','https://mariadb.com/kb/en/reserved-words/');
update help_topic set description = CONCAT(description,
'\n+--------------------------------------------+--------------------------------+\n|
IF |
|\n+--------------------------------------------+--------------------------------+\n|
IGNORE |
|\n+--------------------------------------------+--------------------------------+\n|
IGNORE_DOMAIN_IDS |
|\n+--------------------------------------------+--------------------------------+\n|
IGNORE_SERVER_IDS |
|\n+--------------------------------------------+--------------------------------+\n|
IN |
|\n+--------------------------------------------+--------------------------------+\n|
INDEX |
|\n+--------------------------------------------+--------------------------------+\n|
INFILE |
|\n+--------------------------------------------+--------------------------------+\n|
INNER |
|\n+--------------------------------------------+--------------------------------+\n|
INOUT |
|\n+--------------------------------------------+--------------------------------+\n|
INSENSITIVE |
|\n+--------------------------------------------+--------------------------------+\n|
INSERT |
|\n+--------------------------------------------+--------------------------------+\n|
INT |
|\n+--------------------------------------------+--------------------------------+\n|
INT1 |
|\n+--------------------------------------------+--------------------------------+\n|
INT2 |
|\n+--------------------------------------------+--------------------------------+\n|
INT3 |
|\n+--------------------------------------------+--------------------------------+\n|
INT4 |
|\n+--------------------------------------------+--------------------------------+\n|
INT8 |
|\n+--------------------------------------------+--------------------------------+\n|
INTEGER |
|\n+--------------------------------------------+--------------------------------+\n|
INTERSECT | Added in MariaDB 10.3.0
|\n+--------------------------------------------+--------------------------------+\n|
INTERVAL |
|\n+--------------------------------------------+--------------------------------+\n|
INTO |
|\n+--------------------------------------------+--------------------------------+\n|
IS |
|\n+--------------------------------------------+--------------------------------+\n|
ITERATE |
|\n+--------------------------------------------+--------------------------------+\n|
JOIN |
|\n+--------------------------------------------+--------------------------------+\n|
KEY |
|\n+--------------------------------------------+--------------------------------+\n|
KEYS |
|\n+--------------------------------------------+--------------------------------+\n|
KILL |
|\n+--------------------------------------------+--------------------------------+\n|
LEADING |
|\n+--------------------------------------------+--------------------------------+\n|
LEAVE |
|\n+--------------------------------------------+--------------------------------+\n|
LEFT |
|\n+--------------------------------------------+--------------------------------+\n|
LIKE |
|\n+--------------------------------------------+--------------------------------+\n|
LIMIT |
|\n+--------------------------------------------+--------------------------------+\n|
LINEAR |
|\n+--------------------------------------------+--------------------------------+\n|
LINES |
|\n+--------------------------------------------+--------------------------------+\n|
LOAD |
|\n+--------------------------------------------+--------------------------------+\n|
LOCALTIME |
|\n+--------------------------------------------+--------------------------------+\n|
LOCALTIMESTAMP |
|\n+--------------------------------------------+--------------------------------+\n|
LOCK |
|\n+--------------------------------------------+--------------------------------+\n|
LONG |
|\n+--------------------------------------------+--------------------------------+\n|
LONGBLOB |
|\n+--------------------------------------------+--------------------------------+\n|
LONGTEXT |
|\n+--------------------------------------------+--------------------------------+\n|
LOOP |
|\n+--------------------------------------------+--------------------------------+\n|
LOW_PRIORITY |
|\n+--------------------------------------------+--------------------------------+\n|
MASTER_HEARTBEAT_PERIOD |
|\n+--------------------------------------------+--------------------------------+\n|
MASTER_SSL_VERIFY_SERVER_CERT |
|\n+--------------------------------------------+--------------------------------+\n|
MATCH |
|\n+--------------------------------------------+--------------------------------+\n|
MAXVALUE |
|\n+--------------------------------------------+--------------------------------+\n|
MEDIUMBLOB |
|\n+--------------------------------------------+--------------------------------+\n|
MEDIUMINT |
|\n+--------------------------------------------+--------------------------------+\n|
MEDIUMTEXT |
|\n+--------------------------------------------+--------------------------------+\n|
MIDDLEINT |
|\n+--------------------------------------------+--------------------------------+\n|
MINUTE_MICROSECOND |
|\n+--------------------------------------------+--------------------------------+\n|
MINUTE_SECOND |
|\n+--------------------------------------------+--------------------------------+\n|
MOD |
|\n+--------------------------------------------+--------------------------------+\n|
MODIFIES |
|\n+--------------------------------------------+--------------------------------+\n|
NATURAL |
|\n+--------------------------------------------+--------------------------------+\n|
NOT |
|\n+--------------------------------------------+--------------------------------+\n|
NO_WRITE_TO_BINLOG |
|\n+--------------------------------------------+--------------------------------+\n|
NULL |
|\n+--------------------------------------------+--------------------------------+\n|
NUMERIC |
|\n+--------------------------------------------+--------------------------------+\n|
OFFSET | Added in MariaDB 10.6.0
|\n+--------------------------------------------+--------------------------------+\n|
ON |
|\n+--------------------------------------------+--------------------------------+\n|
OPTIMIZE |
|\n+--------------------------------------------+--------------------------------+\n|
OPTION |
|\n+--------------------------------------------+--------------------------------+\n|
OPTIONALLY |
|\n+--------------------------------------------+--------------------------------+\n|
OR |
|\n+--------------------------------------------+--------------------------------+\n|
ORDER |
|\n+--------------------------------------------+--------------------------------+\n|
OUT |
|\n+--------------------------------------------+--------------------------------+\n|
OUTER |
|\n+--------------------------------------------+--------------------------------+\n|
OUTFILE |
|\n+--------------------------------------------+--------------------------------+\n|
OVER |
|\n+--------------------------------------------+--------------------------------+\n|
PAGE_CHECKSUM |
|\n+--------------------------------------------+--------------------------------+\n|
PARSE_VCOL_EXPR |
|\n+--------------------------------------------+--------------------------------+\n|
PARTITION |
|\n+--------------------------------------------+--------------------------------+\n|
POSITION |
|\n+--------------------------------------------+--------------------------------+\n|
PRECISION |
|\n+--------------------------------------------+--------------------------------+\n|
PRIMARY |
|\n+--------------------------------------------+--------------------------------+\n|
PROCEDURE |
|\n+--------------------------------------------+--------------------------------+\n|
PURGE |
|\n+--------------------------------------------+--------------------------------+\n|
RANGE |
|\n+--------------------------------------------+--------------------------------+\n|
READ |
|\n+--------------------------------------------+--------------------------------+\n|
READS |
|\n+--------------------------------------------+--------------------------------+\n|
READ_WRITE |
|\n+--------------------------------------------+--------------------------------+\n|
REAL |
|\n+--------------------------------------------+--------------------------------+\n|
RECURSIVE |
|\n+--------------------------------------------+--------------------------------+\n|
REF_SYSTEM_ID |
|\n+--------------------------------------------+--------------------------------+\n|
REFERENCES |
|\n+--------------------------------------------+--------------------------------+\n|
REGEXP |
|\n+--------------------------------------------+--------------------------------+\n|
RELEASE |
|\n+--------------------------------------------+--------------------------------+\n|
RENAME |
|') WHERE help_topic_id = 479;
update help_topic set description = CONCAT(description,
'\n+--------------------------------------------+--------------------------------+\n|
REPEAT |
|\n+--------------------------------------------+--------------------------------+\n|
REPLACE |
|\n+--------------------------------------------+--------------------------------+\n|
REQUIRE |
|\n+--------------------------------------------+--------------------------------+\n|
RESIGNAL |
|\n+--------------------------------------------+--------------------------------+\n|
RESTRICT |
|\n+--------------------------------------------+--------------------------------+\n|
RETURN |
|\n+--------------------------------------------+--------------------------------+\n|
RETURNING |
|\n+--------------------------------------------+--------------------------------+\n|
REVOKE |
|\n+--------------------------------------------+--------------------------------+\n|
RIGHT |
|\n+--------------------------------------------+--------------------------------+\n|
RLIKE |
|\n+--------------------------------------------+--------------------------------+\n|
ROWS |
|\n+--------------------------------------------+--------------------------------+\n|
SCHEMA |
|\n+--------------------------------------------+--------------------------------+\n|
SCHEMAS |
|\n+--------------------------------------------+--------------------------------+\n|
SECOND_MICROSECOND |
|\n+--------------------------------------------+--------------------------------+\n|
SELECT |
|\n+--------------------------------------------+--------------------------------+\n|
SENSITIVE |
|\n+--------------------------------------------+--------------------------------+\n|
SEPARATOR |
|\n+--------------------------------------------+--------------------------------+\n|
SET |
|\n+--------------------------------------------+--------------------------------+\n|
SHOW |
|\n+--------------------------------------------+--------------------------------+\n|
SIGNAL |
|\n+--------------------------------------------+--------------------------------+\n|
SLOW |
|\n+--------------------------------------------+--------------------------------+\n|
SMALLINT |
|\n+--------------------------------------------+--------------------------------+\n|
SPATIAL |
|\n+--------------------------------------------+--------------------------------+\n|
SPECIFIC |
|\n+--------------------------------------------+--------------------------------+\n|
SQL |
|\n+--------------------------------------------+--------------------------------+\n|
SQLEXCEPTION |
|\n+--------------------------------------------+--------------------------------+\n|
SQLSTATE |
|\n+--------------------------------------------+--------------------------------+\n|
SQLWARNING |
|\n+--------------------------------------------+--------------------------------+\n|
SQL_BIG_RESULT |
|\n+--------------------------------------------+--------------------------------+\n|
SQL_CALC_FOUND_ROWS |
|\n+--------------------------------------------+--------------------------------+\n|
SQL_SMALL_RESULT |
|\n+--------------------------------------------+--------------------------------+\n|
SSL |
|\n+--------------------------------------------+--------------------------------+\n|
STARTING |
|\n+--------------------------------------------+--------------------------------+\n|
STATS_AUTO_RECALC |
|\n+--------------------------------------------+--------------------------------+\n|
STATS_PERSISTENT |
|\n+--------------------------------------------+--------------------------------+\n|
STATS_SAMPLE_PAGES |
|\n+--------------------------------------------+--------------------------------+\n|
STRAIGHT_JOIN |
|\n+--------------------------------------------+--------------------------------+\n|
TABLE |
|\n+--------------------------------------------+--------------------------------+\n|
TERMINATED |
|\n+--------------------------------------------+--------------------------------+\n|
THEN |
|\n+--------------------------------------------+--------------------------------+\n|
TINYBLOB |
|\n+--------------------------------------------+--------------------------------+\n|
TINYINT |
|\n+--------------------------------------------+--------------------------------+\n|
TINYTEXT |
|\n+--------------------------------------------+--------------------------------+\n|
TO |
|\n+--------------------------------------------+--------------------------------+\n|
TRAILING |
|\n+--------------------------------------------+--------------------------------+\n|
TRIGGER |
|\n+--------------------------------------------+--------------------------------+\n|
TRUE |
|\n+--------------------------------------------+--------------------------------+\n|
UNDO |
|\n+--------------------------------------------+--------------------------------+\n|
UNION |
|\n+--------------------------------------------+--------------------------------+\n|
UNIQUE |
|\n+--------------------------------------------+--------------------------------+\n|
UNLOCK |
|\n+--------------------------------------------+--------------------------------+\n|
UNSIGNED |
|\n+--------------------------------------------+--------------------------------+\n|
UPDATE |
|\n+--------------------------------------------+--------------------------------+\n|
USAGE |
|\n+--------------------------------------------+--------------------------------+\n|
USE |
|\n+--------------------------------------------+--------------------------------+\n|
USING |
|\n+--------------------------------------------+--------------------------------+\n|
UTC_DATE |
|\n+--------------------------------------------+--------------------------------+\n|
UTC_TIME |
|\n+--------------------------------------------+--------------------------------+\n|
UTC_TIMESTAMP |
|\n+--------------------------------------------+--------------------------------+\n|
VALUES |
|\n+--------------------------------------------+--------------------------------+\n|
VARBINARY |
|\n+--------------------------------------------+--------------------------------+\n|
VARCHAR |
|\n+--------------------------------------------+--------------------------------+\n|
VARCHARACTER |
|\n+--------------------------------------------+--------------------------------+\n|
VARYING |
|\n+--------------------------------------------+--------------------------------+\n|
WHEN |
|\n+--------------------------------------------+--------------------------------+\n|
WHERE |
|\n+--------------------------------------------+--------------------------------+\n|
WHILE |
|\n+--------------------------------------------+--------------------------------+\n|
WINDOW | Only disallowed for table
|\n| | aliases.
|\n+--------------------------------------------+--------------------------------+\n|
WITH |
|\n+--------------------------------------------+--------------------------------+\n|
WRITE |
|\n+--------------------------------------------+--------------------------------+\n|
XOR |
|\n+--------------------------------------------+--------------------------------+\n|
YEAR_MONTH |
|\n+--------------------------------------------+--------------------------------+\n|
ZEROFILL |
|\n+--------------------------------------------+--------------------------------+\n\nExceptions\n----------\n\nSome
keywords are exceptions for historical reasons, and are permitted
as\nunquoted identifiers. These
include:\n\n+-----------------------------------------------------------------------------+\n|
Keyword
|\n+-----------------------------------------------------------------------------+\n|
ACTION
|\n+-----------------------------------------------------------------------------+\n|
BIT
|\n+-----------------------------------------------------------------------------+\n|
DATE
|\n+-----------------------------------------------------------------------------+\n|
ENUM
|\n+-----------------------------------------------------------------------------+\n|
NO
|\n+-----------------------------------------------------------------------------+\n|
TEXT
|\n+-----------------------------------------------------------------------------+\n|
TIME
|\n+-----------------------------------------------------------------------------+\n|
TIMESTAMP
|\n+-----------------------------------------------------------------------------+\n\nOracle
Mode\n-----------\n\nIn Oracle mode, from MariaDB 10.3, there are a number
of extra reserved
words:\n\n+--------------------------------------------+--------------------------------+\n|
Keyword | Notes
|\n+--------------------------------------------+--------------------------------+\n|
BODY |
|\n+--------------------------------------------+--------------------------------+\n|
ELSIF |
|\n+--------------------------------------------+--------------------------------+\n|
GOTO |
|\n+--------------------------------------------+--------------------------------+\n|
HISTORY | <= MariaDB 10.3.6 only
|') WHERE help_topic_id = 479;
update help_topic set description = CONCAT(description,
'\n+--------------------------------------------+--------------------------------+\n|
MINUS | From MariaDB 10.6.1
|\n+--------------------------------------------+--------------------------------+\n|
OTHERS |
|\n+--------------------------------------------+--------------------------------+\n|
PACKAGE |
|\n+--------------------------------------------+--------------------------------+\n|
PERIOD | <= MariaDB 10.3.6 only
|\n+--------------------------------------------+--------------------------------+\n|
RAISE |
|\n+--------------------------------------------+--------------------------------+\n|
ROWNUM | From MariaDB 10.6.1
|\n+--------------------------------------------+--------------------------------+\n|
ROWTYPE |
|\n+--------------------------------------------+--------------------------------+\n|
SYSDATE | From MariaDB 10.6.1
|\n+--------------------------------------------+--------------------------------+\n|
SYSTEM | <= MariaDB 10.3.6 only.
Note |\n| | however that
SYSTEM sometimes |\n| | needs
to be quoted to avoid |\n| |
confusion with |\n|
| System-versioned tables.
|\n+--------------------------------------------+--------------------------------+\n|
SYSTEM_TIME | <= MariaDB 10.3.6 only
|\n+--------------------------------------------+--------------------------------+\n|
VERSIONING | <= MariaDB 10.3.6 only
|\n+--------------------------------------------+--------------------------------+\n|
WITHOUT | <= MariaDB 10.3.6 only
|\n+--------------------------------------------+--------------------------------+\n\nFunction
Names\n--------------\n\nIf the IGNORE_SPACE SQL_MODE flag is set, function
names become reserved words.\n\nURL:
https://mariadb.com/kb/en/reserved-words/') WHERE help_topic_id = 479;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(480,29,'String Literals','Strings are sequences of
characters and are enclosed with quotes.\n\nThe syntax
is:\n\n[_charset_name]\'string\' [COLLATE collation_name]\n\nFor
example:\n\n\'The MariaDB Foundation\'\n_utf8
\'Foundation\' COLLATE utf8_unicode_ci;\n\nStrings can either be
enclosed in single quotes or in double quotes (the same\ncharacter must be
used to both open and close the string).\n\nThe ANSI SQL-standard does not
permit double quotes for enclosing strings, and\nalthough MariaDB does by
default, if the MariaDB server has enabled the\nANSI_QUOTES_SQL SQL_MODE,
double quotes will be treated as being used for\nidentifiers instead of
strings.\n\nStrings that are next to each other are automatically
concatenated. For\nexample:\n\n\'The \' \'MariaDB \'
\'Foundation\'\n\nand\n\n\'The MariaDB
Foundation\'\n\nare equivalent.\n\nThe \\ (backslash character) is
used to escape characters (unless the SQL_MODE\nhasn\'t been set to
NO_BACKSLASH_ESCAPES). For example:\n\n\'MariaDB\'s new
features\'\n\nis not a valid string because of the single quote in the
middle of the string,\nwhich is treated as if it closes the string, but is
actually meant as part of\nthe string, an apostrophe. The backslash
character helps in situations like\nthis:\n\n\'MariaDB\\\'s new
features\'\n\nis now a valid string, and if displayed, will appear
without the backslash.\n\nSELECT \'MariaDB\\\'s new
features\';\n+------------------------+\n| MariaDB\'s new
features |\n+------------------------+\n| MariaDB\'s new features
|\n+------------------------+\n\nAnother way to escape the quoting
character is repeating it twice:\n\nSELECT \'I\'\'m
here\',
\"\"\"Double\"\"\";\n+----------+----------+\n|
I\'m here | \"Double\" |\n+----------+----------+\n|
I\'m here | \"Double\" |\n+----------+----------+\n\nEscape
Sequences\n----------------\n\nThere are other escape sequences also. Here
is a full
list:\n\n+-----------------------------------------------+-----------------------------+\n|
Escape sequence | Character
|\n+-----------------------------------------------+-----------------------------+\n|
\\0 | ASCII NUL (0x00).
|\n+-----------------------------------------------+-----------------------------+\n|
\\\' | Single quote
(\"\'\").
|\n+-----------------------------------------------+-----------------------------+\n|
\\\" | Double quote
(\"\"\").
|\n+-----------------------------------------------+-----------------------------+\n|
\\b | Backspace.
|\n+-----------------------------------------------+-----------------------------+\n|
\\n | Newline, or linefeed,.
|\n+-----------------------------------------------+-----------------------------+\n|
\\r | Carriage return.
|\n+-----------------------------------------------+-----------------------------+\n|
\\t | Tab.
|\n+-----------------------------------------------+-----------------------------+\n|
\\Z | ASCII 26 (Control+Z). See
|\n| | note following the
table.
|\n+-----------------------------------------------+-----------------------------+\n|
\\\\ | Backslash
(\"\\\").
|\n+-----------------------------------------------+-----------------------------+\n|
\\% | \"%\" character.
See note |\n| | following
the table.
|\n+-----------------------------------------------+-----------------------------+\n|
\\_ | A \"_\"
character. See note |\n| |
following the table.
|\n+-----------------------------------------------+-----------------------------+\n\nEscaping
the % and _ characters can be necessary when using the LIKE
operator,\nwhich treats them as special characters.\n\nThe ASCII 26
character (\\Z) needs to be escaped when included in a batch file\nwhich
needs to be executed in Windows. The reason is that ASCII 26, in\nWindows,
is the end of file (EOF).\n\nBackslash (\\), if not used as an escape
character, must always be escaped.\nWhen followed by a character that is
not in the above table, backslashes will\nsimply be ignored.\n\nURL:
https://mariadb.com/kb/en/string-literals/','','https://mariadb.com/kb/en/string-literals/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(481,29,'Table Value Constructors','MariaDB starting with
10.3.3\n----------------------------\nTable Value Constructors were
introduced in MariaDB 10.3.3\n\nSyntax\n------\n\nVALUES ( row_value[,
row_value...]), (...)...\n\nDescription\n-----------\n\nIn Unions, Views,
and sub-queries, a Table Value Constructor (TVC) allows you\nto inject
arbitrary values into the result-set. The given values must have the\nsame
number of columns as the result-set, otherwise it returns Error
1222.\n\nExamples\n--------\n\nUsing TVC\'s with UNION
operations:\n\nCREATE TABLE test.t1 (val1 INT, val2 INT);\nINSERT INTO
test.t1 VALUES(5, 8), (3, 4), (1, 2);\n\nSELECT * FROM
test.t1\nUNION\nVALUES (70, 90), (100, 110);\n\n+------+------+\n| val1 |
val2 |\n+------+------+\n| 5 | 8 | \n| 3 | 4 |\n| 1 | 2
|\n| 70 | 90 |\n| 100 | 110 |\n+------+------+\n\nUsing TVC\'s
with a CREATE VIEW statement:\n\nCREATE VIEW v1 AS VALUES (7, 9), (9,
10);\n\nSELECT * FROM v1;\n+---+----+\n| 7 | 9 |\n+---+----+\n| 7 | 9
|\n| 9 | 10 |\n+---+----+\n\nUsing TVC with an ORDER BY clause:\n\nSELECT *
FROM test.t1\nUNION\nVALUES (10, 20), (30, 40), (50, 60), (70, 80)\nORDER
BY val1 DESC;\n\nUsing TVC with LIMIT clause:\n\nSELECT * FROM
test.t1\nUNION\nVALUES (10, 20), (30, 40), (50, 60), (70, 80)\nLIMIT 2
OFFSET 4;\n\n+------+------+\n| val1 | val2 |\n+------+------+\n| 30 |
40 | \n| 50 | 60 |\n+------+------+\n\nURL:
https://mariadb.com/kb/en/table-value-constructors/','','https://mariadb.com/kb/en/table-value-constructors/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(482,29,'User-Defined Variables','User-defined variables are
variables which can be created by the user and\nexist in the session. This
means that no one can access user-defined variables\nthat have been set by
another user, and when the session is closed these\nvariables expire.
However, these variables can be shared between several\nqueries and stored
programs.\n\nUser-defined variables names must be preceded by a single at
character (@).\nWhile it is safe to use a reserved word as a user-variable
name, the only\nallowed characters are ASCII letters, digits, dollar sign
($), underscore (_)\nand dot (.). If other characters are used, the name
can be quoted in one of\nthe following ways:\n\n* @`var_name`\n*
@\'var_name\'\n* @\"var_name\"\n\nThese characters can
be escaped as usual.\n\nUser-variables names are case insensitive, though
they were case sensitive in\nMySQL 4.1 and older versions.\n\nUser-defined
variables cannot be declared. They can be read even if no value\nhas been
set yet; in that case, they are NULL. To set a value for a\nuser-defined
variable you can use:\n\n* SET statement;\n* := operator within a SQL
statement;\n* SELECT ... INTO.\n\nSince user-defined variables type cannot
be declared, the only way to force\ntheir type is using CAST() or
CONVERT():\n\nSET @str = CAST(123 AS CHAR(5));\n\nIf a variable has not
been used yet, its value is NULL:\n\nSELECT @x IS NULL;\n+------------+\n|
@x IS NULL |\n+------------+\n| 1 |\n+------------+\n\nIt is
unsafe to read a user-defined variable and set its value in the
same\nstatement (unless the command is SET), because the order of these
actions is\nundefined.\n\nUser-defined variables can be used in most
MariaDB\'s statements and clauses\nwhich accept an SQL expression.
However there are some exceptions, like the\nLIMIT clause.\n\nThey must be
used to PREPARE a prepared statement:\n\n@sql = \'DELETE FROM my_table
WHERE c>1;\';\nPREPARE stmt FROM @sql;\nEXECUTE stmt;\nDEALLOCATE
PREPARE stmt;\n\nAnother common use is to include a counter in a
query:\n\nSET @var = 0;\nSELECT a, b, c, (@var:=@var+1) AS counter FROM
my_table;\n\nInformation Schema\n------------------\n\nUser-defined
variables can be viewed in the Information Schema USER_VARIABLES\nTable (as
part of the User Variables plugin) from MariaDB 10.2.\n\nFlushing
User-Defined Variables\n-------------------------------\n\nUser-defined
variables are reset and the Information Schema table emptied with\nthe
FLUSH USER_VARIABLES statement.\n\nSET @str = CAST(123 AS
CHAR(5));\n\nSELECT * FROM information_schema.USER_VARIABLES ORDER BY
VARIABLE_NAME;\n+---------------+----------------+---------------+--------------------+\n|
VARIABLE_NAME | VARIABLE_VALUE | VARIABLE_TYPE | CHARACTER_SET_NAME
|\n+---------------+----------------+---------------+--------------------+\n|
str | 123 | VARCHAR | utf8mb3
|\n+---------------+----------------+---------------+--------------------+\n\nFLUSH
USER_VARIABLES;\n\nSELECT * FROM information_schema.USER_VARIABLES ORDER BY
VARIABLE_NAME;\nEmpty set (0.000 sec)\n\nURL:
https://mariadb.com/kb/en/user-defined-variables/','','https://mariadb.com/kb/en/user-defined-variables/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(483,29,'Delimiters','The default delimiter in the mysql
client (from MariaDB 10.4.6, also called\nmariadb) is the
semicolon.\n\nWhen creating stored programs from the command-line, it is
likely you will\nneed to differentiate between the regular delimiter and a
delimiter inside a\nBEGIN END block. To understand better, consider the
following example:\n\nCREATE FUNCTION FortyTwo() RETURNS TINYINT
DETERMINISTIC\nBEGIN\n DECLARE x TINYINT;\n SET x = 42;\n RETURN
x;\nEND;\n\nIf you enter the above line by line, the mysql client will
treat the first\nsemicolon, at the end of the DECLARE x TINYINT line, as
the end of the\nstatement. Since that\'s only a partial definition, it
will throw a syntax\nerror, as follows:\n\nCREATE FUNCTION FortyTwo()
RETURNS TINYINT DETERMINISTIC\nBEGIN\nDECLARE x TINYINT;\nERROR 1064
(42000): You have an error in your SQL syntax; \ncheck the manual that
corresponds to your MariaDB server version\n for the right syntax to use
near \'\' at line 3\n\nThe solution is to specify a distinct
delimiter for the duration of the\nprocess, using the DELIMITER command.
The delimiter can be any set of\ncharacters you choose, but it needs to be
a distinctive set of characters that\nwon\'t cause further confusion.
// is a common choice, and used throughout
the\nknowledgebase.\n\nHere\'s how the function could be successfully
entered from the mysql client\nwith the new delimiter.\n\nDELIMITER
//\n\nCREATE FUNCTION FortyTwo() RETURNS TINYINT DETERMINISTIC\nBEGIN\n
DECLARE x TINYINT;\n SET x = 42;\n RETURN x;\nEND\n\n//\n\nDELIMITER
;\n\nAt the end, the delimiter is restored to the default semicolon. The
\\g and \\G\ndelimiters can always be used, even when a custom delimiter is
specified.\n\nURL:
https://mariadb.com/kb/en/delimiters/','','https://mariadb.com/kb/en/delimiters/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(484,29,'SQL_MODE=ORACLE','From MariaDB 10.3, setting the
sql_mode system variable to Oracle allows the\nserver to understand a
subset of Oracle\'s PL/SQL language. For example:\n\nSET
SQL_MODE=\'ORACLE\';\n\nAll traditional MariaDB SQL/PSM syntax
should work as before, as long as it\ndoes not conflict with Oracle\'s
PL/SQL syntax. All MariaDB functions should be\nsupported in both normal
and Oracle modes.\n\nPrior to MariaDB 10.3, MariaDB does not support
Oracle\'s PL/SQL language, and\nSET SQL_MODE=ORACLE is only an alias
for the following sql_mode in those\nversions:\n\nSET
SQL_MODE=\'PIPES_AS_CONCAT, ANSI_QUOTES, IGNORE_SPACE,
NO_KEY_OPTIONS,\nNO_TABLE_OPTIONS, NO_FIELD_OPTIONS,
NO_AUTO_CREATE_USER\';\n\nFrom MariaDB 10.3, SET SQL_MODE=ORACLE is
same as:\n\nSET
SQL_MODE=\'PIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,ORACLE,NO_KEY_OPTIONS,\nNO_TABLE_OPTIONS,NO_FIELD_OPTIONS,NO_AUTO_CREATE_USER,SIMULTANEOUS_ASSIGNMENT\';\n\nSupported
Syntax in Oracle Mode\n-------------------------------\n\nStored Procedures
and Stored Functions\n--------------------------------------\n\nOracle mode
makes the following changes to Stored Procedures and
Stored\nFunctions:\n\n+-----------------------------------------+-----------------------------------+\n|
Oracle syntax | Description
|\n+-----------------------------------------+-----------------------------------+\n|
CREATE PROCEDURE p1 (param OUT INT) | ANSI uses (OUT param INT)
|\n+-----------------------------------------+-----------------------------------+\n|
CREATE PROCEDURE p1 (a IN OUT INT) | ANSI uses (INOUT param INT)
|\n+-----------------------------------------+-----------------------------------+\n|
AS before function body | CREATE FUNCTION f1 RETURN NUMBER
|\n| | AS BEGIN...
|\n+-----------------------------------------+-----------------------------------+\n|
IS before function body | CREATE FUNCTION f1 RETURN NUMBER
|\n| | IS BEGIN...
|\n+-----------------------------------------+-----------------------------------+\n|
If function has no parameters then | Example: CREATE PROCEDURE p1 AS
|\n| parentheses must be omitted | BEGIN NULL; END;
|\n+-----------------------------------------+-----------------------------------+\n|
CREATE PROCEDURE p1 AS BEGIN END p1; | Optional routine name after END
|\n| | keyword. MDEV-12089
|\n+-----------------------------------------+-----------------------------------+\n|
CREATE FUNCTION f1(a VARCHAR) | VARCHAR can be used without
|\n| | length for routine
parameters |\n| | and RETURN
clause. The length is |\n| |
inherited from the argument at |\n|
| call time. MDEV-10596
|\n+-----------------------------------------+-----------------------------------+\n|
CREATE AGGREGATE FUNCTION f1( ) | Creates an aggregate function,
|\n| | which performs the function
|\n| | against a set of rows
and |\n| | returns one
aggregate result.
|\n+-----------------------------------------+-----------------------------------+\n|
No CALL needed in Stored Procedures | In Oracle mode one can call
|\n| | other stored procedures with
|\n| | name only. MDEV-12107
|\n+-----------------------------------------+-----------------------------------+\n|
RETURN. Can also be used in stored | ANSI uses RETURNS. MariaDB mode
|\n| procedures | only supports RETURNS in
stored |\n| | functions
|\n+-----------------------------------------+-----------------------------------+\n\nCursors\n-------\n\nOracle
mode makes the following changes to
Cursors:\n\n+-----------------------------------------+-----------------------------------+\n|
Oracle syntax | Description
|\n+-----------------------------------------+-----------------------------------+\n|
CREATE PROCEDURE p1 AS CURSOR cur IS | Explicit cursor with FOR loop.
|\n| (SELECT a, b FROM t1); BEGIN FOR rec | MDEV-10581
|\n| IN cur ... |
|\n+-----------------------------------------+-----------------------------------+\n|
CREATE PROCEDURE p1 AS rec IN (SELECT | Implicit cursor with FOR loop.
|\n| a, b FROM t1) | MDEV-12098
|\n+-----------------------------------------+-----------------------------------+\n|
CURSOR c(prm_a VARCHAR2, prm_b | Cursor with parameters.
|\n| VARCHAR2) ... OPEN c(1,2) | MDEV-10597
|\n+-----------------------------------------+-----------------------------------+\n|
CURSOR c(prm_a VARCHAR2, prm_b | Cursor with parameters and FOR
|\n| VARCHAR2) ... FOR rec in c(1,2) | loop. MDEV-12314
|\n+-----------------------------------------+-----------------------------------+\n|
s %ISOPEN, %ROWCOUNT, %FOUND, %NOTFOUND | Explicit cursor attributes.
|\n| | MDEV-10582
|\n+-----------------------------------------+-----------------------------------+\n\nLOOP\n----\n\nOracle
mode makes the following changes to
LOOP:\n\n+-----------------------------------------+-----------------------------------+\n|
Oracle syntax | Description
|\n+-----------------------------------------+-----------------------------------+\n|
FOR i IN 1..10 LOOP ... END LOOP | Numeric FOR loop. MDEV-10580
|\n+-----------------------------------------+-----------------------------------+\n|
GOTO | GOTO statement. MDEV-10697
|\n+-----------------------------------------+-----------------------------------+\n|
<<label>> used with GOTO | ANSI uses label:.
MDEV-10697
|\n+-----------------------------------------+-----------------------------------+\n|
To leave loop block: EXIT [ label ] [ | ANSI syntax is IF bool_expr THEN
|\n| WHEN bool_expr ] | LEAVE label
|\n+-----------------------------------------+-----------------------------------+\n|
[<<label>>] WHILE boolean_expression | Oracle style WHILE
loop |\n| LOOP statement... END LOOP [ label ] ; |
|\n+-----------------------------------------+-----------------------------------+\n|
CONTINUE [ label ] [ WHEN | CONTINUE is only valid inside a
|\n| boolean_expression] | loop
|\n+-----------------------------------------+-----------------------------------+\n\nVariables\n---------\n\n+------------------------------+-----------------+--------------------------+\n|
Oracle syntax | Version | Description
|\n+------------------------------+-----------------+--------------------------+\n|
var:= 10; Can also be used | 10.3 | MariaDB uses SET var=
|\n| with MariaDB systemvariables | | 10;
|\n+------------------------------+-----------------+--------------------------+\n|
var INT := 10 | 10.3 | Default variable value
|\n+------------------------------+-----------------+--------------------------+\n|
var1 | 10.3 | Take data type from a
|\n| table_name.column_name%TYPE | | table column.
MDEV-10577
|\n+------------------------------+-----------------+--------------------------+\n|
var2 var1%TYPE | 10.3 | Take data type from
|\n| | | another variable
|\n+------------------------------+-----------------+--------------------------+\n|
rec1 table_name%ROWTYPE | 10.3 | Take ROW structure from
|\n| | | a table. MDEV-12133
|\n+------------------------------+-----------------+--------------------------+\n|
rec2 rec1%ROWTYPE | 10.3 | Take ROW structure from
|\n| | | ROW variable
|\n+------------------------------+-----------------+--------------------------+\n|
CURSOR c1 IS SELECT a,b | 10.3 | Take ROW structure from
|\n| FROM t1; rec1 c1%ROWTYPE; | | a cursor. MDEV-12011
|\n+------------------------------+-----------------+--------------------------+\n|
Variables can be declared | 10.3 | In MariaDB mode,
|\n| after cursor declarations | | variables must be
|\n| | | declared before
|\n| | | cursors.
MDEV-10598
|\n+------------------------------+-----------------+--------------------------+\n|
Triggers uses :NEW and :OLD | 10.3 | ANSI uses NEW and OLD.
|\n| | | MDEV-10579
|\n+------------------------------+-----------------+--------------------------+\n|
SQLCODE | 10.3 | Returns the number code
|\n| | | of the most recent
|\n| | | exception. Can
only be |\n| | | used in
Stored |\n| | |
Procedures. MDEV-10578
|\n+------------------------------+-----------------+--------------------------+\n|
SQLERRM | 10.3 | Returns the error
|\n| | | message associdated
to |\n| | | it\'s error
number |\n| | |
argument or SQLCODE if |\n| |
| no argument is given. |\n| |
| Can only be used in |\n| |
| Stored Procedures. |\n| |
| MDEV-10578
|\n+------------------------------+-----------------+--------------------------+\n|
SQL%ROWCOUNT | 10.3 | Almost same as
|\n| | | ROW_COUNT().
MDEV-10583
|\n+------------------------------+-----------------+--------------------------+\n|
ROWNUM | 10.6.1 | Returns number of
|\n| | | accepted rows
|\n+------------------------------+-----------------+--------------------------+\n\nExceptions\n----------\n\n+-----------------------------------------+-----------------------------------+\n|
Oracle syntax | Description
|\n+-----------------------------------------+-----------------------------------+\n|
BEGIN ... EXCEPTION WHEN OTHERS THEN | Exception handlers are declared
|\n| BEGIN .. END; END; | at the end of a block
|\n+-----------------------------------------+-----------------------------------+\n|
TOO_MANY_ROWS, NO_DATA_FOUND, | Predefined exceptions. MDEV-10839
|\n| DUP_VAL_ON_INDEX |
|\n+-----------------------------------------+-----------------------------------+\n|
RAISE TOO_MANY_ROWS ; .... EXCEPTION | Exception can be used with RAISE
|\n| WHEN TOO_MANY_ROWS THEN ... | and EXCEPTION...WHEN.
MDEV-10840
|\n+-----------------------------------------+-----------------------------------+\n|
CREATE OR REPLACE FUNCTION f1 (a INT) | User defined exceptions.
|\n| RETURN INT AS e1 EXCEPTION... | MDEV-10587
|\n+-----------------------------------------+-----------------------------------+\n\nBEGIN
Blocks\n------------\n\n+-----------------------------------------+-----------------------------------+\n|
Oracle syntax | Description
|\n+-----------------------------------------+-----------------------------------+\n|
BEGIN to start a block | MariaDB uses BEGIN NOT ATOMIC
|\n| | for anyonymous blocks.
MDEV-10655
|\n+-----------------------------------------+-----------------------------------+\n|
DECLARE is used before BEGIN | DECLARE a INT; b VARCHAR(10);
|\n| | BEGIN v:= 10; END;
|\n+-----------------------------------------+-----------------------------------+\n|
WHEN DUP_VAL_ON_INDEX THEN NULL ; | Do not require BEGIN..END in
|\n| NULL; WHEN OTHERS THEN NULL | multi-statement exception
|\n| | handlers in THEN
clause. |\n| | MDEV-12088
|\n+-----------------------------------------+-----------------------------------+\n\nSimple
Syntax
Compatibility\n---------------------------\n\n+------------------------------+-----------------+--------------------------+\n|
Oracle syntax | Version | Description
|\n+------------------------------+-----------------+--------------------------+\n|
ELSIF | 10.3 | ANSI uses ELSEIF
|\n+------------------------------+-----------------+--------------------------+\n|
SELECT UNIQUE | 10.3 | Same as SELECT
|\n| | | DISTINCT. MDEV-12086
|','','https://mariadb.com/kb/en/sql_modeoracle/');
update help_topic set description = CONCAT(description,
'\n+------------------------------+-----------------+--------------------------+\n|
TRUNCATE TABLE t1 [DROP | 10.3 | DROP STORAGE and REUSE
|\n| STORAGE] or [REUSE STORAGE] | | STORAGE are allowed
as |\n| | | optional
keywords for |\n| | |
TRUNCATE TABLE. |\n| |
| MDEV-10588
|\n+------------------------------+-----------------+--------------------------+\n|
Subqueries in a FROM clause | 10.6 | SELECT * FROM (SELECT 1
|\n| without an alias | | FROM DUAL), (SELECT 2
|\n| | | FROM DUAL)
|\n+------------------------------+-----------------+--------------------------+\n|
UNION, EXCEPT and INTERSECT | 10.3 | INTERSECT has higher
|\n| all have the same | | precedence than UNION
|\n| precedence. | | and EXCEPT in
|\n| | | non-Oracle
modes.
|\n+------------------------------+-----------------+--------------------------+\n|
MINUS | 10.6 | MINUS is a synonym for
|\n| | | EXCEPT.
|\n+------------------------------+-----------------+--------------------------+\n\nFunctions\n---------\n\n+------------------------------+-----------------+--------------------------+\n|
Oracle syntax | Version | Description
|\n+------------------------------+-----------------+--------------------------+\n|
ADD_MONTHS() | 10.6.1 | Added as a wrapper for
|\n| | | DATE_ADD() to enhance
|\n| | | Oracle
compatibility. |\n| | | All
modes.
|\n+------------------------------+-----------------+--------------------------+\n|
CAST(expr as VARCHAR(N)) | 10.3 | Cast expression to a
|\n| | | VARCHAR(N).
MDEV-11275
|\n+------------------------------+-----------------+--------------------------+\n|
DECODE | 10.3 | In Oracle mode,
|\n| | | compares and matches
|\n| | | search expressions
|\n+------------------------------+-----------------+--------------------------+\n|
LENGTH() is same as | 10.3 | MariaDB translates
|\n| CHAR_LENGTH() | | LENGTH() to
|\n| | | OCTET_LENGTH(). In
all |\n| | | modes one can
use |\n| | | LENGTHB()
as a synonym |\n| | | to
OCTET_LENGTH()
|\n+------------------------------+-----------------+--------------------------+\n|
CHR(num) | 10.3 | Returns a VARCHAR(1)
|\n| | | with character set
and |\n| | | collation
according to |\n| | |
@@character_set_database |\n| |
| and @@collation_database
|\n+------------------------------+-----------------+--------------------------+\n|
substr(\'abc\',0 ,3) same as | 10.3 | Position 0 for
substr() |\n| substr(\'abc\', 1 ,3) | |
is same as position 1
|\n+------------------------------+-----------------+--------------------------+\n|
SYS_GUID | 10.6.1 | Generates a globally
|\n| | | unique identifier.
|\n| | | Similar to UUID
but |\n| | | without the
-. All |\n| | | modes.
|\n+------------------------------+-----------------+--------------------------+\n|
TO_CHAR | 10.6.1 | Added to enhance Oracle
|\n| | | compatibility. All
|\n| | | modes.
|\n+------------------------------+-----------------+--------------------------+\n|
TRIM, LTRIM, RTRIM, LPAD | 10.3 | Returns NULL instead of
|\n| and RPAD | | an empty string if
|\n| | | returning an empty
|\n| | | result. These
functions |\n| | | can also
be accessed |\n| | |
outside of ORACLE mode |\n| |
| by suffixing _ORACLE |\n| |
| onto the end of the |\n| |
| function name, such as |\n| |
| TRIM_ORACLE.
|\n+------------------------------+-----------------+--------------------------+\n\nPrepared
Statements\n-------------------\n\nOracle mode makes the following changes
to Prepared
Statements:\n\n+-----------------------------------------+-----------------------------------+\n|
Oracle syntax | Description
|\n+-----------------------------------------+-----------------------------------+\n|
PREPARE stmt FROM \'SELECT :1, :2\' | ANSI uses ?.
MDEV-10801
|\n+-----------------------------------------+-----------------------------------+\n|
EXECUTE IMMEDIATE \'INSERT INTO t1 | Dynamic placeholders.
MDEV-10801 |\n| SELECT (:x,:y) FROM DUAL\' USING 10,20 |
|\n+-----------------------------------------+-----------------------------------+\n\nSynonyms
for Basic SQL
Types\n----------------------------\n\n+--------------------------------+-------------------------------------------+\n|
Oracle type | MariaDB synonym
|\n+--------------------------------+-------------------------------------------+\n|
VARCHAR2 | VARCHAR
|\n+--------------------------------+-------------------------------------------+\n|
NUMBER | DECIMAL
|\n+--------------------------------+-------------------------------------------+\n|
DATE (with time portion) | MariaDB DATETIME
|\n+--------------------------------+-------------------------------------------+\n|
RAW | VARBINARY
|\n+--------------------------------+-------------------------------------------+\n|
CLOB | LONGTEXT
|\n+--------------------------------+-------------------------------------------+\n|
BLOB | LONGBLOB
|\n+--------------------------------+-------------------------------------------+\n\nThis
was implemented as part of MDEV-10343.\n\nIf one does a SHOW CREATE TABLE
in ORACLE mode on a table that has a native\nMariaDB DATE column, it will
be displayed as mariadb_schema.date to not\nconflict with the Oracle DATE
type.\n\nPackages\n--------\n\nThe following syntax has been supported
since MariaDB 10.3.5:\n\n* CREATE PACKAGE\n* CREATE PACKAGE BODY\n* DROP
PACKAGE\n* DROP PACKAGE BODY\n* SHOW CREATE PACKAGE\n* SHOW CREATE PACKAGE
BODY\n\nNULL Handling\n-------------\n\nOracle mode makes the following
changes to NULL handling:\n\nNULL As a
Statement\n-------------------\n\nNULL can be used as a statement:\n\nIF
a=10 THEN NULL; ELSE NULL; END IF\n\nTranslating Empty String Literals to
NULL\n-----------------------------------------\n\nIn Oracle, empty string
(\'\') and NULL are the same thing,\n\nBy using
sql_mode=EMPTY_STRING_IS_NULL you can get a similar experience
in\nMariaDB:\n\nSET sql_mode=EMPTY_STRING_IS_NULL;\nSELECT \'\'
IS NULL; -- returns TRUE\nINSERT INTO t1 VALUES (\'\'); --
inserts NULL\n\nConcat Operator Ignores
NULL\n----------------------------\n\nCONCAT() and || ignore NULL in Oracle
mode. Can also be accessed outside of\nORACLE mode by using
CONCAT_OPERATOR_ORACLE. MDEV-11880 and MDEV-12143.\n\nReserved
Words\n--------------\n\nThere are a number of extra reserved words in
Oracle mode.\n\nSHOW CREATE TABLE\n-----------------\n\nThe SHOW CREATE
TABLE statement will not display MariaDB-specific table\noptions, such as
AUTO_INCREMENT or CHARSET, when Oracle mode is set.\n\nURL:
https://mariadb.com/kb/en/sql_modeoracle/') WHERE help_topic_id = 484;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(485,30,'CONTAINS','Syntax\n------\n\nContains(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether a geometry g1 completely contains geometry\ng2.
CONTAINS() is based on the original MySQL implementation and uses
object\nbounding rectangles, while ST_CONTAINS() uses object
shapes.\n\nThis tests the opposite relationship to Within().\n\nURL:
https://mariadb.com/kb/en/contains/','','https://mariadb.com/kb/en/contains/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(486,30,'CROSSES','Syntax\n------\n\nCrosses(g1,g2)\n\nDescription\n-----------\n\nReturns
1 if g1 spatially crosses g2. Returns NULL if g1 is a Polygon or
a\nMultiPolygon, or if g2 is a Point or a MultiPoint. Otherwise, returns
0.\n\nThe term spatially crosses denotes a spatial relation between two
given\ngeometries that has the following properties:\n\n* The two
geometries intersect\n* Their intersection results in a geometry that has a
dimension that is one\n less than the maximum dimension of the two given
geometries\n* Their intersection is not equal to either of the two given
geometries\n\nCROSSES() is based on the original MySQL implementation, and
uses object\nbounding rectangles, while ST_CROSSES() uses object
shapes.\n\nURL:
https://mariadb.com/kb/en/crosses/','','https://mariadb.com/kb/en/crosses/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(487,30,'DISJOINT','Syntax\n------\n\nDisjoint(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether g1 is spatially disjoint from (does
not\nintersect) g2.\n\nDISJOINT() tests the opposite relationship to
INTERSECTS().\n\nDISJOINT() is based on the original MySQL implementation
and uses object\nbounding rectangles, while ST_DISJOINT() uses object
shapes.\n\nURL:
https://mariadb.com/kb/en/disjoint/','','https://mariadb.com/kb/en/disjoint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(488,30,'EQUALS','Syntax\n------\n\nEquals(g1,g2)\n\nFrom
MariaDB 10.2.3:\n\nMBREQUALS(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether g1 is spatially equal to g2.\n\nEQUALS() is
based on the original MySQL implementation and uses object\nbounding
rectangles, while ST_EQUALS() uses object shapes.\n\nFrom MariaDB 10.2.3,
MBREQUALS is a synonym for Equals.\n\nURL:
https://mariadb.com/kb/en/equals/','','https://mariadb.com/kb/en/equals/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(489,30,'INTERSECTS','Syntax\n------\n\nINTERSECTS(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether geometry g1 spatially intersects
geometry\ng2.\n\nINTERSECTS() is based on the original MySQL implementation
and uses object\nbounding rectangles, while ST_INTERSECTS() uses object
shapes.\n\nINTERSECTS() tests the opposite relationship to
DISJOINT().\n\nURL:
https://mariadb.com/kb/en/intersects/','','https://mariadb.com/kb/en/intersects/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(490,30,'OVERLAPS','Syntax\n------\n\nOVERLAPS(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether g1 spatially overlaps g2. The term\nspatially
overlaps is used if two geometries intersect and their
intersection\nresults in a geometry of the same dimension but not equal to
either of the\ngiven geometries.\n\nOVERLAPS() is based on the original
MySQL implementation and uses object\nbounding rectangles, while
ST_OVERLAPS() uses object shapes.\n\nURL:
https://mariadb.com/kb/en/overlaps/','','https://mariadb.com/kb/en/overlaps/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(491,30,'ST_CONTAINS','Syntax\n------\n\nST_CONTAINS(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether a geometry g1 completely contains
geometry\ng2.\n\nST_CONTAINS() uses object shapes, while CONTAINS(), based
on the original\nMySQL implementation, uses object bounding
rectangles.\n\nST_CONTAINS tests the opposite relationship to
ST_WITHIN().\n\nExamples\n--------\n\nSET @g1 =
ST_GEOMFROMTEXT(\'POLYGON((175 150, 20 40, 50 60, 125 100,
175\n150))\');\n\nSET @g2 = ST_GEOMFROMTEXT(\'POINT(174
149)\');\n\nSELECT ST_CONTAINS(@g1,@g2);\n+----------------------+\n|
ST_CONTAINS(@g1,@g2) |\n+----------------------+\n| 1
|\n+----------------------+\n\nSET @g2 = ST_GEOMFROMTEXT(\'POINT(175
151)\');\n\nSELECT ST_CONTAINS(@g1,@g2);\n+----------------------+\n|
ST_CONTAINS(@g1,@g2) |\n+----------------------+\n| 0
|\n+----------------------+\n\nURL:
https://mariadb.com/kb/en/st-contains/','','https://mariadb.com/kb/en/st-contains/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(492,30,'ST_CROSSES','Syntax\n------\n\nST_CROSSES(g1,g2)\n\nDescription\n-----------\n\nReturns
1 if geometry g1 spatially crosses geometry g2. Returns NULL if g1 is\na
Polygon or a MultiPolygon, or if g2 is a Point or a MultiPoint.
Otherwise,\nreturns 0.\n\nThe term spatially crosses denotes a spatial
relation between two given\ngeometries that has the following
properties:\n\n* The two geometries intersect\n* Their intersection results
in a geometry that has a dimension that is one\n less than the maximum
dimension of the two given geometries\n* Their intersection is not equal to
either of the two given geometries\n\nST_CROSSES() uses object shapes,
while CROSSES(), based on the original MySQL\nimplementation, uses object
bounding rectangles.\n\nExamples\n--------\n\nSET @g1 =
ST_GEOMFROMTEXT(\'LINESTRING(174 149, 176 151)\');\n\nSET @g2 =
ST_GEOMFROMTEXT(\'POLYGON((175 150, 20 40, 50 60, 125 100,
175\n150))\');\n\nSELECT
ST_CROSSES(@g1,@g2);\n+---------------------+\n| ST_CROSSES(@g1,@g2)
|\n+---------------------+\n| 1
|\n+---------------------+\n\nSET @g1 =
ST_GEOMFROMTEXT(\'LINESTRING(176 149, 176 151)\');\n\nSELECT
ST_CROSSES(@g1,@g2);\n+---------------------+\n| ST_CROSSES(@g1,@g2)
|\n+---------------------+\n| 0
|\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/st-crosses/','','https://mariadb.com/kb/en/st-crosses/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(493,30,'ST_DIFFERENCE','Syntax\n------\n\nST_DIFFERENCE(g1,g2)\n\nDescription\n-----------\n\nReturns
a geometry representing the point set difference of the given
geometry\nvalues.\n\nExample\n-------\n\nSET @g1 = POINT(10,10), @g2 =
POINT(20,20);\n\nSELECT ST_AsText(ST_Difference(@g1,
@g2));\n+------------------------------------+\n|
ST_AsText(ST_Difference(@g1, @g2))
|\n+------------------------------------+\n| POINT(10 10)
|\n+------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_difference/','','https://mariadb.com/kb/en/st_difference/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(494,30,'ST_DISJOINT','Syntax\n------\n\nST_DISJOINT(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether geometry g1 is spatially disjoint from\n(does
not intersect with) geometry g2.\n\nST_DISJOINT() uses object shapes, while
DISJOINT(), based on the original\nMySQL implementation, uses object
bounding rectangles.\n\nST_DISJOINT() tests the opposite relationship to
ST_INTERSECTS().\n\nExamples\n--------\n\nSET @g1 =
ST_GEOMFROMTEXT(\'POINT(0 0)\');\n\nSET @g2 =
ST_GEOMFROMTEXT(\'LINESTRING(2 0, 0 2)\');\n\nSELECT
ST_DISJOINT(@g1,@g2);\n+----------------------+\n| ST_DISJOINT(@g1,@g2)
|\n+----------------------+\n| 1
|\n+----------------------+\n\nSET @g2 =
ST_GEOMFROMTEXT(\'LINESTRING(0 0, 0 2)\');\n\nSELECT
ST_DISJOINT(@g1,@g2);\n+----------------------+\n| ST_DISJOINT(@g1,@g2)
|\n+----------------------+\n| 0
|\n+----------------------+\n\nURL:
https://mariadb.com/kb/en/st_disjoint/','','https://mariadb.com/kb/en/st_disjoint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(495,30,'ST_DISTANCE','Syntax\n------\n\nST_DISTANCE(g1,g2)\n\nDescription\n-----------\n\nReturns
the distance between two geometries, or null if not given valid
inputs.\n\nExample\n-------\n\nSELECT
ST_Distance(POINT(1,2),POINT(2,2));\n+------------------------------------+\n|
ST_Distance(POINT(1,2),POINT(2,2))
|\n+------------------------------------+\n|
1 |\n+------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_distance/','','https://mariadb.com/kb/en/st_distance/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(496,30,'ST_DISTANCE_SPHERE','MariaDB starting with
10.2.38\n-----------------------------\nST_DISTANCE_SPHERE was introduced
in MariaDB 10.2.38, MariaDB 10.3.29, MariaDB\n10.4.19 and MariaDB
10.5.10.\n\nSyntax\n------\n\nST_DISTANCE_SPHERE(g1,g2,[r])\n\nDescription\n-----------\n\nReturns
the spherical distance between two geometries (point or multipoint) on\na
sphere with the optional radius r (default is the Earth radius if r is
not\nspecified), or NULL if not given valid
inputs.\n\nExample\n-------\n\nset @zenica =
ST_GeomFromText(\'POINT(17.907743 44.203438)\');\nset @sarajevo =
ST_GeomFromText(\'POINT(18.413076 43.856258)\');\nSELECT
ST_Distance_Sphere(@zenica, @sarajevo);\n55878.59337591705\n\nURL:
https://mariadb.com/kb/en/st_distance_sphere/','','https://mariadb.com/kb/en/st_distance_sphere/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(497,30,'ST_EQUALS','Syntax\n------\n\nST_EQUALS(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether geometry g1 is spatially equal to
geometry\ng2.\n\nST_EQUALS() uses object shapes, while EQUALS(), based on
the original MySQL\nimplementation, uses object bounding
rectangles.\n\nExamples\n--------\n\nSET @g1 =
ST_GEOMFROMTEXT(\'LINESTRING(174 149, 176 151)\');\n\nSET @g2 =
ST_GEOMFROMTEXT(\'LINESTRING(176 151, 174 149)\');\n\nSELECT
ST_EQUALS(@g1,@g2);\n+--------------------+\n| ST_EQUALS(@g1,@g2)
|\n+--------------------+\n| 1
|\n+--------------------+\n\nSET @g1 = ST_GEOMFROMTEXT(\'POINT(0
2)\');\n\nSET @g1 = ST_GEOMFROMTEXT(\'POINT(2
0)\');\n\nSELECT ST_EQUALS(@g1,@g2);\n+--------------------+\n|
ST_EQUALS(@g1,@g2) |\n+--------------------+\n| 0
|\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/st-equals/','','https://mariadb.com/kb/en/st-equals/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(498,30,'ST_INTERSECTS','Syntax\n------\n\nST_INTERSECTS(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether geometry g1 spatially intersects
geometry\ng2.\n\nST_INTERSECTS() uses object shapes, while INTERSECTS(),
based on the original\nMySQL implementation, uses object bounding
rectangles.\n\nST_INTERSECTS() tests the opposite relationship to
ST_DISJOINT().\n\nExamples\n--------\n\nSET @g1 =
ST_GEOMFROMTEXT(\'POINT(0 0)\');\n\nSET @g2 =
ST_GEOMFROMTEXT(\'LINESTRING(0 0, 0 2)\');\n\nSELECT
ST_INTERSECTS(@g1,@g2);\n+------------------------+\n|
ST_INTERSECTS(@g1,@g2) |\n+------------------------+\n|
1 |\n+------------------------+\n\nSET @g2 =
ST_GEOMFROMTEXT(\'LINESTRING(2 0, 0 2)\');\n\nSELECT
ST_INTERSECTS(@g1,@g2);\n+------------------------+\n|
ST_INTERSECTS(@g1,@g2) |\n+------------------------+\n|
0 |\n+------------------------+\n\nURL:
https://mariadb.com/kb/en/st-intersects/','','https://mariadb.com/kb/en/st-intersects/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(499,30,'ST_LENGTH','Syntax\n------\n\nST_LENGTH(ls)\n\nDescription\n-----------\n\nReturns
as a double-precision number the length of the LineString value ls in\nits
associated spatial reference.\n\nExamples\n--------\n\nSET @ls =
\'LineString(1 1,2 2,3 3)\';\n\nSELECT
ST_LENGTH(ST_GeomFromText(@ls));\n+---------------------------------+\n|
ST_LENGTH(ST_GeomFromText(@ls)) |\n+---------------------------------+\n|
2.82842712474619
|\n+---------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_length/','','https://mariadb.com/kb/en/st_length/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(500,30,'ST_OVERLAPS','Syntax\n------\n\nST_OVERLAPS(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether geometry g1 spatially overlaps geometry
g2.\n\nThe term spatially overlaps is used if two geometries intersect and
their\nintersection results in a geometry of the same dimension but not
equal to\neither of the given geometries.\n\nST_OVERLAPS() uses object
shapes, while OVERLAPS(), based on the original\nMySQL implementation, uses
object bounding rectangles.\n\nURL:
https://mariadb.com/kb/en/st-overlaps/','','https://mariadb.com/kb/en/st-overlaps/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(501,30,'ST_TOUCHES','Syntax\n------\n\nST_TOUCHES(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether geometry g1 spatially touches geometry g2.\nTwo
geometries spatially touch if the interiors of the geometries do
not\nintersect, but the boundary of one of the geometries intersects either
the\nboundary or the interior of the other.\n\nST_TOUCHES() uses object
shapes, while TOUCHES(), based on the original MySQL\nimplementation, uses
object bounding rectangles.\n\nExamples\n--------\n\nSET @g1 =
ST_GEOMFROMTEXT(\'POINT(2 0)\');\n\nSET @g2 =
ST_GEOMFROMTEXT(\'LINESTRING(2 0, 0 2)\');\n\nSELECT
ST_TOUCHES(@g1,@g2);\n+---------------------+\n| ST_TOUCHES(@g1,@g2)
|\n+---------------------+\n| 1
|\n+---------------------+\n\nSET @g1 = ST_GEOMFROMTEXT(\'POINT(2
1)\');\n\nSELECT ST_TOUCHES(@g1,@g2);\n+---------------------+\n|
ST_TOUCHES(@g1,@g2) |\n+---------------------+\n| 0
|\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/st-touches/','','https://mariadb.com/kb/en/st-touches/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(502,30,'ST_WITHIN','Syntax\n------\n\nST_WITHIN(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether geometry g1 is spatially within geometry
g2.\n\nThis tests the opposite relationship as
ST_CONTAINS().\n\nST_WITHIN() uses object shapes, while WITHIN(), based on
the original MySQL\nimplementation, uses object bounding
rectangles.\n\nExamples\n--------\n\nSET @g1 =
ST_GEOMFROMTEXT(\'POINT(174 149)\');\n\nSET @g2 =
ST_GEOMFROMTEXT(\'POLYGON((175 150, 20 40, 50 60, 125 100,
175\n150))\');\n\nSELECT
ST_WITHIN(@g1,@g2);\n+--------------------+\n| ST_WITHIN(@g1,@g2)
|\n+--------------------+\n| 1
|\n+--------------------+\n\nSET @g1 = ST_GEOMFROMTEXT(\'POINT(176
151)\');\n\nSELECT ST_WITHIN(@g1,@g2);\n+--------------------+\n|
ST_WITHIN(@g1,@g2) |\n+--------------------+\n| 0
|\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/st-within/','','https://mariadb.com/kb/en/st-within/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(503,30,'TOUCHES','Syntax\n------\n\nTouches(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether g1 spatially touches g2. Two
geometries\nspatially touch if the interiors of the geometries do not
intersect, but the\nboundary of one of the geometries intersects either the
boundary or the\ninterior of the other.\n\nTOUCHES() is based on the
original MySQL implementation and uses object\nbounding rectangles, while
ST_TOUCHES() uses object shapes.\n\nURL:
https://mariadb.com/kb/en/touches/','','https://mariadb.com/kb/en/touches/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(504,30,'WITHIN','Syntax\n------\n\nWithin(g1,g2)\n\nDescription\n-----------\n\nReturns
1 or 0 to indicate whether g1 is spatially within g2. This tests
the\nopposite relationship as Contains().\n\nWITHIN() is based on the
original MySQL implementation, and uses object\nbounding rectangles, while
ST_WITHIN() uses object shapes.\n\nExamples\n--------\n\nSET @g1 =
GEOMFROMTEXT(\'POINT(174 149)\');\nSET @g2 =
GEOMFROMTEXT(\'POINT(176 151)\');\nSET @g3 =
GEOMFROMTEXT(\'POLYGON((175 150, 20 40, 50 60, 125 100, 175
150))\');\n\nSELECT within(@g1,@g3);\n+-----------------+\n|
within(@g1,@g3) |\n+-----------------+\n| 1
|\n+-----------------+\n\nSELECT within(@g2,@g3);\n+-----------------+\n|
within(@g2,@g3) |\n+-----------------+\n| 0
|\n+-----------------+\n\nURL:
https://mariadb.com/kb/en/within/','','https://mariadb.com/kb/en/within/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(505,31,'Microseconds in MariaDB','The TIME, DATETIME, and
TIMESTAMP types, along with the temporal functions,\nCAST and dynamic
columns, support microseconds. The datetime precision of a\ncolumn can be
specified when creating the table with CREATE TABLE, for example:\n\nCREATE
TABLE example(\n col_microsec DATETIME(6),\n col_millisec
TIME(3)\n);\n\nGenerally, the precision can be specified for any TIME,
DATETIME, or TIMESTAMP\ncolumn, in parentheses, after the type name. The
datetime precision specifies\nnumber of digits after the decimal dot and
can be any integer number from 0 to\n6. If no precision is specified it is
assumed to be 0, for backward\ncompatibility reasons.\n\nA datetime
precision can be specified wherever a type name is used. For\nexample:\n\n*
when declaring arguments of stored routines.\n* when specifying a return
type of a stored function.\n* when declaring variables.\n* in a CAST
function:create function example(x datetime(5)) returns time(4)\nbegin\n
declare y timestamp(6);\n return cast(x as time(2));\nend;\n\n%f is used as
the formatting option for microseconds in the STR_TO_DATE,\nDATE_FORMAT and
FROM_UNIXTIME functions, for example:\n\nSELECT STR_TO_DATE(\'20200809
020917076\',\'%Y%m%d
%H%i%s%f\');\n+-----------------------------------------------------+\n|
STR_TO_DATE(\'20200809 020917076\',\'%Y%m%d %H%i%s%f\')
|\n+-----------------------------------------------------+\n| 2020-08-09
02:09:17.076000
|\n+-----------------------------------------------------+\n\nAdditional
Information\n----------------------\n\n* when comparing anything to a
temporal value (DATETIME, TIME, DATE, or\nTIMESTAMP), both values are
compared as temporal values, not as strings.\n* The
INFORMATION_SCHEMA.COLUMNS table has a new column DATETIME_PRECISION\n*
NOW(), CURTIME(), UTC_TIMESTAMP(), UTC_TIME(),
CURRENT_TIME(),\nCURRENT_TIMESTAMP(), LOCALTIME() and LOCALTIMESTAMP() now
accept datetime\nprecision as an optional argument. For example:SELECT
CURTIME(4);\n--> 10:11:12.3456\n\n* TIME_TO_SEC() and UNIX_TIMESTAMP()
preserve microseconds of the argument.\nThese functions will return a
decimal number if the result non-zero datetime\nprecision and an integer
otherwise (for backward
compatibility).SELECT\nTIME_TO_SEC(\'10:10:10.12345\');\n-->
36610.12345\n\n* Current versions of this patch fix a bug in the following
optimization: in\n certain queries with DISTINCT MariaDB can ignore this
clause if it can\n prove that all result rows are unique anyway, for
example, when a primary key\n is compared with a constant. Sometimes this
optimization was applied\n incorrectly, though — for example, when
comparing a\n string with a date constant. This is now fixed.\n* DATE_ADD()
and DATE_SUB() functions can now take a TIME\n expression as an argument
(not just DATETIME as before).SELECT\nTIME(\'10:10:10\') +
INTERVAL 100 MICROSECOND;\n--> 10:10:10.000100\n\n* The event_time field
in the mysql.general_log table and the start_time,\nquery_time, and
lock_time fields in the mysql.slow_log table now store values\nwith
microsecond precision.\n* This patch fixed a bug when comparing a temporal
value using the BETWEEN\noperator and one of the operands is NULL.\n* The
old syntax TIMESTAMP(N), where N is the display width, is no
longer\nsupported. It was deprecated in MySQL 4.1.0 (released on\n
2003-04-03).\n* when a DATETIME value is compared to a TIME value, the
latter is treated as\na full datetime with a zero date part, similar to
comparing DATE to a\nDATETIME, or to comparing DECIMAL numbers.\n Earlier
versions of MariaDB used to compare only the time part of both\noperands in
such a case.\n* In MariaDB, an extra column TIME_MS has been added to
the\nINFORMATION_SCHEMA.PROCESSLIST table, as well as to the output of SHOW
FULL\nPROCESSLIST.\n\nNote: When you convert a temporal value to a value
with a smaller precision,\nit will be truncated, not rounded. This is done
to guarantee that the date\npart is not changed. For example:\n\nSELECT
CAST(\'2009-12-31 23:59:59.998877\' as DATETIME(3));\n->
2009-12-31 23:59:59.998\n\nMySQL 5.6
Microseconds\n----------------------\n\nMySQL 5.6 introduced microseconds
using a slightly different implementation to\nMariaDB 5.3. Since MariaDB
10.1, MariaDB has defaulted to the MySQL format, by\nmeans of the
--mysql56-temporal-format variable. The MySQL version requires\nslightly
more storage but has some advantages in permitting the eventual\nsupport of
negative dates, and in replication.\n\nURL:
https://mariadb.com/kb/en/microseconds-in-mariadb/','','https://mariadb.com/kb/en/microseconds-in-mariadb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(506,31,'Date and Time Units','The INTERVAL keyword can be
used to add or subtract a time interval of time to\na DATETIME, DATE or
TIME value.\n\nThe syntax is:\n\nINTERVAL time_quantity time_unit\n\nFor
example, the SECOND unit is used below by the DATE_ADD()
function:\n\nSELECT \'2008-12-31 23:59:59\' + INTERVAL 1
SECOND;\n+-------------------------------------------+\n| \'2008-12-31
23:59:59\' + INTERVAL 1 SECOND
|\n+-------------------------------------------+\n| 2009-01-01 00:00:00
|\n+-------------------------------------------+\n\nThe
following units are
valid:\n\n+---------------------+------------------------------------------------------+\n|
Unit | Description
|\n+---------------------+------------------------------------------------------+\n|
MICROSECOND | Microseconds
|\n+---------------------+------------------------------------------------------+\n|
SECOND | Seconds
|\n+---------------------+------------------------------------------------------+\n|
MINUTE | Minutes
|\n+---------------------+------------------------------------------------------+\n|
HOUR | Hours
|\n+---------------------+------------------------------------------------------+\n|
DAY | Days
|\n+---------------------+------------------------------------------------------+\n|
WEEK | Weeks
|\n+---------------------+------------------------------------------------------+\n|
MONTH | Months
|\n+---------------------+------------------------------------------------------+\n|
QUARTER | Quarters
|\n+---------------------+------------------------------------------------------+\n|
YEAR | Years
|\n+---------------------+------------------------------------------------------+\n|
SECOND_MICROSECOND | Seconds.Microseconds
|\n+---------------------+------------------------------------------------------+\n|
MINUTE_MICROSECOND | Minutes.Seconds.Microseconds
|\n+---------------------+------------------------------------------------------+\n|
MINUTE_SECOND | Minutes.Seconds
|\n+---------------------+------------------------------------------------------+\n|
HOUR_MICROSECOND | Hours.Minutes.Seconds.Microseconds
|\n+---------------------+------------------------------------------------------+\n|
HOUR_SECOND | Hours.Minutes.Seconds
|\n+---------------------+------------------------------------------------------+\n|
HOUR_MINUTE | Hours.Minutes
|\n+---------------------+------------------------------------------------------+\n|
DAY_MICROSECOND | Days Hours.Minutes.Seconds.Microseconds
|\n+---------------------+------------------------------------------------------+\n|
DAY_SECOND | Days Hours.Minutes.Seconds
|\n+---------------------+------------------------------------------------------+\n|
DAY_MINUTE | Days Hours.Minutes
|\n+---------------------+------------------------------------------------------+\n|
DAY_HOUR | Days Hours
|\n+---------------------+------------------------------------------------------+\n|
YEAR_MONTH | Years-Months
|\n+---------------------+------------------------------------------------------+\n\nThe
time units containing an underscore are composite; that is, they
consist\nof multiple base time units. For base time units, time_quantity is
an integer\nnumber. For composite units, the quantity must be expressed as
a string with\nmultiple integer numbers separated by any punctuation
character.\n\nExample of composite units:\n\nINTERVAL \'2:2\'
YEAR_MONTH\nINTERVAL \'1:30:30\' HOUR_SECOND\nINTERVAL
\'1!30!30\' HOUR_SECOND -- same as above\n\nTime units can be
used in the following contexts:\n\n* after a + or a - operator;\n* with the
following DATE or TIME functions: ADDDATE(), SUBDATE(),
DATE_ADD(),\nDATE_SUB(), TIMESTAMPADD(), TIMESTAMPDIFF(), EXTRACT();\n* in
the ON SCHEDULE clause of CREATE EVENT and ALTER EVENT.\n* when defining a
partitioning BY SYSTEM_TIME\n\nURL:
https://mariadb.com/kb/en/date-and-time-units/','','https://mariadb.com/kb/en/date-and-time-units/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(507,31,'ADD_MONTHS','MariaDB starting with
10.6.1\n----------------------------\nThe ADD_MONTHS function was
introduced in MariaDB 10.6.1 to enhance Oracle\ncompatibility. Similar
functionality can be achieved with the
DATE_ADD\nfunction.\n\nSyntax\n------\n\nADD_MONTHS(date,
months)\n\nDescription\n-----------\n\nADD_MONTHS adds an integer months to
a given date (DATE, DATETIME or\nTIMESTAMP), returning the resulting
date.\n\nmonths can be positive or negative.\n\nThe resulting day component
will remain the same as that specified in date,\nunless the resulting month
has fewer days than the day component of the given\ndate, in which case the
day will be the last day of the resulting month.\n\nReturns NULL if given
an invalid date, or a NULL argument.\n\nExamples\n--------\n\nSELECT
ADD_MONTHS(\'2012-01-31\',
2);\n+-----------------------------+\n|
ADD_MONTHS(\'2012-01-31\', 2)
|\n+-----------------------------+\n| 2012-03-31
|\n+-----------------------------+\n\nSELECT
ADD_MONTHS(\'2012-01-31\',
-5);\n+------------------------------+\n|
ADD_MONTHS(\'2012-01-31\', -5)
|\n+------------------------------+\n| 2011-08-31
|\n+------------------------------+\n\nSELECT
ADD_MONTHS(\'2011-01-31\',
1);\n+-----------------------------+\n|
ADD_MONTHS(\'2011-01-31\', 1)
|\n+-----------------------------+\n| 2011-02-28
|\n+-----------------------------+\n\nSELECT
ADD_MONTHS(\'2012-01-31\',
1);\n+-----------------------------+\n|
ADD_MONTHS(\'2012-01-31\', 1)
|\n+-----------------------------+\n| 2012-02-29
|\n+-----------------------------+\n\nSELECT
ADD_MONTHS(\'2012-01-31\',
2);\n+-----------------------------+\n|
ADD_MONTHS(\'2012-01-31\', 2)
|\n+-----------------------------+\n| 2012-03-31
|\n+-----------------------------+\n\nSELECT
ADD_MONTHS(\'2012-01-31\',
3);\n+-----------------------------+\n|
ADD_MONTHS(\'2012-01-31\', 3)
|\n+-----------------------------+\n| 2012-04-30
|\n+-----------------------------+\n\nURL:
https://mariadb.com/kb/en/add_months/','','https://mariadb.com/kb/en/add_months/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(508,31,'ADDDATE','Syntax\n------\n\nADDDATE(date,INTERVAL
expr unit), ADDDATE(expr,days)\n\nDescription\n-----------\n\nWhen invoked
with the INTERVAL form of the second argument, ADDDATE() is a\nsynonym for
DATE_ADD(). The related function SUBDATE() is a synonym for\nDATE_SUB().
For information on the INTERVAL unit argument, see the discussion\nfor
DATE_ADD().\n\nWhen invoked with the days form of the second argument,
MariaDB treats it as\nan integer number of days to be added to
expr.\n\nExamples\n--------\n\nSELECT DATE_ADD(\'2008-01-02\',
INTERVAL 31 DAY);\n+-----------------------------------------+\n|
DATE_ADD(\'2008-01-02\', INTERVAL 31 DAY)
|\n+-----------------------------------------+\n| 2008-02-02
|\n+-----------------------------------------+\n\nSELECT
ADDDATE(\'2008-01-02\', INTERVAL 31
DAY);\n+----------------------------------------+\n|
ADDDATE(\'2008-01-02\', INTERVAL 31 DAY)
|\n+----------------------------------------+\n| 2008-02-02
|\n+----------------------------------------+\n\nSELECT
ADDDATE(\'2008-01-02\', 31);\n+---------------------------+\n|
ADDDATE(\'2008-01-02\', 31) |\n+---------------------------+\n|
2008-02-02 |\n+---------------------------+\n\nCREATE TABLE
t1 (d DATETIME);\nINSERT INTO t1 VALUES\n (\"2007-01-30
21:31:07\"),\n (\"1983-10-15 06:42:51\"),\n
(\"2011-04-21 12:34:56\"),\n (\"2011-10-30
06:31:41\"),\n (\"2011-01-30 14:03:25\"),\n
(\"2004-10-07 11:19:34\");\n\nSELECT d, ADDDATE(d, 10) from
t1;\n+---------------------+---------------------+\n| d |
ADDDATE(d, 10) |\n+---------------------+---------------------+\n|
2007-01-30 21:31:07 | 2007-02-09 21:31:07 |\n| 1983-10-15 06:42:51 |
1983-10-25 06:42:51 |\n| 2011-04-21 12:34:56 | 2011-05-01 12:34:56 |\n|
2011-10-30 06:31:41 | 2011-11-09 06:31:41 |\n| 2011-01-30 14:03:25 |
2011-02-09 14:03:25 |\n| 2004-10-07 11:19:34 | 2004-10-17 11:19:34
|\n+---------------------+---------------------+\n\nSELECT d, ADDDATE(d,
INTERVAL 10 HOUR) from
t1;\n+---------------------+------------------------------+\n| d
| ADDDATE(d, INTERVAL 10 HOUR)
|\n+---------------------+------------------------------+\n| 2007-01-30
21:31:07 | 2007-01-31 07:31:07 |\n| 1983-10-15 06:42:51 |
1983-10-15 16:42:51 |\n| 2011-04-21 12:34:56 | 2011-04-21 22:34:56
|\n| 2011-10-30 06:31:41 | 2011-10-30 16:31:41 |\n|
2011-01-30 14:03:25 | 2011-01-31 00:03:25 |\n| 2004-10-07 11:19:34
| 2004-10-07 21:19:34
|\n+---------------------+------------------------------+\n\nURL:
https://mariadb.com/kb/en/adddate/','','https://mariadb.com/kb/en/adddate/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(509,31,'ADDTIME','Syntax\n------\n\nADDTIME(expr1,expr2)\n\nDescription\n-----------\n\nADDTIME()
adds expr2 to expr1 and returns the result. expr1 is a time or\ndatetime
expression, and expr2 is a time expression.\n\nExamples\n--------\n\nSELECT
ADDTIME(\'2007-12-31 23:59:59.999999\', \'1
1:1:1.000002\');\n+---------------------------------------------------------+\n|
ADDTIME(\'2007-12-31 23:59:59.999999\', \'1
1:1:1.000002\')
|\n+---------------------------------------------------------+\n|
2008-01-02 01:01:01.000001
|\n+---------------------------------------------------------+\n\nSELECT
ADDTIME(\'01:00:00.999999\',
\'02:00:00.999998\');\n+-----------------------------------------------+\n|
ADDTIME(\'01:00:00.999999\', \'02:00:00.999998\')
|\n+-----------------------------------------------+\n| 03:00:01.999997
|\n+-----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/addtime/','','https://mariadb.com/kb/en/addtime/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(510,31,'CONVERT_TZ','Syntax\n------\n\nCONVERT_TZ(dt,from_tz,to_tz)\n\nDescription\n-----------\n\nCONVERT_TZ()
converts a datetime value dt from the time zone given by from_tz\nto the
time zone given by to_tz and returns the resulting value.\n\nIn order to
use named time zones, such as GMT, MET or Africa/Johannesburg,
the\ntime_zone tables must be loaded (see mysql_tzinfo_to_sql).\n\nNo
conversion will take place if the value falls outside of the
supported\nTIMESTAMP range (\'1970-01-01 00:00:01\' to
\'2038-01-19 05:14:07\' UTC) when\nconverted from from_tz to
UTC.\n\nThis function returns NULL if the arguments are invalid (or named
time zones\nhave not been loaded).\n\nSee time zones for more
information.\n\nExamples\n--------\n\nSELECT CONVERT_TZ(\'2016-01-01
12:00:00\',\'+00:00\',\'+10:00\');\n+-----------------------------------------------------+\n|
CONVERT_TZ(\'2016-01-01
12:00:00\',\'+00:00\',\'+10:00\')
|\n+-----------------------------------------------------+\n| 2016-01-01
22:00:00
|\n+-----------------------------------------------------+\n\nUsing named
time zones (with the time zone tables loaded):\n\nSELECT
CONVERT_TZ(\'2016-01-01
12:00:00\',\'GMT\',\'Africa/Johannesburg\');\n+---------------------------------------------------------------+\n|
CONVERT_TZ(\'2016-01-01
12:00:00\',\'GMT\',\'Africa/Johannesburg\')
|\n+---------------------------------------------------------------+\n|
2016-01-01 14:00:00
|\n+---------------------------------------------------------------+\n\nThe
value is out of the TIMESTAMP range, so no conversion takes
place:\n\nSELECT CONVERT_TZ(\'1969-12-31
22:00:00\',\'+00:00\',\'+10:00\');\n+-----------------------------------------------------+\n|
CONVERT_TZ(\'1969-12-31
22:00:00\',\'+00:00\',\'+10:00\')
|\n+-----------------------------------------------------+\n| 1969-12-31
22:00:00
|\n+-----------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/convert_tz/','','https://mariadb.com/kb/en/convert_tz/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(511,31,'CURDATE','Syntax\n------\n\nCURDATE()\nCURRENT_DATE\nCURRENT_DATE()\n\nDescription\n-----------\n\nCURDATE
returns the current date as a value in \'YYYY-MM-DD\' or
YYYYMMDD\nformat, depending on whether the function is used in a string or
numeric\ncontext.\n\nCURRENT_DATE and CURRENT_DATE() are
synonyms.\n\nExamples\n--------\n\nSELECT CURDATE();\n+------------+\n|
CURDATE() |\n+------------+\n| 2019-03-05 |\n+------------+\n\nIn a
numeric context (note this is not performing date calculations):\n\nSELECT
CURDATE() +0;\n+--------------+\n| CURDATE() +0 |\n+--------------+\n|
20190305 |\n+--------------+\n\nData calculation:\n\nSELECT CURDATE() -
INTERVAL 5 DAY;\n+----------------------------+\n| CURDATE() - INTERVAL 5
DAY |\n+----------------------------+\n| 2019-02-28
|\n+----------------------------+\n\nURL:
https://mariadb.com/kb/en/curdate/','','https://mariadb.com/kb/en/curdate/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(512,31,'CURRENT_DATE','Syntax\n------\n\nCURRENT_DATE,
CURRENT_DATE()\n\nDescription\n-----------\n\nCURRENT_DATE and
CURRENT_DATE() are synonyms for CURDATE().\n\nURL:
https://mariadb.com/kb/en/current_date/','','https://mariadb.com/kb/en/current_date/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(513,31,'CURRENT_TIME','Syntax\n------\n\nCURRENT_TIME\nCURRENT_TIME([precision])\n\nDescription\n-----------\n\nCURRENT_TIME
and CURRENT_TIME() are synonyms for CURTIME().\n\nURL:
https://mariadb.com/kb/en/current_time/','','https://mariadb.com/kb/en/current_time/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(514,31,'CURRENT_TIMESTAMP','Syntax\n------\n\nCURRENT_TIMESTAMP\nCURRENT_TIMESTAMP([precision])\n\nDescription\n-----------\n\nCURRENT_TIMESTAMP
and CURRENT_TIMESTAMP() are synonyms for NOW().\n\nURL:
https://mariadb.com/kb/en/current_timestamp/','','https://mariadb.com/kb/en/current_timestamp/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(515,31,'CURTIME','Syntax\n------\n\nCURTIME([precision])\n\nDescription\n-----------\n\nReturns
the current time as a value in \'HH:MM:SS\' or HHMMSS.uuuuuu
format,\ndepending on whether the function is used in a string or numeric
context. The\nvalue is expressed in the current time zone.\n\nThe optional
precision determines the microsecond precision. See Microseconds\nin
MariaDB.\n\nExamples\n--------\n\nSELECT CURTIME();\n+-----------+\n|
CURTIME() |\n+-----------+\n| 12:45:39 |\n+-----------+\n\nSELECT
CURTIME() + 0;\n+---------------+\n| CURTIME() + 0 |\n+---------------+\n|
124545.000000 |\n+---------------+\n\nWith precision:\n\nSELECT
CURTIME(2);\n+-------------+\n| CURTIME(2) |\n+-------------+\n|
09:49:08.09 |\n+-------------+\n\nURL:
https://mariadb.com/kb/en/curtime/','','https://mariadb.com/kb/en/curtime/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(516,31,'DATE
FUNCTION','Syntax\n------\n\nDATE(expr)\n\nDescription\n-----------\n\nExtracts
the date part of the date or datetime expression
expr.\n\nExamples\n--------\n\nSELECT DATE(\'2013-07-18
12:21:32\');\n+-----------------------------+\n|
DATE(\'2013-07-18 12:21:32\')
|\n+-----------------------------+\n| 2013-07-18
|\n+-----------------------------+\n\nError
Handling\n--------------\n\nUntil MariaDB 5.5.32, some versions of MariaDB
returned 0000-00-00 when passed\nan invalid date. From 5.5.32, NULL is
returned.\n\nURL:
https://mariadb.com/kb/en/date-function/','','https://mariadb.com/kb/en/date-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(517,31,'DATEDIFF','Syntax\n------\n\nDATEDIFF(expr1,expr2)\n\nDescription\n-----------\n\nDATEDIFF()
returns (expr1 – expr2) expressed as a value in days from one date\nto
the other. expr1 and expr2 are date or date-and-time expressions. Only
the\ndate parts of the values are used in the
calculation.\n\nExamples\n--------\n\nSELECT DATEDIFF(\'2007-12-31
23:59:59\',\'2007-12-30\');\n+----------------------------------------------+\n|
DATEDIFF(\'2007-12-31 23:59:59\',\'2007-12-30\')
|\n+----------------------------------------------+\n|
1
|\n+----------------------------------------------+\n\nSELECT
DATEDIFF(\'2010-11-30
23:59:59\',\'2010-12-31\');\n+----------------------------------------------+\n|
DATEDIFF(\'2010-11-30 23:59:59\',\'2010-12-31\')
|\n+----------------------------------------------+\n|
-31
|\n+----------------------------------------------+\n\nCREATE TABLE t1 (d
DATETIME);\nINSERT INTO t1 VALUES\n (\"2007-01-30 21:31:07\"),\n
(\"1983-10-15 06:42:51\"),\n (\"2011-04-21
12:34:56\"),\n (\"2011-10-30 06:31:41\"),\n
(\"2011-01-30 14:03:25\"),\n (\"2004-10-07
11:19:34\");\n\nSELECT NOW();\n+---------------------+\n| NOW()
|\n+---------------------+\n| 2011-05-23 10:56:05
|\n+---------------------+\n\nSELECT d, DATEDIFF(NOW(),d) FROM
t1;\n+---------------------+-------------------+\n| d |
DATEDIFF(NOW(),d) |\n+---------------------+-------------------+\n|
2007-01-30 21:31:07 | 1574 |\n| 1983-10-15 06:42:51 |
10082 |\n| 2011-04-21 12:34:56 | 32 |\n| 2011-10-30
06:31:41 | -160 |\n| 2011-01-30 14:03:25 | 113
|\n| 2004-10-07 11:19:34 | 2419
|\n+---------------------+-------------------+\n\nURL:
https://mariadb.com/kb/en/datediff/','','https://mariadb.com/kb/en/datediff/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(518,31,'DATE_ADD','Syntax\n------\n\nDATE_ADD(date,INTERVAL
expr unit)\n\nDescription\n-----------\n\nPerforms date arithmetic. The
date argument specifies the starting date or\ndatetime value. expr is an
expression specifying the interval value to be\nadded or subtracted from
the starting date. expr is a string; it may start\nwith a \"-\"
for negative intervals. unit is a keyword indicating the units in\nwhich
the expression should be interpreted. See Date and Time Units for
a\ncomplete list of permitted units.\n\nExamples\n--------\n\nSELECT
\'2008-12-31 23:59:59\' + INTERVAL 1
SECOND;\n+-------------------------------------------+\n| \'2008-12-31
23:59:59\' + INTERVAL 1 SECOND
|\n+-------------------------------------------+\n| 2009-01-01 00:00:00
|\n+-------------------------------------------+\n\nSELECT INTERVAL 1 DAY +
\'2008-12-31\';\n+-------------------------------+\n| INTERVAL 1
DAY + \'2008-12-31\' |\n+-------------------------------+\n|
2009-01-01
|\n+-------------------------------+\n\nSELECT \'2005-01-01\' -
INTERVAL 1 SECOND;\n+----------------------------------+\n|
\'2005-01-01\' - INTERVAL 1 SECOND
|\n+----------------------------------+\n| 2004-12-31 23:59:59
|\n+----------------------------------+\n\nSELECT
DATE_ADD(\'2000-12-31 23:59:59\', INTERVAL 1
SECOND);\n+----------------------------------------------------+\n|
DATE_ADD(\'2000-12-31 23:59:59\', INTERVAL 1 SECOND)
|\n+----------------------------------------------------+\n| 2001-01-01
00:00:00
|\n+----------------------------------------------------+\n\nSELECT
DATE_ADD(\'2010-12-31 23:59:59\', INTERVAL 1
DAY);\n+-------------------------------------------------+\n|
DATE_ADD(\'2010-12-31 23:59:59\', INTERVAL 1 DAY)
|\n+-------------------------------------------------+\n| 2011-01-01
23:59:59
|\n+-------------------------------------------------+\n\nSELECT
DATE_ADD(\'2100-12-31 23:59:59\', INTERVAL \'1:1\'
MINUTE_SECOND);\n+---------------------------------------------------------------+\n|
DATE_ADD(\'2100-12-31 23:59:59\', INTERVAL \'1:1\'
MINUTE_SECOND)
|\n+---------------------------------------------------------------+\n|
2101-01-01 00:01:00
|\n+---------------------------------------------------------------+\n\nSELECT
DATE_ADD(\'1900-01-01 00:00:00\', INTERVAL \'-1 10\'
DAY_HOUR);\n+------------------------------------------------------------+\n|
DATE_ADD(\'1900-01-01 00:00:00\', INTERVAL \'-1 10\'
DAY_HOUR)
|\n+------------------------------------------------------------+\n|
1899-12-30 14:00:00
|\n+------------------------------------------------------------+\n\nSELECT
DATE_ADD(\'1992-12-31 23:59:59.000002\', INTERVAL
\'1.999999\'\nSECOND_MICROSECOND);\n+------------------------------------------------------------------------------\n-+\n|
DATE_ADD(\'1992-12-31 23:59:59.000002\', INTERVAL
\'1.999999\'\nSECOND_MICROSECOND)
|\n+------------------------------------------------------------------------------\n-+\n|
1993-01-01 00:00:01.000001
\n
|\n+------------------------------------------------------------------------------\n-+\n\nURL:
https://mariadb.com/kb/en/date_add/','','https://mariadb.com/kb/en/date_add/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(519,31,'DATE_FORMAT','Syntax\n------\n\nDATE_FORMAT(date,
format[, locale])\n\nDescription\n-----------\n\nFormats the date value
according to the format string.\n\nThe language used for the names is
controlled by the value of the\nlc_time_names system variable. See server
locale for more on the supported\nlocales.\n\nThe options that can be used
by DATE_FORMAT(), as well as its inverse\nSTR_TO_DATE() and the
FROM_UNIXTIME() function,
are:\n\n+---------------------------+------------------------------------------------+\n|
Option | Description
|\n+---------------------------+------------------------------------------------+\n|
%a | Short weekday name in current locale
|\n| | (Variable lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%b | Short form month name in current locale. For
|\n| | locale en_US this is one of:
|\n| |
Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov |\n|
| or Dec.
|\n+---------------------------+------------------------------------------------+\n|
%c | Month with 1 or 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%D | Day with English suffix \'th\',
\'nd\', \'st\' or |\n| |
\'rd\'\'. (1st, 2nd, 3rd...).
|\n+---------------------------+------------------------------------------------+\n|
%d | Day with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%e | Day with 1 or 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%f | Microseconds 6 digits.
|\n+---------------------------+------------------------------------------------+\n|
%H | Hour with 2 digits between 00-23.
|\n+---------------------------+------------------------------------------------+\n|
%h | Hour with 2 digits between 01-12.
|\n+---------------------------+------------------------------------------------+\n|
%I | Hour with 2 digits between 01-12.
|\n+---------------------------+------------------------------------------------+\n|
%i | Minute with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%j | Day of the year (001-366)
|\n+---------------------------+------------------------------------------------+\n|
%k | Hour with 1 digits between 0-23.
|\n+---------------------------+------------------------------------------------+\n|
%l | Hour with 1 digits between 1-12.
|\n+---------------------------+------------------------------------------------+\n|
%M | Full month name in current locale (Variable
|\n| | lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%m | Month with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%p | AM/PM according to current locale (Variable
|\n| | lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%r | Time in 12 hour format, followed by AM/PM.
|\n| | Short for \'%I:%i:%S %p\'.
|\n+---------------------------+------------------------------------------------+\n|
%S | Seconds with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%s | Seconds with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%T | Time in 24 hour format. Short for
\'%H:%i:%S\'.
|\n+---------------------------+------------------------------------------------+\n|
%U | Week number (00-53), when first day of the
|\n| | week is Sunday.
|\n+---------------------------+------------------------------------------------+\n|
%u | Week number (00-53), when first day of the
|\n| | week is Monday.
|\n+---------------------------+------------------------------------------------+\n|
%V | Week number (01-53), when first day of the
|\n| | week is Sunday. Used with %X.
|\n+---------------------------+------------------------------------------------+\n|
%v | Week number (01-53), when first day of the
|\n| | week is Monday. Used with %x.
|\n+---------------------------+------------------------------------------------+\n|
%W | Full weekday name in current locale (Variable
|\n| | lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%w | Day of the week. 0 = Sunday, 6 = Saturday.
|\n+---------------------------+------------------------------------------------+\n|
%X | Year with 4 digits when first day of the week
|\n| | is Sunday. Used with %V.
|\n+---------------------------+------------------------------------------------+\n|
%x | Year with 4 digits when first day of the week
|\n| | is Monday. Used with %v.
|\n+---------------------------+------------------------------------------------+\n|
%Y | Year with 4 digits.
|\n+---------------------------+------------------------------------------------+\n|
%y | Year with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%# | For str_to_date(), skip all numbers.
|\n+---------------------------+------------------------------------------------+\n|
%. | For str_to_date(), skip all punctation
|\n| | characters.
|\n+---------------------------+------------------------------------------------+\n|
%@ | For str_to_date(), skip all alpha characters.
|\n+---------------------------+------------------------------------------------+\n|
%% | A literal % character.
|\n+---------------------------+------------------------------------------------+\n\nTo
get a date in one of the standard formats, GET_FORMAT() can be
used.\n\nExamples\n--------\n\nSELECT DATE_FORMAT(\'2009-10-04
22:23:00\', \'%W %M
%Y\');\n+------------------------------------------------+\n|
DATE_FORMAT(\'2009-10-04 22:23:00\', \'%W %M %Y\')
|\n+------------------------------------------------+\n| Sunday October
2009
|\n+------------------------------------------------+\n\nSELECT
DATE_FORMAT(\'2007-10-04 22:23:00\',
\'%H:%i:%s\');\n+------------------------------------------------+\n|
DATE_FORMAT(\'2007-10-04 22:23:00\', \'%H:%i:%s\')
|\n+------------------------------------------------+\n| 22:23:00
|\n+------------------------------------------------+\n\nSELECT
DATE_FORMAT(\'1900-10-04 22:23:00\', \'%D %y %a %d %m %b
%j\');\n+------------------------------------------------------------+\n|
DATE_FORMAT(\'1900-10-04 22:23:00\', \'%D %y %a %d %m %b
%j\')
|\n+------------------------------------------------------------+\n| 4th 00
Thu 04 10 Oct 277
|\n+------------------------------------------------------------+\n\nSELECT
DATE_FORMAT(\'1997-10-04 22:23:00\', \'%H %k %I %r %T %S
%w\');\n+------------------------------------------------------------+\n|
DATE_FORMAT(\'1997-10-04 22:23:00\', \'%H %k %I %r %T %S
%w\')
|\n+------------------------------------------------------------+\n| 22 22
10 10:23:00 PM 22:23:00 00 6
|\n+------------------------------------------------------------+\n\nSELECT
DATE_FORMAT(\'1999-01-01\', \'%X
%V\');\n+------------------------------------+\n|
DATE_FORMAT(\'1999-01-01\', \'%X %V\')
|\n+------------------------------------+\n| 1998 52
|\n+------------------------------------+\n\nSELECT
DATE_FORMAT(\'2006-06-00\',
\'%d\');\n+---------------------------------+\n|
DATE_FORMAT(\'2006-06-00\', \'%d\')
|\n+---------------------------------+\n| 00
|\n+---------------------------------+\n\nMariaDB starting with
10.3.2\n----------------------------\nOptionally, the locale can be
explicitly specified as the third DATE_FORMAT()\nargument. Doing so makes
the function independent from the session settings,\nand the three argument
version of DATE_FORMAT() can be used in virtual indexed\nand persistent
generated-columns:\n\nSELECT DATE_FORMAT(\'2006-01-01\',
\'%W\',
\'el_GR\');\n+------------------------------------------+\n|
DATE_FORMAT(\'2006-01-01\', \'%W\',
\'el_GR\') |\n+------------------------------------------+\n|
Κυριακή
|\n+------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/date_format/','','https://mariadb.com/kb/en/date_format/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(520,31,'DATE_SUB','Syntax\n------\n\nDATE_SUB(date,INTERVAL
expr unit)\n\nDescription\n-----------\n\nPerforms date arithmetic. The
date argument specifies the starting date or\ndatetime value. expr is an
expression specifying the interval value to be\nadded or subtracted from
the starting date. expr is a string; it may start\nwith a \"-\"
for negative intervals. unit is a keyword indicating the units in\nwhich
the expression should be interpreted. See Date and Time Units for
a\ncomplete list of permitted units.\n\nSee also
DATE_ADD().\n\nExamples\n--------\n\nSELECT
DATE_SUB(\'1998-01-02\', INTERVAL 31
DAY);\n+-----------------------------------------+\n|
DATE_SUB(\'1998-01-02\', INTERVAL 31 DAY)
|\n+-----------------------------------------+\n| 1997-12-02
|\n+-----------------------------------------+\n\nSELECT
DATE_SUB(\'2005-01-01 00:00:00\', INTERVAL \'1 1:1:1\'
DAY_SECOND);\n+----------------------------------------------------------------+\n|
DATE_SUB(\'2005-01-01 00:00:00\', INTERVAL \'1 1:1:1\'
DAY_SECOND)
|\n+----------------------------------------------------------------+\n|
2004-12-30 22:58:59
|\n+----------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/date_sub/','','https://mariadb.com/kb/en/date_sub/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(521,31,'DAY','Syntax\n------\n\nDAY(date)\n\nDescription\n-----------\n\nDAY()
is a synonym for DAYOFMONTH().\n\nURL:
https://mariadb.com/kb/en/day/','','https://mariadb.com/kb/en/day/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(522,31,'DAYNAME','Syntax\n------\n\nDAYNAME(date)\n\nDescription\n-----------\n\nReturns
the name of the weekday for date. The language used for the name
is\ncontrolled by the value of the lc_time_names system variable. See
server\nlocale for more on the supported
locales.\n\nExamples\n--------\n\nSELECT
DAYNAME(\'2007-02-03\');\n+-----------------------+\n|
DAYNAME(\'2007-02-03\') |\n+-----------------------+\n| Saturday
|\n+-----------------------+\n\nCREATE TABLE t1 (d
DATETIME);\nINSERT INTO t1 VALUES\n (\"2007-01-30 21:31:07\"),\n
(\"1983-10-15 06:42:51\"),\n (\"2011-04-21
12:34:56\"),\n (\"2011-10-30 06:31:41\"),\n
(\"2011-01-30 14:03:25\"),\n (\"2004-10-07
11:19:34\");\n\nSELECT d, DAYNAME(d) FROM
t1;\n+---------------------+------------+\n| d |
DAYNAME(d) |\n+---------------------+------------+\n| 2007-01-30 21:31:07 |
Tuesday |\n| 1983-10-15 06:42:51 | Saturday |\n| 2011-04-21 12:34:56 |
Thursday |\n| 2011-10-30 06:31:41 | Sunday |\n| 2011-01-30 14:03:25 |
Sunday |\n| 2004-10-07 11:19:34 | Thursday
|\n+---------------------+------------+\n\nChanging the locale:\n\nSET
lc_time_names = \'fr_CA\';\n\nSELECT
DAYNAME(\'2013-04-01\');\n+-----------------------+\n|
DAYNAME(\'2013-04-01\') |\n+-----------------------+\n| lundi
|\n+-----------------------+\n\nURL:
https://mariadb.com/kb/en/dayname/','','https://mariadb.com/kb/en/dayname/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(523,31,'DAYOFMONTH','Syntax\n------\n\nDAYOFMONTH(date)\n\nDescription\n-----------\n\nReturns
the day of the month for date, in the range 1 to 31, or 0 for dates\nsuch
as \'0000-00-00\' or \'2008-00-00\' which have a zero
day part.\n\nDAY() is a synonym.\n\nExamples\n--------\n\nSELECT
DAYOFMONTH(\'2007-02-03\');\n+--------------------------+\n|
DAYOFMONTH(\'2007-02-03\') |\n+--------------------------+\n|
3 |\n+--------------------------+\n\nCREATE TABLE t1 (d
DATETIME);\nINSERT INTO t1 VALUES\n (\"2007-01-30 21:31:07\"),\n
(\"1983-10-15 06:42:51\"),\n (\"2011-04-21
12:34:56\"),\n (\"2011-10-30 06:31:41\"),\n
(\"2011-01-30 14:03:25\"),\n (\"2004-10-07
11:19:34\");\n\nSELECT d FROM t1 where DAYOFMONTH(d) =
30;\n+---------------------+\n| d
|\n+---------------------+\n| 2007-01-30 21:31:07 |\n| 2011-10-30 06:31:41
|\n| 2011-01-30 14:03:25 |\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/dayofmonth/','','https://mariadb.com/kb/en/dayofmonth/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(524,31,'DAYOFWEEK','Syntax\n------\n\nDAYOFWEEK(date)\n\nDescription\n-----------\n\nReturns
the day of the week index for the date (1 = Sunday, 2 = Monday, ..., 7\n=
Saturday). These index values correspond to the ODBC standard.\n\nThis
contrasts with WEEKDAY() which follows a different index numbering (0
=\nMonday, 1 = Tuesday, ... 6 = Sunday).\n\nExamples\n--------\n\nSELECT
DAYOFWEEK(\'2007-02-03\');\n+-------------------------+\n|
DAYOFWEEK(\'2007-02-03\') |\n+-------------------------+\n|
7 |\n+-------------------------+\n\nCREATE TABLE t1 (d
DATETIME);\nINSERT INTO t1 VALUES\n (\"2007-01-30 21:31:07\"),\n
(\"1983-10-15 06:42:51\"),\n (\"2011-04-21
12:34:56\"),\n (\"2011-10-30 06:31:41\"),\n
(\"2011-01-30 14:03:25\"),\n (\"2004-10-07
11:19:34\");\n\nSELECT d, DAYNAME(d), DAYOFWEEK(d), WEEKDAY(d) from
t1;\n+---------------------+------------+--------------+------------+\n| d
| DAYNAME(d) | DAYOFWEEK(d) | WEEKDAY(d)
|\n+---------------------+------------+--------------+------------+\n|
2007-01-30 21:31:07 | Tuesday | 3 | 1 |\n|
1983-10-15 06:42:51 | Saturday | 7 | 5 |\n|
2011-04-21 12:34:56 | Thursday | 5 | 3 |\n|
2011-10-30 06:31:41 | Sunday | 1 | 6 |\n|
2011-01-30 14:03:25 | Sunday | 1 | 6 |\n|
2004-10-07 11:19:34 | Thursday | 5 | 3
|\n+---------------------+------------+--------------+------------+\n\nURL:
https://mariadb.com/kb/en/dayofweek/','','https://mariadb.com/kb/en/dayofweek/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(525,31,'DAYOFYEAR','Syntax\n------\n\nDAYOFYEAR(date)\n\nDescription\n-----------\n\nReturns
the day of the year for date, in the range 1 to
366.\n\nExamples\n--------\n\nSELECT
DAYOFYEAR(\'2018-02-16\');\n+-------------------------+\n|
DAYOFYEAR(\'2018-02-16\') |\n+-------------------------+\n|
47 |\n+-------------------------+\n\nURL:
https://mariadb.com/kb/en/dayofyear/','','https://mariadb.com/kb/en/dayofyear/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(526,31,'EXTRACT','Syntax\n------\n\nEXTRACT(unit FROM
date)\n\nDescription\n-----------\n\nThe EXTRACT() function extracts the
required unit from the date. See Date and\nTime Units for a complete list
of permitted units.\n\nIn MariaDB 10.0.7 and MariaDB 5.5.35, EXTRACT (HOUR
FROM ...) was changed to\nreturn a value from 0 to 23, adhering to the SQL
standard. Until MariaDB\n10.0.6 and MariaDB 5.5.34, and in all versions of
MySQL at least as of MySQL\n5.7, it could return a value > 23. HOUR() is
not a standard function, so\ncontinues to adhere to the old behaviour
inherited from MySQL.\n\nExamples\n--------\n\nSELECT EXTRACT(YEAR FROM
\'2009-07-02\');\n+---------------------------------+\n|
EXTRACT(YEAR FROM \'2009-07-02\')
|\n+---------------------------------+\n| 2009
|\n+---------------------------------+\n\nSELECT EXTRACT(YEAR_MONTH FROM
\'2009-07-02
01:02:03\');\n+------------------------------------------------+\n|
EXTRACT(YEAR_MONTH FROM \'2009-07-02 01:02:03\')
|\n+------------------------------------------------+\n|
200907
|\n+------------------------------------------------+\n\nSELECT
EXTRACT(DAY_MINUTE FROM \'2009-07-02
01:02:03\');\n+------------------------------------------------+\n|
EXTRACT(DAY_MINUTE FROM \'2009-07-02 01:02:03\')
|\n+------------------------------------------------+\n|
20102
|\n+------------------------------------------------+\n\nSELECT
EXTRACT(MICROSECOND FROM \'2003-01-02
10:30:00.000123\');\n+--------------------------------------------------------+\n|
EXTRACT(MICROSECOND FROM \'2003-01-02 10:30:00.000123\')
|\n+--------------------------------------------------------+\n|
123
|\n+--------------------------------------------------------+\n\nFrom
MariaDB 10.0.7 and MariaDB 5.5.35, EXTRACT (HOUR FROM...) returns a
value\nfrom 0 to 23, as per the SQL standard. HOUR is not a standard
function, so\ncontinues to adhere to the old behaviour inherited from
MySQL.\n\nSELECT EXTRACT(HOUR FROM \'26:30:00\'),
HOUR(\'26:30:00\');\n+-------------------------------+------------------+\n|
EXTRACT(HOUR FROM \'26:30:00\') | HOUR(\'26:30:00\')
|\n+-------------------------------+------------------+\n|
2 | 26
|\n+-------------------------------+------------------+\n\nURL:
https://mariadb.com/kb/en/extract/','','https://mariadb.com/kb/en/extract/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(527,31,'FROM_DAYS','Syntax\n------\n\nFROM_DAYS(N)\n\nDescription\n-----------\n\nGiven
a day number N, returns a DATE value. The day count is based on the\nnumber
of days from the start of the standard calendar (0000-00-00).\n\nThe
function is not designed for use with dates before the advent of
the\nGregorian calendar in October 1582. Results will not be reliable since
it\ndoesn\'t account for the lost days when the calendar changed from
the Julian\ncalendar.\n\nThis is the converse of the TO_DAYS()
function.\n\nExamples\n--------\n\nSELECT
FROM_DAYS(730669);\n+-------------------+\n| FROM_DAYS(730669)
|\n+-------------------+\n| 2000-07-03
|\n+-------------------+\n\nURL:
https://mariadb.com/kb/en/from_days/','','https://mariadb.com/kb/en/from_days/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(528,31,'FROM_UNIXTIME','Syntax\n------\n\nFROM_UNIXTIME(unix_timestamp),
FROM_UNIXTIME(unix_timestamp,format)\n\nDescription\n-----------\n\nReturns
a representation of the unix_timestamp argument as a value
in\n\'YYYY-MM-DD HH:MM:SS\' or YYYYMMDDHHMMSS.uuuuuu format,
depending on whether\nthe function is used in a string or numeric context.
The value is expressed in\nthe current time zone. unix_timestamp is an
internal timestamp value such as\nis produced by the UNIX_TIMESTAMP()
function.\n\nIf format is given, the result is formatted according to the
format string,\nwhich is used the same way as listed in the entry for the
DATE_FORMAT()\nfunction.\n\nTimestamps in MariaDB have a maximum value of
2147483647, equivalent to\n2038-01-19 05:14:07. This is due to the
underlying 32-bit limitation. Using\nthe function on a timestamp beyond
this will result in NULL being returned.\nUse DATETIME as a storage type if
you require dates beyond this.\n\nThe options that can be used by
FROM_UNIXTIME(), as well as DATE_FORMAT() and\nSTR_TO_DATE(),
are:\n\n+---------------------------+------------------------------------------------+\n|
Option | Description
|\n+---------------------------+------------------------------------------------+\n|
%a | Short weekday name in current locale
|\n| | (Variable lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%b | Short form month name in current locale. For
|\n| | locale en_US this is one of:
|\n| |
Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov |\n|
| or Dec.
|\n+---------------------------+------------------------------------------------+\n|
%c | Month with 1 or 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%D | Day with English suffix \'th\',
\'nd\', \'st\' or |\n| |
\'rd\'\'. (1st, 2nd, 3rd...).
|\n+---------------------------+------------------------------------------------+\n|
%d | Day with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%e | Day with 1 or 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%f | Microseconds 6 digits.
|\n+---------------------------+------------------------------------------------+\n|
%H | Hour with 2 digits between 00-23.
|\n+---------------------------+------------------------------------------------+\n|
%h | Hour with 2 digits between 01-12.
|\n+---------------------------+------------------------------------------------+\n|
%I | Hour with 2 digits between 01-12.
|\n+---------------------------+------------------------------------------------+\n|
%i | Minute with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%j | Day of the year (001-366)
|\n+---------------------------+------------------------------------------------+\n|
%k | Hour with 1 digits between 0-23.
|\n+---------------------------+------------------------------------------------+\n|
%l | Hour with 1 digits between 1-12.
|\n+---------------------------+------------------------------------------------+\n|
%M | Full month name in current locale (Variable
|\n| | lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%m | Month with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%p | AM/PM according to current locale (Variable
|\n| | lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%r | Time in 12 hour format, followed by AM/PM.
|\n| | Short for \'%I:%i:%S %p\'.
|\n+---------------------------+------------------------------------------------+\n|
%S | Seconds with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%s | Seconds with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%T | Time in 24 hour format. Short for
\'%H:%i:%S\'.
|\n+---------------------------+------------------------------------------------+\n|
%U | Week number (00-53), when first day of the
|\n| | week is Sunday.
|\n+---------------------------+------------------------------------------------+\n|
%u | Week number (00-53), when first day of the
|\n| | week is Monday.
|\n+---------------------------+------------------------------------------------+\n|
%V | Week number (01-53), when first day of the
|\n| | week is Sunday. Used with %X.
|\n+---------------------------+------------------------------------------------+\n|
%v | Week number (01-53), when first day of the
|\n| | week is Monday. Used with %x.
|\n+---------------------------+------------------------------------------------+\n|
%W | Full weekday name in current locale (Variable
|\n| | lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%w | Day of the week. 0 = Sunday, 6 = Saturday.
|\n+---------------------------+------------------------------------------------+\n|
%X | Year with 4 digits when first day of the week
|\n| | is Sunday. Used with %V.
|\n+---------------------------+------------------------------------------------+\n|
%x | Year with 4 digits when first day of the week
|\n| | is Sunday. Used with %v.
|\n+---------------------------+------------------------------------------------+\n|
%Y | Year with 4 digits.
|\n+---------------------------+------------------------------------------------+\n|
%y | Year with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%# | For str_to_date(), skip all numbers.
|\n+---------------------------+------------------------------------------------+\n|
%. | For str_to_date(), skip all punctation
|\n| | characters.
|\n+---------------------------+------------------------------------------------+\n|
%@ | For str_to_date(), skip all alpha characters.
|\n+---------------------------+------------------------------------------------+\n|
%% | A literal % character.
|\n+---------------------------+------------------------------------------------+\n\nPerformance
Considerations\n--------------------------\n\nIf your session time zone is
set to SYSTEM (the default), FROM_UNIXTIME() will\ncall the OS function to
convert the data using the system time zone. At least\non Linux, the
corresponding function (localtime_r) uses a global mutex inside\nglibc that
can cause contention under high concurrent load.\n\nSet your time zone to a
named time zone to avoid this issue. See mysql time\nzone tables for
details on how to do this.\n\nExamples\n--------\n\nSELECT
FROM_UNIXTIME(1196440219);\n+---------------------------+\n|
FROM_UNIXTIME(1196440219) |\n+---------------------------+\n| 2007-11-30
11:30:19 |\n+---------------------------+\n\nSELECT
FROM_UNIXTIME(1196440219) + 0;\n+-------------------------------+\n|
FROM_UNIXTIME(1196440219) + 0 |\n+-------------------------------+\n|
20071130113019.000000 |\n+-------------------------------+\n\nSELECT
FROM_UNIXTIME(UNIX_TIMESTAMP(), \'%Y %D %M %h:%i:%s
%x\');\n+---------------------------------------------------------+\n|
FROM_UNIXTIME(UNIX_TIMESTAMP(), \'%Y %D %M %h:%i:%s %x\')
|\n+---------------------------------------------------------+\n| 2010 27th
March 01:03:47 2010
|\n+---------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/from_unixtime/','','https://mariadb.com/kb/en/from_unixtime/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(529,31,'GET_FORMAT','Syntax\n------\n\nGET_FORMAT({DATE|DATETIME|TIME},
{\'EUR\'|\'USA\'|\'JIS\'|\'ISO\'|\'INTERNAL\'})\n\nDescription\n-----------\n\nReturns
a format string. This function is useful in combination with
the\nDATE_FORMAT() and the STR_TO_DATE() functions.\n\nPossible result
formats
are:\n\n+--------------------------------------+--------------------------------------+\n|
Function Call | Result Format
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(DATE,\'EUR\') | \'%d.%m.%Y\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(DATE,\'USA\') | \'%m.%d.%Y\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(DATE,\'JIS\') | \'%Y-%m-%d\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(DATE,\'ISO\') | \'%Y-%m-%d\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(DATE,\'INTERNAL\') | \'%Y%m%d\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(DATETIME,\'EUR\') | \'%Y-%m-%d
%H.%i.%s\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(DATETIME,\'USA\') | \'%Y-%m-%d
%H.%i.%s\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(DATETIME,\'JIS\') | \'%Y-%m-%d
%H:%i:%s\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(DATETIME,\'ISO\') | \'%Y-%m-%d
%H:%i:%s\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(DATETIME,\'INTERNAL\') |
\'%Y%m%d%H%i%s\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(TIME,\'EUR\') | \'%H.%i.%s\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(TIME,\'USA\') | \'%h:%i:%s
%p\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(TIME,\'JIS\') | \'%H:%i:%s\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(TIME,\'ISO\') | \'%H:%i:%s\'
|\n+--------------------------------------+--------------------------------------+\n|
GET_FORMAT(TIME,\'INTERNAL\') | \'%H%i%s\'
|\n+--------------------------------------+--------------------------------------+\n\nExamples\n--------\n\nObtaining
the string matching to the standard European date format:\n\nSELECT
GET_FORMAT(DATE, \'EUR\');\n+-------------------------+\n|
GET_FORMAT(DATE, \'EUR\') |\n+-------------------------+\n|
%d.%m.%Y |\n+-------------------------+\n\nUsing the same
string to format a date:\n\nSELECT
DATE_FORMAT(\'2003-10-03\',GET_FORMAT(DATE,\'EUR\'));\n+--------------------------------------------------+\n|
DATE_FORMAT(\'2003-10-03\',GET_FORMAT(DATE,\'EUR\'))
|\n+--------------------------------------------------+\n| 03.10.2003
|\n+--------------------------------------------------+\n\nSELECT
STR_TO_DATE(\'10.31.2003\',GET_FORMAT(DATE,\'USA\'));\n+--------------------------------------------------+\n|
STR_TO_DATE(\'10.31.2003\',GET_FORMAT(DATE,\'USA\'))
|\n+--------------------------------------------------+\n| 2003-10-31
|\n+--------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/get_format/','','https://mariadb.com/kb/en/get_format/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(530,31,'HOUR','Syntax\n------\n\nHOUR(time)\n\nDescription\n-----------\n\nReturns
the hour for time. The range of the return value is 0 to 23
for\ntime-of-day values. However, the range of TIME values actually is much
larger,\nso HOUR can return values greater than 23.\n\nThe return value is
always positive, even if a negative TIME value is
provided.\n\nExamples\n--------\n\nSELECT
HOUR(\'10:05:03\');\n+------------------+\n|
HOUR(\'10:05:03\') |\n+------------------+\n| 10
|\n+------------------+\n\nSELECT
HOUR(\'272:59:59\');\n+-------------------+\n|
HOUR(\'272:59:59\') |\n+-------------------+\n| 272
|\n+-------------------+\n\nDifference between EXTRACT (HOUR FROM ...)
(>= MariaDB 10.0.7 and MariaDB\n5.5.35) and HOUR:\n\nSELECT EXTRACT(HOUR
FROM \'26:30:00\'),
HOUR(\'26:30:00\');\n+-------------------------------+------------------+\n|
EXTRACT(HOUR FROM \'26:30:00\') | HOUR(\'26:30:00\')
|\n+-------------------------------+------------------+\n|
2 | 26
|\n+-------------------------------+------------------+\n\nURL:
https://mariadb.com/kb/en/hour/','','https://mariadb.com/kb/en/hour/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(531,31,'LAST_DAY','Syntax\n------\n\nLAST_DAY(date)\n\nDescription\n-----------\n\nTakes
a date or datetime value and returns the corresponding value for the\nlast
day of the month. Returns NULL if the argument is
invalid.\n\nExamples\n--------\n\nSELECT
LAST_DAY(\'2003-02-05\');\n+------------------------+\n|
LAST_DAY(\'2003-02-05\') |\n+------------------------+\n|
2003-02-28 |\n+------------------------+\n\nSELECT
LAST_DAY(\'2004-02-05\');\n+------------------------+\n|
LAST_DAY(\'2004-02-05\') |\n+------------------------+\n|
2004-02-29 |\n+------------------------+\n\nSELECT
LAST_DAY(\'2004-01-01
01:01:01\');\n+---------------------------------+\n|
LAST_DAY(\'2004-01-01 01:01:01\')
|\n+---------------------------------+\n| 2004-01-31
|\n+---------------------------------+\n\nSELECT
LAST_DAY(\'2003-03-32\');\n+------------------------+\n|
LAST_DAY(\'2003-03-32\') |\n+------------------------+\n| NULL
|\n+------------------------+\n1 row in set, 1 warning (0.00
sec)\n\nWarning (Code 1292): Incorrect datetime value:
\'2003-03-32\'\n\nURL:
https://mariadb.com/kb/en/last_day/','','https://mariadb.com/kb/en/last_day/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(532,31,'LOCALTIME','Syntax\n------\n\nLOCALTIME\nLOCALTIME([precision])\n\nDescription\n-----------\n\nLOCALTIME
and LOCALTIME() are synonyms for NOW().\n\nURL:
https://mariadb.com/kb/en/localtime/','','https://mariadb.com/kb/en/localtime/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(533,31,'LOCALTIMESTAMP','Syntax\n------\n\nLOCALTIMESTAMP\nLOCALTIMESTAMP([precision])\n\nDescription\n-----------\n\nLOCALTIMESTAMP
and LOCALTIMESTAMP() are synonyms for NOW().\n\nURL:
https://mariadb.com/kb/en/localtimestamp/','','https://mariadb.com/kb/en/localtimestamp/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(534,31,'MAKEDATE','Syntax\n------\n\nMAKEDATE(year,dayofyear)\n\nDescription\n-----------\n\nReturns
a date, given year and day-of-year values. dayofyear must be greater\nthan
0 or the result is NULL.\n\nExamples\n--------\n\nSELECT MAKEDATE(2011,31),
MAKEDATE(2011,32);\n+-------------------+-------------------+\n|
MAKEDATE(2011,31) | MAKEDATE(2011,32)
|\n+-------------------+-------------------+\n| 2011-01-31 |
2011-02-01 |\n+-------------------+-------------------+\n\nSELECT
MAKEDATE(2011,365),
MAKEDATE(2014,365);\n+--------------------+--------------------+\n|
MAKEDATE(2011,365) | MAKEDATE(2014,365)
|\n+--------------------+--------------------+\n| 2011-12-31 |
2014-12-31 |\n+--------------------+--------------------+\n\nSELECT
MAKEDATE(2011,0);\n+------------------+\n| MAKEDATE(2011,0)
|\n+------------------+\n| NULL |\n+------------------+\n\nURL:
https://mariadb.com/kb/en/makedate/','','https://mariadb.com/kb/en/makedate/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(535,31,'MAKETIME','Syntax\n------\n\nMAKETIME(hour,minute,second)\n\nDescription\n-----------\n\nReturns
a time value calculated from the hour, minute, and second arguments.\n\nIf
minute or second are out of the range 0 to 60, NULL is returned. The
hour\ncan be in the range -838 to 838, outside of which the value is
truncated with\na warning.\n\nExamples\n--------\n\nSELECT
MAKETIME(13,57,33);\n+--------------------+\n| MAKETIME(13,57,33)
|\n+--------------------+\n| 13:57:33
|\n+--------------------+\n\nSELECT
MAKETIME(-13,57,33);\n+---------------------+\n| MAKETIME(-13,57,33)
|\n+---------------------+\n| -13:57:33
|\n+---------------------+\n\nSELECT
MAKETIME(13,67,33);\n+--------------------+\n| MAKETIME(13,67,33)
|\n+--------------------+\n| NULL
|\n+--------------------+\n\nSELECT
MAKETIME(-1000,57,33);\n+-----------------------+\n| MAKETIME(-1000,57,33)
|\n+-----------------------+\n| -838:59:59
|\n+-----------------------+\n1 row in set, 1 warning (0.00 sec)\n\nSHOW
WARNINGS;\n+---------+------+-----------------------------------------------+\n|
Level | Code | Message
|\n+---------+------+-----------------------------------------------+\n|
Warning | 1292 | Truncated incorrect time value: \'-1000:57:33\'
|\n+---------+------+-----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/maketime/','','https://mariadb.com/kb/en/maketime/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(536,31,'MICROSECOND','Syntax\n------\n\nMICROSECOND(expr)\n\nDescription\n-----------\n\nReturns
the microseconds from the time or datetime expression expr as a number\nin
the range from 0 to 999999.\n\nIf expr is a time with no microseconds, zero
is returned, while if expr is a\ndate with no time, zero with a warning is
returned.\n\nExamples\n--------\n\nSELECT
MICROSECOND(\'12:00:00.123456\');\n+--------------------------------+\n|
MICROSECOND(\'12:00:00.123456\')
|\n+--------------------------------+\n| 123456
|\n+--------------------------------+\n\nSELECT
MICROSECOND(\'2009-12-31
23:59:59.000010\');\n+-------------------------------------------+\n|
MICROSECOND(\'2009-12-31 23:59:59.000010\')
|\n+-------------------------------------------+\n|
10
|\n+-------------------------------------------+\n\nSELECT
MICROSECOND(\'2013-08-07
12:13:14\');\n+------------------------------------+\n|
MICROSECOND(\'2013-08-07 12:13:14\')
|\n+------------------------------------+\n|
0 |\n+------------------------------------+\n\nSELECT
MICROSECOND(\'2013-08-07\');\n+---------------------------+\n|
MICROSECOND(\'2013-08-07\') |\n+---------------------------+\n|
0 |\n+---------------------------+\n1 row in set, 1
warning (0.00 sec)\n\nSHOW
WARNINGS;\n+---------+------+----------------------------------------------+\n|
Level | Code | Message
|\n+---------+------+----------------------------------------------+\n|
Warning | 1292 | Truncated incorrect time value: \'2013-08-07\'
|\n+---------+------+----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/microsecond/','','https://mariadb.com/kb/en/microsecond/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(537,31,'MINUTE','Syntax\n------\n\nMINUTE(time)\n\nDescription\n-----------\n\nReturns
the minute for time, in the range 0 to 59.\n\nExamples\n--------\n\nSELECT
MINUTE(\'2013-08-03
11:04:03\');\n+-------------------------------+\n|
MINUTE(\'2013-08-03 11:04:03\')
|\n+-------------------------------+\n| 4
|\n+-------------------------------+\n\nSELECT MINUTE
(\'23:12:50\');\n+---------------------+\n| MINUTE
(\'23:12:50\') |\n+---------------------+\n| 12
|\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/minute/','','https://mariadb.com/kb/en/minute/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(538,31,'MONTH','Syntax\n------\n\nMONTH(date)\n\nDescription\n-----------\n\nReturns
the month for date in the range 1 to 12 for January to December, or 0\nfor
dates such as \'0000-00-00\' or \'2008-00-00\' that
have a zero month part.\n\nExamples\n--------\n\nSELECT
MONTH(\'2019-01-03\');\n+---------------------+\n|
MONTH(\'2019-01-03\') |\n+---------------------+\n|
1 |\n+---------------------+\n\nSELECT
MONTH(\'2019-00-03\');\n+---------------------+\n|
MONTH(\'2019-00-03\') |\n+---------------------+\n|
0 |\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/month/','','https://mariadb.com/kb/en/month/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(539,31,'MONTHNAME','Syntax\n------\n\nMONTHNAME(date)\n\nDescription\n-----------\n\nReturns
the full name of the month for date. The language used for the name
is\ncontrolled by the value of the lc_time_names system variable. See
server\nlocale for more on the supported
locales.\n\nExamples\n--------\n\nSELECT
MONTHNAME(\'2019-02-03\');\n+-------------------------+\n|
MONTHNAME(\'2019-02-03\') |\n+-------------------------+\n|
February |\n+-------------------------+\n\nChanging the
locale:\n\nSET lc_time_names = \'fr_CA\';\n\nSELECT
MONTHNAME(\'2019-05-21\');\n+-------------------------+\n|
MONTHNAME(\'2019-05-21\') |\n+-------------------------+\n| mai
|\n+-------------------------+\n\nURL:
https://mariadb.com/kb/en/monthname/','','https://mariadb.com/kb/en/monthname/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(540,31,'NOW','Syntax\n------\n\nNOW([precision])\nCURRENT_TIMESTAMP\nCURRENT_TIMESTAMP([precision])\nLOCALTIME,
LOCALTIME([precision])\nLOCALTIMESTAMP\nLOCALTIMESTAMP([precision])\n\nDescription\n-----------\n\nReturns
the current date and time as a value in \'YYYY-MM-DD HH:MM:SS\'
or\nYYYYMMDDHHMMSS.uuuuuu format, depending on whether the function is used
in a\nstring or numeric context. The value is expressed in the current time
zone.\n\nThe optional precision determines the microsecond precision. See
Microseconds\nin MariaDB.\n\nNOW() (or its synonyms) can be used as the
default value for TIMESTAMP columns\nas well as, since MariaDB 10.0.1,
DATETIME columns. Before MariaDB 10.0.1, it\nwas only possible for a single
TIMESTAMP column per table to contain the\nCURRENT_TIMESTAMP as its
default.\n\nWhen displayed in the INFORMATION_SCHEMA.COLUMNS table, a
default CURRENT\nTIMESTAMP is displayed as CURRENT_TIMESTAMP up until
MariaDB 10.2.2, and as\ncurrent_timestamp() from MariaDB 10.2.3, due to to
MariaDB 10.2 accepting\nexpressions in the DEFAULT clause.\n\nChanging the
timestamp system variable with a SET timestamp statement affects\nthe value
returned by NOW(), but not by SYSDATE().\n\nExamples\n--------\n\nSELECT
NOW();\n+---------------------+\n| NOW()
|\n+---------------------+\n| 2010-03-27 13:13:25
|\n+---------------------+\n\nSELECT NOW() +
0;\n+-----------------------+\n| NOW() + 0
|\n+-----------------------+\n| 20100327131329.000000
|\n+-----------------------+\n\nWith precision:\n\nSELECT
CURRENT_TIMESTAMP(2);\n+------------------------+\n| CURRENT_TIMESTAMP(2)
|\n+------------------------+\n| 2018-07-10 09:47:26.24
|\n+------------------------+\n\nUsed as a default TIMESTAMP:\n\nCREATE
TABLE t (createdTS TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP);\n\nFrom
MariaDB 10.2.2:\n\nSELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE
TABLE_SCHEMA=\'test\'\n AND COLUMN_NAME LIKE
\'%ts%\'\\G\n*************************** 1. row
***************************\n TABLE_CATALOG: def\n TABLE_SCHEMA:
test\n TABLE_NAME: t\n COLUMN_NAME: ts\n ORDINAL_POSITION:
1\n COLUMN_DEFAULT: current_timestamp()\n...\n\n<= MariaDB
10.2.1\n\nSELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE
TABLE_SCHEMA=\'test\'\n AND COLUMN_NAME LIKE
\'%ts%\'\\G\n*************************** 1. row
***************************\n TABLE_CATALOG: def\n TABLE_SCHEMA:
test\n TABLE_NAME: t\n COLUMN_NAME: createdTS\n
ORDINAL_POSITION: 1\n COLUMN_DEFAULT: CURRENT_TIMESTAMP\n...\n\nURL:
https://mariadb.com/kb/en/now/','','https://mariadb.com/kb/en/now/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(541,31,'PERIOD_ADD','Syntax\n------\n\nPERIOD_ADD(P,N)\n\nDescription\n-----------\n\nAdds
N months to period P. P is in the format YYMM or YYYYMM, and is not a\ndate
value. If P contains a two-digit year, values from 00 to 69 are
converted\nto from 2000 to 2069, while values from 70 are converted to 1970
upwards.\n\nReturns a value in the format
YYYYMM.\n\nExamples\n--------\n\nSELECT
PERIOD_ADD(200801,2);\n+----------------------+\n| PERIOD_ADD(200801,2)
|\n+----------------------+\n| 200803
|\n+----------------------+\n\nSELECT
PERIOD_ADD(6910,2);\n+--------------------+\n| PERIOD_ADD(6910,2)
|\n+--------------------+\n| 206912
|\n+--------------------+\n\nSELECT
PERIOD_ADD(7010,2);\n+--------------------+\n| PERIOD_ADD(7010,2)
|\n+--------------------+\n| 197012
|\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/period_add/','','https://mariadb.com/kb/en/period_add/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(542,31,'PERIOD_DIFF','Syntax\n------\n\nPERIOD_DIFF(P1,P2)\n\nDescription\n-----------\n\nReturns
the number of months between periods P1 and P2. P1 and P2 can be in\nthe
format YYMM or YYYYMM, and are not date values.\n\nIf P1 or P2 contains a
two-digit year, values from 00 to 69 are converted to\nfrom 2000 to 2069,
while values from 70 are converted to 1970
upwards.\n\nExamples\n--------\n\nSELECT
PERIOD_DIFF(200802,200703);\n+----------------------------+\n|
PERIOD_DIFF(200802,200703) |\n+----------------------------+\n|
11 |\n+----------------------------+\n\nSELECT
PERIOD_DIFF(6902,6803);\n+------------------------+\n|
PERIOD_DIFF(6902,6803) |\n+------------------------+\n|
11 |\n+------------------------+\n\nSELECT
PERIOD_DIFF(7002,6803);\n+------------------------+\n|
PERIOD_DIFF(7002,6803) |\n+------------------------+\n|
-1177 |\n+------------------------+\n\nURL:
https://mariadb.com/kb/en/period_diff/','','https://mariadb.com/kb/en/period_diff/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(543,31,'QUARTER','Syntax\n------\n\nQUARTER(date)\n\nDescription\n-----------\n\nReturns
the quarter of the year for date, in the range 1 to 4. Returns 0 if\nmonth
contains a zero value, or NULL if the given value is not otherwise a\nvalid
date (zero values are accepted).\n\nExamples\n--------\n\nSELECT
QUARTER(\'2008-04-01\');\n+-----------------------+\n|
QUARTER(\'2008-04-01\') |\n+-----------------------+\n|
2 |\n+-----------------------+\n\nSELECT
QUARTER(\'2019-00-01\');\n+-----------------------+\n|
QUARTER(\'2019-00-01\') |\n+-----------------------+\n|
0 |\n+-----------------------+\n\nURL:
https://mariadb.com/kb/en/quarter/','','https://mariadb.com/kb/en/quarter/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(544,31,'SECOND','Syntax\n------\n\nSECOND(time)\n\nDescription\n-----------\n\nReturns
the second for a given time (which can include microseconds), in the\nrange
0 to 59, or NULL if not given a valid time
value.\n\nExamples\n--------\n\nSELECT
SECOND(\'10:05:03\');\n+--------------------+\n|
SECOND(\'10:05:03\') |\n+--------------------+\n|
3 |\n+--------------------+\n\nSELECT
SECOND(\'10:05:01.999999\');\n+---------------------------+\n|
SECOND(\'10:05:01.999999\') |\n+---------------------------+\n|
1 |\n+---------------------------+\n\nURL:
https://mariadb.com/kb/en/second/','','https://mariadb.com/kb/en/second/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(545,31,'SEC_TO_TIME','Syntax\n------\n\nSEC_TO_TIME(seconds)\n\nDescription\n-----------\n\nReturns
the seconds argument, converted to hours, minutes, and seconds, as a\nTIME
value. The range of the result is constrained to that of the TIME
data\ntype. A warning occurs if the argument corresponds to a value outside
that\nrange.\n\nThe time will be returned in the format hh:mm:ss, or hhmmss
if used in a\nnumeric calculation.\n\nExamples\n--------\n\nSELECT
SEC_TO_TIME(12414);\n+--------------------+\n| SEC_TO_TIME(12414)
|\n+--------------------+\n| 03:26:54
|\n+--------------------+\n\nSELECT
SEC_TO_TIME(12414)+0;\n+----------------------+\n| SEC_TO_TIME(12414)+0
|\n+----------------------+\n| 32654
|\n+----------------------+\n\nSELECT
SEC_TO_TIME(9999999);\n+----------------------+\n| SEC_TO_TIME(9999999)
|\n+----------------------+\n| 838:59:59
|\n+----------------------+\n1 row in set, 1 warning (0.00 sec)\n\nSHOW
WARNINGS;\n+---------+------+-------------------------------------------+\n|
Level | Code | Message
|\n+---------+------+-------------------------------------------+\n|
Warning | 1292 | Truncated incorrect time value: \'9999999\'
|\n+---------+------+-------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/sec_to_time/','','https://mariadb.com/kb/en/sec_to_time/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(546,31,'STR_TO_DATE','Syntax\n------\n\nSTR_TO_DATE(str,format)\n\nDescription\n-----------\n\nThis
is the inverse of the DATE_FORMAT() function. It takes a string str and
a\nformat string format. STR_TO_DATE() returns a DATETIME value if the
format\nstring contains both date and time parts, or a DATE or TIME value
if the\nstring contains only date or time parts.\n\nThe date, time, or
datetime values contained in str should be given in the\nformat indicated
by format. If str contains an illegal date, time, or datetime\nvalue,
STR_TO_DATE() returns NULL. An illegal value also produces a
warning.\n\nUnder specific SQL_MODE settings an error may also be generated
if the str\nisn\'t a valid date:\n\n* ALLOW_INVALID_DATES\n*
NO_ZERO_DATE\n* NO_ZERO_IN_DATE\n\nThe options that can be used by
STR_TO_DATE(), as well as its inverse\nDATE_FORMAT() and the
FROM_UNIXTIME() function,
are:\n\n+---------------------------+------------------------------------------------+\n|
Option | Description
|\n+---------------------------+------------------------------------------------+\n|
%a | Short weekday name in current locale
|\n| | (Variable lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%b | Short form month name in current locale. For
|\n| | locale en_US this is one of:
|\n| |
Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov |\n|
| or Dec.
|\n+---------------------------+------------------------------------------------+\n|
%c | Month with 1 or 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%D | Day with English suffix \'th\',
\'nd\', \'st\' or |\n| |
\'rd\'\'. (1st, 2nd, 3rd...).
|\n+---------------------------+------------------------------------------------+\n|
%d | Day with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%e | Day with 1 or 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%f | Microseconds 6 digits.
|\n+---------------------------+------------------------------------------------+\n|
%H | Hour with 2 digits between 00-23.
|\n+---------------------------+------------------------------------------------+\n|
%h | Hour with 2 digits between 01-12.
|\n+---------------------------+------------------------------------------------+\n|
%I | Hour with 2 digits between 01-12.
|\n+---------------------------+------------------------------------------------+\n|
%i | Minute with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%j | Day of the year (001-366)
|\n+---------------------------+------------------------------------------------+\n|
%k | Hour with 1 digits between 0-23.
|\n+---------------------------+------------------------------------------------+\n|
%l | Hour with 1 digits between 1-12.
|\n+---------------------------+------------------------------------------------+\n|
%M | Full month name in current locale (Variable
|\n| | lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%m | Month with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%p | AM/PM according to current locale (Variable
|\n| | lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%r | Time in 12 hour format, followed by AM/PM.
|\n| | Short for \'%I:%i:%S %p\'.
|\n+---------------------------+------------------------------------------------+\n|
%S | Seconds with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%s | Seconds with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%T | Time in 24 hour format. Short for
\'%H:%i:%S\'.
|\n+---------------------------+------------------------------------------------+\n|
%U | Week number (00-53), when first day of the
|\n| | week is Sunday.
|\n+---------------------------+------------------------------------------------+\n|
%u | Week number (00-53), when first day of the
|\n| | week is Monday.
|\n+---------------------------+------------------------------------------------+\n|
%V | Week number (01-53), when first day of the
|\n| | week is Sunday. Used with %X.
|\n+---------------------------+------------------------------------------------+\n|
%v | Week number (01-53), when first day of the
|\n| | week is Monday. Used with %x.
|\n+---------------------------+------------------------------------------------+\n|
%W | Full weekday name in current locale (Variable
|\n| | lc_time_names).
|\n+---------------------------+------------------------------------------------+\n|
%w | Day of the week. 0 = Sunday, 6 = Saturday.
|\n+---------------------------+------------------------------------------------+\n|
%X | Year with 4 digits when first day of the week
|\n| | is Sunday. Used with %V.
|\n+---------------------------+------------------------------------------------+\n|
%x | Year with 4 digits when first day of the week
|\n| | is Monday. Used with %v.
|\n+---------------------------+------------------------------------------------+\n|
%Y | Year with 4 digits.
|\n+---------------------------+------------------------------------------------+\n|
%y | Year with 2 digits.
|\n+---------------------------+------------------------------------------------+\n|
%# | For str_to_date(), skip all numbers.
|\n+---------------------------+------------------------------------------------+\n|
%. | For str_to_date(), skip all punctation
|\n| | characters.
|\n+---------------------------+------------------------------------------------+\n|
%@ | For str_to_date(), skip all alpha characters.
|\n+---------------------------+------------------------------------------------+\n|
%% | A literal % character.
|\n+---------------------------+------------------------------------------------+\n\nExamples\n--------\n\nSELECT
STR_TO_DATE(\'Wednesday, June 2, 2014\', \'%W, %M %e,
%Y\');\n+---------------------------------------------------------+\n|
STR_TO_DATE(\'Wednesday, June 2, 2014\', \'%W, %M %e,
%Y\')
|\n+---------------------------------------------------------+\n|
2014-06-02
|\n+---------------------------------------------------------+\n\nSELECT
STR_TO_DATE(\'Wednesday23423, June 2, 2014\', \'%W, %M %e,
%Y\');\n+--------------------------------------------------------------+\n|
STR_TO_DATE(\'Wednesday23423, June 2, 2014\', \'%W, %M %e,
%Y\')
|\n+--------------------------------------------------------------+\n| NULL
|\n+--------------------------------------------------------------+\n1 row
in set, 1 warning (0.00 sec)\n\nSHOW
WARNINGS;\n+---------+------+-------------------------------------------------------------\n---------------------+\n|
Level | Code | Message
\n
|\n+---------+------+-------------------------------------------------------------\n---------------------+\n|
Warning | 1411 | Incorrect datetime value: \'Wednesday23423, June 2,
2014\'\nfor function str_to_date
|\n+---------+------+-------------------------------------------------------------\n---------------------+\n\nSELECT
STR_TO_DATE(\'Wednesday23423, June 2, 2014\', \'%W%#, %M %e,
%Y\');\n+----------------------------------------------------------------+\n|
STR_TO_DATE(\'Wednesday23423, June 2, 2014\', \'%W%#, %M %e,
%Y\')
|\n+----------------------------------------------------------------+\n|
2014-06-02
|\n+----------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/str_to_date/','','https://mariadb.com/kb/en/str_to_date/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(547,31,'SUBDATE','Syntax\n------\n\nSUBDATE(date,INTERVAL
expr unit), SUBDATE(expr,days)\n\nDescription\n-----------\n\nWhen invoked
with the INTERVAL form of the second argument, SUBDATE() is a\nsynonym for
DATE_SUB(). See Date and Time Units for a complete list of\npermitted
units.\n\nThe second form allows the use of an integer value for days. In
such cases, it\nis interpreted as the number of days to be subtracted from
the date or\ndatetime expression expr.\n\nExamples\n--------\n\nSELECT
DATE_SUB(\'2008-01-02\', INTERVAL 31
DAY);\n+-----------------------------------------+\n|
DATE_SUB(\'2008-01-02\', INTERVAL 31 DAY)
|\n+-----------------------------------------+\n| 2007-12-02
|\n+-----------------------------------------+\n\nSELECT
SUBDATE(\'2008-01-02\', INTERVAL 31
DAY);\n+----------------------------------------+\n|
SUBDATE(\'2008-01-02\', INTERVAL 31 DAY)
|\n+----------------------------------------+\n| 2007-12-02
|\n+----------------------------------------+\n\nSELECT
SUBDATE(\'2008-01-02 12:00:00\',
31);\n+------------------------------------+\n| SUBDATE(\'2008-01-02
12:00:00\', 31) |\n+------------------------------------+\n|
2007-12-02 12:00:00
|\n+------------------------------------+\n\nCREATE TABLE t1 (d
DATETIME);\nINSERT INTO t1 VALUES\n (\"2007-01-30 21:31:07\"),\n
(\"1983-10-15 06:42:51\"),\n (\"2011-04-21
12:34:56\"),\n (\"2011-10-30 06:31:41\"),\n
(\"2011-01-30 14:03:25\"),\n (\"2004-10-07
11:19:34\");\n\nSELECT d, SUBDATE(d, 10) from
t1;\n+---------------------+---------------------+\n| d |
SUBDATE(d, 10) |\n+---------------------+---------------------+\n|
2007-01-30 21:31:07 | 2007-01-20 21:31:07 |\n| 1983-10-15 06:42:51 |
1983-10-05 06:42:51 |\n| 2011-04-21 12:34:56 | 2011-04-11 12:34:56 |\n|
2011-10-30 06:31:41 | 2011-10-20 06:31:41 |\n| 2011-01-30 14:03:25 |
2011-01-20 14:03:25 |\n| 2004-10-07 11:19:34 | 2004-09-27 11:19:34
|\n+---------------------+---------------------+\n\nSELECT d, SUBDATE(d,
INTERVAL 10 MINUTE) from
t1;\n+---------------------+--------------------------------+\n| d
| SUBDATE(d, INTERVAL 10 MINUTE)
|\n+---------------------+--------------------------------+\n| 2007-01-30
21:31:07 | 2007-01-30 21:21:07 |\n| 1983-10-15 06:42:51 |
1983-10-15 06:32:51 |\n| 2011-04-21 12:34:56 | 2011-04-21
12:24:56 |\n| 2011-10-30 06:31:41 | 2011-10-30 06:21:41
|\n| 2011-01-30 14:03:25 | 2011-01-30 13:53:25 |\n| 2004-10-07
11:19:34 | 2004-10-07 11:09:34
|\n+---------------------+--------------------------------+\n\nURL:
https://mariadb.com/kb/en/subdate/','','https://mariadb.com/kb/en/subdate/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(548,31,'SUBTIME','Syntax\n------\n\nSUBTIME(expr1,expr2)\n\nDescription\n-----------\n\nSUBTIME()
returns expr1 - expr2 expressed as a value in the same format as\nexpr1.
expr1 is a time or datetime expression, and expr2 is a time
expression.\n\nExamples\n--------\n\nSELECT SUBTIME(\'2007-12-31
23:59:59.999999\',\'1
1:1:1.000002\');\n+--------------------------------------------------------+\n|
SUBTIME(\'2007-12-31 23:59:59.999999\',\'1
1:1:1.000002\')
|\n+--------------------------------------------------------+\n| 2007-12-30
22:58:58.999997
|\n+--------------------------------------------------------+\n\nSELECT
SUBTIME(\'01:00:00.999999\',
\'02:00:00.999998\');\n+-----------------------------------------------+\n|
SUBTIME(\'01:00:00.999999\', \'02:00:00.999998\')
|\n+-----------------------------------------------+\n| -00:59:59.999999
|\n+-----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/subtime/','','https://mariadb.com/kb/en/subtime/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(549,31,'SYSDATE','Syntax\n------\n\nSYSDATE([precision])\n\nDescription\n-----------\n\nReturns
the current date and time as a value in \'YYYY-MM-DD HH:MM:SS\'
or\nYYYYMMDDHHMMSS.uuuuuu format, depending on whether the function is used
in a\nstring or numeric context.\n\nThe optional precision determines the
microsecond precision. See Microseconds\nin MariaDB.\n\nSYSDATE() returns
the time at which it executes. This differs from the\nbehavior for NOW(),
which returns a constant time that indicates the time at\nwhich the
statement began to execute. (Within a stored routine or trigger,\nNOW()
returns the time at which the routine or triggering statement began
to\nexecute.)\n\nIn addition, changing the timestamp system variable with a
SET timestamp\nstatement affects the value returned by NOW() but not by
SYSDATE(). This means\nthat timestamp settings in the binary log have no
effect on invocations of\nSYSDATE().\n\nBecause SYSDATE() can return
different values even within the same statement,\nand is not affected by
SET TIMESTAMP, it is non-deterministic and therefore\nunsafe for
replication if statement-based binary logging is used. If that is
a\nproblem, you can use row-based logging, or start the server with the
mysqld\noption --sysdate-is-now to cause SYSDATE() to be an alias for
NOW(). The\nnon-deterministic nature of SYSDATE() also means that indexes
cannot be used\nfor evaluating expressions that refer to it, and that
statements using the\nSYSDATE() function are unsafe for statement-based
replication.\n\nExamples\n--------\n\nDifference between NOW() and
SYSDATE():\n\nSELECT NOW(), SLEEP(2),
NOW();\n+---------------------+----------+---------------------+\n| NOW()
| SLEEP(2) | NOW()
|\n+---------------------+----------+---------------------+\n| 2010-03-27
13:23:40 | 0 | 2010-03-27 13:23:40
|\n+---------------------+----------+---------------------+\n\nSELECT
SYSDATE(), SLEEP(2),
SYSDATE();\n+---------------------+----------+---------------------+\n|
SYSDATE() | SLEEP(2) | SYSDATE()
|\n+---------------------+----------+---------------------+\n| 2010-03-27
13:23:52 | 0 | 2010-03-27 13:23:54
|\n+---------------------+----------+---------------------+\n\nWith
precision:\n\nSELECT SYSDATE(4);\n+--------------------------+\n|
SYSDATE(4) |\n+--------------------------+\n| 2018-07-10
10:17:13.1689 |\n+--------------------------+\n\nURL:
https://mariadb.com/kb/en/sysdate/','','https://mariadb.com/kb/en/sysdate/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(550,31,'TIME
Function','Syntax\n------\n\nTIME(expr)\n\nDescription\n-----------\n\nExtracts
the time part of the time or datetime expression expr and returns it\nas a
string.\n\nExamples\n--------\n\nSELECT TIME(\'2003-12-31
01:02:03\');\n+-----------------------------+\n|
TIME(\'2003-12-31 01:02:03\')
|\n+-----------------------------+\n| 01:02:03
|\n+-----------------------------+\n\nSELECT TIME(\'2003-12-31
01:02:03.000123\');\n+------------------------------------+\n|
TIME(\'2003-12-31 01:02:03.000123\')
|\n+------------------------------------+\n| 01:02:03.000123
|\n+------------------------------------+\n\nURL:
https://mariadb.com/kb/en/time-function/','','https://mariadb.com/kb/en/time-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(551,31,'TIMEDIFF','Syntax\n------\n\nTIMEDIFF(expr1,expr2)\n\nDescription\n-----------\n\nTIMEDIFF()
returns expr1 - expr2 expressed as a time value. expr1 and expr2\nare time
or date-and-time expressions, but both must be of the same
type.\n\nExamples\n--------\n\nSELECT TIMEDIFF(\'2000:01:01
00:00:00\', \'2000:01:01
00:00:00.000001\');\n+---------------------------------------------------------------+\n|
TIMEDIFF(\'2000:01:01 00:00:00\', \'2000:01:01
00:00:00.000001\')
|\n+---------------------------------------------------------------+\n|
-00:00:00.000001
|\n+---------------------------------------------------------------+\n\nSELECT
TIMEDIFF(\'2008-12-31 23:59:59.000001\', \'2008-12-30
01:01:01.000002\');\n+----------------------------------------------------------------------+\n|
TIMEDIFF(\'2008-12-31 23:59:59.000001\', \'2008-12-30
01:01:01.000002\')
|\n+----------------------------------------------------------------------+\n|
46:58:57.999999
|\n+----------------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/timediff/','','https://mariadb.com/kb/en/timediff/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(552,31,'TIMESTAMP
FUNCTION','Syntax\n------\n\nTIMESTAMP(expr),
TIMESTAMP(expr1,expr2)\n\nDescription\n-----------\n\nWith a single
argument, this function returns the date or datetime expression\nexpr as a
datetime value. With two arguments, it adds the time expression\nexpr2 to
the date or datetime expression expr1 and returns the result as a\ndatetime
value.\n\nExamples\n--------\n\nSELECT
TIMESTAMP(\'2003-12-31\');\n+-------------------------+\n|
TIMESTAMP(\'2003-12-31\') |\n+-------------------------+\n|
2003-12-31 00:00:00 |\n+-------------------------+\n\nSELECT
TIMESTAMP(\'2003-12-31
12:00:00\',\'6:30:00\');\n+--------------------------------------------+\n|
TIMESTAMP(\'2003-12-31 12:00:00\',\'6:30:00\')
|\n+--------------------------------------------+\n| 2003-12-31 18:30:00
|\n+--------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/timestamp-function/','','https://mariadb.com/kb/en/timestamp-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(553,31,'TIMESTAMPADD','Syntax\n------\n\nTIMESTAMPADD(unit,interval,datetime_expr)\n\nDescription\n-----------\n\nAdds
the integer expression interval to the date or datetime
expression\ndatetime_expr. The unit for interval is given by the unit
argument, which\nshould be one of the following values: MICROSECOND,
SECOND, MINUTE, HOUR, DAY,\nWEEK, MONTH, QUARTER, or YEAR.\n\nThe unit
value may be specified using one of keywords as shown, or with a\nprefix of
SQL_TSI_. For example, DAY and SQL_TSI_DAY both are legal.\n\nBefore
MariaDB 5.5, FRAC_SECOND was permitted as a synonym for
MICROSECOND.\n\nExamples\n--------\n\nSELECT
TIMESTAMPADD(MINUTE,1,\'2003-01-02\');\n+-------------------------------------+\n|
TIMESTAMPADD(MINUTE,1,\'2003-01-02\')
|\n+-------------------------------------+\n| 2003-01-02 00:01:00
|\n+-------------------------------------+\n\nSELECT
TIMESTAMPADD(WEEK,1,\'2003-01-02\');\n+-----------------------------------+\n|
TIMESTAMPADD(WEEK,1,\'2003-01-02\')
|\n+-----------------------------------+\n| 2003-01-09
|\n+-----------------------------------+\n\nURL:
https://mariadb.com/kb/en/timestampadd/','','https://mariadb.com/kb/en/timestampadd/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(554,31,'TIMESTAMPDIFF','Syntax\n------\n\nTIMESTAMPDIFF(unit,datetime_expr1,datetime_expr2)\n\nDescription\n-----------\n\nReturns
datetime_expr2 - datetime_expr1, where datetime_expr1 and\ndatetime_expr2
are date or datetime expressions. One expression may be a date\nand the
other a datetime; a date value is treated as a datetime having the\ntime
part \'00:00:00\' where necessary. The unit for the result (an
integer) is\ngiven by the unit argument. The legal values for unit are the
same as those\nlisted in the description of the TIMESTAMPADD() function,
i.e MICROSECOND,\nSECOND, MINUTE, HOUR, DAY, WEEK, MONTH, QUARTER, or
YEAR.\n\nTIMESTAMPDIFF can also be used to calculate
age.\n\nExamples\n--------\n\nSELECT
TIMESTAMPDIFF(MONTH,\'2003-02-01\',\'2003-05-01\');\n+------------------------------------------------+\n|
TIMESTAMPDIFF(MONTH,\'2003-02-01\',\'2003-05-01\')
|\n+------------------------------------------------+\n|
3
|\n+------------------------------------------------+\n\nSELECT
TIMESTAMPDIFF(YEAR,\'2002-05-01\',\'2001-01-01\');\n+-----------------------------------------------+\n|
TIMESTAMPDIFF(YEAR,\'2002-05-01\',\'2001-01-01\')
|\n+-----------------------------------------------+\n|
-1
|\n+-----------------------------------------------+\n\nSELECT
TIMESTAMPDIFF(MINUTE,\'2003-02-01\',\'2003-05-01
12:05:55\');\n+----------------------------------------------------------+\n|
TIMESTAMPDIFF(MINUTE,\'2003-02-01\',\'2003-05-01
12:05:55\')
|\n+----------------------------------------------------------+\n|
128885
|\n+----------------------------------------------------------+\n\nCalculating
age:\n\nSELECT CURDATE();\n+------------+\n| CURDATE()
|\n+------------+\n| 2019-05-27 |\n+------------+\n\nSELECT
TIMESTAMPDIFF(YEAR, \'1971-06-06\', CURDATE()) AS
age;\n+------+\n| age |\n+------+\n| 47 |\n+------+\n\nSELECT
TIMESTAMPDIFF(YEAR, \'1971-05-06\', CURDATE()) AS
age;\n+------+\n| age |\n+------+\n| 48 |\n+------+\n\nAge as of
2014-08-02:\n\nSELECT name, date_of_birth,
TIMESTAMPDIFF(YEAR,date_of_birth,\'2014-08-02\') AS\nage \n FROM
student_details;\n+---------+---------------+------+\n| name |
date_of_birth | age |\n+---------+---------------+------+\n| Chun |
1993-12-31 | 20 |\n| Esben | 1946-01-01 | 68 |\n| Kaolin |
1996-07-16 | 18 |\n| Tatiana | 1988-04-13 | 26
|\n+---------+---------------+------+\n\nURL:
https://mariadb.com/kb/en/timestampdiff/','','https://mariadb.com/kb/en/timestampdiff/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(555,31,'TIME_FORMAT','Syntax\n------\n\nTIME_FORMAT(time,format)\n\nDescription\n-----------\n\nThis
is used like the DATE_FORMAT() function, but the format string may\ncontain
format specifiers only for hours, minutes, and seconds. Other\nspecifiers
produce a NULL value or 0.\n\nExamples\n--------\n\nSELECT
TIME_FORMAT(\'100:00:00\', \'%H %k %h %I
%l\');\n+--------------------------------------------+\n|
TIME_FORMAT(\'100:00:00\', \'%H %k %h %I %l\')
|\n+--------------------------------------------+\n| 100 100 04 04 4
|\n+--------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/time_format/','','https://mariadb.com/kb/en/time_format/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(556,31,'TIME_TO_SEC','Syntax\n------\n\nTIME_TO_SEC(time)\n\nDescription\n-----------\n\nReturns
the time argument, converted to seconds.\n\nThe value returned by
TIME_TO_SEC is of type DOUBLE. Before MariaDB 5.3 (and\nMySQL 5.6), the
type was INT. The returned value preserves microseconds of the\nargument.
See also Microseconds in MariaDB.\n\nExamples\n--------\n\nSELECT
TIME_TO_SEC(\'22:23:00\');\n+-------------------------+\n|
TIME_TO_SEC(\'22:23:00\') |\n+-------------------------+\n|
80580 |\n+-------------------------+\n\nSELECT
TIME_TO_SEC(\'00:39:38\');\n+-------------------------+\n|
TIME_TO_SEC(\'00:39:38\') |\n+-------------------------+\n|
2378 |\n+-------------------------+\n\nSELECT
TIME_TO_SEC(\'09:12:55.2355\');\n+------------------------------+\n|
TIME_TO_SEC(\'09:12:55.2355\')
|\n+------------------------------+\n| 33175.2355
|\n+------------------------------+\n1 row in set (0.000 sec)\n\nURL:
https://mariadb.com/kb/en/time_to_sec/','','https://mariadb.com/kb/en/time_to_sec/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(557,31,'TO_DAYS','Syntax\n------\n\nTO_DAYS(date)\n\nDescription\n-----------\n\nGiven
a date date, returns the number of days since the start of the
current\ncalendar (0000-00-00).\n\nThe function is not designed for use
with dates before the advent of the\nGregorian calendar in October 1582.
Results will not be reliable since it\ndoesn\'t account for the lost
days when the calendar changed from the Julian\ncalendar.\n\nThis is the
converse of the FROM_DAYS() function.\n\nExamples\n--------\n\nSELECT
TO_DAYS(\'2007-10-07\');\n+-----------------------+\n|
TO_DAYS(\'2007-10-07\') |\n+-----------------------+\n|
733321 |\n+-----------------------+\n\nSELECT
TO_DAYS(\'0000-01-01\');\n+-----------------------+\n|
TO_DAYS(\'0000-01-01\') |\n+-----------------------+\n|
1 |\n+-----------------------+\n\nSELECT
TO_DAYS(950501);\n+-----------------+\n| TO_DAYS(950501)
|\n+-----------------+\n| 728779 |\n+-----------------+\n\nURL:
https://mariadb.com/kb/en/to_days/','','https://mariadb.com/kb/en/to_days/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(558,31,'TO_SECONDS','Syntax\n------\n\nTO_SECONDS(expr)\n\nDescription\n-----------\n\nReturns
the number of seconds from year 0 till expr, or NULL if expr is not
a\nvalid date or datetime.\n\nExamples\n--------\n\nSELECT
TO_SECONDS(\'2013-06-13\');\n+--------------------------+\n|
TO_SECONDS(\'2013-06-13\') |\n+--------------------------+\n|
63538300800 |\n+--------------------------+\n\nSELECT
TO_SECONDS(\'2013-06-13
21:45:13\');\n+-----------------------------------+\n|
TO_SECONDS(\'2013-06-13 21:45:13\')
|\n+-----------------------------------+\n|
63538379113 |\n+-----------------------------------+\n\nSELECT
TO_SECONDS(NOW());\n+-------------------+\n| TO_SECONDS(NOW())
|\n+-------------------+\n| 63543530875
|\n+-------------------+\n\nSELECT
TO_SECONDS(20130513);\n+----------------------+\n| TO_SECONDS(20130513)
|\n+----------------------+\n| 63535622400
|\n+----------------------+\n1 row in set (0.00 sec)\n\nSELECT
TO_SECONDS(130513);\n+--------------------+\n| TO_SECONDS(130513)
|\n+--------------------+\n| 63535622400
|\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/to_seconds/','','https://mariadb.com/kb/en/to_seconds/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(559,31,'UNIX_TIMESTAMP','Syntax\n------\n\nUNIX_TIMESTAMP()\nUNIX_TIMESTAMP(date)\n\nDescription\n-----------\n\nIf
called with no argument, returns a Unix timestamp (seconds
since\n\'1970-01-01 00:00:00\' UTC) as an unsigned integer. If
UNIX_TIMESTAMP() is\ncalled with a date argument, it returns the value of
the argument as seconds\nsince \'1970-01-01 00:00:00\' UTC. date
may be a DATE string, a DATETIME string,\na TIMESTAMP, or a number in the
format YYMMDD or YYYYMMDD. The server\ninterprets date as a value in the
current time zone and converts it to an\ninternal value in UTC. Clients can
set their time zone as described in time\nzones.\n\nThe inverse function of
UNIX_TIMESTAMP() is FROM_UNIXTIME()\n\nUNIX_TIMESTAMP() supports
microseconds.\n\nTimestamps in MariaDB have a maximum value of 2147483647,
equivalent to\n2038-01-19 05:14:07. This is due to the underlying 32-bit
limitation. Using\nthe function on a date beyond this will result in NULL
being returned. Use\nDATETIME as a storage type if you require dates beyond
this.\n\nError Handling\n--------------\n\nReturns NULL for wrong arguments
to UNIX_TIMESTAMP(). In MySQL and MariaDB\nbefore 5.3 wrong arguments to
UNIX_TIMESTAMP() returned 0.\n\nCompatibility\n-------------\n\nAs you can
see in the examples above, UNIX_TIMESTAMP(constant-date-string)\nreturns a
timestamp with 6 decimals while MariaDB 5.2 and before returns it\nwithout
decimals. This can cause a problem if you are using UNIX_TIMESTAMP()\nas a
partitioning function. You can fix this by using\nFLOOR(UNIX_TIMESTAMP(..))
or changing the date string to a date number,
like\n20080101000000.\n\nExamples\n--------\n\nSELECT
UNIX_TIMESTAMP();\n+------------------+\n| UNIX_TIMESTAMP()
|\n+------------------+\n| 1269711082
|\n+------------------+\n\nSELECT UNIX_TIMESTAMP(\'2007-11-30
10:30:19\');\n+---------------------------------------+\n|
UNIX_TIMESTAMP(\'2007-11-30 10:30:19\')
|\n+---------------------------------------+\n|
1196436619.000000 |\n+---------------------------------------+\n\nSELECT
UNIX_TIMESTAMP(\"2007-11-30
10:30:19.123456\");\n+----------------------------------------------+\n|
unix_timestamp(\"2007-11-30 10:30:19.123456\")
|\n+----------------------------------------------+\n|
1196411419.123456
|\n+----------------------------------------------+\n\nSELECT
FROM_UNIXTIME(UNIX_TIMESTAMP(\'2007-11-30
10:30:19\'));\n+------------------------------------------------------+\n|
FROM_UNIXTIME(UNIX_TIMESTAMP(\'2007-11-30 10:30:19\'))
|\n+------------------------------------------------------+\n| 2007-11-30
10:30:19.000000
|\n+------------------------------------------------------+\n\nSELECT
FROM_UNIXTIME(FLOOR(UNIX_TIMESTAMP(\'2007-11-30
10:30:19\')));\n+-------------------------------------------------------------+\n|
FROM_UNIXTIME(FLOOR(UNIX_TIMESTAMP(\'2007-11-30 10:30:19\')))
|\n+-------------------------------------------------------------+\n|
2007-11-30 10:30:19
|\n+-------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/unix_timestamp/','','https://mariadb.com/kb/en/unix_timestamp/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(560,31,'UTC_DATE','Syntax\n------\n\nUTC_DATE,
UTC_DATE()\n\nDescription\n-----------\n\nReturns the current UTC date as a
value in \'YYYY-MM-DD\' or YYYYMMDD format,\ndepending on whether
the function is used in a string or numeric
context.\n\nExamples\n--------\n\nSELECT UTC_DATE(), UTC_DATE() +
0;\n+------------+----------------+\n| UTC_DATE() | UTC_DATE() + 0
|\n+------------+----------------+\n| 2010-03-27 | 20100327
|\n+------------+----------------+\n\nURL:
https://mariadb.com/kb/en/utc_date/','','https://mariadb.com/kb/en/utc_date/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(561,31,'UTC_TIME','Syntax\n------\n\nUTC_TIME\nUTC_TIME([precision])\n\nDescription\n-----------\n\nReturns
the current UTC time as a value in \'HH:MM:SS\' or HHMMSS.uuuuuu
format,\ndepending on whether the function is used in a string or numeric
context.\n\nThe optional precision determines the microsecond precision.
See Microseconds\nin MariaDB.\n\nExamples\n--------\n\nSELECT UTC_TIME(),
UTC_TIME() + 0;\n+------------+----------------+\n| UTC_TIME() | UTC_TIME()
+ 0 |\n+------------+----------------+\n| 17:32:34 | 173234.000000
|\n+------------+----------------+\n\nWith precision:\n\nSELECT
UTC_TIME(5);\n+----------------+\n| UTC_TIME(5) |\n+----------------+\n|
07:52:50.78369 |\n+----------------+\n\nURL:
https://mariadb.com/kb/en/utc_time/','','https://mariadb.com/kb/en/utc_time/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(562,31,'UTC_TIMESTAMP','Syntax\n------\n\nUTC_TIMESTAMP\nUTC_TIMESTAMP([precision])\n\nDescription\n-----------\n\nReturns
the current UTC date and time as a value in \'YYYY-MM-DD
HH:MM:SS\' or\nYYYYMMDDHHMMSS.uuuuuu format, depending on whether the
function is used in a\nstring or numeric context.\n\nThe optional precision
determines the microsecond precision. See Microseconds\nin
MariaDB.\n\nExamples\n--------\n\nSELECT UTC_TIMESTAMP(), UTC_TIMESTAMP() +
0;\n+---------------------+-----------------------+\n| UTC_TIMESTAMP()
| UTC_TIMESTAMP() + 0
|\n+---------------------+-----------------------+\n| 2010-03-27 17:33:16 |
20100327173316.000000
|\n+---------------------+-----------------------+\n\nWith
precision:\n\nSELECT UTC_TIMESTAMP(4);\n+--------------------------+\n|
UTC_TIMESTAMP(4) |\n+--------------------------+\n| 2018-07-10
07:51:09.1019 |\n+--------------------------+\n\nURL:
https://mariadb.com/kb/en/utc_timestamp/','','https://mariadb.com/kb/en/utc_timestamp/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(563,31,'WEEK','Syntax\n------\n\nWEEK(date[,mode])\n\nDescription\n-----------\n\nThis
function returns the week number for date. The two-argument form of\nWEEK()
allows you to specify whether the week starts on Sunday or Monday
and\nwhether the return value should be in the range from 0 to 53 or from 1
to 53.\nIf the mode argument is omitted, the value of the
default_week_format system\nvariable is
used.\n\nModes\n-----\n\n+-------+---------------------+--------+------------------------------------+\n|
Mode | 1st day of week | Range | Week 1 is the 1st week with
|\n+-------+---------------------+--------+------------------------------------+\n|
0 | Sunday | 0-53 | a Sunday in this year
|\n+-------+---------------------+--------+------------------------------------+\n|
1 | Monday | 0-53 | more than 3 days this year
|\n+-------+---------------------+--------+------------------------------------+\n|
2 | Sunday | 1-53 | a Sunday in this year
|\n+-------+---------------------+--------+------------------------------------+\n|
3 | Monday | 1-53 | more than 3 days this year
|\n+-------+---------------------+--------+------------------------------------+\n|
4 | Sunday | 0-53 | more than 3 days this year
|\n+-------+---------------------+--------+------------------------------------+\n|
5 | Monday | 0-53 | a Monday in this year
|\n+-------+---------------------+--------+------------------------------------+\n|
6 | Sunday | 1-53 | more than 3 days this year
|\n+-------+---------------------+--------+------------------------------------+\n|
7 | Monday | 1-53 | a Monday in this year
|\n+-------+---------------------+--------+------------------------------------+\n\nWith
the mode value of 3, which means \'more than 3 days this year\',
weeks are\nnumbered according to ISO
8601:1988.\n\nExamples\n--------\n\nSELECT
WEEK(\'2008-02-20\');\n+--------------------+\n|
WEEK(\'2008-02-20\') |\n+--------------------+\n|
7 |\n+--------------------+\n\nSELECT
WEEK(\'2008-02-20\',0);\n+----------------------+\n|
WEEK(\'2008-02-20\',0) |\n+----------------------+\n|
7 |\n+----------------------+\n\nSELECT
WEEK(\'2008-02-20\',1);\n+----------------------+\n|
WEEK(\'2008-02-20\',1) |\n+----------------------+\n|
8 |\n+----------------------+\n\nSELECT
WEEK(\'2008-12-31\',0);\n+----------------------+\n|
WEEK(\'2008-12-31\',0) |\n+----------------------+\n|
52 |\n+----------------------+\n\nSELECT
WEEK(\'2008-12-31\',1);\n+----------------------+\n|
WEEK(\'2008-12-31\',1) |\n+----------------------+\n|
53 |\n+----------------------+\n\nSELECT
WEEK(\'2019-12-30\',3);\n+----------------------+\n|
WEEK(\'2019-12-30\',3) |\n+----------------------+\n|
1 |\n+----------------------+\n\nCREATE TABLE t1 (d
DATETIME);\nINSERT INTO t1 VALUES\n (\"2007-01-30 21:31:07\"),\n
(\"1983-10-15 06:42:51\"),\n (\"2011-04-21
12:34:56\"),\n (\"2011-10-30 06:31:41\"),\n
(\"2011-01-30 14:03:25\"),\n (\"2004-10-07
11:19:34\");\n\nSELECT d, WEEK(d,0), WEEK(d,1) from
t1;\n+---------------------+-----------+-----------+\n| d
| WEEK(d,0) | WEEK(d,1)
|\n+---------------------+-----------+-----------+\n| 2007-01-30 21:31:07 |
4 | 5 |\n| 1983-10-15 06:42:51 | 41 | 41 |\n|
2011-04-21 12:34:56 | 16 | 16 |\n| 2011-10-30 06:31:41 |
44 | 43 |\n| 2011-01-30 14:03:25 | 5 | 4 |\n|
2004-10-07 11:19:34 | 40 | 41
|\n+---------------------+-----------+-----------+\n\nURL:
https://mariadb.com/kb/en/week/','','https://mariadb.com/kb/en/week/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(564,31,'WEEKDAY','Syntax\n------\n\nWEEKDAY(date)\n\nDescription\n-----------\n\nReturns
the weekday index for date (0 = Monday, 1 = Tuesday, ... 6 =
Sunday).\n\nThis contrasts with DAYOFWEEK() which follows the ODBC standard
(1 = Sunday, 2\n= Monday, ..., 7 =
Saturday).\n\nExamples\n--------\n\nSELECT WEEKDAY(\'2008-02-03
22:23:00\');\n+--------------------------------+\n|
WEEKDAY(\'2008-02-03 22:23:00\')
|\n+--------------------------------+\n| 6
|\n+--------------------------------+\n\nSELECT
WEEKDAY(\'2007-11-06\');\n+-----------------------+\n|
WEEKDAY(\'2007-11-06\') |\n+-----------------------+\n|
1 |\n+-----------------------+\n\nCREATE TABLE t1 (d
DATETIME);\nINSERT INTO t1 VALUES\n (\"2007-01-30 21:31:07\"),\n
(\"1983-10-15 06:42:51\"),\n (\"2011-04-21
12:34:56\"),\n (\"2011-10-30 06:31:41\"),\n
(\"2011-01-30 14:03:25\"),\n (\"2004-10-07
11:19:34\");\n\nSELECT d FROM t1 where WEEKDAY(d) =
6;\n+---------------------+\n| d
|\n+---------------------+\n| 2011-10-30 06:31:41 |\n| 2011-01-30 14:03:25
|\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/weekday/','','https://mariadb.com/kb/en/weekday/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(565,31,'WEEKOFYEAR','Syntax\n------\n\nWEEKOFYEAR(date)\n\nDescription\n-----------\n\nReturns
the calendar week of the date as a number in the range from 1 to
53.\nWEEKOFYEAR() is a compatibility function that is equivalent to
WEEK(date,3).\n\nExamples\n--------\n\nSELECT
WEEKOFYEAR(\'2008-02-20\');\n+--------------------------+\n|
WEEKOFYEAR(\'2008-02-20\') |\n+--------------------------+\n|
8 |\n+--------------------------+\n\nCREATE TABLE t1 (d
DATETIME);\nINSERT INTO t1 VALUES\n (\"2007-01-30 21:31:07\"),\n
(\"1983-10-15 06:42:51\"),\n (\"2011-04-21
12:34:56\"),\n (\"2011-10-30 06:31:41\"),\n
(\"2011-01-30 14:03:25\"),\n (\"2004-10-07
11:19:34\");\n\nselect * from t1;\n+---------------------+\n| d
|\n+---------------------+\n| 2007-01-30 21:31:07 |\n|
1983-10-15 06:42:51 |\n| 2011-04-21 12:34:56 |\n| 2011-10-30 06:31:41 |\n|
2011-01-30 14:03:25 |\n| 2004-10-07 11:19:34
|\n+---------------------+\n\nSELECT d, WEEKOFYEAR(d), WEEK(d,3) from
t1;\n+---------------------+---------------+-----------+\n| d
| WEEKOFYEAR(d) | WEEK(d,3)
|\n+---------------------+---------------+-----------+\n| 2007-01-30
21:31:07 | 5 | 5 |\n| 1983-10-15 06:42:51 |
41 | 41 |\n| 2011-04-21 12:34:56 | 16 | 16 |\n|
2011-10-30 06:31:41 | 43 | 43 |\n| 2011-01-30 14:03:25 |
4 | 4 |\n| 2004-10-07 11:19:34 | 41 |
41 |\n+---------------------+---------------+-----------+\n\nURL:
https://mariadb.com/kb/en/weekofyear/','','https://mariadb.com/kb/en/weekofyear/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(566,31,'YEAR','Syntax\n------\n\nYEAR(date)\n\nDescription\n-----------\n\nReturns
the year for the given date, in the range 1000 to 9999, or 0 for
the\n\"zero\" date.\n\nExamples\n--------\n\nCREATE TABLE t1 (d
DATETIME);\nINSERT INTO t1 VALUES\n (\"2007-01-30 21:31:07\"),\n
(\"1983-10-15 06:42:51\"),\n (\"2011-04-21
12:34:56\"),\n (\"2011-10-30 06:31:41\"),\n
(\"2011-01-30 14:03:25\"),\n (\"2004-10-07
11:19:34\");\n\nSELECT * FROM t1;\n+---------------------+\n| d
|\n+---------------------+\n| 2007-01-30 21:31:07 |\n|
1983-10-15 06:42:51 |\n| 2011-04-21 12:34:56 |\n| 2011-10-30 06:31:41 |\n|
2011-01-30 14:03:25 |\n| 2004-10-07 11:19:34
|\n+---------------------+\n\nSELECT * FROM t1 WHERE YEAR(d) =
2011;\n+---------------------+\n| d
|\n+---------------------+\n| 2011-04-21 12:34:56 |\n| 2011-10-30 06:31:41
|\n| 2011-01-30 14:03:25 |\n+---------------------+\n\nSELECT
YEAR(\'1987-01-01\');\n+--------------------+\n|
YEAR(\'1987-01-01\') |\n+--------------------+\n|
1987 |\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/year/','','https://mariadb.com/kb/en/year/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(567,31,'YEARWEEK','Syntax\n------\n\nYEARWEEK(date),
YEARWEEK(date,mode)\n\nDescription\n-----------\n\nReturns year and week
for a date. The mode argument works exactly like the\nmode argument to
WEEK(). The year in the result may be different from the year\nin the date
argument for the first and the last week of the
year.\n\nExamples\n--------\n\nSELECT
YEARWEEK(\'1987-01-01\');\n+------------------------+\n|
YEARWEEK(\'1987-01-01\') |\n+------------------------+\n|
198652 |\n+------------------------+\n\nCREATE TABLE t1 (d
DATETIME);\nINSERT INTO t1 VALUES\n (\"2007-01-30 21:31:07\"),\n
(\"1983-10-15 06:42:51\"),\n (\"2011-04-21
12:34:56\"),\n (\"2011-10-30 06:31:41\"),\n
(\"2011-01-30 14:03:25\"),\n (\"2004-10-07
11:19:34\");\n\nSELECT * FROM t1;\n+---------------------+\n| d
|\n+---------------------+\n| 2007-01-30 21:31:07 |\n|
1983-10-15 06:42:51 |\n| 2011-04-21 12:34:56 |\n| 2011-10-30 06:31:41 |\n|
2011-01-30 14:03:25 |\n| 2004-10-07 11:19:34 |\n+---------------------+\n6
rows in set (0.02 sec)\n\nSELECT YEARWEEK(d) FROM t1 WHERE YEAR(d) =
2011;\n+-------------+\n| YEARWEEK(d) |\n+-------------+\n| 201116
|\n| 201144 |\n| 201105 |\n+-------------+\n3 rows in set (0.03
sec)\n\nURL:
https://mariadb.com/kb/en/yearweek/','','https://mariadb.com/kb/en/yearweek/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(568,32,'Well-Known Binary (WKB) Format','WKB stands for
Well-Known Binary, a format for representing geographical and\ngeometrical
data.\n\nWKB uses 1-byte unsigned integers, 4-byte unsigned integers, and
8-byte\ndouble-precision numbers.\n\n* The first byte indicates the byte
order. 00 for big endian, or 01 for little\nendian.\n* The next 4 bytes
indicate the geometry type. Values from 1 to 7 indicate\nwhether the type
is Point, LineString, Polygon, MultiPoint, MultiLineString,\nMultiPolygon,
or GeometryCollection respectively. \n* The 8-byte floats represent the
co-ordinates.\n\nTake the following example, a sequence of 21 bytes each
represented by two
hex\ndigits:\n\n000000000140000000000000004010000000000000\n\n* It\'s
big endian\n000000000140000000000000004010000000000000\n\n* It\'s a
POINT\n000000000140000000000000004010000000000000\n\n* The X co-ordinate is
2.0\n000000000140000000000000004010000000000000\n\n* The Y-co-ordinate is
4.0\n000000000140000000000000004010000000000000\n\nURL:
https://mariadb.com/kb/en/well-known-binary-wkb-format/','','https://mariadb.com/kb/en/well-known-binary-wkb-format/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(569,32,'AsBinary','A synonym for ST_AsBinary().\n\nURL:
https://mariadb.com/kb/en/wkb-asbinary/','','https://mariadb.com/kb/en/wkb-asbinary/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(570,32,'AsWKB','A synonym for ST_AsBinary().\n\nURL:
https://mariadb.com/kb/en/aswkb/','','https://mariadb.com/kb/en/aswkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(571,32,'MLineFromWKB','Syntax\n------\n\nMLineFromWKB(wkb[,srid])\nMultiLineStringFromWKB(wkb[,srid])\n\nDescription\n-----------\n\nConstructs
a MULTILINESTRING value using its WKB representation and
SRID.\n\nMLineFromWKB() and MultiLineStringFromWKB() are
synonyms.\n\nExamples\n--------\n\nSET @g =
ST_AsBinary(MLineFromText(\'MULTILINESTRING((10 48,10 21,10
0),(16\n0,16 23,16 48))\'));\n\nSELECT
ST_AsText(MLineFromWKB(@g));\n+--------------------------------------------------------+\n|
ST_AsText(MLineFromWKB(@g))
|\n+--------------------------------------------------------+\n|
MULTILINESTRING((10 48,10 21,10 0),(16 0,16 23,16 48))
|\n+--------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/mlinefromwkb/','','https://mariadb.com/kb/en/mlinefromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(572,32,'MPointFromWKB','Syntax\n------\n\nMPointFromWKB(wkb[,srid])\nMultiPointFromWKB(wkb[,srid])\n\nDescription\n-----------\n\nConstructs
a MULTIPOINT value using its WKB representation and
SRID.\n\nMPointFromWKB() and MultiPointFromWKB() are
synonyms.\n\nExamples\n--------\n\nSET @g =
ST_AsBinary(MPointFromText(\'MultiPoint( 1 1, 2 2, 5 3, 7 2, 9 3, 8
4,\n6 6, 6 9, 4 9, 1 5 )\'));\n\nSELECT
ST_AsText(MPointFromWKB(@g));\n+-----------------------------------------------------+\n|
ST_AsText(MPointFromWKB(@g))
|\n+-----------------------------------------------------+\n| MULTIPOINT(1
1,2 2,5 3,7 2,9 3,8 4,6 6,6 9,4 9,1 5)
|\n+-----------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/mpointfromwkb/','','https://mariadb.com/kb/en/mpointfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(573,32,'MPolyFromWKB','Syntax\n------\n\nMPolyFromWKB(wkb[,srid])\nMultiPolygonFromWKB(wkb[,srid])\n\nDescription\n-----------\n\nConstructs
a MULTIPOLYGON value using its WKB representation and
SRID.\n\nMPolyFromWKB() and MultiPolygonFromWKB() are
synonyms.\n\nExamples\n--------\n\nSET @g =
ST_AsBinary(MPointFromText(\'MULTIPOLYGON(((28 26,28 0,84 0,84
42,28\n26),(52 18,66 23,73 9,48 6,52 18)),((59 18,67 18,67 13,59 13,59
18)))\'));\n\nSELECT
ST_AsText(MPolyFromWKB(@g))\\G\n*************************** 1. row
***************************\nST_AsText(MPolyFromWKB(@g)): MULTIPOLYGON(((28
26,28 0,84 0,84 42,28 26),(52\n18,66 23,73 9,48 6,52 18)),((59 18,67 18,67
13,59 13,59 18)))\n\nURL:
https://mariadb.com/kb/en/mpolyfromwkb/','','https://mariadb.com/kb/en/mpolyfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(574,32,'GeomCollFromWKB','A synonym for
ST_GeomCollFromWKB.\n\nURL:
https://mariadb.com/kb/en/wkb-geomcollfromwkb/','','https://mariadb.com/kb/en/wkb-geomcollfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(575,32,'GeometryCollectionFromWKB','A synonym for
ST_GeomCollFromWKB.\n\nURL:
https://mariadb.com/kb/en/geometrycollectionfromwkb/','','https://mariadb.com/kb/en/geometrycollectionfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(576,32,'GeometryFromWKB','A synonym for
ST_GeomFromWKB.\n\nURL:
https://mariadb.com/kb/en/geometryfromwkb/','','https://mariadb.com/kb/en/geometryfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(577,32,'GeomFromWKB','A synonym for ST_GeomFromWKB.\n\nURL:
https://mariadb.com/kb/en/wkb-geomfromwkb/','','https://mariadb.com/kb/en/wkb-geomfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(578,32,'LineFromWKB','A synonym for ST_LineFromWKB.\n\nURL:
https://mariadb.com/kb/en/wkb-linefromwkb/','','https://mariadb.com/kb/en/wkb-linefromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(579,32,'LineStringFromWKB','A synonym for
ST_LineFromWKB.\n\nURL:
https://mariadb.com/kb/en/linestringfromwkb/','','https://mariadb.com/kb/en/linestringfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(580,32,'MultiLineStringFromWKB','A synonym for
MLineFromWKB().\n\nURL:
https://mariadb.com/kb/en/multilinestringfromwkb/','','https://mariadb.com/kb/en/multilinestringfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(581,32,'MultiPointFromWKB','A synonym for
MPointFromWKB.\n\nURL:
https://mariadb.com/kb/en/multipointfromwkb/','','https://mariadb.com/kb/en/multipointfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(582,32,'MultiPolygonFromWKB','Synonym for
MPolyFromWKB.\n\nURL:
https://mariadb.com/kb/en/multipolygonfromwkb/','','https://mariadb.com/kb/en/multipolygonfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(583,32,'PointFromWKB','A synonym for
ST_PointFromWKB.\n\nURL:
https://mariadb.com/kb/en/wkb-pointfromwkb/','','https://mariadb.com/kb/en/wkb-pointfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(584,32,'PolyFromWKB','A synonym for ST_PolyFromWKB.\n\nURL:
https://mariadb.com/kb/en/wkb-polyfromwkb/','','https://mariadb.com/kb/en/wkb-polyfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(585,32,'PolygonFromWKB','A synonym for
ST_PolyFromWKB.\n\nURL:
https://mariadb.com/kb/en/polygonfromwkb/','','https://mariadb.com/kb/en/polygonfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(586,32,'ST_AsBinary','Syntax\n------\n\nST_AsBinary(g)\nAsBinary(g)\nST_AsWKB(g)\nAsWKB(g)\n\nDescription\n-----------\n\nConverts
a value in internal geometry format to its WKB representation and\nreturns
the binary result.\n\nST_AsBinary(), AsBinary(), ST_AsWKB() and AsWKB() are
synonyms,\n\nExamples\n--------\n\nSET @poly =
ST_GeomFromText(\'POLYGON((0 0,0 1,1 1,1 0,0 0))\');\nSELECT
ST_AsBinary(@poly);\n\nSELECT
ST_AsText(ST_GeomFromWKB(ST_AsWKB(@poly)));\n+--------------------------------------------+\n|
ST_AsText(ST_GeomFromWKB(ST_AsWKB(@poly)))
|\n+--------------------------------------------+\n| POLYGON((0 0,0 1,1 1,1
0,0 0))
|\n+--------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_asbinary/','','https://mariadb.com/kb/en/st_asbinary/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(587,32,'ST_AsWKB','A synonym for ST_AsBinary().\n\nURL:
https://mariadb.com/kb/en/st_aswkb/','','https://mariadb.com/kb/en/st_aswkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(588,32,'ST_GeomCollFromWKB','Syntax\n------\n\nST_GeomCollFromWKB(wkb[,srid])\nST_GeometryCollectionFromWKB(wkb[,srid])\nGeomCollFromWKB(wkb[,srid])\nGeometryCollectionFromWKB(wkb[,srid])\n\nDescription\n-----------\n\nConstructs
a GEOMETRYCOLLECTION value using its WKB representation and
SRID.\n\nST_GeomCollFromWKB(), ST_GeometryCollectionFromWKB(),
GeomCollFromWKB() and\nGeometryCollectionFromWKB() are
synonyms.\n\nExamples\n--------\n\nSET @g =
ST_AsBinary(ST_GeomFromText(\'GEOMETRYCOLLECTION(\n POLYGON((5 5,10
5,10 10,5 5)),POINT(10 10))\'));\n\nSELECT
ST_AsText(ST_GeomCollFromWKB(@g));\n+----------------------------------------------------------------+\n|
ST_AsText(ST_GeomCollFromWKB(@g))
|\n+----------------------------------------------------------------+\n|
GEOMETRYCOLLECTION(POLYGON((5 5,10 5,10 10,5 5)),POINT(10 10))
|\n+----------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_geomcollfromwkb/','','https://mariadb.com/kb/en/st_geomcollfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(589,32,'ST_GeometryCollectionFromWKB','A synonym for
ST_GeomCollFromWKB.\n\nURL:
https://mariadb.com/kb/en/st_geometrycollectionfromwkb/','','https://mariadb.com/kb/en/st_geometrycollectionfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(590,32,'ST_GeometryFromWKB','A synonym for
ST_GeomFromWKB.\n\nURL:
https://mariadb.com/kb/en/st_geometryfromwkb/','','https://mariadb.com/kb/en/st_geometryfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(591,32,'ST_GeomFromWKB','Syntax\n------\n\nST_GeomFromWKB(wkb[,srid])\nST_GeometryFromWKB(wkb[,srid])\nGeomFromWKB(wkb[,srid])\nGeometryFromWKB(wkb[,srid])\n\nDescription\n-----------\n\nConstructs
a geometry value of any type using its WKB representation and
SRID.\n\nST_GeomFromWKB(), ST_GeometryFromWKB(), GeomFromWKB() and
GeometryFromWKB()\nare synonyms.\n\nExamples\n--------\n\nSET @g =
ST_AsBinary(ST_LineFromText(\'LINESTRING(0 4, 4 6)\'));\n\nSELECT
ST_AsText(ST_GeomFromWKB(@g));\n+-------------------------------+\n|
ST_AsText(ST_GeomFromWKB(@g)) |\n+-------------------------------+\n|
LINESTRING(0 4,4 6) |\n+-------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_geomfromwkb/','','https://mariadb.com/kb/en/st_geomfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(592,32,'ST_LineFromWKB','Syntax\n------\n\nST_LineFromWKB(wkb[,srid])\nLineFromWKB(wkb[,srid])\nST_LineStringFromWKB(wkb[,srid])\nLineStringFromWKB(wkb[,srid])\n\nDescription\n-----------\n\nConstructs
a LINESTRING value using its WKB representation and
SRID.\n\nST_LineFromWKB(), LineFromWKB(), ST_LineStringFromWKB(),
and\nLineStringFromWKB() are synonyms.\n\nExamples\n--------\n\nSET @g =
ST_AsBinary(ST_LineFromText(\'LineString(0 4,4 6)\'));\n\nSELECT
ST_AsText(ST_LineFromWKB(@g)) AS l;\n+---------------------+\n| l
|\n+---------------------+\n| LINESTRING(0 4,4 6)
|\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/st_linefromwkb/','','https://mariadb.com/kb/en/st_linefromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(593,32,'ST_LineStringFromWKB','A synonym for
ST_LineFromWKB.\n\nURL:
https://mariadb.com/kb/en/st_linestringfromwkb/','','https://mariadb.com/kb/en/st_linestringfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(594,32,'ST_PointFromWKB','Syntax\n------\n\nST_PointFromWKB(wkb[,srid])\nPointFromWKB(wkb[,srid])\n\nDescription\n-----------\n\nConstructs
a POINT value using its WKB representation and SRID.\n\nST_PointFromWKB()
and PointFromWKB() are synonyms.\n\nExamples\n--------\n\nSET @g =
ST_AsBinary(ST_PointFromText(\'POINT(0 4)\'));\n\nSELECT
ST_AsText(ST_PointFromWKB(@g)) AS p;\n+------------+\n| p
|\n+------------+\n| POINT(0 4) |\n+------------+\n\nURL:
https://mariadb.com/kb/en/st_pointfromwkb/','','https://mariadb.com/kb/en/st_pointfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(595,32,'ST_PolyFromWKB','Syntax\n------\n\nST_PolyFromWKB(wkb[,srid])\nST_PolygonFromWKB(wkb[,srid])\nPolyFromWKB(wkb[,srid])\nPolygonFromWKB(wkb[,srid])\n\nDescription\n-----------\n\nConstructs
a POLYGON value using its WKB representation and SRID.\n\nST_PolyFromWKB(),
ST_PolygonFromWKB(), PolyFromWKB() and PolygonFromWKB()
are\nsynonyms.\n\nExamples\n--------\n\nSET @g =
ST_AsBinary(ST_PolyFromText(\'POLYGON((1 1,1 5,4 9,6 9,9 3,7
2,1\n1))\'));\n\nSELECT ST_AsText(ST_PolyFromWKB(@g)) AS
p;\n+----------------------------------------+\n| p
|\n+----------------------------------------+\n| POLYGON((1
1,1 5,4 9,6 9,9 3,7 2,1 1))
|\n+----------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_polyfromwkb/','','https://mariadb.com/kb/en/st_polyfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(596,32,'ST_PolygonFromWKB','A synonym for
ST_PolyFromWKB.\n\nURL:
https://mariadb.com/kb/en/st_polygonfromwkb/','','https://mariadb.com/kb/en/st_polygonfromwkb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(597,34,'Geometry
Types','Description\n-----------\n\nMariaDB provides a standard
way of creating spatial columns for geometry\ntypes, for example, with
CREATE TABLE or ALTER TABLE. Currently, spatial\ncolumns are supported for
MyISAM, InnoDB and ARCHIVE tables. See also SPATIAL\nINDEX.\n\nThe basic
geometry type is GEOMETRY. But the type can be more specific.
The\nfollowing types are
supported:\n\n+-----------------------------------------------------------------------------+\n|
Geometry Types
|\n+-----------------------------------------------------------------------------+\n|
POINT
|\n+-----------------------------------------------------------------------------+\n|
LINESTRING
|\n+-----------------------------------------------------------------------------+\n|
POLYGON
|\n+-----------------------------------------------------------------------------+\n|
MULTIPOINT
|\n+-----------------------------------------------------------------------------+\n|
MULTILINESTRING
|\n+-----------------------------------------------------------------------------+\n|
MULTIPOLYGON
|\n+-----------------------------------------------------------------------------+\n|
GEOMETRYCOLLECTION
|\n+-----------------------------------------------------------------------------+\n|
GEOMETRY
|\n+-----------------------------------------------------------------------------+\n\nExamples\n--------\n\nNote:
For clarity, only one type is listed per table in the examples below,\nbut
a table row can contain multiple types. For example:\n\nCREATE TABLE object
(shapeA POLYGON, shapeB LINESTRING);\n\nPOINT\n-----\n\nCREATE TABLE
gis_point (g POINT);\nSHOW FIELDS FROM gis_point;\nINSERT INTO gis_point
VALUES\n (PointFromText(\'POINT(10 10)\')),\n
(PointFromText(\'POINT(20 10)\')),\n
(PointFromText(\'POINT(20 20)\')),\n
(PointFromWKB(AsWKB(PointFromText(\'POINT(10
20)\'))));\n\nLINESTRING\n----------\n\nCREATE TABLE gis_line (g
LINESTRING);\nSHOW FIELDS FROM gis_line;\nINSERT INTO gis_line VALUES\n
(LineFromText(\'LINESTRING(0 0,0 10,10 0)\')),\n
(LineStringFromText(\'LINESTRING(10 10,20 10,20 20,10 20,10
10)\')),\n (LineStringFromWKB(AsWKB(LineString(Point(10, 10),
Point(40, 10)))));\n\nPOLYGON\n-------\n\nCREATE TABLE gis_polygon (g
POLYGON);\nSHOW FIELDS FROM gis_polygon;\nINSERT INTO gis_polygon VALUES\n
(PolygonFromText(\'POLYGON((10 10,20 10,20 20,10 20,10
10))\')),\n (PolyFromText(\'POLYGON((0 0,50 0,50 50,0 50,0 0),
(10 10,20 10,20 20,10\n20,10 10))\')),\n
(PolyFromWKB(AsWKB(Polygon(LineString(Point(0, 0), Point(30, 0),
Point(30,\n30), Point(0, 0))))));\n\nMULTIPOINT\n----------\n\nCREATE TABLE
gis_multi_point (g MULTIPOINT);\nSHOW FIELDS FROM gis_multi_point;\nINSERT
INTO gis_multi_point VALUES\n (MultiPointFromText(\'MULTIPOINT(0 0,10
10,10 20,20 20)\')),\n (MPointFromText(\'MULTIPOINT(1 1,11 11,11
21,21 21)\')),\n (MPointFromWKB(AsWKB(MultiPoint(Point(3, 6),
Point(4, 10)))));\n\nMULTILINESTRING\n---------------\n\nCREATE TABLE
gis_multi_line (g MULTILINESTRING);\nSHOW FIELDS FROM
gis_multi_line;\nINSERT INTO gis_multi_line VALUES\n
(MultiLineStringFromText(\'MULTILINESTRING((10 48,10 21,10 0),(16
0,16\n23,16 48))\')),\n (MLineFromText(\'MULTILINESTRING((10
48,10 21,10 0))\')),\n
(MLineFromWKB(AsWKB(MultiLineString(LineString(Point(1, 2), Point(3,
5)),\nLineString(Point(2, 5), Point(5, 8), Point(21,
7))))));\n\nMULTIPOLYGON\n------------\n\nCREATE TABLE gis_multi_polygon
(g MULTIPOLYGON);\nSHOW FIELDS FROM gis_multi_polygon;\nINSERT INTO
gis_multi_polygon VALUES\n (MultiPolygonFromText(\'MULTIPOLYGON(((28
26,28 0,84 0,84 42,28 26),(52\n18,66 23,73 9,48 6,52 18)),((59 18,67 18,67
13,59 13,59 18)))\')),\n (MPolyFromText(\'MULTIPOLYGON(((28
26,28 0,84 0,84 42,28 26),(52 18,66\n23,73 9,48 6,52 18)),((59 18,67 18,67
13,59 13,59 18)))\')),\n
(MPolyFromWKB(AsWKB(MultiPolygon(Polygon(LineString(Point(0, 3),
Point(3,\n3), Point(3, 0), Point(0,
3)))))));\n\nGEOMETRYCOLLECTION\n------------------\n\nCREATE TABLE
gis_geometrycollection (g GEOMETRYCOLLECTION);\nSHOW FIELDS FROM
gis_geometrycollection;\nINSERT INTO gis_geometrycollection VALUES\n
(GeomCollFromText(\'GEOMETRYCOLLECTION(POINT(0 0), LINESTRING(0
0,10\n10))\')),\n (GeometryFromWKB(AsWKB(GeometryCollection(Point(44,
6),\nLineString(Point(3, 6), Point(7, 9)))))),\n
(GeomFromText(\'GeometryCollection()\')),\n
(GeomFromText(\'GeometryCollection
EMPTY\'));\n\nGEOMETRY\n--------\n\nCREATE TABLE gis_geometry (g
GEOMETRY);\nSHOW FIELDS FROM gis_geometry;\nINSERT into gis_geometry SELECT
* FROM gis_point;\nINSERT into gis_geometry SELECT * FROM gis_line;\nINSERT
into gis_geometry SELECT * FROM gis_polygon;\nINSERT into gis_geometry
SELECT * FROM gis_multi_point;\nINSERT into gis_geometry SELECT * FROM
gis_multi_line;\nINSERT into gis_geometry SELECT * FROM
gis_multi_polygon;\nINSERT into gis_geometry SELECT * FROM
gis_geometrycollection;\n\nURL:
https://mariadb.com/kb/en/geometry-types/','','https://mariadb.com/kb/en/geometry-types/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(598,34,'Geometry
Hierarchy','Description\n-----------\n\nGeometry is the base
class. It is an abstract class. The instantiable\nsubclasses of Geometry
are restricted to zero-, one-, and two-dimensional\ngeometric objects that
exist in two-dimensional coordinate space. All\ninstantiable geometry
classes are defined so that valid instances of a\ngeometry class are
topologically closed (that is, all defined geometries\ninclude their
boundary).\n\nThe base Geometry class has subclasses for Point, Curve,
Surface, and\nGeometryCollection:\n\n* Point represents zero-dimensional
objects.\n* Curve represents one-dimensional objects, and has subclass
LineString, with\nsub-subclasses Line and LinearRing.\n* Surface is
designed for two-dimensional objects and has subclass Polygon.\n*
GeometryCollection has specialized zero-, one-, and
two-dimensional\ncollection classes named MultiPoint, MultiLineString, and
MultiPolygon for\nmodeling geometries corresponding to collections of
Points, LineStrings, and\nPolygons, respectively. MultiCurve and
MultiSurface are introduced as abstract\nsuperclasses that generalize the
collection interfaces to handle Curves and\nSurfaces.\n\nGeometry, Curve,
Surface, MultiCurve, and MultiSurface are defined as\nnon-instantiable
classes. They define a common set of methods for their\nsubclasses and are
included for extensibility.\n\nPoint, LineString, Polygon,
GeometryCollection, MultiPoint, MultiLineString,\nand MultiPolygon are
instantiable classes.\n\nURL:
https://mariadb.com/kb/en/geometry-hierarchy/','','https://mariadb.com/kb/en/geometry-hierarchy/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(599,34,'SPATIAL INDEX','Description\n-----------\n\nOn
MyISAM, Aria and InnoDB tables, MariaDB can create spatial indexes
(an\nR-tree index) using syntax similar to that for creating regular
indexes, but\nextended with the SPATIAL keyword. Currently, columns in
spatial indexes must\nbe declared NOT NULL.\n\nSpatial indexes can be
created when the table is created, or added after the\nfact like so:\n\n*
with CREATE TABLE: CREATE TABLE geom (g GEOMETRY NOT NULL, SPATIAL
INDEX(g));\n\n* with ALTER TABLE: ALTER TABLE geom ADD SPATIAL
INDEX(g);\n\n* with CREATE INDEX: CREATE SPATIAL INDEX sp_index ON geom
(g);\n\nSPATIAL INDEX creates an R-tree index. For storage engines that
support\nnon-spatial indexing of spatial columns, the engine creates a
B-tree index. A\nB-tree index on spatial values is useful for exact-value
lookups, but not for\nrange scans.\n\nFor more information on indexing
spatial columns, see CREATE INDEX.\n\nTo drop spatial indexes, use ALTER
TABLE or DROP INDEX:\n\n* with ALTER TABLE: ALTER TABLE geom DROP INDEX
g;\n\n* with DROP INDEX: DROP INDEX sp_index ON geom;\n\nData-at-Rest
Encyption\n----------------------\n\nBefore MariaDB 10.4.3, InnoDB\'s
spatial indexes could not be encrypted. If an\nInnoDB table was encrypted
and if it contained spatial indexes, then those\nindexes would be
unencrypted.\n\nIn MariaDB 10.4.3 and later, if innodb_checksum_algorithm
is set to full_crc32\nor strict_full_crc32, and if the table does not use
ROW_FORMAT=COMPRESSED,\nthen InnoDB spatial indexes will be encrypted if
the table is encrypted.\n\nSee MDEV-12026 for more information.\n\nURL:
https://mariadb.com/kb/en/spatial-index/','','https://mariadb.com/kb/en/spatial-index/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(600,35,'BOUNDARY','A synonym for ST_BOUNDARY.\n\nURL:
https://mariadb.com/kb/en/geometry-properties-boundary/','','https://mariadb.com/kb/en/geometry-properties-boundary/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(601,35,'DIMENSION','A synonym for ST_DIMENSION.\n\nURL:
https://mariadb.com/kb/en/dimension/','','https://mariadb.com/kb/en/dimension/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(602,35,'ENVELOPE','A synonym for ST_ENVELOPE.\n\nURL:
https://mariadb.com/kb/en/geometry-properties-envelope/','','https://mariadb.com/kb/en/geometry-properties-envelope/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(603,35,'GeometryN','A synonym for ST_GeometryN.\n\nURL:
https://mariadb.com/kb/en/geometry-properties-geometryn/','','https://mariadb.com/kb/en/geometry-properties-geometryn/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(604,35,'GeometryType','A synonym for
ST_GeometryType.\n\nURL:
https://mariadb.com/kb/en/geometry-properties-geometrytype/','','https://mariadb.com/kb/en/geometry-properties-geometrytype/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(605,35,'IsClosed','A synonym for ST_IsClosed.\n\nURL:
https://mariadb.com/kb/en/isclosed/','','https://mariadb.com/kb/en/isclosed/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(606,35,'IsEmpty','A synonym for ST_IsEmpty.\n\nURL:
https://mariadb.com/kb/en/geometry-properties-isempty/','','https://mariadb.com/kb/en/geometry-properties-isempty/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(607,35,'IsRing','A synonym for ST_IsRing.\n\nURL:
https://mariadb.com/kb/en/isring/','','https://mariadb.com/kb/en/isring/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(608,35,'IsSimple','A synonym for ST_IsSImple.\n\nURL:
https://mariadb.com/kb/en/geometry-properties-issimple/','','https://mariadb.com/kb/en/geometry-properties-issimple/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(609,35,'NumGeometries','A synonym for
ST_NumGeometries.\n\nURL:
https://mariadb.com/kb/en/geometry-properties-numgeometries/','','https://mariadb.com/kb/en/geometry-properties-numgeometries/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(610,35,'SRID','A synonym for ST_SRID.\n\nURL:
https://mariadb.com/kb/en/geometry-properties-srid/','','https://mariadb.com/kb/en/geometry-properties-srid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(611,35,'ST_BOUNDARY','MariaDB starting with
10.1.2\n----------------------------\nThe ST_BOUNDARY function was
introduced in MariaDB
10.1.2\n\nSyntax\n------\n\nST_BOUNDARY(g)\nBOUNDARY(g)\n\nDescription\n-----------\n\nReturns
a geometry that is the closure of the combinatorial boundary of
the\ngeometry value g.\n\nBOUNDARY() is a
synonym.\n\nExamples\n--------\n\nSELECT
ST_AsText(ST_Boundary(ST_GeomFromText(\'LINESTRING(3 3,0 0, -3
3)\')));\n+----------------------------------------------------------------------+\n|
ST_AsText(ST_Boundary(ST_GeomFromText(\'LINESTRING(3 3,0 0, -3
3)\')))
|\n+----------------------------------------------------------------------+\n|
MULTIPOINT(3 3,-3 3)
|\n+----------------------------------------------------------------------+\n\nSELECT
ST_AsText(ST_Boundary(ST_GeomFromText(\'POLYGON((3 3,0 0, -3 3,
3\n3))\')));\n+--------------------------------------------------------------------------+\n|
ST_AsText(ST_Boundary(ST_GeomFromText(\'POLYGON((3 3,0 0, -3 3, 3
3))\')))
|\n+--------------------------------------------------------------------------+\n|
LINESTRING(3 3,0 0,-3 3,3 3)
|\n+--------------------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_boundary/','','https://mariadb.com/kb/en/st_boundary/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(612,35,'ST_DIMENSION','Syntax\n------\n\nST_Dimension(g)\nDimension(g)\n\nDescription\n-----------\n\nReturns
the inherent dimension of the geometry value g. The result can
be\n\n+------------------------------------+---------------------------------------+\n|
Dimension | Definition
|\n+------------------------------------+---------------------------------------+\n|
-1 | empty geometry
|\n+------------------------------------+---------------------------------------+\n|
0 | geometry with no length or area
|\n+------------------------------------+---------------------------------------+\n|
1 | geometry with no area but nonzero
|\n| | length
|\n+------------------------------------+---------------------------------------+\n|
2 | geometry with nonzero area
|\n+------------------------------------+---------------------------------------+\n\nST_Dimension()
and Dimension() are synonyms.\n\nExamples\n--------\n\nSELECT
Dimension(GeomFromText(\'LineString(1 1,2
2)\'));\n+------------------------------------------------+\n|
Dimension(GeomFromText(\'LineString(1 1,2 2)\'))
|\n+------------------------------------------------+\n|
1
|\n+------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_dimension/','','https://mariadb.com/kb/en/st_dimension/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(613,35,'ST_ENVELOPE','Syntax\n------\n\nST_ENVELOPE(g)\nENVELOPE(g)\n\nDescription\n-----------\n\nReturns
the Minimum Bounding Rectangle (MBR) for the geometry value g. The\nresult
is returned as a Polygon value.\n\nThe polygon is defined by the corner
points of the bounding box:\n\nPOLYGON((MINX MINY, MAXX MINY, MAXX MAXY,
MINX MAXY, MINX MINY))\n\nST_ENVELOPE() and ENVELOPE() are
synonyms.\n\nExamples\n--------\n\nSELECT
AsText(ST_ENVELOPE(GeomFromText(\'LineString(1 1,4
4)\')));\n+----------------------------------------------------------+\n|
AsText(ST_ENVELOPE(GeomFromText(\'LineString(1 1,4 4)\')))
|\n+----------------------------------------------------------+\n|
POLYGON((1 1,4 1,4 4,1 4,1 1))
|\n+----------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_envelope/','','https://mariadb.com/kb/en/st_envelope/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(614,35,'ST_GEOMETRYN','Syntax\n------\n\nST_GeometryN(gc,N)\nGeometryN(gc,N)\n\nDescription\n-----------\n\nReturns
the N-th geometry in the GeometryCollection gc. Geometries are\nnumbered
beginning with 1.\n\nST_GeometryN() and GeometryN() are
synonyms.\n\nExample\n-------\n\nSET @gc =
\'GeometryCollection(Point(1 1),LineString(12 14, 9
11))\';\n\nSELECT
AsText(GeometryN(GeomFromText(@gc),1));\n+----------------------------------------+\n|
AsText(GeometryN(GeomFromText(@gc),1))
|\n+----------------------------------------+\n| POINT(1 1)
|\n+----------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_geometryn/','','https://mariadb.com/kb/en/st_geometryn/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(615,35,'ST_GEOMETRYTYPE','Syntax\n------\n\nST_GeometryType(g)\nGeometryType(g)\n\nDescription\n-----------\n\nReturns
as a string the name of the geometry type of which the geometry\ninstance g
is a member. The name corresponds to one of the instantiable\nGeometry
subclasses.\n\nST_GeometryType() and GeometryType() are
synonyms.\n\nExamples\n--------\n\nSELECT
GeometryType(GeomFromText(\'POINT(1
1)\'));\n+------------------------------------------+\n|
GeometryType(GeomFromText(\'POINT(1 1)\'))
|\n+------------------------------------------+\n| POINT
|\n+------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_geometrytype/','','https://mariadb.com/kb/en/st_geometrytype/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(616,35,'ST_ISCLOSED','Syntax\n------\n\nST_IsClosed(g)\nIsClosed(g)\n\nDescription\n-----------\n\nReturns
1 if a given LINESTRING\'s start and end points are the same, or 0
if\nthey are not the same. Before MariaDB 10.1.5, returns NULL if not given
a\nLINESTRING. After MariaDB 10.1.5, returns -1.\n\nST_IsClosed() and
IsClosed() are synonyms.\n\nExamples\n--------\n\nSET @ls =
\'LineString(0 0, 0 4, 4 4, 0 0)\';\nSELECT
ST_ISCLOSED(GEOMFROMTEXT(@ls));\n+--------------------------------+\n|
ST_ISCLOSED(GEOMFROMTEXT(@ls)) |\n+--------------------------------+\n|
1 |\n+--------------------------------+\n\nSET @ls
= \'LineString(0 0, 0 4, 4 4, 0 1)\';\nSELECT
ST_ISCLOSED(GEOMFROMTEXT(@ls));\n+--------------------------------+\n|
ST_ISCLOSED(GEOMFROMTEXT(@ls)) |\n+--------------------------------+\n|
0 |\n+--------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_isclosed/','','https://mariadb.com/kb/en/st_isclosed/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(617,35,'ST_ISEMPTY','Syntax\n------\n\nST_IsEmpty(g)\nIsEmpty(g)\n\nDescription\n-----------\n\nIsEmpty
is a function defined by the OpenGIS specification, but is not
fully\nimplemented by MariaDB or MySQL.\n\nSince MariaDB and MySQL do not
support GIS EMPTY values such as POINT EMPTY,\nas implemented it simply
returns 1 if the geometry value g is invalid, 0 if it\nis valid, and NULL
if the argument is NULL.\n\nST_IsEmpty() and IsEmpty() are
synonyms.\n\nURL:
https://mariadb.com/kb/en/st_isempty/','','https://mariadb.com/kb/en/st_isempty/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(618,35,'ST_IsRing','MariaDB starting with
10.1.2\n----------------------------\nThe ST_IsRing function was introduced
in MariaDB
10.1.2\n\nSyntax\n------\n\nST_IsRing(g)\nIsRing(g)\n\nDescription\n-----------\n\nReturns
true if a given LINESTRING is a ring, that is, both ST_IsClosed
and\nST_IsSimple. A simple curve does not pass through the same point more
than\nonce. However, see MDEV-7510.\n\nSt_IsRing() and IsRing() are
synonyms.\n\nURL:
https://mariadb.com/kb/en/st_isring/','','https://mariadb.com/kb/en/st_isring/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(619,35,'ST_IsSimple','Syntax\n------\n\nST_IsSimple(g)\nIsSimple(g)\n\nDescription\n-----------\n\nReturns
true if the given Geometry has no anomalous geometric points, false if\nit
does, or NULL if given a NULL value.\n\nST_IsSimple() and IsSimple() are
synonyms.\n\nExamples\n--------\n\nA POINT is always simple.\n\nSET @g =
\'Point(1 2)\';\n\nSELECT
ST_ISSIMPLE(GEOMFROMTEXT(@g));\n+-------------------------------+\n|
ST_ISSIMPLE(GEOMFROMTEXT(@g)) |\n+-------------------------------+\n|
1 |\n+-------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_issimple/','','https://mariadb.com/kb/en/st_issimple/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(620,35,'ST_NUMGEOMETRIES','Syntax\n------\n\nST_NumGeometries(gc)\nNumGeometries(gc)\n\nDescription\n-----------\n\nReturns
the number of geometries in the GeometryCollection
gc.\n\nST_NumGeometries() and NumGeometries() are
synonyms.\n\nExample\n-------\n\nSET @gc =
\'GeometryCollection(Point(1 1),LineString(2 2, 3
3))\';\n\nSELECT
NUMGEOMETRIES(GeomFromText(@gc));\n+----------------------------------+\n|
NUMGEOMETRIES(GeomFromText(@gc)) |\n+----------------------------------+\n|
2
|\n+----------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_numgeometries/','','https://mariadb.com/kb/en/st_numgeometries/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(621,35,'ST_RELATE','MariaDB starting with
10.1.2\n----------------------------\nThe ST_RELATE() function was
introduced in MariaDB 10.1.2\n\nSyntax\n------\n\nST_Relate(g1, g2,
i)\n\nDescription\n-----------\n\nReturns true if Geometry g1 is spatially
related to Geometryg2 by testing for\nintersections between the interior,
boundary and exterior of the two\ngeometries as specified by the values in
intersection matrix pattern i.\n\nURL:
https://mariadb.com/kb/en/st_relate/','','https://mariadb.com/kb/en/st_relate/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(622,35,'ST_SRID','Syntax\n------\n\nST_SRID(g)\nSRID(g)\n\nDescription\n-----------\n\nReturns
an integer indicating the Spatial Reference System ID for the
geometry\nvalue g.\n\nIn MariaDB, the SRID value is just an integer
associated with the geometry\nvalue. All calculations are done assuming
Euclidean (planar) geometry.\n\nST_SRID() and SRID() are
synonyms.\n\nExamples\n--------\n\nSELECT
SRID(GeomFromText(\'LineString(1 1,2
2)\',101));\n+-----------------------------------------------+\n|
SRID(GeomFromText(\'LineString(1 1,2 2)\',101))
|\n+-----------------------------------------------+\n|
101
|\n+-----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_srid/','','https://mariadb.com/kb/en/st_srid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(623,36,'LOAD_FILE','Syntax\n------\n\nLOAD_FILE(file_name)\n\nDescription\n-----------\n\nReads
the file and returns the file contents as a string. To use this\nfunction,
the file must be located on the server host, you must specify the\nfull
path name to the file, and you must have the FILE privilege. The file\nmust
be readable by all and it must be less than the size, in bytes, of
the\nmax_allowed_packet system variable. If the secure_file_priv system
variable is\nset to a non-empty directory name, the file to be loaded must
be located in\nthat directory.\n\nIf the file does not exist or cannot be
read because one of the preceding\nconditions is not satisfied, the
function returns NULL.\n\nSince MariaDB 5.1, the character_set_filesystem
system variable has controlled\ninterpretation of file names that are given
as literal strings.\n\nStatements using the LOAD_FILE() function are not
safe for statement based\nreplication. This is because the slave will
execute the LOAD_FILE() command\nitself. If the file doesn\'t exist on
the slave, the function will return NULL.\n\nExamples\n--------\n\nUPDATE t
SET blob_col=LOAD_FILE(\'/tmp/picture\') WHERE id=1;\n\nURL:
https://mariadb.com/kb/en/load_file/','','https://mariadb.com/kb/en/load_file/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(624,36,'NOT REGEXP','Syntax\n------\n\nexpr NOT REGEXP pat,
expr NOT RLIKE pat\n\nDescription\n-----------\n\nThis is the same as NOT
(expr REGEXP pat).\n\nURL:
https://mariadb.com/kb/en/not-regexp/','','https://mariadb.com/kb/en/not-regexp/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(625,36,'REGEXP','Syntax\n------\n\nexpr REGEXP pat, expr
RLIKE pat\n\nDescription\n-----------\n\nPerforms a pattern match of a
string expression expr against a pattern pat.\nThe pattern can be an
extended regular expression. See Regular Expressions\nOverview for details
on the syntax for regular expressions (see also PCRE\nRegular
Expressions).\n\nReturns 1 if expr matches pat or 0 if it doesn\'t
match. If either expr or pat\nare NULL, the result is NULL.\n\nThe negative
form NOT REGEXP also exists, as an alias for NOT (string REGEXP\npattern).
RLIKE and NOT RLIKE are synonyms for REGEXP and NOT REGEXP,\noriginally
provided for mSQL compatibility.\n\nThe pattern need not be a literal
string. For example, it can be specified as\na string expression or table
column.\n\nNote: Because MariaDB uses the C escape syntax in strings (for
example, \"\\n\"\nto represent the newline character), you must
double any \"\\\" that you use in\nyour REGEXP strings.\n\nREGEXP
is not case sensitive, except when used with binary strings.\n\nMariaDB
10.0.5 moved to the PCRE regex library - see PCRE Regular Expressions\nfor
enhancements to REGEXP introduced in MariaDB 10.0.5.\n\nThe
default_regex_flags variable addresses the remaining
compatibilities\nbetween PCRE and the old regex
library.\n\nExamples\n--------\n\nSELECT \'Monty!\' REGEXP
\'m%y%%\';\n+-------------------------+\n| \'Monty!\'
REGEXP \'m%y%%\' |\n+-------------------------+\n|
0 |\n+-------------------------+\n\nSELECT \'Monty!\'
REGEXP \'.*\';\n+----------------------+\n| \'Monty!\'
REGEXP \'.*\' |\n+----------------------+\n| 1
|\n+----------------------+\n\nSELECT \'new*\\n*line\' REGEXP
\'new\\\\*.\\\\*line\';\n+---------------------------------------+\n|
\'new*\\n*line\' REGEXP \'new\\\\*.\\\\*line\'
|\n+---------------------------------------+\n|
1 |\n+---------------------------------------+\n\nSELECT
\'a\' REGEXP \'A\', \'a\' REGEXP BINARY
\'A\';\n+----------------+-----------------------+\n|
\'a\' REGEXP \'A\' | \'a\' REGEXP BINARY
\'A\' |\n+----------------+-----------------------+\n|
1 | 0
|\n+----------------+-----------------------+\n\nSELECT \'a\'
REGEXP \'^[a-d]\';\n+---------------------+\n| \'a\'
REGEXP \'^[a-d]\' |\n+---------------------+\n|
1 |\n+---------------------+\n\ndefault_regex_flags
examples\n----------------------------\n\nMariaDB 10.0.11 introduced the
default_regex_flags variable to address the\nremaining compatibilities
between PCRE and the old regex library.\n\nThe default behaviour (multiline
match is off)\n\nSELECT \'a\\nb\\nc\' RLIKE
\'^b$\';\n+---------------------------+\n|
\'(?m)a\\nb\\nc\' RLIKE \'^b$\'
|\n+---------------------------+\n| 0
|\n+---------------------------+\n\nEnabling the multiline option using the
PCRE option syntax:\n\nSELECT \'a\\nb\\nc\' RLIKE
\'(?m)^b$\';\n+---------------------------+\n|
\'a\\nb\\nc\' RLIKE \'(?m)^b$\'
|\n+---------------------------+\n| 1
|\n+---------------------------+\n\nEnabling the multiline option using
default_regex_flags\n\nSET
default_regex_flags=\'MULTILINE\';\nSELECT
\'a\\nb\\nc\' RLIKE
\'^b$\';\n+-----------------------+\n| \'a\\nb\\nc\'
RLIKE \'^b$\' |\n+-----------------------+\n|
1 |\n+-----------------------+\n\nURL:
https://mariadb.com/kb/en/regexp/','','https://mariadb.com/kb/en/regexp/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(626,36,'REGEXP_INSTR','Syntax\n------\n\nREGEXP_INSTR(subject,
pattern)\n\nReturns the position of the first occurrence of the regular
expression pattern\nin the string subject, or 0 if pattern was not
found.\n\nThe positions start with 1 and are measured in characters (i.e.
not in bytes),\nwhich is important for multi-byte character sets. You can
cast a multi-byte\ncharacter set to BINARY to get offsets in bytes.\n\nThe
function follows the case sensitivity rules of the effective
collation.\nMatching is performed case insensitively for case insensitive
collations, and\ncase sensitively for case sensitive collations and for
binary data.\n\nThe collation case sensitivity can be overwritten using the
(?i) and (?-i)\nPCRE flags.\n\nMariaDB uses the PCRE regular expression
library for enhanced regular\nexpression performance, and REGEXP_INSTR was
introduced as part of this\nenhancement.\n\nExamples\n--------\n\nSELECT
REGEXP_INSTR(\'abc\',\'b\');\n-> 2\n\nSELECT
REGEXP_INSTR(\'abc\',\'x\');\n-> 0\n\nSELECT
REGEXP_INSTR(\'BJÖRN\',\'N\');\n-> 5\n\nCasting a
multi-byte character set as BINARY to get offsets in bytes:\n\nSELECT
REGEXP_INSTR(BINARY \'BJÖRN\',\'N\') AS
cast_utf8_to_binary;\n-> 6\n\nCase sensitivity:\n\nSELECT
REGEXP_INSTR(\'ABC\',\'b\');\n-> 2\n\nSELECT
REGEXP_INSTR(\'ABC\' COLLATE utf8_bin,\'b\');\n->
0\n\nSELECT REGEXP_INSTR(BINARY\'ABC\',\'b\');\n->
0\n\nSELECT REGEXP_INSTR(\'ABC\',\'(?-i)b\');\n->
0\n\nSELECT REGEXP_INSTR(\'ABC\' COLLATE
utf8_bin,\'(?i)b\');\n-> 2\n\nURL:
https://mariadb.com/kb/en/regexp_instr/','','https://mariadb.com/kb/en/regexp_instr/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(627,36,'REGEXP_REPLACE','Syntax\n------\n\nREGEXP_REPLACE(subject,
pattern, replace)\n\nDescription\n-----------\n\nREGEXP_REPLACE returns the
string subject with all occurrences of the regular\nexpression pattern
replaced by the string replace. If no occurrences are\nfound, then subject
is returned as is.\n\nThe replace string can have backreferences to the
subexpressions in the form\n\\N, where N is a number from 1 to 9.\n\nThe
function follows the case sensitivity rules of the effective
collation.\nMatching is performed case insensitively for case insensitive
collations, and\ncase sensitively for case sensitive collations and for
binary data.\n\nThe collation case sensitivity can be overwritten using the
(?i) and (?-i)\nPCRE flags.\n\nMariaDB uses the PCRE regular expression
library for enhanced regular\nexpression performance, and REGEXP_REPLACE
was introduced as part of this\nenhancement.\n\nThe default_regex_flags
variable addresses the remaining compatibilities\nbetween PCRE and the old
regex library.\n\nExamples\n--------\n\nSELECT
REGEXP_REPLACE(\'ab12cd\',\'[0-9]\',\'\') AS
remove_digits;\n->
abcd\n\nSELECT\nREGEXP_REPLACE(\'<html><head><title>title</title><body>body</body></htm>\',\n\'<.+?>\',\'
\')\nAS strip_html;\n-> title body\n\nBackreferences to the
subexpressions in the form \\N, where N is a number from\n1 to 9:\n\nSELECT
REGEXP_REPLACE(\'James Bond\',\'^(.*)
(.*)$\',\'\\\\2, \\\\1\') AS reorder_name;\n-> Bond,
James\n\nCase insensitive and case sensitive matches:\n\nSELECT
REGEXP_REPLACE(\'ABC\',\'b\',\'-\') AS
case_insensitive;\n-> A-C\n\nSELECT REGEXP_REPLACE(\'ABC\'
COLLATE utf8_bin,\'b\',\'-\') AS case_sensitive;\n->
ABC\n\nSELECT REGEXP_REPLACE(BINARY
\'ABC\',\'b\',\'-\') AS binary_data;\n->
ABC\n\nOverwriting the collation case sensitivity using the (?i) and (?-i)
PCRE flags.\n\nSELECT
REGEXP_REPLACE(\'ABC\',\'(?-i)b\',\'-\') AS
force_case_sensitive;\n-> ABC\n\nSELECT REGEXP_REPLACE(BINARY
\'ABC\',\'(?i)b\',\'-\') AS
force_case_insensitive;\n-> A-C\n\nURL:
https://mariadb.com/kb/en/regexp_replace/','','https://mariadb.com/kb/en/regexp_replace/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(628,36,'REGEXP_SUBSTR','Syntax\n------\n\nREGEXP_SUBSTR(subject,pattern)\n\nDescription\n-----------\n\nReturns
the part of the string subject that matches the regular
expression\npattern, or an empty string if pattern was not found.\n\nThe
function follows the case sensitivity rules of the effective
collation.\nMatching is performed case insensitively for case insensitive
collations, and\ncase sensitively for case sensitive collations and for
binary data.\n\nThe collation case sensitivity can be overwritten using the
(?i) and (?-i)\nPCRE flags.\n\nMariaDB uses the PCRE regular expression
library for enhanced regular\nexpression performance, and REGEXP_SUBSTR was
introduced as part of this\nenhancement.\n\nThe default_regex_flags
variable addresses the remaining compatibilities\nbetween PCRE and the old
regex library.\n\nExamples\n--------\n\nSELECT
REGEXP_SUBSTR(\'ab12cd\',\'[0-9]+\');\n->
12\n\nSELECT REGEXP_SUBSTR(\n \'See https://mariadb.org/en/foundation/
for details\',\n \'https?://[^/]*\');\n->
https://mariadb.org\n\nSELECT
REGEXP_SUBSTR(\'ABC\',\'b\');\n-> B\n\nSELECT
REGEXP_SUBSTR(\'ABC\' COLLATE
utf8_bin,\'b\');\n->\n\nSELECT
REGEXP_SUBSTR(BINARY\'ABC\',\'b\');\n->\n\nSELECT
REGEXP_SUBSTR(\'ABC\',\'(?i)b\');\n-> B\n\nSELECT
REGEXP_SUBSTR(\'ABC\' COLLATE
utf8_bin,\'(?+i)b\');\n-> B\n\nURL:
https://mariadb.com/kb/en/regexp_substr/','','https://mariadb.com/kb/en/regexp_substr/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(629,36,'ASCII','Syntax\n------\n\nASCII(str)\n\nDescription\n-----------\n\nReturns
the numeric ASCII value of the leftmost character of the string\nargument.
Returns 0 if the given string is empty and NULL if it is NULL.\n\nASCII()
works for 8-bit characters.\n\nExamples\n--------\n\nSELECT
ASCII(9);\n+----------+\n| ASCII(9) |\n+----------+\n| 57
|\n+----------+\n\nSELECT ASCII(\'9\');\n+------------+\n|
ASCII(\'9\') |\n+------------+\n| 57
|\n+------------+\n\nSELECT ASCII(\'abc\');\n+--------------+\n|
ASCII(\'abc\') |\n+--------------+\n| 97
|\n+--------------+\n\nURL:
https://mariadb.com/kb/en/ascii/','','https://mariadb.com/kb/en/ascii/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(630,36,'BIN','Syntax\n------\n\nBIN(N)\n\nDescription\n-----------\n\nReturns
a string representation of the binary value of the given longlong\n(that
is, BIGINT) number. This is equivalent to CONV(N,10,2). The
argument\nshould be positive. If it is a FLOAT, it will be truncated.
Returns NULL if\nthe argument is NULL.\n\nExamples\n--------\n\nSELECT
BIN(12);\n+---------+\n| BIN(12) |\n+---------+\n| 1100
|\n+---------+\n\nURL:
https://mariadb.com/kb/en/bin/','','https://mariadb.com/kb/en/bin/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(631,36,'BINARY Operator','This page describes the BINARY
operator. For details about the data type, see\nBinary Data
Type.\n\nSyntax\n------\n\nBINARY\n\nDescription\n-----------\n\nThe BINARY
operator casts the string following it to a binary string. This is\nan easy
way to force a column comparison to be done byte by byte rather
than\ncharacter by character. This causes the comparison to be case
sensitive even\nif the column isn\'t defined as BINARY or
BLOB.\n\nBINARY also causes trailing spaces to be
significant.\n\nExamples\n--------\n\nSELECT \'a\' =
\'A\';\n+-----------+\n| \'a\' = \'A\'
|\n+-----------+\n| 1 |\n+-----------+\n\nSELECT BINARY
\'a\' = \'A\';\n+------------------+\n| BINARY
\'a\' = \'A\' |\n+------------------+\n|
0 |\n+------------------+\n\nSELECT \'a\' = \'a
\';\n+------------+\n| \'a\' = \'a \'
|\n+------------+\n| 1 |\n+------------+\n\nSELECT BINARY
\'a\' = \'a \';\n+-------------------+\n| BINARY
\'a\' = \'a \' |\n+-------------------+\n|
0 |\n+-------------------+\n\nURL:
https://mariadb.com/kb/en/binary-operator/','','https://mariadb.com/kb/en/binary-operator/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(632,36,'BIT_LENGTH','Syntax\n------\n\nBIT_LENGTH(str)\n\nDescription\n-----------\n\nReturns
the length of the given string argument in bits. If the argument is\nnot a
string, it will be converted to string. If the argument is NULL,
it\nreturns NULL.\n\nExamples\n--------\n\nSELECT
BIT_LENGTH(\'text\');\n+--------------------+\n|
BIT_LENGTH(\'text\') |\n+--------------------+\n|
32 |\n+--------------------+\n\nSELECT
BIT_LENGTH(\'\');\n+----------------+\n|
BIT_LENGTH(\'\') |\n+----------------+\n| 0
|\n+----------------+\n\nCompatibility\n-------------\n\nPostgreSQL and
Sybase support BIT_LENGTH().\n\nURL:
https://mariadb.com/kb/en/bit_length/','','https://mariadb.com/kb/en/bit_length/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(633,36,'CAST','Syntax\n------\n\nCAST(expr AS
type)\n\nDescription\n-----------\n\nThe CAST() function takes a value of
one type and produces a value of another\ntype, similar to the CONVERT()
function.\n\nThe type can be one of the following values:\n\n* BINARY\n*
CHAR\n* DATE\n* DATETIME\n* DECIMAL[(M[,D])]\n* DOUBLE\n* FLOAT (from
MariaDB 10.4.5)\n* INTEGER\nShort for SIGNED INTEGER\n\n* SIGNED
[INTEGER]\n* UNSIGNED [INTEGER]\n* TIME\n* VARCHAR (in Oracle mode, from
MariaDB 10.3)\n\nThe main difference between CAST and CONVERT() is that
CONVERT(expr,type) is\nODBC syntax while CAST(expr as type) and CONVERT(...
USING ...) are SQL92\nsyntax.\n\nIn MariaDB 10.4 and later, you can use the
CAST() function with the INTERVAL\nkeyword.\n\nUntil MariaDB 5.5.31,
X\'HHHH\', the standard SQL syntax for binary string\nliterals,
erroneously worked in the same way as 0xHHHH. In 5.5.31 it
was\nintentionally changed to behave as a string in all contexts (and never
as a\nnumber).\n\nThis introduced an incompatibility with previous versions
of MariaDB, and all\nversions of MySQL (see the example
below).\n\nExamples\n--------\n\nSimple casts:\n\nSELECT
CAST(\"abc\" AS BINARY);\nSELECT CAST(\"1\" AS UNSIGNED
INTEGER);\nSELECT CAST(123 AS CHAR CHARACTER SET utf8)\n\nNote that when
one casts to CHAR without specifying the character set,
the\ncollation_connection character set collation will be used. When used
with CHAR\nCHARACTER SET, the default collation for that character set will
be used.\n\nSELECT COLLATION(CAST(123 AS
CHAR));\n+------------------------------+\n| COLLATION(CAST(123 AS CHAR))
|\n+------------------------------+\n| latin1_swedish_ci
|\n+------------------------------+\n\nSELECT COLLATION(CAST(123 AS CHAR
CHARACTER SET
utf8));\n+-------------------------------------------------+\n|
COLLATION(CAST(123 AS CHAR CHARACTER SET utf8))
|\n+-------------------------------------------------+\n| utf8_general_ci
|\n+-------------------------------------------------+\n\nIf you also want
to change the collation, you have to use the COLLATE operator:\n\nSELECT
COLLATION(CAST(123 AS CHAR CHARACTER SET utf8) \n COLLATE
utf8_unicode_ci);\n+-------------------------------------------------------------------------+\n|
COLLATION(CAST(123 AS CHAR CHARACTER SET utf8) COLLATE utf8_unicode_ci)
|\n+-------------------------------------------------------------------------+\n|
utf8_unicode_ci
|\n+-------------------------------------------------------------------------+\n\nUsing
CAST() to order an ENUM field as a CHAR rather than the internal\nnumerical
value:\n\nCREATE TABLE enum_list (enum_field
enum(\'c\',\'a\',\'b\'));\n\nINSERT INTO
enum_list (enum_field)
\nVALUES(\'c\'),(\'a\'),(\'c\'),(\'b\');\n\nSELECT
* FROM enum_list \nORDER BY enum_field;\n+------------+\n| enum_field
|\n+------------+\n| c |\n| c |\n| a |\n| b
|\n+------------+\n\nSELECT * FROM enum_list \nORDER BY CAST(enum_field
AS CHAR);\n+------------+\n| enum_field |\n+------------+\n| a
|\n| b |\n| c |\n| c |\n+------------+\n\nFrom
MariaDB 5.5.31, the following will trigger warnings, since
x\'aa\' and\n\'X\'aa\' no longer behave as a
number. Previously, and in all versions of MySQL,\nno warnings are
triggered since they did erroneously behave as a number:\n\nSELECT
CAST(0xAA AS UNSIGNED), CAST(x\'aa\' AS UNSIGNED),
CAST(X\'aa\'
AS\nUNSIGNED);\n+------------------------+-------------------------+-------------------------+\n|
CAST(0xAA AS UNSIGNED) | CAST(x\'aa\' AS UNSIGNED) |
CAST(X\'aa\' AS UNSIGNED)
|\n+------------------------+-------------------------+-------------------------+\n|
170 | 0 | 0
|\n+------------------------+-------------------------+-------------------------+\n1
row in set, 2 warnings (0.00 sec)\n\nWarning (Code 1292): Truncated
incorrect INTEGER value: \'\\xAA\'\nWarning (Code 1292):
Truncated incorrect INTEGER value: \'\\xAA\'\n\nCasting to
intervals:\n\nSELECT CAST(2019-01-04 INTERVAL AS DAY_SECOND(2)) AS
\"Cast\";\n\n+-------------+\n| Cast |\n+-------------+\n|
00:20:17.00 |\n+-------------+\n\nURL:
https://mariadb.com/kb/en/cast/','','https://mariadb.com/kb/en/cast/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(634,36,'CHAR Function','Syntax\n------\n\nCHAR(N,... [USING
charset_name])\n\nDescription\n-----------\n\nCHAR() interprets each
argument as an INT and returns a string consisting of\nthe characters given
by the code values of those integers. NULL values are\nskipped. By default,
CHAR() returns a binary string. To produce a string in a\ngiven character
set, use the optional USING clause:\n\nSELECT CHARSET(CHAR(0x65)),
CHARSET(CHAR(0x65 USING
utf8));\n+---------------------+--------------------------------+\n|
CHARSET(CHAR(0x65)) | CHARSET(CHAR(0x65 USING utf8))
|\n+---------------------+--------------------------------+\n| binary
| utf8
|\n+---------------------+--------------------------------+\n\nIf USING is
given and the result string is illegal for the given character\nset, a
warning is issued. Also, if strict SQL mode is enabled, the result
from\nCHAR() becomes NULL.\n\nExamples\n--------\n\nSELECT
CHAR(77,97,114,\'105\',97,\'68\',66);\n+----------------------------------+\n|
CHAR(77,97,114,\'105\',97,\'68\',66)
|\n+----------------------------------+\n| MariaDB
|\n+----------------------------------+\n\nSELECT
CHAR(77,77.3,\'77.3\');\n+----------------------+\n|
CHAR(77,77.3,\'77.3\') |\n+----------------------+\n| MMM
|\n+----------------------+\n1 row in set, 1 warning (0.00
sec)\n\nWarning (Code 1292): Truncated incorrect INTEGER value:
\'77.3\'\n\nURL:
https://mariadb.com/kb/en/char-function/','','https://mariadb.com/kb/en/char-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(635,36,'CHAR_LENGTH','Syntax\n------\n\nCHAR_LENGTH(str)\nCHARACTER_LENGTH(str)\n\nDescription\n-----------\n\nReturns
the length of the given string argument, measured in characters.
A\nmulti-byte character counts as a single character. This means that for
a\nstring containing five two-byte characters, LENGTH() (or OCTET_LENGTH()
in\nOracle mode) returns 10, whereas CHAR_LENGTH() returns 5. If the
argument is\nNULL, it returns NULL.\n\nIf the argument is not a string
value, it is converted into a string.\n\nIt is synonymous with the
CHARACTER_LENGTH() function.\n\nExamples\n--------\n\nSELECT
CHAR_LENGTH(\'MariaDB\');\n+------------------------+\n|
CHAR_LENGTH(\'MariaDB\') |\n+------------------------+\n|
7 |\n+------------------------+\n\nWhen Oracle mode from
MariaDB 10.3 is not set:\n\nSELECT CHAR_LENGTH(\'π\'),
LENGTH(\'π\'), LENGTHB(\'π\'),
OCTET_LENGTH(\'π\');\n+-------------------+--------------+---------------+--------------------+\n|
CHAR_LENGTH(\'π\') | LENGTH(\'π\') |
LENGTHB(\'π\') | OCTET_LENGTH(\'π\')
|\n+-------------------+--------------+---------------+--------------------+\n|
1 | 2 | 2 | 2
|\n+-------------------+--------------+---------------+--------------------+\n\nIn
Oracle mode from MariaDB 10.3:\n\nSELECT CHAR_LENGTH(\'π\'),
LENGTH(\'π\'), LENGTHB(\'π\'),
OCTET_LENGTH(\'π\');\n+-------------------+--------------+---------------+--------------------+\n|
CHAR_LENGTH(\'π\') | LENGTH(\'π\') |
LENGTHB(\'π\') | OCTET_LENGTH(\'π\')
|\n+-------------------+--------------+---------------+--------------------+\n|
1 | 1 | 2 | 2
|\n+-------------------+--------------+---------------+--------------------+\n\nURL:
https://mariadb.com/kb/en/char_length/','','https://mariadb.com/kb/en/char_length/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(636,36,'CHR','MariaDB starting with
10.3.1\n----------------------------\nThe CHR() function was introduced in
MariaDB 10.3.1 to provide
Oracle\ncompatibility\n\nSyntax\n------\n\nCHR(N)\n\nDescription\n-----------\n\nCHR()
interprets each argument N as an integer and returns a VARCHAR(1)
string\nconsisting of the character given by the code values of the
integer. The\ncharacter set and collation of the string are set according
to the values of\nthe character_set_database and collation_database system
variables.\n\nCHR() is similar to the CHAR() function, but only accepts a
single argument.\n\nCHR() is available in all
sql_modes.\n\nExamples\n--------\n\nSELECT CHR(67);\n+---------+\n| CHR(67)
|\n+---------+\n| C |\n+---------+\n\nSELECT
CHR(\'67\');\n+-----------+\n| CHR(\'67\')
|\n+-----------+\n| C |\n+-----------+\n\nSELECT
CHR(\'C\');\n+----------+\n| CHR(\'C\')
|\n+----------+\n| |\n+----------+\n1 row in set, 1 warning (0.000
sec)\n\nSHOW
WARNINGS;\n+---------+------+----------------------------------------+\n|
Level | Code | Message
|\n+---------+------+----------------------------------------+\n| Warning |
1292 | Truncated incorrect INTEGER value: \'C\'
|\n+---------+------+----------------------------------------+\n\nURL:
https://mariadb.com/kb/en/chr/','','https://mariadb.com/kb/en/chr/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(637,36,'CONCAT','Syntax\n------\n\nCONCAT(str1,str2,...)\n\nDescription\n-----------\n\nReturns
the string that results from concatenating the arguments. May have one\nor
more arguments. If all arguments are non-binary strings, the result is
a\nnon-binary string. If the arguments include any binary strings, the
result is\na binary string. A numeric argument is converted to its
equivalent binary\nstring form; if you want to avoid that, you can use an
explicit type cast, as\nin this example:\n\nSELECT CONCAT(CAST(int_col AS
CHAR), char_col);\n\nCONCAT() returns NULL if any argument is NULL.\n\nA
NULL parameter hides all information contained in other parameters from
the\nresult. Sometimes this is not desirable; to avoid this, you can:\n\n*
Use the CONCAT_WS() function with an empty separator, because that
function\nis NULL-safe.\n* Use IFNULL() to turn NULLs into empty
strings.\n\nOracle Mode\n-----------\n\nMariaDB starting with
10.3\n--------------------------\nIn Oracle mode from MariaDB 10.3, CONCAT
ignores NULL.\n\nExamples\n--------\n\nSELECT CONCAT(\'Ma\',
\'ria\', \'DB\');\n+---------------------------+\n|
CONCAT(\'Ma\', \'ria\', \'DB\')
|\n+---------------------------+\n| MariaDB
|\n+---------------------------+\n\nSELECT CONCAT(\'Ma\',
\'ria\', NULL,
\'DB\');\n+---------------------------------+\n|
CONCAT(\'Ma\', \'ria\', NULL, \'DB\')
|\n+---------------------------------+\n| NULL
|\n+---------------------------------+\n\nSELECT
CONCAT(42.0);\n+--------------+\n| CONCAT(42.0) |\n+--------------+\n| 42.0
|\n+--------------+\n\nUsing IFNULL() to handle NULLs:\n\nSELECT
CONCAT(\'The value of @v is: \', IFNULL(@v,
\'\'));\n+------------------------------------------------+\n|
CONCAT(\'The value of @v is: \', IFNULL(@v, \'\'))
|\n+------------------------------------------------+\n| The value of @v
is:
|\n+------------------------------------------------+\n\nIn Oracle mode,
from MariaDB 10.3:\n\nSELECT CONCAT(\'Ma\', \'ria\',
NULL, \'DB\');\n+---------------------------------+\n|
CONCAT(\'Ma\', \'ria\', NULL, \'DB\')
|\n+---------------------------------+\n| MariaDB
|\n+---------------------------------+\n\nURL:
https://mariadb.com/kb/en/concat/','','https://mariadb.com/kb/en/concat/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(638,36,'CONCAT_WS','Syntax\n------\n\nCONCAT_WS(separator,str1,str2,...)\n\nDescription\n-----------\n\nCONCAT_WS()
stands for Concatenate With Separator and is a special form of\nCONCAT().
The first argument is the separator for the rest of the arguments.\nThe
separator is added between the strings to be concatenated. The
separator\ncan be a string, as can the rest of the arguments.\n\nIf the
separator is NULL, the result is NULL; all other NULL values are\nskipped.
This makes CONCAT_WS() suitable when you want to concatenate some\nvalues
and avoid losing all information if one of them is
NULL.\n\nExamples\n--------\n\nSELECT
CONCAT_WS(\',\',\'First name\',\'Second
name\',\'Last
Name\');\n+-------------------------------------------------------+\n|
CONCAT_WS(\',\',\'First name\',\'Second
name\',\'Last Name\')
|\n+-------------------------------------------------------+\n| First
name,Second name,Last Name
|\n+-------------------------------------------------------+\n\nSELECT
CONCAT_WS(\'-\',\'Floor\',NULL,\'Room\');\n+------------------------------------+\n|
CONCAT_WS(\'-\',\'Floor\',NULL,\'Room\')
|\n+------------------------------------+\n| Floor-Room
|\n+------------------------------------+\n\nIn some cases, remember to
include a space in the separator string:\n\nSET @a = \'gnu\', @b
= \'penguin\', @c = \'sea lion\';\nQuery OK, 0 rows
affected (0.00 sec)\n\nSELECT CONCAT_WS(\', \', @a, @b,
@c);\n+-----------------------------+\n| CONCAT_WS(\', \', @a,
@b, @c) |\n+-----------------------------+\n| gnu, penguin, sea lion
|\n+-----------------------------+\n\nUsing CONCAT_WS() to handle
NULLs:\n\nSET @a = \'a\', @b = NULL, @c =
\'c\';\n\nSELECT CONCAT_WS(\'\', @a, @b,
@c);\n+---------------------------+\n| CONCAT_WS(\'\', @a, @b,
@c) |\n+---------------------------+\n| ac
|\n+---------------------------+\n\nURL:
https://mariadb.com/kb/en/concat_ws/','','https://mariadb.com/kb/en/concat_ws/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(639,36,'CONVERT','Syntax\n------\n\nCONVERT(expr,type),
CONVERT(expr USING
transcoding_name)\n\nDescription\n-----------\n\nThe CONVERT() and CAST()
functions take a value of one type and produce a\nvalue of another
type.\n\nThe type can be one of the following values:\n\n* BINARY\n*
CHAR\n* DATE\n* DATETIME\n* DECIMAL[(M[,D])]\n* DOUBLE\n* FLOAT (from
MariaDB 10.4.5)\n* INTEGER\nShort for SIGNED INTEGER\n\n* SIGNED
[INTEGER]\n* UNSIGNED [INTEGER]\n* TIME\n* VARCHAR (in Oracle mode, from
MariaDB 10.3)\n\nNote that in MariaDB, INT and INTEGER are the same
thing.\n\nBINARY produces a string with the BINARY data type. If the
optional length is\ngiven, BINARY(N) causes the cast to use no more than N
bytes of the argument.\nValues shorter than the given number in bytes are
padded with 0x00 bytes to\nmake them equal the length value.\n\nCHAR(N)
causes the cast to use no more than the number of characters given in\nthe
argument.\n\nThe main difference between the CAST() and CONVERT() is
that\nCONVERT(expr,type) is ODBC syntax while CAST(expr as type) and
CONVERT(...\nUSING ...) are SQL92 syntax.\n\nCONVERT() with USING is used
to convert data between different character sets.\nIn MariaDB, transcoding
names are the same as the corresponding character set\nnames. For example,
this statement converts the string \'abc\' in the
default\ncharacter set to the corresponding string in the utf8 character
set:\n\nSELECT CONVERT(\'abc\' USING
utf8);\n\nExamples\n--------\n\nSELECT enum_col FROM tbl_name \nORDER BY
CAST(enum_col AS CHAR);\n\nConverting a BINARY to string to permit the
LOWER function to work:\n\nSET @x = \'AardVark\';\n\nSET @x =
BINARY \'AardVark\';\n\nSELECT LOWER(@x), LOWER(CONVERT (@x USING
latin1));\n+-----------+----------------------------------+\n| LOWER(@x) |
LOWER(CONVERT (@x USING latin1))
|\n+-----------+----------------------------------+\n| AardVark | aardvark
|\n+-----------+----------------------------------+\n\nURL:
https://mariadb.com/kb/en/convert/','','https://mariadb.com/kb/en/convert/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(640,36,'ELT','Syntax\n------\n\nELT(N, str1[, str2,
str3,...])\n\nDescription\n-----------\n\nTakes a numeric argument and a
series of string arguments. Returns the string\nthat corresponds to the
given numeric position. For instance, it returns str1\nif N is 1, str2 if N
is 2, and so on. If the numeric argument is a FLOAT,\nMariaDB rounds it to
the nearest INTEGER. If the numeric argument is less than\n1, greater than
the total number of arguments, or not a number, ELT() returns\nNULL. It
must have at least two arguments.\n\nIt is complementary to the FIELD()
function.\n\nExamples\n--------\n\nSELECT ELT(1, \'ej\',
\'Heja\', \'hej\',
\'foo\');\n+------------------------------------+\n| ELT(1,
\'ej\', \'Heja\', \'hej\', \'foo\')
|\n+------------------------------------+\n| ej
|\n+------------------------------------+\n\nSELECT ELT(4,
\'ej\', \'Heja\', \'hej\',
\'foo\');\n+------------------------------------+\n| ELT(4,
\'ej\', \'Heja\', \'hej\', \'foo\')
|\n+------------------------------------+\n| foo
|\n+------------------------------------+\n\nURL:
https://mariadb.com/kb/en/elt/','','https://mariadb.com/kb/en/elt/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(641,36,'EXPORT_SET','Syntax\n------\n\nEXPORT_SET(bits, on,
off[, separator[, number_of_bits]])\n\nDescription\n-----------\n\nTakes a
minimum of three arguments. Returns a string where each bit in the\ngiven
bits argument is returned, with the string values given for on and
off.\n\nBits are examined from right to left, (from low-order to high-order
bits).\nStrings are added to the result from left to right, separated by a
separator\nstring (defaults as \',\'). You can optionally limit
the number of bits the\nEXPORT_SET() function examines using the
number_of_bits option.\n\nIf any of the arguments are set as NULL, the
function returns NULL.\n\nExamples\n--------\n\nSELECT
EXPORT_SET(5,\'Y\',\'N\',\',\',4);\n+-----------------------------+\n|
EXPORT_SET(5,\'Y\',\'N\',\',\',4)
|\n+-----------------------------+\n| Y,N,Y,N
|\n+-----------------------------+\n\nSELECT
EXPORT_SET(6,\'1\',\'0\',\',\',10);\n+------------------------------+\n|
EXPORT_SET(6,\'1\',\'0\',\',\',10)
|\n+------------------------------+\n| 0,1,1,0,0,0,0,0,0,0
|\n+------------------------------+\n\nURL:
https://mariadb.com/kb/en/export_set/','','https://mariadb.com/kb/en/export_set/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(642,36,'EXTRACTVALUE','Syntax\n------\n\nEXTRACTVALUE(xml_frag,
xpath_expr)\n\nDescription\n-----------\n\nThe EXTRACTVALUE() function
takes two string arguments: a fragment of XML\nmarkup and an XPath
expression, (also known as a locator). It returns the text\n(That is,
CDDATA), of the first text node which is a child of the element
or\nelements matching the XPath expression.\n\nIn cases where a valid XPath
expression does not match any text nodes in a\nvalid XML fragment,
(including the implicit /text() expression), the\nEXTRACTVALUE() function
returns an empty string.\n\nInvalid Arguments\n-----------------\n\nWhen
either the XML fragment or the XPath expression is NULL,
the\nEXTRACTVALUE() function returns NULL. When the XML fragment is
invalid, it\nraises a warning Code 1525:\n\nWarning (Code 1525): Incorrect
XML value: \'parse error at line 1 pos 11:\nunexpected
END-OF-INPUT\'\n\nWhen the XPath value is invalid, it generates an
Error 1105:\n\nERROR 1105 (HY000): XPATH syntax error:
\')\'\n\nExplicit text()
Expressions\n---------------------------\n\nThis function is the equivalent
of performing a match using the XPath\nexpression after appending /text().
In other words:\n\nSELECT\n
EXTRACTVALUE(\'<cases><case>example</case></cases>\',
\'/cases/case\')\n AS \'Base Example\',\n
EXTRACTVALUE(\'<cases><case>example</case></cases>\',
\'/cases/case/text()\')\n AS \'text()
Example\';\n+--------------+----------------+\n| Base Example | text()
Example |\n+--------------+----------------+\n| example | example
|\n+--------------+----------------+\n\nCount
Matches\n-------------\n\nWhen EXTRACTVALUE() returns multiple matches, it
returns the content of the\nfirst child text node of each matching element,
in the matched order, as a\nsingle, space-delimited string.\n\nBy design,
the EXTRACTVALUE() function makes no distinction between a match on\nan
empty element and no match at all. If you need to determine whether
no\nmatching element was found in the XML fragment or if an element was
found that\ncontained no child text nodes, use the XPath count()
function.\n\nFor instance, when looking for a value that exists, but
contains no child text\nnodes, you would get a count of the number of
matching instances:\n\nSELECT\n
EXTRACTVALUE(\'<cases><case/></cases>\',
\'/cases/case\')\n AS \'Empty Example\',\n
EXTRACTVALUE(\'<cases><case/></cases>\',
\'count(/cases/case)\')\n AS \'count()
Example\';\n+---------------+-----------------+\n| Empty Example |
count() Example |\n+---------------+-----------------+\n| |
1 |\n+---------------+-----------------+\n\nAlternatively, when
looking for a value that doesn\'t exist, count() returns
0.\n\nSELECT\n
EXTRACTVALUE(\'<cases><case/></cases>\',
\'/cases/person\')\n AS \'No Match Example\',\n
EXTRACTVALUE(\'<cases><case/></cases>\',
\'count(/cases/person)\')\n AS \'count()
Example\';\n+------------------+-----------------+\n| No Match Example
| count() Example |\n+------------------+-----------------+\n|
|
0|\n+------------------+-----------------+\n\nMatches\n-------\n\nImportant:
The EXTRACTVALUE() function only returns CDDATA. It does not return\ntags
that the element might contain or the text that these child
elements\ncontain.\n\nSELECT\n\nEXTRACTVALUE(\'<cases><case>Person<email>x@example.com</email></case></cases>\',\n\'/cases\')\n
AS Case;\n+--------+\n| Case |\n+--------+\n| Person
|\n+--------+\n\nNote, in the above example, while the XPath expression
matches to the parent\n<case> instance, it does not return the
contained <email> tag or its
content.\n\nExamples\n--------\n\nSELECT\n
ExtractValue(\'<a>ccc<b>ddd</b></a>\',
\'/a\') AS val1,\n
ExtractValue(\'<a>ccc<b>ddd</b></a>\',
\'/a/b\') AS val2,\n
ExtractValue(\'<a>ccc<b>ddd</b></a>\',
\'//b\') AS val3,\n
ExtractValue(\'<a>ccc<b>ddd</b></a>\',
\'/b\') AS val4,\n
ExtractValue(\'<a>ccc<b>ddd</b><b>eee</b></a>\',
\'//b\') AS val5;\n+------+------+------+------+---------+\n|
val1 | val2 | val3 | val4 | val5
|\n+------+------+------+------+---------+\n| ccc | ddd | ddd | |
ddd eee |\n+------+------+------+------+---------+\n\nURL:
https://mariadb.com/kb/en/extractvalue/','','https://mariadb.com/kb/en/extractvalue/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(643,36,'FIELD','Syntax\n------\n\nFIELD(pattern,
str1[,str2,...])\n\nDescription\n-----------\n\nReturns the index position
of the string or number matching the given pattern.\nReturns 0 in the event
that none of the arguments match the pattern. Raises an\nError 1582 if not
given at least two arguments.\n\nWhen all arguments given to the FIELD()
function are strings, they are treated\nas case-insensitive. When all the
arguments are numbers, they are treated as\nnumbers. Otherwise, they are
treated as doubles.\n\nIf the given pattern occurs more than once,
the FIELD() function only returns\nthe index of the first instance. If the
given pattern is NULL, the function\nreturns 0, as a NULL pattern always
fails to match.\n\nThis function is complementary to the ELT()
function.\n\nExamples\n--------\n\nSELECT FIELD(\'ej\',
\'Hej\', \'ej\', \'Heja\', \'hej\',
\'foo\') \n AS \'Field Results\';\n+---------------+\n|
Field Results | \n+---------------+\n| 2
|\n+---------------+\n\nSELECT FIELD(\'fo\', \'Hej\',
\'ej\', \'Heja\', \'hej\',
\'foo\')\n AS \'Field Results\';\n+---------------+\n|
Field Results | \n+---------------+\n| 0
|\n+---------------+\n\nSELECT FIELD(1, 2, 3, 4, 5, 1) AS \'Field
Results\';\n+---------------+\n| Field Results |\n+---------------+\n|
5 |\n+---------------+\n\nSELECT FIELD(NULL, 2, 3) AS
\'Field Results\';\n+---------------+\n| Field Results
|\n+---------------+\n| 0 |\n+---------------+\n\nSELECT
FIELD(\'fail\') AS \'Field Results\';\nError 1582
(42000): Incorrect parameter count in call\nto native function
\'field\'\n\nURL:
https://mariadb.com/kb/en/field/','','https://mariadb.com/kb/en/field/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(644,36,'FIND_IN_SET','Syntax\n------\n\nFIND_IN_SET(pattern,
strlist)\n\nDescription\n-----------\n\nReturns the index position where
the given pattern occurs in a string list.\nThe first argument is the
pattern you want to search for. The second argument\nis a string containing
comma-separated variables. If the second argument is of\nthe SET data-type,
the function is optimized to use bit arithmetic.\n\nIf the pattern does not
occur in the string list or if the string list is an\nempty string, the
function returns 0. If either argument is NULL, the function\nreturns NULL.
The function does not return the correct result if the pattern\ncontains a
comma (\",\") character.\n\nExamples\n--------\n\nSELECT
FIND_IN_SET(\'b\',\'a,b,c,d\') AS \"Found
Results\";\n+---------------+\n| Found Results |\n+---------------+\n|
2 |\n+---------------+\n\nURL:
https://mariadb.com/kb/en/find_in_set/','','https://mariadb.com/kb/en/find_in_set/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(645,36,'FORMAT','Syntax\n------\n\nFORMAT(num,
decimal_position[, locale])\n\nDescription\n-----------\n\nFormats the
given number for display as a string, adding separators to\nappropriate
position and rounding the results to the given decimal position.\nFor
instance, it would format 15233.345 to 15,233.35.\n\nIf the given decimal
position is 0, it rounds to return no decimal point or\nfractional part.
You can optionally specify a locale value to format numbers\nto the pattern
appropriate for the given region.\n\nExamples\n--------\n\nSELECT
FORMAT(1234567890.09876543210, 4) AS
\'Format\';\n+--------------------+\n| Format
|\n+--------------------+\n| 1,234,567,890.0988
|\n+--------------------+\n\nSELECT FORMAT(1234567.89, 4) AS
\'Format\';\n+----------------+\n| Format
|\n+----------------+\n| 1,234,567.8900 |\n+----------------+\n\nSELECT
FORMAT(1234567.89, 0) AS \'Format\';\n+-----------+\n| Format
|\n+-----------+\n| 1,234,568 |\n+-----------+\n\nSELECT
FORMAT(123456789,2,\'rm_CH\') AS
\'Format\';\n+----------------+\n| Format
|\n+----------------+\n| 123\'456\'789,00
|\n+----------------+\n\nURL:
https://mariadb.com/kb/en/format/','','https://mariadb.com/kb/en/format/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(646,36,'FROM_BASE64','Syntax\n------\n\nFROM_BASE64(str)\n\nDescription\n-----------\n\nDecodes
the given base-64 encode string, returning the result as a binary\nstring.
Returns NULL if the given string is NULL or if it\'s invalid.\n\nIt is
the reverse of the TO_BASE64 function.\n\nThere are numerous methods to
base-64 encode a string. MariaDB uses the\nfollowing:\n\n* It encodes
alphabet value 64 as \'+\'.\n* It encodes alphabet value 63 as
\'/\'.\n* It codes output in groups of four printable characters.
Each three byte of\ndata encoded uses four characters. If the final group
is incomplete, it pads\nthe difference with the \'=\'
character.\n* It divides long output, adding a new line very 76
characters.\n* In decoding, it recognizes and ignores newlines, carriage
returns, tabs and\nspace whitespace characters.\n\nSELECT
TO_BASE64(\'Maria\') AS \'Input\';\n+-----------+\n|
Input |\n+-----------+\n| TWFyaWE= |\n+-----------+\n\nSELECT
FROM_BASE64(\'TWFyaWE=\') AS \'Output\';\n+--------+\n|
Output |\n+--------+\n| Maria |\n+--------+\n\nURL:
https://mariadb.com/kb/en/from_base64/','','https://mariadb.com/kb/en/from_base64/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(647,36,'HEX','Syntax\n------\n\nHEX(N_or_S)\n\nDescription\n-----------\n\nIf
N_or_S is a number, returns a string representation of the
hexadecimal\nvalue of N, where N is a longlong (BIGINT) number. This is
equivalent to\nCONV(N,10,16).\n\nIf N_or_S is a string, returns a
hexadecimal string representation of N_or_S\nwhere each byte of each
character in N_or_S is converted to two hexadecimal\ndigits. If N_or_S is
NULL, returns NULL. The inverse of this operation is\nperformed by the
UNHEX() function.\n\nMariaDB starting with
10.5.0\n----------------------------\nHEX() with an INET6 argument returns
a hexadecimal representation of the\nunderlying 16-byte binary
string.\n\nExamples\n--------\n\nSELECT HEX(255);\n+----------+\n| HEX(255)
|\n+----------+\n| FF |\n+----------+\n\nSELECT
0x4D617269614442;\n+------------------+\n| 0x4D617269614442
|\n+------------------+\n| MariaDB
|\n+------------------+\n\nSELECT
HEX(\'MariaDB\');\n+----------------+\n|
HEX(\'MariaDB\') |\n+----------------+\n| 4D617269614442
|\n+----------------+\n\nFrom MariaDB 10.5.0:\n\nSELECT
HEX(CAST(\'2001:db8::ff00:42:8329\' AS
INET6));\n+----------------------------------------------+\n|
HEX(CAST(\'2001:db8::ff00:42:8329\' AS INET6))
|\n+----------------------------------------------+\n|
20010DB8000000000000FF0000428329
|\n+----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/hex/','','https://mariadb.com/kb/en/hex/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(648,36,'INSTR','Syntax\n------\n\nINSTR(str,substr)\n\nDescription\n-----------\n\nReturns
the position of the first occurrence of substring substr in string\nstr.
This is the same as the two-argument form of LOCATE(), except that
the\norder of the arguments is reversed.\n\nINSTR() performs a
case-insensitive search.\n\nIf any argument is NULL, returns
NULL.\n\nExamples\n--------\n\nSELECT INSTR(\'foobarbar\',
\'bar\');\n+---------------------------+\n|
INSTR(\'foobarbar\', \'bar\')
|\n+---------------------------+\n| 4
|\n+---------------------------+\n\nSELECT INSTR(\'My\',
\'Maria\');\n+----------------------+\n| INSTR(\'My\',
\'Maria\') |\n+----------------------+\n| 0
|\n+----------------------+\n\nURL:
https://mariadb.com/kb/en/instr/','','https://mariadb.com/kb/en/instr/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(649,36,'LCASE','Syntax\n------\n\nLCASE(str)\n\nDescription\n-----------\n\nLCASE()
is a synonym for LOWER().\n\nURL:
https://mariadb.com/kb/en/lcase/','','https://mariadb.com/kb/en/lcase/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(650,36,'LEFT','Syntax\n------\n\nLEFT(str,len)\n\nDescription\n-----------\n\nReturns
the leftmost len characters from the string str, or NULL if any\nargument
is NULL.\n\nExamples\n--------\n\nSELECT LEFT(\'MariaDB\',
5);\n+--------------------+\n| LEFT(\'MariaDB\', 5)
|\n+--------------------+\n| Maria
|\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/left/','','https://mariadb.com/kb/en/left/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(651,36,'INSERT
Function','Syntax\n------\n\nINSERT(str,pos,len,newstr)\n\nDescription\n-----------\n\nReturns
the string str, with the substring beginning at position pos and
len\ncharacters long replaced by the string newstr. Returns the original
string if\npos is not within the length of the string. Replaces the rest of
the string\nfrom position pos if len is not within the length of the rest
of the string.\nReturns NULL if any argument is
NULL.\n\nExamples\n--------\n\nSELECT INSERT(\'Quadratic\', 3, 4,
\'What\');\n+-----------------------------------+\n|
INSERT(\'Quadratic\', 3, 4, \'What\')
|\n+-----------------------------------+\n| QuWhattic
|\n+-----------------------------------+\n\nSELECT
INSERT(\'Quadratic\', -1, 4,
\'What\');\n+------------------------------------+\n|
INSERT(\'Quadratic\', -1, 4, \'What\')
|\n+------------------------------------+\n| Quadratic
|\n+------------------------------------+\n\nSELECT
INSERT(\'Quadratic\', 3, 100,
\'What\');\n+-------------------------------------+\n|
INSERT(\'Quadratic\', 3, 100, \'What\')
|\n+-------------------------------------+\n| QuWhat
|\n+-------------------------------------+\n\nURL:
https://mariadb.com/kb/en/insert-function/','','https://mariadb.com/kb/en/insert-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(652,36,'LENGTH','Syntax\n------\n\nLENGTH(str)\n\nDescription\n-----------\n\nReturns
the length of the string str.\n\nIn the default mode, when Oracle mode from
MariaDB 10.3 is not set, the length\nis measured in bytes. In this case, a
multi-byte character counts as multiple\nbytes. This means that for a
string containing five two-byte characters,\nLENGTH() returns 10, whereas
CHAR_LENGTH() returns 5.\n\nWhen running Oracle mode from MariaDB 10.3, the
length is measured in\ncharacters, and LENGTH is a synonym for
CHAR_LENGTH().\n\nIf str is not a string value, it is converted into a
string. If str is NULL,\nthe function returns
NULL.\n\nExamples\n--------\n\nSELECT
LENGTH(\'MariaDB\');\n+-------------------+\n|
LENGTH(\'MariaDB\') |\n+-------------------+\n| 7
|\n+-------------------+\n\nWhen Oracle mode from MariaDB 10.3 is not
set:\n\nSELECT CHAR_LENGTH(\'π\'), LENGTH(\'π\'),
LENGTHB(\'π\'),
OCTET_LENGTH(\'π\');\n+-------------------+--------------+---------------+--------------------+\n|
CHAR_LENGTH(\'π\') | LENGTH(\'π\') |
LENGTHB(\'π\') | OCTET_LENGTH(\'π\')
|\n+-------------------+--------------+---------------+--------------------+\n|
1 | 2 | 2 | 2
|\n+-------------------+--------------+---------------+--------------------+\n\nIn
Oracle mode from MariaDB 10.3:\n\nSELECT CHAR_LENGTH(\'π\'),
LENGTH(\'π\'), LENGTHB(\'π\'),
OCTET_LENGTH(\'π\');\n+-------------------+--------------+---------------+--------------------+\n|
CHAR_LENGTH(\'π\') | LENGTH(\'π\') |
LENGTHB(\'π\') | OCTET_LENGTH(\'π\')
|\n+-------------------+--------------+---------------+--------------------+\n|
1 | 1 | 2 | 2
|\n+-------------------+--------------+---------------+--------------------+\n\nURL:
https://mariadb.com/kb/en/length/','','https://mariadb.com/kb/en/length/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(653,36,'LENGTHB','MariaDB starting with
10.3.1\n----------------------------\nIntroduced in MariaDB 10.3.1 as part
of the Oracle compatibility
enhancements.\n\nSyntax\n------\n\nLENGTHB(str)\n\nDescription\n-----------\n\nLENGTHB()
returns the length of the given string, in bytes. When Oracle mode\nis not
set, this is a synonym for LENGTH.\n\nA multi-byte character counts as
multiple bytes. This means that for a string\ncontaining five two-byte
characters, LENGTHB() returns 10, whereas\nCHAR_LENGTH() returns 5.\n\nIf
str is not a string value, it is converted into a string. If str is
NULL,\nthe function returns NULL.\n\nExamples\n--------\n\nWhen Oracle mode
from MariaDB 10.3 is not set:\n\nSELECT CHAR_LENGTH(\'π\'),
LENGTH(\'π\'), LENGTHB(\'π\'),
OCTET_LENGTH(\'π\');\n+-------------------+--------------+---------------+--------------------+\n|
CHAR_LENGTH(\'π\') | LENGTH(\'π\') |
LENGTHB(\'π\') | OCTET_LENGTH(\'π\')
|\n+-------------------+--------------+---------------+--------------------+\n|
1 | 2 | 2 | 2
|\n+-------------------+--------------+---------------+--------------------+\n\nIn
Oracle mode from MariaDB 10.3:\n\nSELECT CHAR_LENGTH(\'π\'),
LENGTH(\'π\'), LENGTHB(\'π\'),
OCTET_LENGTH(\'π\');\n+-------------------+--------------+---------------+--------------------+\n|
CHAR_LENGTH(\'π\') | LENGTH(\'π\') |
LENGTHB(\'π\') | OCTET_LENGTH(\'π\')
|\n+-------------------+--------------+---------------+--------------------+\n|
1 | 1 | 2 | 2
|\n+-------------------+--------------+---------------+--------------------+\n\nURL:
https://mariadb.com/kb/en/lengthb/','','https://mariadb.com/kb/en/lengthb/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(654,36,'LIKE','Syntax\n------\n\nexpr LIKE pat [ESCAPE
\'escape_char\']\nexpr NOT LIKE pat [ESCAPE
\'escape_char\']\n\nDescription\n-----------\n\nTests whether
expr matches the pattern pat. Returns either 1 (TRUE) or 0\n(FALSE). Both
expr and pat may be any valid expression and are evaluated to\nstrings.
Patterns may use the following wildcard characters:\n\n* % matches any
number of characters, including zero.\n* _ matches any single
character.\n\nUse NOT LIKE to test if a string does not match a pattern.
This is equivalent\nto using the NOT operator on the entire LIKE
expression.\n\nIf either the expression or the pattern is NULL, the result
is NULL.\n\nLIKE performs case-insensitive substring matches if the
collation for the\nexpression and pattern is case-insensitive. For
case-sensitive matches,\ndeclare either argument to use a binary collation
using COLLATE, or coerce\neither of them to a BINARY string using CAST. Use
SHOW COLLATION to get a list\nof available collations. Collations ending in
_bin are case-sensitive.\n\nNumeric arguments are coerced to binary
strings.\n\nThe _ wildcard matches a single character, not byte. It will
only match a\nmulti-byte character if it is valid in the expression\'s
character set. For\nexample, _ will match _utf8\"€\", but it
will not match _latin1\"€\" because the\nEuro sign is not a
valid latin1 character. If necessary, use CONVERT to use\nthe expression in
a different character set.\n\nIf you need to match the characters _ or %,
you must escape them. By default,\nyou can prefix the wildcard characters
the backslash character \\ to escape\nthem. The backslash is used both to
encode special characters like newlines\nwhen a string is parsed as well as
to escape wildcards in a pattern after\nparsing. Thus, to match an actual
backslash, you sometimes need to\ndouble-escape it as
\"\\\\\\\\\".\n\nTo avoid difficulties with the backslash
character, you can change the\nwildcard escape character using ESCAPE in a
LIKE expression. The argument to\nESCAPE must be a single-character
string.\n\nExamples\n--------\n\nSelect the days that begin with
\"T\":\n\nCREATE TABLE t1 (d VARCHAR(16));\nINSERT INTO t1 VALUES
\n (\"Monday\"), (\"Tuesday\"),
(\"Wednesday\"),\n (\"Thursday\"),
(\"Friday\"), (\"Saturday\"),
(\"Sunday\");\nSELECT * FROM t1 WHERE d LIKE
\"T%\";\n\nSELECT * FROM t1 WHERE d LIKE
\"T%\";\n+----------+\n| d |\n+----------+\n| Tuesday
|\n| Thursday |\n+----------+\n\nSelect the days that contain the substring
\"es\":\n\nSELECT * FROM t1 WHERE d LIKE
\"%es%\";\n\nSELECT * FROM t1 WHERE d LIKE
\"%es%\";\n+-----------+\n| d |\n+-----------+\n| Tuesday
|\n| Wednesday |\n+-----------+\n\nSelect the six-character day
names:\n\nSELECT * FROM t1 WHERE d like \"___day\";\n\nSELECT *
FROM t1 WHERE d like \"___day\";\n+---------+\n| d
|\n+---------+\n| Monday |\n| Friday |\n| Sunday |\n+---------+\n\nWith
the default collations, LIKE is case-insensitive:\n\nSELECT * FROM t1 where
d like \"t%\";\n\nSELECT * FROM t1 where d like
\"t%\";\n+----------+\n| d |\n+----------+\n| Tuesday
|\n| Thursday |\n+----------+\n\nUse COLLATE to specify a binary collation,
forcing case-sensitive matches:\n\nSELECT * FROM t1 WHERE d like
\"t%\" COLLATE latin1_bin;\n\nSELECT * FROM t1 WHERE d like
\"t%\" COLLATE latin1_bin;\nEmpty set (0.00 sec)\n\nYou can
include functions and operators in the expression to match. Select\ndates
based on their day name:\n\nCREATE TABLE t2 (d DATETIME);\nINSERT INTO t2
VALUES\n (\"2007-01-30 21:31:07\"),\n (\"1983-10-15
06:42:51\"),\n (\"2011-04-21 12:34:56\"),\n
(\"2011-10-30 06:31:41\"),\n (\"2011-01-30
14:03:25\"),\n (\"2004-10-07 11:19:34\");\nSELECT * FROM t2
WHERE DAYNAME(d) LIKE \"T%\";\n\nSELECT * FROM t2 WHERE
DAYNAME(d) LIKE \"T%\";\n+------------------+\n| d
|\n+------------------+\n| 2007-01-30 21:31 |\n| 2011-04-21 12:34 |\n|
2004-10-07 11:19 |\n+------------------+\n3 rows in set, 7 warnings (0.00
sec)\n\nOptimizing LIKE\n---------------\n\n* MariaDB can use indexes for
LIKE on string columns in the case where the\nLIKE doesn\'t start with
% or _.\n* Starting from MariaDB 10.0, one can set
the\noptimizer_use_condition_selectivity variable to 5. If this is done,
then the\noptimizer will read optimizer_selectivity_sampling_limit rows to
calculate the\nselectivity of the LIKE expression before starting to
calculate the query\nplan. This can help speed up some LIKE queries by
providing the optimizer with\nmore information about your data.\n\nURL:
https://mariadb.com/kb/en/like/','','https://mariadb.com/kb/en/like/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(655,36,'LOCATE','Syntax\n------\n\nLOCATE(substr,str),
LOCATE(substr,str,pos)\n\nDescription\n-----------\n\nThe first syntax
returns the position of the first occurrence of substring\nsubstr in string
str. The second syntax returns the position of the first\noccurrence of
substring substr in string str, starting at position pos.\nReturns 0 if
substr is not in str.\n\nLOCATE() performs a case-insensitive search.\n\nIf
any argument is NULL, returns NULL.\n\nINSTR() is the same as the
two-argument form of LOCATE(), except that the\norder of the arguments is
reversed.\n\nExamples\n--------\n\nSELECT LOCATE(\'bar\',
\'foobarbar\');\n+----------------------------+\n|
LOCATE(\'bar\', \'foobarbar\')
|\n+----------------------------+\n| 4
|\n+----------------------------+\n\nSELECT LOCATE(\'My\',
\'Maria\');\n+-----------------------+\n|
LOCATE(\'My\', \'Maria\')
|\n+-----------------------+\n| 0
|\n+-----------------------+\n\nSELECT LOCATE(\'bar\',
\'foobarbar\', 5);\n+-------------------------------+\n|
LOCATE(\'bar\', \'foobarbar\', 5)
|\n+-------------------------------+\n| 7
|\n+-------------------------------+\n\nURL:
https://mariadb.com/kb/en/locate/','','https://mariadb.com/kb/en/locate/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(656,36,'LOWER','Syntax\n------\n\nLOWER(str)\n\nDescription\n-----------\n\nReturns
the string str with all characters changed to lowercase according to\nthe
current character set mapping. The default is latin1 (cp1252
West\nEuropean).\n\nExamples\n--------\n\nSELECT
LOWER(\'QUADRATICALLY\');\n+------------------------+\n|
LOWER(\'QUADRATICALLY\') |\n+------------------------+\n|
quadratically |\n+------------------------+\n\nLOWER() (and
UPPER()) are ineffective when applied to binary strings
(BINARY,\nVARBINARY, BLOB). To perform lettercase conversion, CONVERT the
string to a\nnon-binary string:\n\nSET @str = BINARY \'North
Carolina\';\n\nSELECT LOWER(@str), LOWER(CONVERT(@str USING
latin1));\n+----------------+-----------------------------------+\n|
LOWER(@str) | LOWER(CONVERT(@str USING latin1))
|\n+----------------+-----------------------------------+\n| North Carolina
| north carolina
|\n+----------------+-----------------------------------+\n\nURL:
https://mariadb.com/kb/en/lower/','','https://mariadb.com/kb/en/lower/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(657,36,'LPAD','Syntax\n------\n\nLPAD(str, len
[,padstr])\n\nDescription\n-----------\n\nReturns the string str,
left-padded with the string padstr to a length of len\ncharacters. If str
is longer than len, the return value is shortened to len\ncharacters. If
padstr is omitted, the LPAD function pads spaces.\n\nPrior to MariaDB
10.3.1, the padstr parameter was mandatory.\n\nReturns NULL if given a NULL
argument. If the result is empty (zero length),\nreturns either an empty
string or, from MariaDB 10.3.6 with SQL_MODE=Oracle,\nNULL.\n\nThe Oracle
mode version of the function can be accessed outside of Oracle mode\nby
using LPAD_ORACLE as the function name.\n\nExamples\n--------\n\nSELECT
LPAD(\'hello\',10,\'.\');\n+----------------------+\n|
LPAD(\'hello\',10,\'.\') |\n+----------------------+\n|
.....hello |\n+----------------------+\n\nSELECT
LPAD(\'hello\',2,\'.\');\n+---------------------+\n|
LPAD(\'hello\',2,\'.\') |\n+---------------------+\n|
he |\n+---------------------+\n\nFrom MariaDB 10.3.1, with
the pad string defaulting to space.\n\nSELECT
LPAD(\'hello\',10);\n+------------------+\n|
LPAD(\'hello\',10) |\n+------------------+\n| hello
|\n+------------------+\n\nOracle mode version from MariaDB
10.3.6:\n\nSELECT
LPAD(\'\',0),LPAD_ORACLE(\'\',0);\n+------------+-------------------+\n|
LPAD(\'\',0) | LPAD_ORACLE(\'\',0)
|\n+------------+-------------------+\n| | NULL
|\n+------------+-------------------+\n\nURL:
https://mariadb.com/kb/en/lpad/','','https://mariadb.com/kb/en/lpad/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(658,36,'LTRIM','Syntax\n------\n\nLTRIM(str)\n\nDescription\n-----------\n\nReturns
the string str with leading space characters removed.\n\nReturns NULL if
given a NULL argument. If the result is empty, returns either\nan empty
string, or, from MariaDB 10.3.6 with SQL_MODE=Oracle, NULL.\n\nThe Oracle
mode version of the function can be accessed outside of Oracle mode\nby
using LTRIM_ORACLE as the function name.\n\nExamples\n--------\n\nSELECT
QUOTE(LTRIM(\' MariaDB
\'));\n+-------------------------------+\n| QUOTE(LTRIM(\'
MariaDB \')) |\n+-------------------------------+\n| \'MariaDB
\' |\n+-------------------------------+\n\nOracle
mode version from MariaDB 10.3.6:\n\nSELECT
LTRIM(\'\'),LTRIM_ORACLE(\'\');\n+-----------+------------------+\n|
LTRIM(\'\') | LTRIM_ORACLE(\'\')
|\n+-----------+------------------+\n| | NULL
|\n+-----------+------------------+\n\nURL:
https://mariadb.com/kb/en/ltrim/','','https://mariadb.com/kb/en/ltrim/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(659,36,'MAKE_SET','Syntax\n------\n\nMAKE_SET(bits,str1,str2,...)\n\nDescription\n-----------\n\nReturns
a set value (a string containing substrings separated by
\",\"\ncharacters) consisting of the strings that have the
corresponding bit in bits\nset. str1 corresponds to bit 0, str2 to bit 1,
and so on. NULL values in str1,\nstr2, ... are not appended to the
result.\n\nExamples\n--------\n\nSELECT
MAKE_SET(1,\'a\',\'b\',\'c\');\n+-------------------------+\n|
MAKE_SET(1,\'a\',\'b\',\'c\')
|\n+-------------------------+\n| a
|\n+-------------------------+\n\nSELECT MAKE_SET(1 |
4,\'hello\',\'nice\',\'world\');\n+----------------------------------------+\n|
MAKE_SET(1 | 4,\'hello\',\'nice\',\'world\')
|\n+----------------------------------------+\n| hello,world
|\n+----------------------------------------+\n\nSELECT
MAKE_SET(1 |
4,\'hello\',\'nice\',NULL,\'world\');\n+---------------------------------------------+\n|
MAKE_SET(1 |
4,\'hello\',\'nice\',NULL,\'world\')
|\n+---------------------------------------------+\n| hello
|\n+---------------------------------------------+\n\nSELECT
QUOTE(MAKE_SET(0,\'a\',\'b\',\'c\'));\n+--------------------------------+\n|
QUOTE(MAKE_SET(0,\'a\',\'b\',\'c\'))
|\n+--------------------------------+\n| \'\'
|\n+--------------------------------+\n\nURL:
https://mariadb.com/kb/en/make_set/','','https://mariadb.com/kb/en/make_set/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(660,36,'MATCH AGAINST','Syntax\n------\n\nMATCH
(col1,col2,...) AGAINST (expr
[search_modifier])\n\nDescription\n-----------\n\nA special construct used
to perform a fulltext search on a fulltext index.\n\nSee Fulltext Index
Overview for a full description, and Full-text Indexes for\nmore articles
on the topic.\n\nExamples\n--------\n\nCREATE TABLE ft_myisam(copy
TEXT,FULLTEXT(copy)) ENGINE=MyISAM;\n\nINSERT INTO ft_myisam(copy) VALUES
(\'Once upon a time\'), (\'There was a
wicked\nwitch\'), \n (\'Who ate everybody up\');\n\nSELECT *
FROM ft_myisam WHERE MATCH(copy)
AGAINST(\'wicked\');\n+--------------------------+\n| copy
|\n+--------------------------+\n| There was a wicked witch
|\n+--------------------------+\n\nSELECT id, body, MATCH (title,body)
AGAINST\n (\'Security implications of running MySQL as root\'\n
IN NATURAL LANGUAGE MODE) AS score\n FROM articles WHERE MATCH
(title,body) AGAINST\n (\'Security implications of running MySQL as
root\'\n IN NATURAL LANGUAGE
MODE);\n+----+-------------------------------------+-----------------+\n|
id | body | score
|\n+----+-------------------------------------+-----------------+\n| 4 |
1. Never run mysqld as root. 2. ... | 1.5219271183014 |\n| 6 | When
configured properly, MySQL ... | 1.3114095926285
|\n+----+-------------------------------------+-----------------+\n\nURL:
https://mariadb.com/kb/en/match-against/','','https://mariadb.com/kb/en/match-against/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(661,36,'MID','Syntax\n------\n\nMID(str,pos,len)\n\nDescription\n-----------\n\nMID(str,pos,len)
is a synonym for SUBSTRING(str,pos,len).\n\nExamples\n--------\n\nSELECT
MID(\'abcd\',4,1);\n+-----------------+\n|
MID(\'abcd\',4,1) |\n+-----------------+\n| d
|\n+-----------------+\n\nSELECT
MID(\'abcd\',2,2);\n+-----------------+\n|
MID(\'abcd\',2,2) |\n+-----------------+\n| bc
|\n+-----------------+\n\nA negative starting position:\n\nSELECT
MID(\'abcd\',-2,4);\n+------------------+\n|
MID(\'abcd\',-2,4) |\n+------------------+\n| cd
|\n+------------------+\n\nURL:
https://mariadb.com/kb/en/mid/','','https://mariadb.com/kb/en/mid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(662,36,'NOT LIKE','Syntax\n------\n\nexpr NOT LIKE pat
[ESCAPE \'escape_char\']\n\nDescription\n-----------\n\nThis is
the same as NOT (expr LIKE pat [ESCAPE \'escape_char\']).\n\nURL:
https://mariadb.com/kb/en/not-like/','','https://mariadb.com/kb/en/not-like/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(663,36,'OCTET_LENGTH','Syntax\n------\n\nOCTET_LENGTH(str)\n\nDescription\n-----------\n\nOCTET_LENGTH()
returns the length of the given string, in octets (bytes). This\nis a
synonym for LENGTHB(), and, when Oracle mode from MariaDB 10.3 is not\nset,
a synonym for LENGTH().\n\nA multi-byte character counts as multiple bytes.
This means that for a string\ncontaining five two-byte characters,
OCTET_LENGTH() returns 10, whereas\nCHAR_LENGTH() returns 5.\n\nIf str is
not a string value, it is converted into a string. If str is NULL,\nthe
function returns NULL.\n\nExamples\n--------\n\nWhen Oracle mode from
MariaDB 10.3 is not set:\n\nSELECT CHAR_LENGTH(\'π\'),
LENGTH(\'π\'), LENGTHB(\'π\'),
OCTET_LENGTH(\'π\');\n+-------------------+--------------+---------------+--------------------+\n|
CHAR_LENGTH(\'π\') | LENGTH(\'π\') |
LENGTHB(\'π\') | OCTET_LENGTH(\'π\')
|\n+-------------------+--------------+---------------+--------------------+\n|
1 | 2 | 2 | 2
|\n+-------------------+--------------+---------------+--------------------+\n\nIn
Oracle mode from MariaDB 10.3:\n\nSELECT CHAR_LENGTH(\'π\'),
LENGTH(\'π\'), LENGTHB(\'π\'),
OCTET_LENGTH(\'π\');\n+-------------------+--------------+---------------+--------------------+\n|
CHAR_LENGTH(\'π\') | LENGTH(\'π\') |
LENGTHB(\'π\') | OCTET_LENGTH(\'π\')
|\n+-------------------+--------------+---------------+--------------------+\n|
1 | 1 | 2 | 2
|\n+-------------------+--------------+---------------+--------------------+\n\nURL:
https://mariadb.com/kb/en/octet_length/','','https://mariadb.com/kb/en/octet_length/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(664,36,'ORD','Syntax\n------\n\nORD(str)\n\nDescription\n-----------\n\nIf
the leftmost character of the string str is a multi-byte character,
returns\nthe code for that character, calculated from the numeric values of
its\nconstituent bytes using this formula:\n\n(1st byte code)\n+ (2nd byte
code x 256)\n+ (3rd byte code x 256 x 256) ...\n\nIf the leftmost character
is not a multi-byte character, ORD() returns the\nsame value as the ASCII()
function.\n\nExamples\n--------\n\nSELECT
ORD(\'2\');\n+----------+\n| ORD(\'2\')
|\n+----------+\n| 50 |\n+----------+\n\nURL:
https://mariadb.com/kb/en/ord/','','https://mariadb.com/kb/en/ord/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(665,36,'POSITION','Syntax\n------\n\nPOSITION(substr IN
str)\n\nDescription\n-----------\n\nPOSITION(substr IN str) is a synonym
for LOCATE(substr,str).\n\nIt\'s part of ODBC 3.0.\n\nURL:
https://mariadb.com/kb/en/position/','','https://mariadb.com/kb/en/position/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(666,36,'QUOTE','Syntax\n------\n\nQUOTE(str)\n\nDescription\n-----------\n\nQuotes
a string to produce a result that can be used as a properly escaped\ndata
value in an SQL statement. The string is returned enclosed by
single\nquotes and with each instance of single quote
(\"\'\"), backslash (\"\\\"), ASCII\nNUL, and
Control-Z preceded by a backslash. If the argument is NULL, the\nreturn
value is the word \"NULL\" without enclosing single
quotes.\n\nExamples\n--------\n\nSELECT
QUOTE(\"Don\'t!\");\n+-----------------+\n|
QUOTE(\"Don\'t!\") |\n+-----------------+\n|
\'Don\\\'t!\' |\n+-----------------+\n\nSELECT
QUOTE(NULL); \n+-------------+\n| QUOTE(NULL) |\n+-------------+\n| NULL
|\n+-------------+\n\nURL:
https://mariadb.com/kb/en/quote/','','https://mariadb.com/kb/en/quote/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(667,36,'REPEAT
Function','Syntax\n------\n\nREPEAT(str,count)\n\nDescription\n-----------\n\nReturns
a string consisting of the string str repeated count times. If count\nis
less than 1, returns an empty string. Returns NULL if str or count are
NULL.\n\nExamples\n--------\n\nSELECT QUOTE(REPEAT(\'MariaDB
\',4));\n+------------------------------------+\n|
QUOTE(REPEAT(\'MariaDB \',4))
|\n+------------------------------------+\n| \'MariaDB MariaDB MariaDB
MariaDB \' |\n+------------------------------------+\n\nURL:
https://mariadb.com/kb/en/repeat-function/','','https://mariadb.com/kb/en/repeat-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(668,36,'REPLACE
Function','Syntax\n------\n\nREPLACE(str,from_str,to_str)\n\nDescription\n-----------\n\nReturns
the string str with all occurrences of the string from_str replaced by\nthe
string to_str. REPLACE() performs a case-sensitive match when
searching\nfor from_str.\n\nExamples\n--------\n\nSELECT
REPLACE(\'www.mariadb.org\', \'w\',
\'Ww\');\n+---------------------------------------+\n|
REPLACE(\'www.mariadb.org\', \'w\', \'Ww\')
|\n+---------------------------------------+\n| WwWwWw.mariadb.org
|\n+---------------------------------------+\n\nURL:
https://mariadb.com/kb/en/replace-function/','','https://mariadb.com/kb/en/replace-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(669,36,'REVERSE','Syntax\n------\n\nREVERSE(str)\n\nDescription\n-----------\n\nReturns
the string str with the order of the characters
reversed.\n\nExamples\n--------\n\nSELECT
REVERSE(\'desserts\');\n+---------------------+\n|
REVERSE(\'desserts\') |\n+---------------------+\n| stressed
|\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/reverse/','','https://mariadb.com/kb/en/reverse/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(670,36,'RIGHT','Syntax\n------\n\nRIGHT(str,len)\n\nDescription\n-----------\n\nReturns
the rightmost len characters from the string str, or NULL if any\nargument
is NULL.\n\nExamples\n--------\n\nSELECT RIGHT(\'MariaDB\',
2);\n+---------------------+\n| RIGHT(\'MariaDB\', 2)
|\n+---------------------+\n| DB
|\n+---------------------+\n\nURL:
https://mariadb.com/kb/en/right/','','https://mariadb.com/kb/en/right/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(671,36,'RPAD','Syntax\n------\n\nRPAD(str, len [,
padstr])\n\nDescription\n-----------\n\nReturns the string str,
right-padded with the string padstr to a length of len\ncharacters. If str
is longer than len, the return value is shortened to len\ncharacters. If
padstr is omitted, the RPAD function pads spaces.\n\nPrior to MariaDB
10.3.1, the padstr parameter was mandatory.\n\nReturns NULL if given a NULL
argument. If the result is empty (a length of\nzero), returns either an
empty string, or, from MariaDB 10.3.6 with\nSQL_MODE=Oracle, NULL.\n\nThe
Oracle mode version of the function can be accessed outside of Oracle
mode\nby using RPAD_ORACLE as the function
name.\n\nExamples\n--------\n\nSELECT
RPAD(\'hello\',10,\'.\');\n+----------------------+\n|
RPAD(\'hello\',10,\'.\') |\n+----------------------+\n|
hello..... |\n+----------------------+\n\nSELECT
RPAD(\'hello\',2,\'.\');\n+---------------------+\n|
RPAD(\'hello\',2,\'.\') |\n+---------------------+\n|
he |\n+---------------------+\n\nFrom MariaDB 10.3.1, with
the pad string defaulting to space.\n\nSELECT
RPAD(\'hello\',30);\n+--------------------------------+\n|
RPAD(\'hello\',30)
|\n+--------------------------------+\n| hello
|\n+--------------------------------+\n\nOracle mode version from MariaDB
10.3.6:\n\nSELECT
RPAD(\'\',0),RPAD_ORACLE(\'\',0);\n+------------+-------------------+\n|
RPAD(\'\',0) | RPAD_ORACLE(\'\',0)
|\n+------------+-------------------+\n| | NULL
|\n+------------+-------------------+\n\nURL:
https://mariadb.com/kb/en/rpad/','','https://mariadb.com/kb/en/rpad/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(672,36,'RTRIM','Syntax\n------\n\nRTRIM(str)\n\nDescription\n-----------\n\nReturns
the string str with trailing space characters removed.\n\nReturns NULL if
given a NULL argument. If the result is empty, returns either\nan empty
string, or, from MariaDB 10.3.6 with SQL_MODE=Oracle, NULL.\n\nThe Oracle
mode version of the function can be accessed outside of Oracle mode\nby
using RTRIM_ORACLE as the function name.\n\nExamples\n--------\n\nSELECT
QUOTE(RTRIM(\'MariaDB
\'));\n+-----------------------------+\n| QUOTE(RTRIM(\'MariaDB
\')) |\n+-----------------------------+\n| \'MariaDB\'
|\n+-----------------------------+\n\nOracle mode version from
MariaDB 10.3.6:\n\nSELECT
RTRIM(\'\'),RTRIM_ORACLE(\'\');\n+-----------+------------------+\n|
RTRIM(\'\') | RTRIM_ORACLE(\'\')
|\n+-----------+------------------+\n| | NULL
|\n+-----------+------------------+\n\nURL:
https://mariadb.com/kb/en/rtrim/','','https://mariadb.com/kb/en/rtrim/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(673,36,'SOUNDEX','Syntax\n------\n\nSOUNDEX(str)\n\nDescription\n-----------\n\nReturns
a soundex string from str. Two strings that sound almost the same\nshould
have identical soundex strings. A standard soundex string is
four\ncharacters long, but the SOUNDEX() function returns an arbitrarily
long\nstring. You can use SUBSTRING() on the result to get a standard
soundex\nstring. All non-alphabetic characters in str are ignored. All
international\nalphabetic characters outside the A-Z range are treated as
vowels.\n\nImportant: When using SOUNDEX(), you should be aware of the
following details:\n\n* This function, as currently implemented, is
intended to work well with\n strings that are in the English language only.
Strings in other languages may\n not produce reasonable results.\n\n* This
function implements the original Soundex algorithm, not the more\npopular
enhanced version (also described by D. Knuth). The difference is
that\noriginal version discards vowels first and duplicates second, whereas
the\nenhanced version discards duplicates first and vowels
second.\n\nExamples\n--------\n\nSOUNDEX(\'Hello\');\n+------------------+\n|
SOUNDEX(\'Hello\') |\n+------------------+\n| H400
|\n+------------------+\n\nSELECT
SOUNDEX(\'MariaDB\');\n+--------------------+\n|
SOUNDEX(\'MariaDB\') |\n+--------------------+\n| M631
|\n+--------------------+\n\nSELECT
SOUNDEX(\'Knowledgebase\');\n+--------------------------+\n|
SOUNDEX(\'Knowledgebase\') |\n+--------------------------+\n|
K543212 |\n+--------------------------+\n\nSELECT
givenname, surname FROM users WHERE SOUNDEX(givenname)
=\nSOUNDEX(\"robert\");\n+-----------+---------+\n| givenname |
surname |\n+-----------+---------+\n| Roberto | Castro
|\n+-----------+---------+\n\nURL:
https://mariadb.com/kb/en/soundex/','','https://mariadb.com/kb/en/soundex/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(674,36,'SOUNDS LIKE','Syntax\n------\n\nexpr1 SOUNDS LIKE
expr2\n\nDescription\n-----------\n\nThis is the same as SOUNDEX(expr1) =
SOUNDEX(expr2).\n\nExample\n-------\n\nSELECT givenname, surname FROM users
WHERE givenname SOUNDS LIKE
\"robert\";\n+-----------+---------+\n| givenname | surname
|\n+-----------+---------+\n| Roberto | Castro
|\n+-----------+---------+\n\nURL:
https://mariadb.com/kb/en/sounds-like/','','https://mariadb.com/kb/en/sounds-like/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(675,36,'SPACE','Syntax\n------\n\nSPACE(N)\n\nDescription\n-----------\n\nReturns
a string consisting of N space characters. If N is NULL, returns
NULL.\n\nExamples\n--------\n\nSELECT
QUOTE(SPACE(6));\n+-----------------+\n| QUOTE(SPACE(6))
|\n+-----------------+\n| \' \'
|\n+-----------------+\n\nURL:
https://mariadb.com/kb/en/space/','','https://mariadb.com/kb/en/space/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(676,36,'STRCMP','Syntax\n------\n\nSTRCMP(expr1,expr2)\n\nDescription\n-----------\n\nSTRCMP()
returns 0 if the strings are the same, -1 if the first argument is\nsmaller
than the second according to the current sort order, and 1 if the\nstrings
are otherwise not the same. Returns NULL is either argument is
NULL.\n\nExamples\n--------\n\nSELECT STRCMP(\'text\',
\'text2\');\n+-------------------------+\n|
STRCMP(\'text\', \'text2\')
|\n+-------------------------+\n| -1
|\n+-------------------------+\n\nSELECT STRCMP(\'text2\',
\'text\');\n+-------------------------+\n|
STRCMP(\'text2\', \'text\')
|\n+-------------------------+\n| 1
|\n+-------------------------+\n\nSELECT STRCMP(\'text\',
\'text\');\n+------------------------+\n|
STRCMP(\'text\', \'text\')
|\n+------------------------+\n| 0
|\n+------------------------+\n\nURL:
https://mariadb.com/kb/en/strcmp/','','https://mariadb.com/kb/en/strcmp/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(677,36,'SUBSTR','Description\n-----------\n\nSUBSTR() is a
synonym for SUBSTRING().\n\nURL:
https://mariadb.com/kb/en/substr/','','https://mariadb.com/kb/en/substr/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(678,36,'SUBSTRING','Syntax\n------\n\nSUBSTRING(str,pos),
\nSUBSTRING(str FROM pos), \nSUBSTRING(str,pos,len),\nSUBSTRING(str FROM
pos FOR len)\n\nSUBSTR(str,pos), \nSUBSTR(str FROM pos),
\nSUBSTR(str,pos,len),\nSUBSTR(str FROM pos FOR
len)\n\nDescription\n-----------\n\nThe forms without a len argument return
a substring from string str starting\nat position pos.\n\nThe forms with a
len argument return a substring len characters long from\nstring str,
starting at position pos.\n\nThe forms that use FROM are standard SQL
syntax.\n\nIt is also possible to use a negative value for pos. In this
case, the\nbeginning of the substring is pos characters from the end of the
string,\nrather than the beginning. A negative value may be used for pos in
any of the\nforms of this function.\n\nBy default, the position of the
first character in the string from which the\nsubstring is to be extracted
is reckoned as 1. For Oracle-compatibility, from\nMariaDB 10.3.3, when
sql_mode is set to \'oracle\', position zero is treated
as\nposition 1 (although the first character is still reckoned as 1).\n\nIf
any argument is NULL, returns NULL.\n\nExamples\n--------\n\nSELECT
SUBSTRING(\'Knowledgebase\',5);\n+------------------------------+\n|
SUBSTRING(\'Knowledgebase\',5)
|\n+------------------------------+\n| ledgebase
|\n+------------------------------+\n\nSELECT
SUBSTRING(\'MariaDB\' FROM
6);\n+-----------------------------+\n| SUBSTRING(\'MariaDB\'
FROM 6) |\n+-----------------------------+\n| DB
|\n+-----------------------------+\n\nSELECT
SUBSTRING(\'Knowledgebase\',3,7);\n+--------------------------------+\n|
SUBSTRING(\'Knowledgebase\',3,7)
|\n+--------------------------------+\n| owledge
|\n+--------------------------------+\n\nSELECT
SUBSTRING(\'Knowledgebase\',
-4);\n+--------------------------------+\n|
SUBSTRING(\'Knowledgebase\', -4)
|\n+--------------------------------+\n| base
|\n+--------------------------------+\n\nSELECT
SUBSTRING(\'Knowledgebase\', -8,
4);\n+-----------------------------------+\n|
SUBSTRING(\'Knowledgebase\', -8, 4)
|\n+-----------------------------------+\n| edge
|\n+-----------------------------------+\n\nSELECT
SUBSTRING(\'Knowledgebase\' FROM -8 FOR
4);\n+------------------------------------------+\n|
SUBSTRING(\'Knowledgebase\' FROM -8 FOR 4)
|\n+------------------------------------------+\n| edge
|\n+------------------------------------------+\n\nOracle
mode from MariaDB 10.3.3:\n\nSELECT
SUBSTR(\'abc\',0,3);\n+-------------------+\n|
SUBSTR(\'abc\',0,3) |\n+-------------------+\n|
|\n+-------------------+\n\nSELECT
SUBSTR(\'abc\',1,2);\n+-------------------+\n|
SUBSTR(\'abc\',1,2) |\n+-------------------+\n| ab
|\n+-------------------+\n\nSET sql_mode=\'oracle\';\n\nSELECT
SUBSTR(\'abc\',0,3);\n+-------------------+\n|
SUBSTR(\'abc\',0,3) |\n+-------------------+\n| abc
|\n+-------------------+\n\nSELECT
SUBSTR(\'abc\',1,2);\n+-------------------+\n|
SUBSTR(\'abc\',1,2) |\n+-------------------+\n| ab
|\n+-------------------+\n\nURL:
https://mariadb.com/kb/en/substring/','','https://mariadb.com/kb/en/substring/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(679,36,'SUBSTRING_INDEX','Syntax\n------\n\nSUBSTRING_INDEX(str,delim,count)\n\nDescription\n-----------\n\nReturns
the substring from string str before count occurrences of the\ndelimiter
delim. If count is positive, everything to the left of the final\ndelimiter
(counting from the left) is returned. If count is negative,\neverything to
the right of the final delimiter (counting from the right) is\nreturned.
SUBSTRING_INDEX() performs a case-sensitive match when searching
for\ndelim.\n\nIf any argument is NULL, returns NULL.\n\nFor
example\n\nSUBSTRING_INDEX(\'www.mariadb.org\', \'.\',
2)\n\nmeans \"Return all of the characters up to the 2nd occurrence of
.\"\n\nExamples\n--------\n\nSELECT
SUBSTRING_INDEX(\'www.mariadb.org\', \'.\',
2);\n+--------------------------------------------+\n|
SUBSTRING_INDEX(\'www.mariadb.org\', \'.\', 2)
|\n+--------------------------------------------+\n| www.mariadb
|\n+--------------------------------------------+\n\nSELECT
SUBSTRING_INDEX(\'www.mariadb.org\', \'.\',
-2);\n+---------------------------------------------+\n|
SUBSTRING_INDEX(\'www.mariadb.org\', \'.\', -2)
|\n+---------------------------------------------+\n| mariadb.org
|\n+---------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/substring_index/','','https://mariadb.com/kb/en/substring_index/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(680,36,'TO_BASE64','Syntax\n------\n\nTO_BASE64(str)\n\nDescription\n-----------\n\nConverts
the string argument str to its base-64 encoded form, returning the\nresult
as a character string in the connection character set and collation.\n\nThe
argument str will be converted to string first if it is not a string.
A\nNULL argument will return a NULL result.\n\nThe reverse function,
FROM_BASE64(), decodes an encoded base-64 string.\n\nThere are a numerous
different methods to base-64 encode a string. The\nfollowing are used by
MariaDB and MySQL:\n\n* Alphabet value 64 is encoded as \'+\'.\n*
Alphabet value 63 is encoded as \'/\'.\n* Encoding output is made
up of groups of four printable characters, with each\nthree bytes of data
encoded using four characters. If the final group is not\ncomplete, it is
padded with \'=\' characters to make up a length of four.\n* To
divide long output, a newline is added after every 76 characters.\n*
Decoding will recognize and ignore newlines, carriage returns, tabs,
and\nspaces.\n\nExamples\n--------\n\nSELECT
TO_BASE64(\'Maria\');\n+--------------------+\n|
TO_BASE64(\'Maria\') |\n+--------------------+\n| TWFyaWE=
|\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/to_base64/','','https://mariadb.com/kb/en/to_base64/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(681,36,'TO_CHAR','MariaDB starting with
10.6.1\n----------------------------\nThe TO_CHAR function was introduced
in MariaDB 10.6.1 to enhance
Oracle\ncompatibility.\n\nSyntax\n------\n\nTO_CHAR(expr[,
fmt])\n\nDescription\n-----------\n\nThe TO_CHAR function converts an expr
of type date, datetime, time or\ntimestamp to a string. The optional fmt
argument
supports\nYYYY/YYY/YY/RRRR/RR/MM/MON/MONTH/MI/DD/DY/HH/HH12/HH24/SS and
special\ncharacters. The default value is \"YYYY-MM-DD
HH24:MI:SS\".\n\nIn Oracle, TO_CHAR can also be used to convert
numbers to strings, but this is\nnot supported in MariaDB and will give an
error.\n\nExamples\n--------\n\nSELECT TO_CHAR(\'1980-01-11
04:50:39\',
\'YYYY-MM-DD\');\n+----------------------------------------------+\n|
TO_CHAR(\'1980-01-11 04:50:39\', \'YYYY-MM-DD\')
|\n+----------------------------------------------+\n| 1980-01-11
|\n+----------------------------------------------+\n\nSELECT
TO_CHAR(\'1980-01-11 04:50:39\',
\'HH24-MI-SS\');\n+----------------------------------------------+\n|
TO_CHAR(\'1980-01-11 04:50:39\', \'HH24-MI-SS\')
|\n+----------------------------------------------+\n| 04-50-39
|\n+----------------------------------------------+\n\nSELECT
TO_CHAR(\'00-01-01 00:00:00\', \'YY-MM-DD
HH24:MI:SS\');\n+-----------------------------------------------------+\n|
TO_CHAR(\'00-01-01 00:00:00\', \'YY-MM-DD HH24:MI:SS\')
|\n+-----------------------------------------------------+\n| 00-01-01
00:00:00
|\n+-----------------------------------------------------+\n\nSELECT
TO_CHAR(\'99-12-31 23:59:59\', \'YY-MM-DD
HH24:MI:SS\');\n+-----------------------------------------------------+\n|
TO_CHAR(\'99-12-31 23:59:59\', \'YY-MM-DD HH24:MI:SS\')
|\n+-----------------------------------------------------+\n| 99-12-31
23:59:59
|\n+-----------------------------------------------------+\n\nSELECT
TO_CHAR(\'9999-12-31 23:59:59\', \'YY-MM-DD
HH24:MI:SS\');\n+-------------------------------------------------------+\n|
TO_CHAR(\'9999-12-31 23:59:59\', \'YY-MM-DD
HH24:MI:SS\')
|\n+-------------------------------------------------------+\n| 99-12-31
23:59:59
|\n+-------------------------------------------------------+\n\nSELECT
TO_CHAR(\'21-01-03 08:30:00\', \'Y-MONTH-DY
HH:MI:SS\');\n+-----------------------------------------------------+\n|
TO_CHAR(\'21-01-03 08:30:00\', \'Y-MONTH-DY HH:MI:SS\')
|\n+-----------------------------------------------------+\n| 1-January
-Sun 08:30:00
|\n+-----------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/to_char/','','https://mariadb.com/kb/en/to_char/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(682,36,'TRIM','Syntax\n------\n\nTRIM([{BOTH | LEADING |
TRAILING} [remstr] FROM] str), TRIM([remstr FROM] str)\n\nFrom MariaDB
10.3.6\n\nTRIM_ORACLE([{BOTH | LEADING | TRAILING} [remstr] FROM] str),
TRIM([remstr\nFROM] str)\n\nDescription\n-----------\n\nReturns the string
str with all remstr prefixes or suffixes removed. If none\nof the
specifiers BOTH, LEADING, or TRAILING is given, BOTH is assumed. remstr\nis
optional and, if not specified, spaces are removed.\n\nReturns NULL if
given a NULL argument. If the result is empty, returns either\nan empty
string, or, from MariaDB 10.3.6 with SQL_MODE=Oracle,
NULL.\nSQL_MODE=Oracle is not set by default.\n\nThe Oracle mode version of
the function can be accessed in any mode by using\nTRIM_ORACLE as the
function name.\n\nExamples\n--------\n\nSELECT TRIM(\' bar
\')\\G\n*************************** 1. row
***************************\nTRIM(\' bar \'): bar\n\nSELECT
TRIM(LEADING \'x\' FROM
\'xxxbarxxx\')\\G\n*************************** 1. row
***************************\nTRIM(LEADING \'x\' FROM
\'xxxbarxxx\'): barxxx\n\nSELECT TRIM(BOTH \'x\' FROM
\'xxxbarxxx\')\\G\n*************************** 1. row
***************************\nTRIM(BOTH \'x\' FROM
\'xxxbarxxx\'): bar\n\nSELECT TRIM(TRAILING \'xyz\'
FROM \'barxxyz\')\\G\n*************************** 1. row
***************************\nTRIM(TRAILING \'xyz\' FROM
\'barxxyz\'): barx\n\nFrom MariaDB 10.3.6, with SQL_MODE=Oracle
not set:\n\nSELECT
TRIM(\'\'),TRIM_ORACLE(\'\');\n+----------+-----------------+\n|
TRIM(\'\') | TRIM_ORACLE(\'\')
|\n+----------+-----------------+\n| | NULL
|\n+----------+-----------------+\n\nFrom MariaDB 10.3.6, with
SQL_MODE=Oracle set:\n\nSELECT
TRIM(\'\'),TRIM_ORACLE(\'\');\n+----------+-----------------+\n|
TRIM(\'\') | TRIM_ORACLE(\'\')
|\n+----------+-----------------+\n| NULL | NULL
|\n+----------+-----------------+\n\nURL:
https://mariadb.com/kb/en/trim/','','https://mariadb.com/kb/en/trim/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(683,36,'UCASE','Syntax\n------\n\nUCASE(str)\n\nDescription\n-----------\n\nUCASE()
is a synonym for UPPER().\n\nURL:
https://mariadb.com/kb/en/ucase/','','https://mariadb.com/kb/en/ucase/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(684,36,'UNCOMPRESSED_LENGTH','Syntax\n------\n\nUNCOMPRESSED_LENGTH(compressed_string)\n\nDescription\n-----------\n\nReturns
the length that the compressed string had before being compressed
with\nCOMPRESS().\n\nUNCOMPRESSED_LENGTH() returns NULL or an incorrect
result if the string is not\ncompressed.\n\nUntil MariaDB 10.3.1, returns
MYSQL_TYPE_LONGLONG, or bigint(10), in all\ncases. From MariaDB 10.3.1,
returns MYSQL_TYPE_LONG, or int(10), when the\nresult would fit within
32-bits.\n\nExamples\n--------\n\nSELECT
UNCOMPRESSED_LENGTH(COMPRESS(REPEAT(\'a\',30)));\n+-----------------------------------------------+\n|
UNCOMPRESSED_LENGTH(COMPRESS(REPEAT(\'a\',30)))
|\n+-----------------------------------------------+\n|
30
|\n+-----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/uncompressed_length/','','https://mariadb.com/kb/en/uncompressed_length/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(685,36,'UNHEX','Syntax\n------\n\nUNHEX(str)\n\nDescription\n-----------\n\nPerforms
the inverse operation of HEX(str). That is, it interprets each pair\nof
hexadecimal digits in the argument as a number and converts it to
the\ncharacter represented by the number. The resulting characters are
returned as\na binary string.\n\nIf str is NULL, UNHEX() returns
NULL.\n\nExamples\n--------\n\nSELECT
HEX(\'MariaDB\');\n+----------------+\n|
HEX(\'MariaDB\') |\n+----------------+\n| 4D617269614442
|\n+----------------+\n\nSELECT
UNHEX(\'4D617269614442\');\n+-------------------------+\n|
UNHEX(\'4D617269614442\') |\n+-------------------------+\n|
MariaDB |\n+-------------------------+\n\nSELECT
0x4D617269614442;\n+------------------+\n| 0x4D617269614442
|\n+------------------+\n| MariaDB
|\n+------------------+\n\nSELECT
UNHEX(HEX(\'string\'));\n+----------------------+\n|
UNHEX(HEX(\'string\')) |\n+----------------------+\n| string
|\n+----------------------+\n\nSELECT
HEX(UNHEX(\'1267\'));\n+--------------------+\n|
HEX(UNHEX(\'1267\')) |\n+--------------------+\n| 1267
|\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/unhex/','','https://mariadb.com/kb/en/unhex/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(686,36,'UPDATEXML','Syntax\n------\n\nUpdateXML(xml_target,
xpath_expr, new_xml)\n\nDescription\n-----------\n\nThis function replaces
a single portion of a given fragment of XML markup\nxml_target with a new
XML fragment new_xml, and then returns the changed XML.\nThe portion of
xml_target that is replaced matches an XPath expression\nxpath_expr
supplied by the user. If no expression matching xpath_expr is\nfound, or if
multiple matches are found, the function returns the original\nxml_target
XML fragment. All three arguments should be
strings.\n\nExamples\n--------\n\nSELECT\n
UpdateXML(\'<a><b>ccc</b><d></d></a>\',
\'/a\', \'<e>fff</e>\') AS val1,\n
UpdateXML(\'<a><b>ccc</b><d></d></a>\',
\'/b\', \'<e>fff</e>\') AS val2,\n
UpdateXML(\'<a><b>ccc</b><d></d></a>\',
\'//b\', \'<e>fff</e>\') AS val3,\n
UpdateXML(\'<a><b>ccc</b><d></d></a>\',
\'/a/d\', \'<e>fff</e>\') AS val4,\n
UpdateXML(\'<a><d></d><b>ccc</b><d></d></a>\',
\'/a/d\', \'<e>fff</e>\') AS val5\n
\\G\n*************************** 1. row ***************************\nval1:
<e>fff</e>\nval2:
<a><b>ccc</b><d></d></a>\nval3:
<a><e>fff</e><d></d></a>\nval4:
<a><b>ccc</b><e>fff</e></a>\nval5:
<a><d></d><b>ccc</b><d></d></a>\n1
row in set (0.00 sec)\n\nURL:
https://mariadb.com/kb/en/updatexml/','','https://mariadb.com/kb/en/updatexml/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(687,36,'UPPER','Syntax\n------\n\nUPPER(str)\n\nDescription\n-----------\n\nReturns
the string str with all characters changed to uppercase according to\nthe
current character set mapping. The default is latin1 (cp1252
West\nEuropean).\n\nSELECT UPPER(surname), givenname FROM users ORDER BY
surname;\n+----------------+------------+\n| UPPER(surname) | givenname
|\n+----------------+------------+\n| ABEL | Jacinto |\n|
CASTRO | Robert |\n| COSTA | Phestos |\n| MOSCHELLA
| Hippolytos |\n+----------------+------------+\n\nUPPER() is
ineffective when applied to binary strings (BINARY, VARBINARY,\nBLOB). The
description of LOWER() shows how to perform lettercase conversion\nof
binary strings.\n\nURL:
https://mariadb.com/kb/en/upper/','','https://mariadb.com/kb/en/upper/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(688,36,'WEIGHT_STRING','Syntax\n------\n\nWEIGHT_STRING(str
[AS {CHAR|BINARY}(N)] [LEVEL levels] [flags])\n levels: N
[ASC|DESC|REVERSE] [, N [ASC|DESC|REVERSE]]
...\n\nDescription\n-----------\n\nReturns a binary string representing the
string\'s sorting and comparison\nvalue. A string with a lower result
means that for sorting purposes the string\nappears before a string with a
higher result.\n\nWEIGHT_STRING() is particularly useful when adding new
collations, for testing\npurposes.\n\nIf str is a non-binary string (CHAR,
VARCHAR or TEXT), WEIGHT_STRING returns\nthe string\'s collation
weight. If str is a binary string (BINARY, VARBINARY or\nBLOB), the return
value is simply the input value, since the weight for each\nbyte in a
binary string is the byte value.\n\nWEIGHT_STRING() returns NULL if given a
NULL input.\n\nThe optional AS clause permits casting the input string to a
binary or\nnon-binary string, as well as to a particular length.\n\nAS
BINARY(N) measures the length in bytes rather than characters, and
right\npads with 0x00 bytes to the desired length.\n\nAS CHAR(N) measures
the length in characters, and right pads with spaces to\nthe desired
length.\n\nN has a minimum value of 1, and if it is less than the length of
the input\nstring, the string is truncated without warning.\n\nThe optional
LEVEL clause specifies that the return value should contain\nweights for
specific collation levels. The levels specifier can either be a\nsingle
integer, a comma-separated list of integers, or a range of
integers\nseparated by a dash (whitespace is ignored). Integers can range
from 1 to a\nmaximum of 6, dependent on the collation, and need to be
listed in ascending\norder.\n\nIf the LEVEL clause is no provided, a
default of 1 to the maximum for the\ncollation is assumed.\n\nIf the LEVEL
is specified without using a range, an optional modifier
is\npermitted.\n\nASC, the default, returns the weights without any
modification.\n\nDESC returns bitwise-inverted weights.\n\nREVERSE returns
the weights in reverse order.\n\nExamples\n--------\n\nThe examples below
use the HEX() function to represent non-printable results\nin hexadecimal
format.\n\nSELECT
HEX(WEIGHT_STRING(\'x\'));\n+-------------------------+\n|
HEX(WEIGHT_STRING(\'x\')) |\n+-------------------------+\n| 0058
|\n+-------------------------+\n\nSELECT
HEX(WEIGHT_STRING(\'x\' AS
BINARY(4)));\n+--------------------------------------+\n|
HEX(WEIGHT_STRING(\'x\' AS BINARY(4)))
|\n+--------------------------------------+\n| 78000000
|\n+--------------------------------------+\n\nSELECT
HEX(WEIGHT_STRING(\'x\' AS
CHAR(4)));\n+------------------------------------+\n|
HEX(WEIGHT_STRING(\'x\' AS CHAR(4)))
|\n+------------------------------------+\n| 0058002000200020
|\n+------------------------------------+\n\nSELECT
HEX(WEIGHT_STRING(0xaa22ee LEVEL
1));\n+--------------------------------------+\n|
HEX(WEIGHT_STRING(0xaa22ee LEVEL 1))
|\n+--------------------------------------+\n| AA22EE
|\n+--------------------------------------+\n\nSELECT
HEX(WEIGHT_STRING(0xaa22ee LEVEL 1
DESC));\n+-------------------------------------------+\n|
HEX(WEIGHT_STRING(0xaa22ee LEVEL 1 DESC))
|\n+-------------------------------------------+\n| 55DD11
|\n+-------------------------------------------+\n\nSELECT
HEX(WEIGHT_STRING(0xaa22ee LEVEL 1
REVERSE));\n+----------------------------------------------+\n|
HEX(WEIGHT_STRING(0xaa22ee LEVEL 1 REVERSE))
|\n+----------------------------------------------+\n| EE22AA
|\n+----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/weight_string/','','https://mariadb.com/kb/en/weight_string/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(689,36,'Type Conversion','Implicit type conversion takes
place when MariaDB is using operands or\ndifferent types, in order to make
the operands compatible.\n\nIt is best practice not to rely upon implicit
conversion; rather use CAST to\nexplicitly convert types.\n\nRules for
Conversion on Comparison\n----------------------------------\n\n* If
either argument is NULL, the result of the comparison is NULL unless
the\nNULL-safe <=> equality comparison operator is used.\n* If both
arguments are integers, they are compared as integers.\n* If both arguments
are strings, they are compared as strings.\n* If one argument is decimal
and the other argument is decimal or integer,\nthey are compared as
decimals.\n* If one argument is decimal and the other argument is a
floating point, they\nare compared as floating point values.\n* If one
argument is string and the other argument is integer, they are\ncompared as
decimals. This conversion was added in MariaDB 10.3.36. Prior to\n10.3.36,
this combination was compared as floating point values, which did
not\nalways work well for huge 64-bit integers because of a possible
precision loss\non conversion to double.\n* If a hexadecimal argument is
not compared to a number, it is treated as a\nbinary string.\n* If a
constant is compared to a TIMESTAMP or DATETIME, the constant is\nconverted
to a timestamp, unless used as an argument to the IN function.\n* In other
cases, arguments are compared as floating point, or real, numbers.\n\nNote
that if a string column is being compared with a numeric value,
MariaDB\nwill not use the index on the column, as there are numerous
alternatives that\nmay evaluate as equal (see examples
below).\n\nComparison Examples\n-------------------\n\nConverting a string
to a number:\n\nSELECT 15+\'15\';\n+---------+\n|
15+\'15\' |\n+---------+\n| 30 |\n+---------+\n\nConverting
a number to a string:\n\nSELECT
CONCAT(15,\'15\');\n+-----------------+\n|
CONCAT(15,\'15\') |\n+-----------------+\n| 1515
|\n+-----------------+\n\nFloating point number errors:\n\nSELECT
\'9746718491924563214\' =
9746718491924563213;\n+---------------------------------------------+\n|
\'9746718491924563214\' = 9746718491924563213
|\n+---------------------------------------------+\n|
1
|\n+---------------------------------------------+\n\nNumeric equivalence
with strings:\n\nSELECT \'5\' = 5;\n+---------+\n|
\'5\' = 5 |\n+---------+\n| 1 |\n+---------+\n\nSELECT
\' 5\' = 5;\n+------------+\n| \' 5\' = 5
|\n+------------+\n| 1 |\n+------------+\n\nSELECT \' 5
\' = 5;\n+--------------+\n| \' 5 \' = 5
|\n+--------------+\n| 1 |\n+--------------+\n1 row in set, 1
warning (0.000 sec)\n\nSHOW
WARNINGS;\n+-------+------+--------------------------------------------+\n|
Level | Code | Message
|\n+-------+------+--------------------------------------------+\n| Note |
1292 | Truncated incorrect DOUBLE value: \' 5 \'
|\n+-------+------+--------------------------------------------+\n\nAs a
result of the above, MariaDB cannot use the index when comparing a
string\nwith a numeric value in the example below:\n\nCREATE TABLE t (a
VARCHAR(10), b VARCHAR(10), INDEX idx_a (a));\n\nINSERT INTO t VALUES \n
(\'1\', \'1\'), (\'2\', \'2\'),
(\'3\', \'3\'),\n (\'4\', \'4\'),
(\'5\', \'5\'), (\'1\',
\'5\');\n\nEXPLAIN SELECT * FROM t WHERE a = \'3\'
\\G\n*************************** 1. row ***************************\n
id: 1\n select_type: SIMPLE\n table: t\n type: ref\npossible_keys:
idx_a\n key: idx_a\n key_len: 13\n ref: const\n rows: 1\n
Extra: Using index condition\n\nEXPLAIN SELECT * FROM t WHERE a = 3
\\G\n*************************** 1. row ***************************\n
id: 1\n select_type: SIMPLE\n table: t\n type: ALL\npossible_keys:
idx_a\n key: NULL\n key_len: NULL\n ref: NULL\n rows: 6\n
Extra: Using where\n\nRules for Conversion on Dyadic Arithmetic
Operations\n----------------------------------------------------\n\nImplicit
type conversion also takes place on dyadic arithmetic
operations\n(+,-,*,/). MariaDB chooses the minimum data type that is
guaranteed to fit the\nresult and converts both arguments to the result
data type.\n\nFor addition (+), subtraction (-) and multiplication (*), the
result data type\nis chosen as follows:\n\n* If either of the arguments is
an approximate number (float, double), the\nresult is double.\n* If either
of the arguments is a string (char, varchar, text), the result
is\ndouble.\n* If either of the arguments is a decimal number, the result
is decimal.\n* If either of the arguments is of a temporal type with a
non-zero fractional\nsecond precision (time(N), datetime(N), timestamp(N)),
the result is decimal.\n* If either of the arguments is of a temporal type
with a zero fractional\nsecond precision (time(0), date, datetime(0),
timestamp(0)), the result may\nvary between int, int unsigned, bigint or
bigint unsigned, depending on the\nexact data type combination.\n* If both
arguments are integer numbers (tinyint, smallint, mediumint,\nbigint), the
result may vary between int, int unsigned, bigint or bigint\nunsigned,
depending of the exact data types and their signs.\n\nFor division (/), the
result data type is chosen as follows:\n\n* If either of the arguments is
an approximate number (float, double), the\nresult is double.\n* If either
of the arguments is a string (char, varchar, text), the result
is\ndouble.\n* Otherwise, the result is decimal.\n\nArithmetic
Examples\n-------------------\n\nNote, the above rules mean that when an
argument of a temporal data type\nappears in addition or subtraction,
it\'s treated as a number by default.\n\nSELECT
TIME\'10:20:30\' + 1;\n+--------------------+\n|
TIME\'10:20:30\' + 1 |\n+--------------------+\n|
102031 |\n+--------------------+\n\nIn order to do temporal addition or
subtraction instead, use the DATE_ADD() or\nDATE_SUB() functions, or an
INTERVAL expression as the second argument:\n\nSELECT
TIME\'10:20:30\' + INTERVAL 1
SECOND;\n+------------------------------------+\n|
TIME\'10:20:30\' + INTERVAL 1 SECOND
|\n+------------------------------------+\n| 10:20:31
|\n+------------------------------------+\n\nSELECT \"2.2\" +
3;\n+-----------+\n| \"2.2\" + 3 |\n+-----------+\n| 5.2
|\n+-----------+\n\nSELECT 2.2 + 3;\n+---------+\n| 2.2 + 3
|\n+---------+\n| 5.2 |\n+---------+\n\nSELECT 2.2 / 3;\n+---------+\n|
2.2 / 3 |\n+---------+\n| 0.73333 |\n+---------+\n\nSELECT
\"2.2\" / 3;\n+--------------------+\n| \"2.2\" / 3
|\n+--------------------+\n| 0.7333333333333334
|\n+--------------------+\n\nURL:
https://mariadb.com/kb/en/type-conversion/','','https://mariadb.com/kb/en/type-conversion/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(690,37,'_rowid','Syntax\n------\n\n_rowid\n\nDescription\n-----------\n\nThe
_rowid pseudo column is mapped to the primary key in the related
table.\nThis can be used as a replacement of the rowid pseudo column in
other\ndatabases. Another usage is to simplify sql queries as one
doesn\'t have to\nknow the name of the primary
key.\n\nExamples\n--------\n\ncreate table t1 (a int primary key, b
varchar(80));\ninsert into t1 values
(1,\"one\"),(2,\"two\");\nselect * from t1 where
_rowid=1;\n\n+---+------+\n| a | b |\n+---+------+\n| 1 | one
|\n+---+------+\n\nupdate t1 set b=\"three\" where
_rowid=2;\nselect * from t1 where _rowid>=1 and
_rowid<=10;\n\n+---+-------+\n| a | b |\n+---+-------+\n| 1 | one
|\n| 2 | three |\n+---+-------+\n\nURL:
https://mariadb.com/kb/en/_rowid/','','https://mariadb.com/kb/en/_rowid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(691,38,'ALTER TABLE','Syntax\n------\n\nALTER [ONLINE]
[IGNORE] TABLE [IF EXISTS] tbl_name\n [WAIT n | NOWAIT]\n
alter_specification [, alter_specification] ...\nalter_specification:\n
table_option ...\n | ADD [COLUMN] [IF NOT EXISTS] col_name
column_definition\n [FIRST | AFTER col_name ]\n | ADD [COLUMN] [IF NOT
EXISTS] (col_name column_definition,...)\n | ADD {INDEX|KEY} [IF NOT
EXISTS] [index_name]\n [index_type] (index_col_name,...) [index_option]
...\n | ADD [CONSTRAINT [symbol]] PRIMARY KEY\n [index_type]
(index_col_name,...) [index_option] ...\n | ADD [CONSTRAINT [symbol]]\n
UNIQUE [INDEX|KEY] [index_name]\n [index_type] (index_col_name,...)
[index_option] ...\n | ADD FULLTEXT [INDEX|KEY] [index_name]\n
(index_col_name,...) [index_option] ...\n | ADD SPATIAL [INDEX|KEY]
[index_name]\n (index_col_name,...) [index_option] ...\n | ADD
[CONSTRAINT [symbol]]\n FOREIGN KEY [IF NOT EXISTS] [index_name]
(index_col_name,...)\n reference_definition\n | ADD PERIOD FOR
SYSTEM_TIME (start_column_name, end_column_name)\n | ALTER [COLUMN]
col_name SET DEFAULT literal | (expression)\n | ALTER [COLUMN] col_name
DROP DEFAULT\n | ALTER {INDEX|KEY} index_name [NOT] INVISIBLE\n | CHANGE
[COLUMN] [IF EXISTS] old_col_name new_col_name column_definition\n
[FIRST|AFTER col_name]\n | MODIFY [COLUMN] [IF EXISTS] col_name
column_definition\n [FIRST | AFTER col_name]\n | DROP [COLUMN] [IF
EXISTS] col_name [RESTRICT|CASCADE]\n | DROP PRIMARY KEY\n | DROP
{INDEX|KEY} [IF EXISTS] index_name\n | DROP FOREIGN KEY [IF EXISTS]
fk_symbol\n | DROP CONSTRAINT [IF EXISTS] constraint_name\n | DISABLE
KEYS\n | ENABLE KEYS\n | RENAME [TO] new_tbl_name\n | ORDER BY col_name [,
col_name] ...\n | RENAME COLUMN old_col_name TO new_col_name\n | RENAME
{INDEX|KEY} old_index_name TO new_index_name\n | CONVERT TO CHARACTER SET
charset_name [COLLATE collation_name]\n | [DEFAULT] CHARACTER SET [=]
charset_name\n | [DEFAULT] COLLATE [=] collation_name\n | DISCARD
TABLESPACE\n | IMPORT TABLESPACE\n | ALGORITHM [=]
{DEFAULT|INPLACE|COPY|NOCOPY|INSTANT}\n | LOCK [=]
{DEFAULT|NONE|SHARED|EXCLUSIVE}\n | FORCE\n | partition_options\n | ADD
PARTITION [IF NOT EXISTS] (partition_definition)\n | DROP PARTITION [IF
EXISTS] partition_names\n | COALESCE PARTITION number\n | REORGANIZE
PARTITION [partition_names INTO (partition_definitions)]\n | ANALYZE
PARTITION partition_names\n | CHECK PARTITION partition_names\n | OPTIMIZE
PARTITION partition_names\n | REBUILD PARTITION partition_names\n | REPAIR
PARTITION partition_names\n | EXCHANGE PARTITION partition_name WITH TABLE
tbl_name\n | REMOVE PARTITIONING\n | ADD SYSTEM VERSIONING\n | DROP SYSTEM
VERSIONING\nindex_col_name:\n col_name [(length)] [ASC |
DESC]\nindex_type:\n USING {BTREE | HASH | RTREE}\nindex_option:\n [
KEY_BLOCK_SIZE [=] value\n | index_type\n | WITH PARSER parser_name\n |
COMMENT \'string\'\n | CLUSTERING={YES| NO} ]\n [ IGNORED | NOT
IGNORED ]\ntable_options:\n table_option [[,] table_option]
...\n\nDescription\n-----------\n\nALTER TABLE enables you to change the
structure of an existing table. For\nexample, you can add or delete
columns, create or destroy indexes, change the\ntype of existing columns,
or rename columns or the table itself. You can also\nchange the comment for
the table and the storage engine of the table.\n\nIf another connection is
using the table, a metadata lock is active, and this\nstatement will wait
until the lock is released. This is also true for\nnon-transactional
tables.\n\nWhen adding a UNIQUE index on a column (or a set of columns)
which have\nduplicated values, an error will be produced and the statement
will be\nstopped. To suppress the error and force the creation of UNIQUE
indexes,\ndiscarding duplicates, the IGNORE option can be specified. This
can be useful\nif a column (or a set of columns) should be UNIQUE but it
contains duplicate\nvalues; however, this technique provides no control on
which rows are\npreserved and which are deleted. Also, note that IGNORE is
accepted but\nignored in ALTER TABLE ... EXCHANGE PARTITION
statements.\n\nThis statement can also be used to rename a table. For
details see RENAME\nTABLE.\n\nWhen an index is created, the storage engine
may use a configurable buffer in\nthe process. Incrementing the buffer
speeds up the index creation. Aria and\nMyISAM allocate a buffer whose size
is defined by aria_sort_buffer_size or\nmyisam_sort_buffer_size, also used
for REPAIR TABLE. InnoDB allocates three\nbuffers whose size is defined by
innodb_sort_buffer_size.\n\nPrivileges\n----------\n\nExecuting the ALTER
TABLE statement generally requires at least the ALTER\nprivilege for the
table or the database..\n\nIf you are renaming a table, then it also
requires the DROP, CREATE and INSERT\nprivileges for the table or the
database as well.\n\nOnline DDL\n----------\n\nOnline DDL is supported with
the ALGORITHM and LOCK clauses.\n\nSee InnoDB Online DDL Overview for more
information on online DDL with InnoDB.\n\nALTER ONLINE
TABLE\n------------------\n\nALTER ONLINE TABLE also works for partitioned
tables.\n\nOnline ALTER TABLE is available by executing the
following:\n\nALTER ONLINE TABLE ...;\n\nThis statement has the following
semantics:\n\nThis statement is equivalent to the following:\n\nALTER TABLE
... LOCK=NONE;\n\nSee the LOCK alter specification for more
information.\n\nThis statement is equivalent to the following:\n\nALTER
TABLE ... ALGORITHM=INPLACE;\n\nSee the ALGORITHM alter specification for
more information.\n\nWAIT/NOWAIT\n-----------\n\nMariaDB starting with
10.3.0\n----------------------------\nSet the lock wait timeout. See WAIT
and NOWAIT.\n\nIF EXISTS\n---------\n\nThe IF EXISTS and IF NOT EXISTS
clauses are available for the following:\n\nADD COLUMN [IF NOT
EXISTS]\nADD INDEX [IF NOT EXISTS]\nADD FOREIGN KEY [IF NOT
EXISTS]\nADD PARTITION [IF NOT EXISTS]\nCREATE INDEX [IF NOT
EXISTS]\nDROP COLUMN [IF EXISTS]\nDROP INDEX [IF EXISTS]\nDROP
FOREIGN KEY [IF EXISTS]\nDROP PARTITION [IF EXISTS]\nCHANGE COLUMN [IF
EXISTS]\nMODIFY COLUMN [IF EXISTS]\nDROP INDEX [IF EXISTS]\nWhen
IF EXISTS and IF NOT EXISTS are used in clauses, queries will not
report\nerrors when the condition is triggered for that clause. A warning
with the\nsame message text will be issued and the ALTER will move on to
the next clause\nin the statement (or end if finished).\n\nMariaDB starting
with 10.5.2\n----------------------------\nIf this is directive is used
after ALTER ... TABLE, one will not get an error\nif the table
doesn\'t exist.\n\nColumn Definitions\n------------------\n\nSee
CREATE TABLE: Column Definitions for information about column
definitions.\n\nIndex Definitions\n-----------------\n\nSee CREATE TABLE:
Index Definitions for information about index definitions.\n\nThe CREATE
INDEX and DROP INDEX statements can also be used to add or remove\nan
index.\n\nCharacter Sets and
Collations\n-----------------------------\n\nCONVERT TO CHARACTER SET
charset_name [COLLATE collation_name]\n[DEFAULT] CHARACTER SET [=]
charset_name\n[DEFAULT] COLLATE [=] collation_name\nSee Setting Character
Sets and Collations for details on setting the character\nsets and
collations.\n\nAlter Specifications\n--------------------\n\nTable
Options\n-------------\n\nSee CREATE TABLE: Table Options for information
about table options.\n\nADD COLUMN\n----------\n\n... ADD COLUMN [IF NOT
EXISTS] (col_name column_definition,...)\nAdds a column to the table. The
syntax is the same as in CREATE TABLE. If you\nare using IF NOT_EXISTS the
column will not be added if it was not there\nalready. This is very useful
when doing scripts to modify tables.\n\nThe FIRST and AFTER clauses affect
the physical order of columns in the\ndatafile. Use FIRST to add a column
in the first (leftmost) position, or AFTER\nfollowed by a column name to
add the new column in any other position. Note\nthat, nowadays, the
physical position of a column is usually irrelevant.\n\nSee also Instant
ADD COLUMN for InnoDB.\n\nDROP COLUMN\n-----------\n\n... DROP COLUMN [IF
EXISTS] col_name [CASCADE|RESTRICT]\nDrops the column from the table. If
you are using IF EXISTS you will not get\nan error if the column
didn\'t exist. If the column is part of any index, the\ncolumn will be
dropped from them, except if you add a new column with\nidentical name at
the same time. The index will be dropped if all columns from\nthe index
were dropped. If the column was used in a view or trigger, you will\nget an
error next time the view or trigger is accessed.\n\nMariaDB starting with
10.2.8\n----------------------------\nDropping a column that is part of a
multi-column UNIQUE constraint is not\npermitted. For example:\n\nCREATE
TABLE a (\n a int,\n b int,\n primary key (a,b)\n);\n\nALTER TABLE x DROP
COLUMN a;\n[42000][1072] Key column \'A\' doesn\'t exist in
table\n\nThe reason is that dropping column a would result in the new
constraint that\nall values in column b be unique. In order to drop the
column, an explicit\nDROP PRIMARY KEY and ADD PRIMARY KEY would be
required. Up until MariaDB\n10.2.7, the column was dropped and the
additional constraint applied,\nresulting in the following
structure:\n\nALTER TABLE x DROP COLUMN a;\nQuery OK, 0 rows affected (0.46
sec)\n\nDESC x;\n+-------+---------+------+-----+---------+-------+\n|
Field | Type | Null | Key | Default | Extra
|\n+-------+---------+------+-----+---------+-------+\n| b | int(11) |
NO | PRI | NULL |
|\n+-------+---------+------+-----+---------+-------+\n\nMariaDB starting
with 10.4.0\n----------------------------\nMariaDB 10.4.0 supports instant
DROP COLUMN. DROP COLUMN of an indexed column\nwould imply DROP INDEX (and
in the case of a non-UNIQUE multi-column index,\npossibly ADD INDEX). These
will not be allowed with ALGORITHM=INSTANT, but\nunlike before, they can be
allowed with ALGORITHM=NOCOPY\n\nRESTRICT and CASCADE are allowed to make
porting from other database systems\neasier. In MariaDB, they do
nothing.\n\nMODIFY COLUMN\n-------------\n\nAllows you to modify the type
of a column. The column will be at the same\nplace as the original column
and all indexes on the column will be kept. Note\nthat when modifying
column, you should specify all attributes for the new\ncolumn.\n\nCREATE
TABLE t1 (a INT UNSIGNED AUTO_INCREMENT, PRIMARY KEY((a));\nALTER TABLE t1
MODIFY a BIGINT UNSIGNED AUTO_INCREMENT;\n\nCHANGE
COLUMN\n-------------\n\nWorks like MODIFY COLUMN except that you can also
change the name of the\ncolumn. The column will be at the same place as the
original column and all\nindex on the column will be kept.\n\nCREATE TABLE
t1 (a INT UNSIGNED AUTO_INCREMENT, PRIMARY KEY(a));\nALTER TABLE t1 CHANGE
a b BIGINT UNSIGNED AUTO_INCREMENT;\n\nALTER COLUMN\n------------\n\nThis
lets you change column options.\n\nCREATE TABLE t1 (a INT UNSIGNED
AUTO_INCREMENT, b varchar(50), PRIMARY KEY(a));\nALTER TABLE t1 ALTER b SET
DEFAULT \'hello\';\n\nRENAME
INDEX/KEY\n----------------\n\nMariaDB starting with
10.5.2\n----------------------------\nFrom MariaDB 10.5.2, it is possible
to rename an index using the RENAME INDEX\n(or RENAME KEY) syntax, for
example:\n\nALTER TABLE t1 RENAME INDEX i_old TO i_new;\n\nRENAME
COLUMN\n-------------\n\nMariaDB starting with
10.5.2\n----------------------------\nFrom MariaDB 10.5.2, it is possible
to rename a column using the RENAME COLUMN\nsyntax, for example:\n\nALTER
TABLE t1 RENAME COLUMN c_old TO c_new;\n\nADD PRIMARY
KEY\n---------------\n\nAdd a primary key.\n\nFor PRIMARY KEY indexes, you
can specify a name for the index, but it is\nsilently ignored, and the name
of the index is always PRIMARY.\n\nSee Getting Started with Indexes:
Primary Key for more information.\n\nDROP PRIMARY
KEY\n----------------\n\nDrop a primary key.\n\nFor PRIMARY KEY indexes,
you can specify a name for the index, but it is\nsilently ignored, and the
name of the index is always PRIMARY.\n\nSee Getting Started with Indexes:
Primary Key for more information.\n\nADD FOREIGN
KEY\n---------------\n\nAdd a foreign key.\n\nFor FOREIGN KEY indexes, a
reference definition must be provided.\n\nFor FOREIGN KEY indexes, you can
specify a name for the constraint, using the\nCONSTRAINT keyword. That name
will be used in error messages.\n\nFirst, you have to specify the name of
the target (parent) table and a column\nor a column list which must be
indexed and whose values must match to the\nforeign key\'s values. The
MATCH clause is accepted to improve the\ncompatibility with other
DBMS\'s, but has no meaning in MariaDB. The ON DELETE\nand ON UPDATE
clauses specify what must be done when a DELETE (or a REPLACE)\nstatements
attempts to delete a referenced row from the parent table, and when\nan
UPDATE statement attempts to modify the referenced foreign key columns in
a\nparent table row, respectively. The following options are allowed:\n\n*
RESTRICT: The delete/update operation is not performed. The
statement\nterminates with a 1451 error (SQLSTATE \'2300\').\n*
NO ACTION: Synonym for RESTRICT.\n* CASCADE: The delete/update operation is
performed in both tables.\n* SET NULL: The update or delete goes ahead in
the parent table, and the\ncorresponding foreign key fields in the child
table are set to NULL. (They\nmust not be defined as NOT NULL for this to
succeed).\n* SET DEFAULT: This option is implemented only for the legacy
PBXT storage\nengine, which is disabled by default and no longer
maintained. It sets the\nchild table\'s foreign key fields to their
DEFAULT values when the referenced\nparent table key entries are updated or
deleted.\n\nIf either clause is omitted, the default behavior for the
omitted clause is\nRESTRICT.\n\nSee Foreign Keys for more
information.\n\nDROP FOREIGN KEY\n----------------\n\nDrop a foreign
key.\n\nSee Foreign Keys for more information.\n\nADD
INDEX\n---------\n\nAdd a plain index.\n\nPlain indexes are regular indexes
that are not unique, and are not acting as a\nprimary key or a foreign key.
They are also not the \"specialized\" FULLTEXT or\nSPATIAL
indexes.\n\nSee Getting Started with Indexes: Plain Indexes for more
information.\n\nDROP INDEX\n----------\n\nDrop a plain index.\n\nPlain
indexes are regular indexes that are not unique, and are not acting as
a\nprimary key or a foreign key. They are also not the
\"specialized\" FULLTEXT or\nSPATIAL indexes.\n\nSee Getting
Started with Indexes: Plain Indexes for more information.\n\nADD UNIQUE
INDEX\n----------------\n\nAdd a unique index.\n\nThe UNIQUE keyword means
that the index will not accept duplicated
values,','','https://mariadb.com/kb/en/alter-table/');
update help_topic set description = CONCAT(description, '\nexcept for
NULLs. An error will raise if you try to insert duplicate values in\na
UNIQUE index.\n\nFor UNIQUE indexes, you can specify a name for the
constraint, using the\nCONSTRAINT keyword. That name will be used in error
messages.\n\nSee Getting Started with Indexes: Unique Index for more
information.\n\nDROP UNIQUE INDEX\n-----------------\n\nDrop a unique
index.\n\nThe UNIQUE keyword means that the index will not accept
duplicated values,\nexcept for NULLs. An error will raise if you try to
insert duplicate values in\na UNIQUE index.\n\nFor UNIQUE indexes, you can
specify a name for the constraint, using the\nCONSTRAINT keyword. That name
will be used in error messages.\n\nSee Getting Started with Indexes: Unique
Index for more information.\n\nADD FULLTEXT
INDEX\n------------------\n\nAdd a FULLTEXT index.\n\nSee Full-Text Indexes
for more information.\n\nDROP FULLTEXT INDEX\n-------------------\n\nDrop a
FULLTEXT index.\n\nSee Full-Text Indexes for more information.\n\nADD
SPATIAL INDEX\n-----------------\n\nAdd a SPATIAL index.\n\nSee SPATIAL
INDEX for more information.\n\nDROP SPATIAL
INDEX\n------------------\n\nDrop a SPATIAL index.\n\nSee SPATIAL INDEX for
more information.\n\nENABLE/ DISABLE KEYS\n--------------------\n\nDISABLE
KEYS will disable all non unique keys for the table for storage\nengines
that support this (at least MyISAM and Aria). This can be used to\nspeed up
inserts into empty tables.\n\nENABLE KEYS will enable all disabled
keys.\n\nRENAME TO\n---------\n\nRenames the table. See also RENAME
TABLE.\n\nADD CONSTRAINT\n--------------\n\nModifies the table adding a
constraint on a particular column or columns.\n\nMariaDB starting with
10.2.1\n----------------------------\nMariaDB 10.2.1 introduced new ways to
define a constraint.\n\nNote: Before MariaDB 10.2.1, constraint expressions
were accepted in syntax,\nbut ignored.\n\nALTER TABLE table_name \nADD
CONSTRAINT [constraint_name] CHECK(expression);\nBefore a row is inserted
or updated, all constraints are evaluated in the\norder they are defined.
If any constraint fails, then the row will not be\nupdated. One can use
most deterministic functions in a constraint,
including\nUDF\'s.\n\nCREATE TABLE account_ledger (\n id INT PRIMARY
KEY AUTO_INCREMENT,\n transaction_name VARCHAR(100),\n credit_account
VARCHAR(100),\n credit_amount INT,\n debit_account
VARCHAR(100),\n debit_amount INT);\n\nALTER TABLE account_ledger \nADD
CONSTRAINT is_balanced \n CHECK((debit_amount + credit_amount) =
0);\n\nThe constraint_name is optional. If you don\'t provide one in
the ALTER TABLE\nstatement, MariaDB auto-generates a name for you. This is
done so that you can\nremove it later using DROP CONSTRAINT clause.\n\nYou
can disable all constraint expression checks by setting the
variable\ncheck_constraint_checks to OFF. You may find this useful when
loading a table\nthat violates some constraints that you want to later find
and fix in SQL.\n\nTo view constraints on a table, query
information_schema.TABLE_CONSTRAINTS:\n\nSELECT CONSTRAINT_NAME,
TABLE_NAME, CONSTRAINT_TYPE \nFROM
information_schema.TABLE_CONSTRAINTS\nWHERE TABLE_NAME =
\'account_ledger\';\n\n+-----------------+----------------+-----------------+\n|
CONSTRAINT_NAME | TABLE_NAME | CONSTRAINT_TYPE
|\n+-----------------+----------------+-----------------+\n| is_balanced
| account_ledger | CHECK
|\n+-----------------+----------------+-----------------+\n\nDROP
CONSTRAINT\n---------------\n\nMariaDB starting with
10.2.22\n-----------------------------\nDROP CONSTRAINT for UNIQUE and
FOREIGN KEY constraints was introduced in\nMariaDB 10.2.22 and MariaDB
10.3.13.\n\nMariaDB starting with
10.2.1\n----------------------------\nDROP CONSTRAINT for CHECK constraints
was introduced in MariaDB 10.2.1\n\nModifies the table, removing the given
constraint.\n\nALTER TABLE table_name\nDROP CONSTRAINT
constraint_name;\n\nWhen you add a constraint to a table, whether through a
CREATE TABLE or ALTER\nTABLE...ADD CONSTRAINT statement, you can either set
a constraint_name\nyourself, or allow MariaDB to auto-generate one for you.
To view constraints\non a table, query
information_schema.TABLE_CONSTRAINTS. For instance,\n\nCREATE TABLE t (\n a
INT,\n b INT,\n c INT,\n CONSTRAINT CHECK(a > b),\n CONSTRAINT
check_equals CHECK(a = c));\n\nSELECT CONSTRAINT_NAME, TABLE_NAME,
CONSTRAINT_TYPE \nFROM information_schema.TABLE_CONSTRAINTS\nWHERE
TABLE_NAME =
\'t\';\n\n+-----------------+----------------+-----------------+\n|
CONSTRAINT_NAME | TABLE_NAME | CONSTRAINT_TYPE
|\n+-----------------+----------------+-----------------+\n| check_equals
| t | CHECK |\n| CONSTRAINT_1 | t |
CHECK
|\n+-----------------+----------------+-----------------+\n\nTo remove a
constraint from the table, issue an ALTER TABLE...DROP
CONSTRAINT\nstatement. For example,\n\nALTER TABLE t DROP CONSTRAINT
is_unique;\n\nADD SYSTEM VERSIONING\n---------------------\n\nMariaDB
starting with 10.3.4\n----------------------------\nSystem-versioned tables
was added in MariaDB 10.3.4.\n\nAdd system versioning.\n\nDROP SYSTEM
VERSIONING\n----------------------\n\nMariaDB starting with
10.3.4\n----------------------------\nSystem-versioned tables was added in
MariaDB 10.3.4.\n\nDrop system versioning.\n\nADD PERIOD FOR
SYSTEM_TIME\n--------------------------\n\nMariaDB starting with
10.3.4\n----------------------------\nSystem-versioned tables was added in
MariaDB 10.3.4.\n\nFORCE\n-----\n\nALTER TABLE ... FORCE can force MariaDB
to re-build the table.\n\nIn MariaDB 5.5 and before, this could only be
done by setting the ENGINE table\noption to its old value. For example, for
an InnoDB table, one could execute\nthe following:\n\nALTER TABLE tab_name
ENGINE = InnoDB;\n\nThe FORCE option can be used instead. For example,
:\n\nALTER TABLE tab_name FORCE;\n\nWith InnoDB, the table rebuild will
only reclaim unused space (i.e. the space\npreviously used for deleted
rows) if the innodb_file_per_table system variable\nis set to ON (the
default). If the system variable is OFF, then the space will\nnot be
reclaimed, but it will be-re-used for new data that\'s later
added.\n\nEXCHANGE PARTITION\n------------------\n\nThis is used to
exchange the contents of a partition with another table.\n\nThis is
performed by swapping the tablespaces of the partition with the
other\ntable.\n\nSee copying InnoDB\'s transportable tablespaces for
more information.\n\nDISCARD TABLESPACE\n------------------\n\nThis is used
to discard an InnoDB table\'s tablespace.\n\nSee copying
InnoDB\'s transportable tablespaces for more information.\n\nIMPORT
TABLESPACE\n-----------------\n\nThis is used to import an InnoDB
table\'s tablespace. The tablespace should\nhave been copied from its
original server after executing FLUSH TABLES FOR\nEXPORT.\n\nSee copying
InnoDB\'s transportable tablespaces for more information.\n\nALTER
TABLE ... IMPORT only applies to InnoDB tables. Most other popular\nstorage
engines, such as Aria and MyISAM, will recognize their data files as\nsoon
as they\'ve been placed in the proper directory under the datadir, and
no\nspecial DDL is required to import them.\n\nALGORITHM\n---------\n\nThe
ALTER TABLE statement supports the ALGORITHM clause. This clause is one
of\nthe clauses that is used to implement online DDL. ALTER TABLE supports
several\ndifferent algorithms. An algorithm can be explicitly chosen for an
ALTER TABLE\noperation by setting the ALGORITHM clause. The supported
values are:\n\n* ALGORITHM=DEFAULT - This implies the default behavior for
the specific\nstatement, such as if no ALGORITHM clause is specified.\n*
ALGORITHM=COPY\n* ALGORITHM=INPLACE\n* ALGORITHM=NOCOPY - This was added in
MariaDB 10.3.7.\n* ALGORITHM=INSTANT - This was added in MariaDB
10.3.7.\n\nSee InnoDB Online DDL Overview: ALGORITHM for information on how
the ALGORITHM\nclause affects
InnoDB.\n\nALGORITHM=DEFAULT\n-----------------\n\nThe default behavior,
which occurs if ALGORITHM=DEFAULT is specified, or if\nALGORITHM is not
specified at all, usually only makes a copy if the operation\ndoesn\'t
support being done in-place at all. In this case, the most
efficient\navailable algorithm will usually be used.\n\nHowever, in MariaDB
10.3.6 and before, if the value of the old_alter_table\nsystem variable is
set to ON, then the default behavior is to perform ALTER\nTABLE operations
by making a copy of the table using the old algorithm.\n\nIn MariaDB 10.3.7
and later, the old_alter_table system variable is\ndeprecated. Instead, the
alter_algorithm system variable defines the default\nalgorithm for ALTER
TABLE operations.\n\nALGORITHM=COPY\n--------------\n\nALGORITHM=COPY is
the name for the original ALTER TABLE algorithm from early\nMariaDB
versions.\n\nWhen ALGORITHM=COPY is set, MariaDB essentially does the
following operations:\n\n-- Create a temporary table with the new
definition\nCREATE TEMPORARY TABLE tmp_tab (\n...\n);\n\n-- Copy the data
from the original table\nINSERT INTO tmp_tab\n SELECT * FROM
original_tab;\n\n-- Drop the original table\nDROP TABLE original_tab;\n\n--
Rename the temporary table, so that it replaces the original one\nRENAME
TABLE tmp_tab TO original_tab;\n\nThis algorithm is very inefficient, but
it is generic, so it works for all\nstorage engines.\n\nIf ALGORITHM=COPY
is specified, then the copy algorithm will be used even if\nit is not
necessary. This can result in a lengthy table copy. If multiple\nALTER
TABLE operations are required that each require the table to be
rebuilt,\nthen it is best to specify all operations in a single ALTER TABLE
statement,\nso that the table is only rebuilt
once.\n\nALGORITHM=INPLACE\n-----------------\n\nALGORITHM=COPY can be
incredibly slow, because the whole table has to be\ncopied and rebuilt.
ALGORITHM=INPLACE was introduced as a way to avoid this by\nperforming
operations in-place and avoiding the table copy and rebuild,
when\npossible.\n\nWhen ALGORITHM=INPLACE is set, the underlying storage
engine uses\noptimizations to perform the operation while avoiding the
table copy and\nrebuild. However, INPLACE is a bit of a misnomer, since
some operations may\nstill require the table to be rebuilt for some storage
engines. Regardless,\nseveral operations can be performed without a full
copy of the table for some\nstorage engines.\n\nA more accurate name would
have been ALGORITHM=ENGINE, where ENGINE refers to\nan
\"engine-specific\" algorithm.\n\nIf an ALTER TABLE operation
supports ALGORITHM=INPLACE, then it can be\nperformed using optimizations
by the underlying storage engine, but it may\nrebuilt.\n\nSee InnoDB Online
DDL Operations with ALGORITHM=INPLACE for
more.\n\nALGORITHM=NOCOPY\n----------------\n\nALGORITHM=NOCOPY was
introduced in MariaDB 10.3.7.\n\nALGORITHM=INPLACE can sometimes be
surprisingly slow in instances where it has\nto rebuild the clustered
index, because when the clustered index has to be\nrebuilt, the whole table
has to be rebuilt. ALGORITHM=NOCOPY was introduced as\na way to avoid
this.\n\nIf an ALTER TABLE operation supports ALGORITHM=NOCOPY, then it can
be\nperformed without rebuilding the clustered index.\n\nIf
ALGORITHM=NOCOPY is specified for an ALTER TABLE operation that does
not\nsupport ALGORITHM=NOCOPY, then an error will be raised. In this case,
raising\nan error is preferable, if the alternative is for the operation to
rebuild the\nclustered index, and perform unexpectedly slowly.\n\nSee
InnoDB Online DDL Operations with ALGORITHM=NOCOPY for
more.\n\nALGORITHM=INSTANT\n-----------------\n\nALGORITHM=INSTANT was
introduced in MariaDB 10.3.7.\n\nALGORITHM=INPLACE can sometimes be
surprisingly slow in instances where it has\nto modify data files.
ALGORITHM=INSTANT was introduced as a way to avoid this.\n\nIf an ALTER
TABLE operation supports ALGORITHM=INSTANT, then it can be\nperformed
without modifying any data files.\n\nIf ALGORITHM=INSTANT is specified for
an ALTER TABLE operation that does not\nsupport ALGORITHM=INSTANT, then an
error will be raised. In this case, raising\nan error is preferable, if the
alternative is for the operation to modify data\nfiles, and perform
unexpectedly slowly.\n\nSee InnoDB Online DDL Operations with
ALGORITHM=INSTANT for more.\n\nLOCK\n----\n\nThe ALTER TABLE statement
supports the LOCK clause. This clause is one of the\nclauses that is used
to implement online DDL. ALTER TABLE supports several\ndifferent locking
strategies. A locking strategy can be explicitly chosen for\nan ALTER TABLE
operation by setting the LOCK clause. The supported values are:\n\n*
DEFAULT: Acquire the least restrictive lock on the table that is
supported\nfor the specific operation. Permit the maximum amount of
concurrency that is\nsupported for the specific operation.\n* NONE: Acquire
no lock on the table. Permit all concurrent DML. If this\nlocking strategy
is not permitted for an operation, then an error is raised.\n* SHARED:
Acquire a read lock on the table. Permit read-only concurrent DML.\nIf this
locking strategy is not permitted for an operation, then an error
is\nraised.\n* EXCLUSIVE: Acquire a write lock on the table. Do not permit
concurrent DML.\n\nDifferent storage engines support different locking
strategies for different\noperations. If a specific locking strategy is
chosen for an ALTER TABLE\noperation, and that table\'s storage engine
does not support that locking\nstrategy for that specific operation, then
an error will be raised.\n\nIf the LOCK clause is not explicitly set, then
the operation uses LOCK=DEFAULT.\n\nALTER ONLINE TABLE is equivalent to
LOCK=NONE. Therefore, the ALTER ONLINE\nTABLE statement can be used to
ensure that your ALTER TABLE operation allows\nall concurrent DML.\n\nSee
InnoDB Online DDL Overview: LOCK for information on how the LOCK
clause\naffects InnoDB.\n\nProgress
Reporting\n------------------\n\nMariaDB provides progress reporting for
ALTER TABLE statement for clients that\nsupport the new progress reporting
protocol. For example, if you were using\nthe mysql client, then the
progress report might look like this::\n\nALTER TABLE test
ENGINE=Aria;\nStage: 1 of 2 \'copy to tmp table\' 46% of
stage\n\nThe progress report is also shown in the output of the SHOW
PROCESSLIST\nstatement and in the contents of the
information_schema.PROCESSLIST table.\n\nSee Progress Reporting for more
information.\n\nAborting ALTER TABLE
Operations\n-------------------------------\n\nIf an ALTER TABLE operation
is being performed and the connection is killed,') WHERE help_topic_id
= 691;
update help_topic set description = CONCAT(description, '\nthe changes
will be rolled back in a controlled manner. The rollback can be a\nslow
operation as the time it takes is relative to how far the operation
has\nprogressed.\n\nMariaDB starting with
10.2.13\n-----------------------------\nAborting ALTER TABLE ...
ALGORITHM=COPY was made faster by removing excessive\nundo logging
(MDEV-11415). This significantly shortens the time it takes to\nabort a
running ALTER TABLE operation.\n\nAtomic ALTER
TABLE\n------------------\n\nMariaDB starting with
10.6.1\n----------------------------\nFrom MariaDB 10.6, ALTER TABLE is
atomic for most engines, including InnoDB,\nMyRocks, MyISAM and Aria
(MDEV-25180). This means that if there is a crash\n(server down or power
outage) during an ALTER TABLE operation, after recovery,\neither the old
table and associated triggers and status will be intact, or the\nnew table
will be active.\n\nIn older MariaDB versions one could get leftover
#sql-alter..\',\n\'#sql-backup..\' or
\'table_name.frm˝\' files if the system crashed during
the\nALTER TABLE operation.\n\nSee Atomic DDL for more
information.\n\nReplication\n-----------\n\nMariaDB starting with
10.8.1\n----------------------------\nBefore MariaDB 10.8.1, ALTER TABLE
got fully executed on the primary first,\nand only then was it replicated
and started executing on replicas. From\nMariaDB 10.8.1, ALTER TABLE gains
an option to replicate sooner and begin\nexecuting on replicas when it
merely starts executing on the primary, not when\nit finishes. This way the
replication lag caused by a heavy ALTER TABLE can be\ncompletely eliminated
(MDEV-11675).\n\nExamples\n--------\n\nAdding a new column:\n\nALTER TABLE
t1 ADD x INT;\n\nDropping a column:\n\nALTER TABLE t1 DROP x;\n\nModifying
the type of a column:\n\nALTER TABLE t1 MODIFY x bigint
unsigned;\n\nChanging the name and type of a column:\n\nALTER TABLE t1
CHANGE a b bigint unsigned auto_increment;\n\nCombining multiple clauses in
a single ALTER TABLE statement, separated by\ncommas:\n\nALTER TABLE t1
DROP x, ADD x2 INT, CHANGE y y2 INT;\n\nChanging the storage engine and
adding a comment:\n\nALTER TABLE t1 \n ENGINE = InnoDB\n COMMENT =
\'First of three tables containing usage info\';\n\nRebuilding
the table (the previous example will also rebuild the table if it\nwas
already InnoDB):\n\nALTER TABLE t1 FORCE;\n\nDropping an index:\n\nALTER
TABLE rooms DROP INDEX u;\n\nAdding a unique index:\n\nALTER TABLE rooms
ADD UNIQUE INDEX u(room_number);\n\nFrom MariaDB 10.5.3, adding a primary
key for an application-time period table\nwith a WITHOUT OVERLAPS
constraint:\n\nALTER TABLE rooms ADD PRIMARY KEY(room_number, p WITHOUT
OVERLAPS);\n\nFrom MariaDB 10.8.1, ALTER query can be replicated faster
with the setting of\n\nSET @@SESSION.binlog_alter_two_phase =
true;\n\nprior the ALTER query. Binlog would contain two event groups\n\n|
master-bin.000001 | 495 | Gtid | 1 | 537 |
GTID\n0-1-2 START ALTER |\n|
master-bin.000001 | 537 | Query | 1 | 655 |
use\n`test`; alter table t add column b int, algorithm=inplace |\n|
master-bin.000001 | 655 | Gtid | 1 | 700 |
GTID\n0-1-3 COMMIT ALTER id=2 |\n|
master-bin.000001 | 700 | Query | 1 | 835 |
use\n`test`; alter table t add column b int, algorithm=inplace |\n\nof
which the first one gets delivered to replicas before ALTER is taken
to\nactual execution on the primary.\n\nURL:
https://mariadb.com/kb/en/alter-table/') WHERE help_topic_id = 691;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(692,38,'ALTER DATABASE','Modifies a database, changing its
overall characteristics.\n\nSyntax\n------\n\nALTER {DATABASE | SCHEMA}
[db_name]\n alter_specification ...\nALTER {DATABASE | SCHEMA} db_name\n
UPGRADE DATA DIRECTORY NAME\n\nalter_specification:\n [DEFAULT] CHARACTER
SET [=] charset_name\n | [DEFAULT] COLLATE [=] collation_name\n | COMMENT
[=] \'comment\'\n\nDescription\n-----------\n\nALTER DATABASE
enables you to change the overall characteristics of a\ndatabase. These
characteristics are stored in the db.opt file in the database\ndirectory.
To use ALTER DATABASE, you need the ALTER privilege on the\ndatabase. ALTER
SCHEMA is a synonym for ALTER DATABASE.\n\nThe CHARACTER SET clause changes
the default database character set. The\nCOLLATE clause changes the default
database collation. See Character Sets and\nCollations for more.\n\nYou can
see what character sets and collations are available using,\nrespectively,
the SHOW CHARACTER SET and SHOW COLLATION statements.\n\nChanging the
default character set/collation of a database does not change
the\ncharacter set/collation of any stored procedures or stored functions
that were\npreviously created, and relied on the defaults. These need to be
dropped and\nrecreated in order to apply the character set/collation
changes.\n\nThe database name can be omitted from the first syntax, in
which case the\nstatement applies to the default database.\n\nThe syntax
that includes the UPGRADE DATA DIRECTORY NAME clause was added in\nMySQL
5.1.23. It updates the name of the directory associated with the\ndatabase
to use the encoding implemented in MySQL 5.1 for mapping database\nnames to
database directory names (see Identifier to File Name Mapping).
This\nclause is for use under these conditions:\n\n* It is intended when
upgrading MySQL to 5.1 or later from older versions.\n* It is intended to
update a database directory name to the current encoding\nformat if the
name contains special characters that need encoding.\n* The statement is
used by mysqlcheck (as invoked by mysql_upgrade).\n\nFor example,if a
database in MySQL 5.0 has a name of a-b-c, the name contains\ninstance of
the `-\' character. In 5.0, the database directory is also
named\na-b-c, which is not necessarily safe for all file systems. In MySQL
5.1 and\nup, the same database name is encoded as a@002db@002dc to produce
a file\nsystem-neutral directory name.\n\nWhen a MySQL installation is
upgraded to MySQL 5.1 or later from an older\nversion,the server displays a
name such as a-b-c (which is in the old format)\nas #mysql50#a-b-c, and you
must refer to the name using the #mysql50# prefix.\nUse UPGRADE DATA
DIRECTORY NAME in this case to explicitly tell the server to\nre-encode the
database directory name to the current encoding format:\n\nALTER DATABASE
`#mysql50#a-b-c` UPGRADE DATA DIRECTORY NAME;\n\nAfter executing this
statement, you can refer to the database as a-b-c without\nthe special
#mysql50# prefix.\n\nCOMMENT\n-------\n\nMariaDB starting with
10.5.0\n----------------------------\nFrom MariaDB 10.5.0, it is possible
to add a comment of a maximum of 1024\nbytes. If the comment length exceeds
this length, a error/warning code 4144 is\nthrown. The database comment is
also added to the db.opt file, as well as to\nthe
information_schema.schemata table.\n\nExamples\n--------\n\nALTER DATABASE
test CHARACTER SET=\'utf8\'
COLLATE=\'utf8_bin\';\n\nFrom MariaDB 10.5.0:\n\nALTER DATABASE p
COMMENT=\'Presentations\';\n\nURL:
https://mariadb.com/kb/en/alter-database/','','https://mariadb.com/kb/en/alter-database/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(693,38,'ALTER EVENT','Modifies one or more characteristics
of an existing event.\n\nSyntax\n------\n\nALTER\n [DEFINER = { user |
CURRENT_USER }]\n EVENT event_name\n [ON SCHEDULE schedule]\n [ON
COMPLETION [NOT] PRESERVE]\n [RENAME TO new_event_name]\n [ENABLE |
DISABLE | DISABLE ON SLAVE]\n [COMMENT \'comment\']\n [DO
sql_statement]\n\nDescription\n-----------\n\nThe ALTER EVENT statement is
used to change one or more of the characteristics\nof an existing event
without the need to drop and recreate it. The syntax for\neach of the
DEFINER, ON SCHEDULE, ON COMPLETION, COMMENT, ENABLE / DISABLE,\nand DO
clauses is exactly the same as when used with CREATE EVENT.\n\nThis
statement requires the EVENT privilege. When a user executes a
successful\nALTER EVENT statement, that user becomes the definer for the
affected event.\n\n(In MySQL 5.1.11 and earlier, an event could be altered
only by its definer,\nor by a user having the SUPER privilege.)\n\nALTER
EVENT works only with an existing event:\n\nALTER EVENT no_such_event ON
SCHEDULE EVERY \'2:3\' DAY_HOUR;\nERROR 1539 (HY000): Unknown
event \'no_such_event\'\n\nExamples\n--------\n\nALTER EVENT
myevent \n ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 2 HOUR\n DO\n
UPDATE myschema.mytable SET mycol = mycol + 1;\n\nURL:
https://mariadb.com/kb/en/alter-event/','','https://mariadb.com/kb/en/alter-event/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(694,38,'ALTER FUNCTION','Syntax\n------\n\nALTER FUNCTION
func_name [characteristic ...]\n\ncharacteristic:\n { CONTAINS SQL | NO
SQL | READS SQL DATA | MODIFIES SQL DATA }\n | SQL SECURITY { DEFINER |
INVOKER }\n | COMMENT
\'string\'\n\nDescription\n-----------\n\nThis statement can be
used to change the characteristics of a stored function.\nMore than one
change may be specified in an ALTER FUNCTION statement. However,\nyou
cannot change the parameters or body of a stored function using
this\nstatement; to make such changes, you must drop and re-create the
function\nusing DROP FUNCTION and CREATE FUNCTION.\n\nYou must have the
ALTER ROUTINE privilege for the function. (That privilege is\ngranted
automatically to the function creator.) If binary logging is enabled,\nthe
ALTER FUNCTION statement might also require the SUPER privilege,
as\ndescribed in Binary Logging of Stored
Routines.\n\nExample\n-------\n\nALTER FUNCTION hello SQL SECURITY
INVOKER;\n\nURL:
https://mariadb.com/kb/en/alter-function/','','https://mariadb.com/kb/en/alter-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(695,38,'ALTER LOGFILE GROUP','Syntax\n------\n\nALTER
LOGFILE GROUP logfile_group\n ADD UNDOFILE \'file_name\'\n
[INITIAL_SIZE [=] size]\n [WAIT]\n ENGINE [=] engine_name\n\nThe ALTER
LOGFILE GROUP statement is not supported by MariaDB. It was\noriginally
inherited from MySQL NDB Cluster. See MDEV-19295 for
more\ninformation.\n\nURL:
https://mariadb.com/kb/en/alter-logfile-group/','','https://mariadb.com/kb/en/alter-logfile-group/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(696,38,'ALTER PROCEDURE','Syntax\n------\n\nALTER PROCEDURE
proc_name [characteristic ...]\n\ncharacteristic:\n { CONTAINS SQL | NO
SQL | READS SQL DATA | MODIFIES SQL DATA }\n | SQL SECURITY { DEFINER |
INVOKER }\n | COMMENT
\'string\'\n\nDescription\n-----------\n\nThis statement can be
used to change the characteristics of a stored\nprocedure. More than one
change may be specified in an ALTER PROCEDURE\nstatement. However, you
cannot change the parameters or body of a stored\nprocedure using this
statement. To make such changes, you must drop and\nre-create the procedure
using either CREATE OR REPLACE PROCEDURE (since\nMariaDB 10.1.3) or DROP
PROCEDURE and CREATE PROCEDURE (MariaDB 10.1.2 and\nbefore).\n\nYou must
have the ALTER ROUTINE privilege for the procedure. By default,
that\nprivilege is granted automatically to the procedure creator. See
Stored\nRoutine Privileges.\n\nExample\n-------\n\nALTER PROCEDURE
simpleproc SQL SECURITY INVOKER;\n\nURL:
https://mariadb.com/kb/en/alter-procedure/','','https://mariadb.com/kb/en/alter-procedure/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(697,38,'ALTER SERVER','Syntax\n------\n\nALTER SERVER
server_name\n OPTIONS (option [, option]
...)\n\nDescription\n-----------\n\nAlters the server information for
server_name, adjusting the specified options\nas per the CREATE SERVER
command. The corresponding fields in the\nmysql.servers table are updated
accordingly. This statement requires the SUPER\nprivilege or, from MariaDB
10.5.2, the FEDERATED ADMIN privilege.\n\nALTER SERVER is not written to
the binary log, irrespective of the binary log\nformat being used. From
MariaDB 10.1.13, Galera replicates the CREATE SERVER,\nALTER SERVER and
DROP SERVER statements.\n\nExamples\n--------\n\nALTER SERVER s OPTIONS
(USER \'sally\');\n\nURL:
https://mariadb.com/kb/en/alter-server/','','https://mariadb.com/kb/en/alter-server/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(698,38,'ALTER TABLESPACE','The ALTER TABLESPACE statement
is not supported by MariaDB. It was originally\ninherited from MySQL NDB
Cluster. In MySQL 5.7 and later, the statement is\nalso supported for
InnoDB. However, MariaDB has chosen not to include that\nspecific feature.
See MDEV-19294 for more information.\n\nURL:
https://mariadb.com/kb/en/alter-tablespace/','','https://mariadb.com/kb/en/alter-tablespace/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(699,38,'ALTER VIEW','Syntax\n------\n\nALTER\n [ALGORITHM
= {UNDEFINED | MERGE | TEMPTABLE}]\n [DEFINER = { user | CURRENT_USER }]\n
[SQL SECURITY { DEFINER | INVOKER }]\n VIEW view_name [(column_list)]\n
AS select_statement\n [WITH [CASCADED | LOCAL] CHECK
OPTION]\n\nDescription\n-----------\n\nThis statement changes the
definition of a view, which must exist. The syntax\nis similar to that for
CREATE VIEW and the effect is the same as for CREATE OR\nREPLACE VIEW if
the view exists. This statement requires the CREATE VIEW and\nDROP
privileges for the view, and some privilege for each column referred to\nin
the SELECT statement. ALTER VIEW is allowed only to the definer or
users\nwith the SUPER privilege.\n\nExample\n-------\n\nALTER VIEW v AS
SELECT a, a*3 AS a2 FROM t;\n\nURL:
https://mariadb.com/kb/en/alter-view/','','https://mariadb.com/kb/en/alter-view/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(700,38,'CREATE TABLE','Syntax\n------\n\nCREATE [OR
REPLACE] [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name\n
(create_definition,...) [table_options ]... [partition_options]\nCREATE
[OR REPLACE] [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name\n
[(create_definition,...)] [table_options ]... [partition_options]\n
select_statement\nCREATE [OR REPLACE] [TEMPORARY] TABLE [IF NOT EXISTS]
tbl_name\n { LIKE old_table_name | (LIKE old_table_name)
}\nselect_statement:\n [IGNORE | REPLACE] [AS] SELECT ... (Some legal
select statement)\n\nDescription\n-----------\n\nUse the CREATE TABLE
statement to create a table with the given name.\n\nIn its most basic form,
the CREATE TABLE statement provides a table name\nfollowed by a list of
columns, indexes, and constraints. By default, the table\nis created in the
default database. Specify a database with db_name.tbl_name.\nIf you quote
the table name, you must quote the database name and table name\nseparately
as `db_name`.`tbl_name`. This is particularly useful for CREATE\nTABLE ...
SELECT, because it allows to create a table into a database,
which\ncontains data from other databases. See Identifier Qualifiers.\n\nIf
a table with the same name exists, error 1050 results. Use IF NOT EXISTS
to\nsuppress this error and issue a note instead. Use SHOW WARNINGS to see
notes.\n\nThe CREATE TABLE statement automatically commits the current
transaction,\nexcept when using the TEMPORARY keyword.\n\nFor valid
identifiers to use as table names, see Identifier Names.\n\nNote: if the
default_storage_engine is set to ColumnStore then it needs\nsetting on all
UMs. Otherwise when the tables using the default engine are\nreplicated
across UMs they will use the wrong engine. You should therefore not\nuse
this option as a session variable with ColumnStore.\n\nMicrosecond
precision can be between 0-6. If no precision is specified it is\nassumed
to be 0, for backward compatibility
reasons.\n\nPrivileges\n----------\n\nExecuting the CREATE TABLE statement
requires the CREATE privilege for the\ntable or the database.\n\nCREATE OR
REPLACE\n-----------------\n\nIf the OR REPLACE clause is used and the
table already exists, then instead of\nreturning an error, the server will
drop the existing table and replace it\nwith the newly defined
table.\n\nThis syntax was originally added to make replication more robust
if it has to\nrollback and repeat statements such as CREATE ... SELECT on
replicas.\n\nCREATE OR REPLACE TABLE table_name (a int);\n\nis basically
the same as:\n\nDROP TABLE IF EXISTS table_name;\nCREATE TABLE table_name
(a int);\n\nwith the following exceptions:\n\n* If table_name was locked
with LOCK TABLES it will continue to be locked\nafter the statement.\n*
Temporary tables are only dropped if the TEMPORARY keyword was used.
(With\nDROP TABLE, temporary tables are preferred to be dropped before
normal\ntables).\n\nThings to be Aware of With CREATE OR
REPLACE\n--------------------------------------------\n\n* The table is
dropped first (if it existed), after that the CREATE is done.\nBecause of
this, if the CREATE fails, then the table will not exist anymore\nafter the
statement. If the table was used with LOCK TABLES it will be\nunlocked.\n*
One can\'t use OR REPLACE together with IF EXISTS.\n* Slaves in
replication will by default use CREATE OR REPLACE when replicating\nCREATE
statements that don\'\'t use IF EXISTS. This can be changed by
setting\nthe variable slave-ddl-exec-mode to STRICT.\n\nCREATE TABLE IF NOT
EXISTS\n--------------------------\n\nIf the IF NOT EXISTS clause is used,
then the table will only be created if a\ntable with the same name does not
already exist. If the table already exists,\nthen a warning will be
triggered by default.\n\nCREATE TEMPORARY
TABLE\n----------------------\n\nUse the TEMPORARY keyword to create a
temporary table that is only available\nto the current session. Temporary
tables are dropped when the session ends.\nTemporary table names are
specific to the session. They will not conflict with\nother temporary
tables from other sessions even if they share the same name.\nThey will
shadow names of non-temporary tables or views, if they are\nidentical. A
temporary table can have the same name as a non-temporary table\nwhich is
located in the same database. In that case, their name will reference\nthe
temporary table when used in SQL statements. You must have the
CREATE\nTEMPORARY TABLES privilege on the database to create temporary
tables. If no\nstorage engine is specified, the default_tmp_storage_engine
setting will\ndetermine the engine.\n\nROCKSDB temporary tables cannot be
created by setting the\ndefault_tmp_storage_engine system variable, or
using CREATE TEMPORARY TABLE\nLIKE. Before MariaDB 10.7, they could be
specified, but would silently fail,\nand a MyISAM table would be created
instead. From MariaDB 10.7 an error is\nreturned. Explicitly creating a
temporary table with ENGINE=ROCKSDB has never\nbeen permitted.\n\nCREATE
TABLE ... LIKE\n---------------------\n\nUse the LIKE clause instead of a
full table definition to create a table with\nthe same definition as
another table, including columns, indexes, and table\noptions. Foreign key
definitions, as well as any DATA DIRECTORY or INDEX\nDIRECTORY table
options specified on the original table, will not be created.\n\nCREATE
TABLE ... SELECT\n-----------------------\n\nYou can create a table
containing data from other tables using the CREATE ...\nSELECT statement.
Columns will be created in the table for each field returned\nby the SELECT
query.\n\nYou can also define some columns normally and add other columns
from a SELECT.\nYou can also create columns in the normal way and assign
them some values\nusing the query, this is done to force a certain type or
other field\ncharacteristics. The columns that are not named in the query
will be placed\nbefore the others. For example:\n\nCREATE TABLE test (a INT
NOT NULL, b CHAR(10)) ENGINE=MyISAM\n SELECT 5 AS b, c, d FROM
another_table;\n\nRemember that the query just returns data. If you want to
use the same\nindexes, or the same columns attributes ([NOT] NULL, DEFAULT,
AUTO_INCREMENT)\nin the new table, you need to specify them manually. Types
and sizes are not\nautomatically preserved if no data returned by the
SELECT requires the full\nsize, and VARCHAR could be converted into CHAR.
The CAST() function can be\nused to forcee the new table to use certain
types.\n\nAliases (AS) are taken into account, and they should always be
used when you\nSELECT an expression (function, arithmetical operation,
etc).\n\nIf an error occurs during the query, the table will not be created
at all.\n\nIf the new table has a primary key or UNIQUE indexes, you can
use the IGNORE\nor REPLACE keywords to handle duplicate key errors during
the query. IGNORE\nmeans that the newer values must not be inserted an
identical value exists in\nthe index. REPLACE means that older values must
be overwritten.\n\nIf the columns in the new table are more than the rows
returned by the query,\nthe columns populated by the query will be placed
after other columns. Note\nthat if the strict SQL_MODE is on, and the
columns that are not names in the\nquery do not have a DEFAULT value, an
error will raise and no rows will be\ncopied.\n\nConcurrent inserts are not
used during the execution of a CREATE ... SELECT.\n\nIf the table already
exists, an error similar to the following will be\nreturned:\n\nERROR 1050
(42S01): Table \'t\' already exists\n\nIf the IF NOT EXISTS
clause is used and the table exists, a note will be\nproduced instead of an
error.\n\nTo insert rows from a query into an existing table, INSERT ...
SELECT can be\nused.\n\nColumn
Definitions\n------------------\n\ncreate_definition:\n { col_name
column_definition | index_definition | period_definition | CHECK\n(expr)
}\ncolumn_definition:\n data_type\n [NOT NULL | NULL] [DEFAULT
default_value | (expression)]\n [ON UPDATE [NOW | CURRENT_TIMESTAMP]
[(precision)]]\n [AUTO_INCREMENT] [ZEROFILL] [UNIQUE [KEY] | [PRIMARY]
KEY]\n [INVISIBLE] [{WITH|WITHOUT} SYSTEM VERSIONING]\n [COMMENT
\'string\'] [REF_SYSTEM_ID = value]\n [reference_definition]\n |
data_type [GENERATED ALWAYS]\n AS { { ROW {START|END} } | { (expression)
[VIRTUAL | PERSISTENT | STORED] } }\n [UNIQUE [KEY]] [COMMENT
\'string\']\nconstraint_definition:\n CONSTRAINT
[constraint_name] CHECK (expression)\nNote: Until MariaDB 10.4, MariaDB
accepts the shortcut format with a\nREFERENCES clause only in ALTER TABLE
and CREATE TABLE statements, but that\nsyntax does nothing. For
example:\n\nCREATE TABLE b(for_key INT REFERENCES a(not_key));\n\nMariaDB
simply parses it without returning any error or warning, for\ncompatibility
with other DBMS\'s. Before MariaDB 10.2.1 this was also true
for\nCHECK constraints. However, only the syntax described below creates
foreign\nkeys.\n\nFrom MariaDB 10.5, MariaDB will attempt to apply the
constraint. See Foreign\nKeys examples.\n\nEach definition either creates a
column in the table or specifies and index or\nconstraint on one or more
columns. See Indexes below for details on creating\nindexes.\n\nCreate a
column by specifying a column name and a data type, optionally\nfollowed by
column options. See Data Types for a full list of data types\nallowed in
MariaDB.\n\nNULL and NOT NULL\n-----------------\n\nUse the NULL or NOT
NULL options to specify that values in the column may or\nmay not be NULL,
respectively. By default, values may be NULL. See also NULL\nValues in
MariaDB.\n\nDEFAULT Column Option\n---------------------\n\nMariaDB
starting with 10.2.1\n----------------------------\nThe DEFAULT clause was
enhanced in MariaDB 10.2.1. Some enhancements include\n\n* BLOB and TEXT
columns now support DEFAULT.\n* The DEFAULT clause can now be used with an
expression or function.\n\nSpecify a default value using the DEFAULT
clause. If you don\'t specify DEFAULT\nthen the following rules
apply:\n\n* If the column is not defined with NOT NULL, AUTO_INCREMENT or
TIMESTAMP, an\nexplicit DEFAULT NULL will be added.\nNote that in MySQL and
in MariaDB before 10.1.6, you may get an explicit\nDEFAULT for primary key
parts, if not specified with NOT NULL.\n\nThe default value will be used if
you INSERT a row without specifying a value\nfor that column, or if you
specify DEFAULT for that column. Before MariaDB\n10.2.1 you couldn\'t
usually provide an expression or function to evaluate at\ninsertion time.
You had to provide a constant default value instead. The one\nexception is
that you may use CURRENT_TIMESTAMP as the default value for a\nTIMESTAMP
column to use the current timestamp at insertion time.\n\nCURRENT_TIMESTAMP
may also be used as the default value for a DATETIME\n\nFrom MariaDB 10.2.1
you can use most functions in DEFAULT. Expressions should\nhave parentheses
around them. If you use a non deterministic function in\nDEFAULT then all
inserts to the table will be replicated in row mode. You can\neven refer to
earlier columns in the DEFAULT expression (excluding\nAUTO_INCREMENT
columns):\n\nCREATE TABLE t1 (a int DEFAULT (1+1), b int DEFAULT
(a+1));\nCREATE TABLE t2 (a bigint primary key DEFAULT
UUID_SHORT());\n\nThe DEFAULT clause cannot contain any stored functions or
subqueries, and a\ncolumn used in the clause must already have been defined
earlier in the\nstatement.\n\nSince MariaDB 10.2.1, it is possible to
assign BLOB or TEXT columns a DEFAULT\nvalue. In earlier versions,
assigning a default to these columns was not\npossible.\n\nMariaDB starting
with 10.3.3\n----------------------------\nStarting from 10.3.3 you can
also use DEFAULT (NEXT VALUE FOR sequence)\n\nAUTO_INCREMENT Column
Option\n----------------------------\n\nUse AUTO_INCREMENT to create a
column whose value can can be set automatically\nfrom a simple counter. You
can only use AUTO_INCREMENT on a column with an\ninteger type. The column
must be a key, and there can only be one\nAUTO_INCREMENT column in a table.
If you insert a row without specifying a\nvalue for that column (or if you
specify 0, NULL, or DEFAULT as the value),\nthe actual value will be taken
from the counter, with each insertion\nincrementing the counter by one. You
can still insert a value explicitly. If\nyou insert a value that is greater
than the current counter value, the counter\nis set based on the new value.
An AUTO_INCREMENT column is implicitly NOT\nNULL. Use LAST_INSERT_ID to get
the AUTO_INCREMENT value most recently used by\nan INSERT
statement.\n\nZEROFILL Column Option\n----------------------\n\nIf the
ZEROFILL column option is specified for a column using a numeric
data\ntype, then the column will be set to UNSIGNED and the spaces used by
default\nto pad the field are replaced with zeros. ZEROFILL is ignored in
expressions\nor as part of a UNION. ZEROFILL is a non-standard MySQL and
MariaDB\nenhancement.\n\nPRIMARY KEY Column
Option\n-------------------------\n\nUse PRIMARY KEY to make a column a
primary key. A primary key is a special\ntype of a unique key. There can be
at most one primary key per table, and it\nis implicitly NOT
NULL.\n\nSpecifying a column as a unique key creates a unique index on that
column. See\nthe Index Definitions section below for more
information.\n\nUNIQUE KEY Column Option\n------------------------\n\nUse
UNIQUE KEY (or just UNIQUE) to specify that all values in the column
must\nbe distinct from each other. Unless the column is NOT NULL, there may
be\nmultiple rows with NULL in the column.\n\nSpecifying a column as a
unique key creates a unique index on that column. See\nthe Index
Definitions section below for more information.\n\nCOMMENT Column
Option\n---------------------\n\nYou can provide a comment for each column
using the COMMENT clause. The\nmaximum length is 1024 characters. Use the
SHOW FULL COLUMNS statement to see\ncolumn
comments.\n\nREF_SYSTEM_ID\n-------------\n\nREF_SYSTEM_ID can be used to
specify Spatial Reference System IDs for spatial\ndata type columns. For
example:\n\nCREATE TABLE t1(g GEOMETRY(9,4)
REF_SYSTEM_ID=101);\n\nGenerated Columns\n-----------------\n\nA generated
column is a column in a table that cannot explicitly be set to a\nspecific
value in a DML query. Instead, its value is automatically generated\nbased
on an expression. This expression might generate the value based on
the\nvalues of other columns in the table, or it might generate the value
by\ncalling built-in functions or user-defined functions (UDFs).\n\nThere
are two types of generated columns:\n\n* PERSISTENT or STORED: This
type\'s value is actually stored in the
table.','','https://mariadb.com/kb/en/create-table/');
update help_topic set description = CONCAT(description, '\n* VIRTUAL:
This type\'s value is not stored at all. Instead, the value
is\ngenerated dynamically when the table is queried. This type is the
default.\n\nGenerated columns are also sometimes called computed columns or
virtual\ncolumns.\n\nFor a complete description about generated columns and
their limitations, see\nGenerated (Virtual and Persistent/Stored)
Columns.\n\nCOMPRESSED\n----------\n\nMariaDB starting with
10.3.3\n----------------------------\nCertain columns may be compressed.
See Storage-Engine Independent
Column\nCompression.\n\nINVISIBLE\n---------\n\nMariaDB starting with
10.3.3\n----------------------------\nColumns may be made invisible, and
hidden in certain contexts. See Invisible\nColumns.\n\nWITH SYSTEM
VERSIONING Column Option\n------------------------------------\n\nMariaDB
starting with 10.3.4\n----------------------------\nColumns may be
explicitly marked as included from system versioning. See\nSystem-versioned
tables for details.\n\nWITHOUT SYSTEM VERSIONING Column
Option\n---------------------------------------\n\nMariaDB starting with
10.3.4\n----------------------------\nColumns may be explicitly marked as
excluded from system versioning. See\nSystem-versioned tables for
details.\n\nIndex Definitions\n-----------------\n\nindex_definition:\n
{INDEX|KEY} [index_name] [index_type] (index_col_name,...)
[index_option]\n...\n {{{|}}} {FULLTEXT|SPATIAL} [INDEX|KEY] [index_name]
(index_col_name,...)\n[index_option] ...\n {{{|}}} [CONSTRAINT [symbol]]
PRIMARY KEY [index_type] (index_col_name,...)\n[index_option] ...\n {{{|}}}
[CONSTRAINT [symbol]] UNIQUE [INDEX|KEY] [index_name]
[index_type]\n(index_col_name,...) [index_option] ...\n {{{|}}} [CONSTRAINT
[symbol]] FOREIGN KEY [index_name]
(index_col_name,...)\nreference_definition\n\nindex_col_name:\n col_name
[(length)] [ASC | DESC]\n\nindex_type:\n USING {BTREE | HASH |
RTREE}\n\nindex_option:\n [ KEY_BLOCK_SIZE [=] value\n {{{|}}}
index_type\n {{{|}}} WITH PARSER parser_name\n {{{|}}} COMMENT
\'string\'\n {{{|}}} CLUSTERING={YES| NO} ]\n [ IGNORED | NOT
IGNORED ]\n\nreference_definition:\n REFERENCES tbl_name
(index_col_name,...)\n [MATCH FULL | MATCH PARTIAL | MATCH SIMPLE]\n
[ON DELETE reference_option]\n [ON UPDATE
reference_option]\n\nreference_option:\n RESTRICT | CASCADE | SET NULL |
NO ACTION\n\nINDEX and KEY are synonyms.\n\nIndex names are optional, if
not specified an automatic name will be assigned.\nIndex name are needed to
drop indexes and appear in error messages when a\nconstraint is
violated.\n\nIndex Categories\n----------------\n\nPlain
Indexes\n-------------\n\nPlain indexes are regular indexes that are not
unique, and are not acting as a\nprimary key or a foreign key. They are
also not the \"specialized\" FULLTEXT or\nSPATIAL indexes.\n\nSee
Getting Started with Indexes: Plain Indexes for more
information.\n\nPRIMARY KEY\n-----------\n\nFor PRIMARY KEY indexes, you
can specify a name for the index, but it is\nignored, and the name of the
index is always PRIMARY. From MariaDB 10.3.18 and\nMariaDB 10.4.8, a
warning is explicitly issued if a name is specified. Before\nthen, the name
was silently ignored.\n\nSee Getting Started with Indexes: Primary Key for
more information.\n\nUNIQUE\n------\n\nThe UNIQUE keyword means that the
index will not accept duplicated values,\nexcept for NULLs. An error will
raise if you try to insert duplicate values in\na UNIQUE index.\n\nFor
UNIQUE indexes, you can specify a name for the constraint, using
the\nCONSTRAINT keyword. That name will be used in error messages.\n\nSee
Getting Started with Indexes: Unique Index for more information.\n\nFOREIGN
KEY\n-----------\n\nFor FOREIGN KEY indexes, a reference definition must be
provided.\n\nFor FOREIGN KEY indexes, you can specify a name for the
constraint, using the\nCONSTRAINT keyword. That name will be used in error
messages.\n\nFirst, you have to specify the name of the target (parent)
table and a column\nor a column list which must be indexed and whose values
must match to the\nforeign key\'s values. The MATCH clause is accepted
to improve the\ncompatibility with other DBMS\'s, but has no meaning
in MariaDB. The ON DELETE\nand ON UPDATE clauses specify what must be done
when a DELETE (or a REPLACE)\nstatements attempts to delete a referenced
row from the parent table, and when\nan UPDATE statement attempts to modify
the referenced foreign key columns in a\nparent table row, respectively.
The following options are allowed:\n\n* RESTRICT: The delete/update
operation is not performed. The statement\nterminates with a 1451 error
(SQLSTATE \'2300\').\n* NO ACTION: Synonym for RESTRICT.\n*
CASCADE: The delete/update operation is performed in both tables.\n* SET
NULL: The update or delete goes ahead in the parent table, and
the\ncorresponding foreign key fields in the child table are set to NULL.
(They\nmust not be defined as NOT NULL for this to succeed).\n* SET
DEFAULT: This option is currently implemented only for the PBXT
storage\nengine, which is disabled by default and no longer maintained. It
sets the\nchild table\'s foreign key fields to their DEFAULT values
when the referenced\nparent table key entries are updated or deleted.\n\nIf
either clause is omitted, the default behavior for the omitted clause
is\nRESTRICT.\n\nSee Foreign Keys for more
information.\n\nFULLTEXT\n--------\n\nUse the FULLTEXT keyword to create
full-text indexes.\n\nSee Full-Text Indexes for more
information.\n\nSPATIAL\n-------\n\nUse the SPATIAL keyword to create
geometric indexes.\n\nSee SPATIAL INDEX for more information.\n\nIndex
Options\n-------------\n\nKEY_BLOCK_SIZE Index
Option\n---------------------------\n\nThe KEY_BLOCK_SIZE index option is
similar to the KEY_BLOCK_SIZE table option.\n\nWith the InnoDB storage
engine, if you specify a non-zero value for the\nKEY_BLOCK_SIZE table
option for the whole table, then the table will\nimplicitly be created with
the ROW_FORMAT table option set to COMPRESSED.\nHowever, this does not
happen if you just set the KEY_BLOCK_SIZE index option\nfor one or more
indexes in the table. The InnoDB storage engine ignores the\nKEY_BLOCK_SIZE
index option. However, the SHOW CREATE TABLE statement may\nstill report it
for the index.\n\nFor information about the KEY_BLOCK_SIZE index option,
see the KEY_BLOCK_SIZE\ntable option below.\n\nIndex
Types\n-----------\n\nEach storage engine supports some or all index types.
See Storage Engine Index\nTypes for details on permitted index types for
each storage engine.\n\nDifferent index types are optimized for different
kind of operations:\n\n* BTREE is the default type, and normally is the
best choice. It is supported\nby all storage engines. It can be used to
compare a column\'s value with a\nvalue using the =, >, >=,
<, <=, BETWEEN, and LIKE operators. BTREE can also\nbe used to find
NULL values. Searches against an index prefix are possible.\n* HASH is only
supported by the MEMORY storage engine. HASH indexes can only\nbe used for
=, <=, and >= comparisons. It can not be used for the ORDER
BY\nclause. Searches against an index prefix are not possible.\n* RTREE is
the default for SPATIAL indexes, but if the storage engine does
not\nsupport it BTREE can be used.\n\nIndex columns names are listed
between parenthesis. After each column, a\nprefix length can be specified.
If no length is specified, the whole column\nwill be indexed. ASC and DESC
can be specified for compatibility with are\nDBMS\'s, but have no
meaning in MariaDB.\n\nWITH PARSER Index
Option\n------------------------\n\nThe WITH PARSER index option only
applies to FULLTEXT indexes and contains the\nfulltext parser name. The
fulltext parser must be an installed plugin.\n\nCOMMENT Index
Option\n--------------------\n\nA comment of up to 1024 characters is
permitted with the COMMENT index option.\n\nThe COMMENT index option allows
you to specify a comment with user-readable\ntext describing what the index
is for. This information is not used by the\nserver itself.\n\nCLUSTERING
Index Option\n-----------------------\n\nThe CLUSTERING index option is
only valid for tables using the TokuDB storage\nengine.\n\nIGNORED / NOT
IGNORED\n---------------------\n\nMariaDB starting with
10.6.0\n----------------------------\nFrom MariaDB 10.6.0, indexes can be
specified to be ignored by the optimizer.\nSee Ignored
Indexes.\n\nPeriods\n-------\n\nMariaDB starting with
10.3.4\n----------------------------\n\nperiod_definition:\n PERIOD FOR
SYSTEM_TIME (start_column_name, end_column_name)\nMariaDB supports a subset
of the standard syntax for periods. At the moment\nit\'s only used for
creating System-versioned tables. Both columns must be\ncreated, must be
either of a TIMESTAMP(6) or BIGINT UNSIGNED type, and be\ngenerated as ROW
START and ROW END accordingly. See System-versioned tables\nfor
details.\n\nThe table must also have the WITH SYSTEM VERSIONING
clause.\n\nConstraint Expressions\n----------------------\n\nMariaDB
starting with 10.2.1\n----------------------------\nMariaDB 10.2.1
introduced new ways to define a constraint.\n\nNote: Before MariaDB 10.2.1,
constraint expressions were accepted in the\nsyntax but ignored.\n\nMariaDB
10.2.1 introduced two ways to define a constraint:\n\n* CHECK(expression)
given as part of a column definition.\n* CONSTRAINT [constraint_name] CHECK
(expression)\n\nBefore a row is inserted or updated, all constraints are
evaluated in the\norder they are defined. If any constraints fails, then
the row will not be\nupdated. One can use most deterministic functions in a
constraint, including\nUDFs.\n\ncreate table t1 (a int check(a>0) ,b int
check (b> 0), constraint abc check\n(a>b));\n\nIf you use the second
format and you don\'t give a name to the constraint, then\nthe
constraint will get a auto generated name. This is done so that you
can\nlater delete the constraint with ALTER TABLE DROP
constraint_name.\n\nOne can disable all constraint expression checks by
setting the variable\ncheck_constraint_checks to OFF. This is useful for
example when loading a\ntable that violates some constraints that you want
to later find and fix in\nSQL.\n\nSee CONSTRAINT for more
information.\n\nTable Options\n-------------\n\nFor each individual table
you create (or alter), you can set some table\noptions. The general syntax
for setting options is:\n\n<OPTION_NAME> = <option_value>,
[<OPTION_NAME> = <option_value> ...]\n\nThe equal sign is
optional.\n\nSome options are supported by the server and can be used for
all tables, no\nmatter what storage engine they use; other options can be
specified for all\nstorage engines, but have a meaning only for some
engines. Also, engines can\nextend CREATE TABLE with new options.\n\nIf the
IGNORE_BAD_TABLE_OPTIONS SQL_MODE is enabled, wrong table options\ngenerate
a warning; otherwise, they generate an error.\n\ntable_option: \n
[STORAGE] ENGINE [=] engine_name\n | AUTO_INCREMENT [=] value\n |
AVG_ROW_LENGTH [=] value\n | [DEFAULT] CHARACTER SET [=] charset_name\n |
CHECKSUM [=] {0 | 1}\n | [DEFAULT] COLLATE [=] collation_name\n | COMMENT
[=] \'string\'\n | CONNECTION [=] \'connect_string\'\n
| DATA DIRECTORY [=] \'absolute path to directory\'\n |
DELAY_KEY_WRITE [=] {0 | 1}\n | ENCRYPTED [=] {YES | NO}\n |
ENCRYPTION_KEY_ID [=] value\n | IETF_QUOTES [=] {YES | NO}\n | INDEX
DIRECTORY [=] \'absolute path to directory\'\n | INSERT_METHOD
[=] { NO | FIRST | LAST }\n | KEY_BLOCK_SIZE [=] value\n | MAX_ROWS [=]
value\n | MIN_ROWS [=] value\n | PACK_KEYS [=] {0 | 1 | DEFAULT}\n |
PAGE_CHECKSUM [=] {0 | 1}\n | PAGE_COMPRESSED [=] {0 | 1}\n |
PAGE_COMPRESSION_LEVEL [=] {0 .. 9}\n | PASSWORD [=] \'string\'\n
| ROW_FORMAT [=]
{DEFAULT|DYNAMIC|FIXED|COMPRESSED|REDUNDANT|COMPACT|PAGE}\n | SEQUENCE [=]
{0|1}\n | STATS_AUTO_RECALC [=] {DEFAULT|0|1}\n | STATS_PERSISTENT [=]
{DEFAULT|0|1}\n | STATS_SAMPLE_PAGES [=] {DEFAULT|value}\n | TABLESPACE
tablespace_name\n | TRANSACTIONAL [=] {0 | 1}\n | UNION [=]
(tbl_name[,tbl_name]...)\n | WITH SYSTEM VERSIONING\n\n[STORAGE]
ENGINE\n----------------\n\n[STORAGE] ENGINE specifies a storage engine for
the table. If this option is\nnot used, the default storage engine is used
instead. That is, the\ndefault_storage_engine session option value if it is
set, or the value\nspecified for the --default-storage-engine mysqld
startup option, or the\ndefault storage engine, InnoDB. If the specified
storage engine is not\ninstalled and active, the default value will be
used, unless the\nNO_ENGINE_SUBSTITUTION SQL MODE is set (default). This is
only true for CREATE\nTABLE, not for ALTER TABLE. For a list of storage
engines that are present in\nyour server, issue a SHOW
ENGINES.\n\nAUTO_INCREMENT\n--------------\n\nAUTO_INCREMENT specifies the
initial value for the AUTO_INCREMENT primary key.\nThis works for MyISAM,
Aria, InnoDB, MEMORY, and ARCHIVE tables. You can\nchange this option with
ALTER TABLE, but in that case the new value must be\nhigher than the
highest value which is present in the AUTO_INCREMENT column.\nIf the
storage engine does not support this option, you can insert (and
then\ndelete) a row having the wanted value - 1 in the AUTO_INCREMENT
column.\n\nAVG_ROW_LENGTH\n--------------\n\nAVG_ROW_LENGTH is the average
rows size. It only applies to tables using\nMyISAM and Aria storage engines
that have the ROW_FORMAT table option set to\nFIXED format.\n\nMyISAM uses
MAX_ROWS and AVG_ROW_LENGTH to decide the maximum size of a
table\n(default: 256TB, or the maximum file size allowed by the
system).\n\n[DEFAULT] CHARACTER
SET/CHARSET\n-------------------------------\n\n[DEFAULT] CHARACTER SET (or
[DEFAULT] CHARSET) is used to set a default\ncharacter set for the table.
This is the character set used for all columns\nwhere an explicit character
set is not specified. If this option is omitted or\nDEFAULT is specified,
database\'s default character set will be used. See\nSetting Character
Sets and Collations for details on setting the
character\nsets.\n\nCHECKSUM/TABLE_CHECKSUM\n-----------------------\n\nCHECKSUM
(or TABLE_CHECKSUM) can be set to 1 to maintain a live checksum for\nall
table\'s rows. This makes write operations slower, but CHECKSUM TABLE
will\nbe very fast. This option is only supported for MyISAM and Aria
tables.\n\n[DEFAULT] COLLATE\n-----------------\n\n[DEFAULT] COLLATE is
used to set a default collation for the table. This is\nthe collation used
for all columns where an explicit character set is not\nspecified. If this
option is omitted or DEFAULT is specified, database\'s') WHERE
help_topic_id = 700;
update help_topic set description = CONCAT(description, '\ndefault
option will be used. See Setting Character Sets and Collations for\ndetails
on setting the collations\n\nCOMMENT\n-------\n\nCOMMENT is a comment for
the table. The maximum length is 2048 characters.\nAlso used to define
table parameters when creating a Spider
table.\n\nCONNECTION\n----------\n\nCONNECTION is used to specify a server
name or a connection string for a\nSpider, CONNECT, Federated or FederatedX
table.\n\nDATA DIRECTORY/INDEX
DIRECTORY\n------------------------------\n\nDATA DIRECTORY and INDEX
DIRECTORY are supported for MyISAM and Aria, and DATA\nDIRECTORY is also
supported by InnoDB if the innodb_file_per_table server\nsystem variable is
enabled, but only in CREATE TABLE, not in ALTER TABLE. So,\ncarefully
choose a path for InnoDB tables at creation time, because it cannot\nbe
changed without dropping and re-creating the table. These options
specify\nthe paths for data files and index files, respectively. If these
options are\nomitted, the database\'s directory will be used to store
data files and index\nfiles. Note that these table options do not work for
partitioned tables (use\nthe partition options instead), or if the server
has been invoked with the\n--skip-symbolic-links startup option. To avoid
the overwriting of old files\nwith the same name that could be present in
the directories, you can use the\n--keep_files_on_create option (an error
will be issued if files already\nexist). These options are ignored if the
NO_DIR_IN_CREATE SQL_MODE is enabled\n(useful for replication slaves). Also
note that symbolic links cannot be used\nfor InnoDB tables.\n\nDATA
DIRECTORY works by creating symlinks from where the table would
normally\nhave been (inside the datadir) to where the option specifies. For
security\nreasons, to avoid bypassing the privilege system, the server does
not permit\nsymlinks inside the datadir. Therefore, DATA DIRECTORY cannot
be used to\nspecify a location inside the datadir. An attempt to do so will
result in an\nerror 1210 (HY000) Incorrect arguments to DATA
DIRECTORY.\n\nDELAY_KEY_WRITE\n---------------\n\nDELAY_KEY_WRITE is
supported by MyISAM and Aria, and can be set to 1 to speed\nup write
operations. In that case, when data are modified, the indexes are
not\nupdated until the table is closed. Writing the changes to the index
file\naltogether can be much faster. However, note that this option is
applied only\nif the delay_key_write server variable is set to
\'ON\'. If it is \'OFF\' the\ndelayed index writes are
always disabled, and if it is \'ALL\' the delayed index\nwrites
are always used, disregarding the value of
DELAY_KEY_WRITE.\n\nENCRYPTED\n---------\n\nThe ENCRYPTED table option can
be used to manually set the encryption status\nof an InnoDB table. See
InnoDB Encryption for more information.\n\nAria does not support the
ENCRYPTED table option. See MDEV-18049.\n\nSee Data-at-Rest Encryption for
more information.\n\nENCRYPTION_KEY_ID\n-----------------\n\nThe
ENCRYPTION_KEY_ID table option can be used to manually set the
encryption\nkey of an InnoDB table. See InnoDB Encryption for more
information.\n\nAria does not support the ENCRYPTION_KEY_ID table option.
See MDEV-18049.\n\nSee Data-at-Rest Encryption for more
information.\n\nIETF_QUOTES\n-----------\n\nFor the CSV storage engine, the
IETF_QUOTES option, when set to YES, enables\nIETF-compatible parsing of
embedded quote and comma characters. Enabling this\noption for a table
improves compatibility with other tools that use CSV, but\nis not
compatible with MySQL CSV tables, or MariaDB CSV tables created
without\nthis option. Disabled by
default.\n\nINSERT_METHOD\n-------------\n\nINSERT_METHOD is only used with
MERGE tables. This option determines in which\nunderlying table the new
rows should be inserted. If you set it to \'NO\' (which\nis the
default) no new rows can be added to the table (but you will still be\nable
to perform INSERTs directly against the underlying tables). FIRST
means\nthat the rows are inserted into the first table, and LAST means that
thet are\ninserted into the last
table.\n\nKEY_BLOCK_SIZE\n--------------\n\nKEY_BLOCK_SIZE is used to
determine the size of key blocks, in bytes or\nkilobytes. However, this
value is just a hint, and the storage engine could\nmodify or ignore it. If
KEY_BLOCK_SIZE is set to 0, the storage engine\'s\ndefault value will
be used.\n\nWith the InnoDB storage engine, if you specify a non-zero value
for the\nKEY_BLOCK_SIZE table option for the whole table, then the table
will\nimplicitly be created with the ROW_FORMAT table option set to
COMPRESSED.\n\nMIN_ROWS/MAX_ROWS\n-----------------\n\nMIN_ROWS and
MAX_ROWS let the storage engine know how many rows you are\nplanning to
store as a minimum and as a maximum. These values will not be used\nas real
limits, but they help the storage engine to optimize the table.\nMIN_ROWS
is only used by MEMORY storage engine to decide the minimum memory\nthat is
always allocated. MAX_ROWS is used to decide the minimum size
for\nindexes.\n\nPACK_KEYS\n---------\n\nPACK_KEYS can be used to determine
whether the indexes will be compressed. Set\nit to 1 to compress all keys.
With a value of 0, compression will not be used.\nWith the DEFAULT value,
only long strings will be compressed. Uncompressed\nkeys are
faster.\n\nPAGE_CHECKSUM\n-------------\n\nPAGE_CHECKSUM is only applicable
to Aria tables, and determines whether\nindexes and data should use page
checksums for extra
safety.\n\nPAGE_COMPRESSED\n---------------\n\nPAGE_COMPRESSED is used to
enable InnoDB page compression for InnoDB
tables.\n\nPAGE_COMPRESSION_LEVEL\n----------------------\n\nPAGE_COMPRESSION_LEVEL
is used to set the compression level for InnoDB page\ncompression for
InnoDB tables. The table must also have the PAGE_COMPRESSED\ntable option
set to 1.\n\nValid values for PAGE_COMPRESSION_LEVEL are 1 (the best speed)
through 9 (the\nbest compression), .\n\nPASSWORD\n--------\n\nPASSWORD is
unused.\n\nRAID_TYPE\n---------\n\nRAID_TYPE is an obsolete option, as the
raid support has been disabled since\nMySQL
5.0.\n\nROW_FORMAT\n----------\n\nThe ROW_FORMAT table option specifies the
row format for the data file.\nPossible values are
engine-dependent.\n\nSupported MyISAM Row
Formats\n----------------------------\n\nFor MyISAM, the supported row
formats are:\n\n* FIXED\n* DYNAMIC\n* COMPRESSED\n\nThe COMPRESSED row
format can only be set by the myisampack command line tool.\n\nSee MyISAM
Storage Formats for more information.\n\nSupported Aria Row
Formats\n--------------------------\n\nFor Aria, the supported row formats
are:\n\n* PAGE\n* FIXED\n* DYNAMIC.\n\nSee Aria Storage Formats for more
information.\n\nSupported InnoDB Row
Formats\n----------------------------\n\nFor InnoDB, the supported row
formats are:\n\n* COMPACT\n* REDUNDANT\n* COMPRESSED\n* DYNAMIC.\n\nIf the
ROW_FORMAT table option is set to FIXED for an InnoDB table, then
the\nserver will either return an error or a warning depending on the value
of the\ninnodb_strict_mode system variable. If the innodb_strict_mode
system variable\nis set to OFF, then a warning is issued, and MariaDB will
create the table\nusing the default row format for the specific MariaDB
server version. If the\ninnodb_strict_mode system variable is set to ON,
then an error will be raised.\n\nSee InnoDB Storage Formats for more
information.\n\nOther Storage Engines and
ROW_FORMAT\n------------------------------------\n\nOther storage engines
do not support the ROW_FORMAT table
option.\n\nSEQUENCE\n--------\n\nMariaDB starting with
10.3\n--------------------------\nIf the table is a sequence, then it will
have the SEQUENCE set to
1.\n\nSTATS_AUTO_RECALC\n-----------------\n\nSTATS_AUTO_RECALC indicates
whether to automatically recalculate persistent\nstatistics (see
STATS_PERSISTENT, below) for an InnoDB table. If set to 1,\nstatistics will
be recalculated when more than 10% of the data has changed.\nWhen set to 0,
stats will be recalculated only when an ANALYZE TABLE is run.\nIf set to
DEFAULT, or left out, the value set by the innodb_stats_auto_recalc\nsystem
variable applies. See InnoDB Persistent
Statistics.\n\nSTATS_PERSISTENT\n----------------\n\nSTATS_PERSISTENT
indicates whether the InnoDB statistics created by ANALYZE\nTABLE will
remain on disk or not. It can be set to 1 (on disk), 0 (not on\ndisk, the
pre-MariaDB 10 behavior), or DEFAULT (the same as leaving out the\noption),
in which case the value set by the innodb_stats_persistent system\nvariable
will apply. Persistent statistics stored on disk allow the statistics\nto
survive server restarts, and provide better query plan stability.
See\nInnoDB Persistent
Statistics.\n\nSTATS_SAMPLE_PAGES\n------------------\n\nSTATS_SAMPLE_PAGES
indicates how many pages are used to sample index\nstatistics. If 0 or
DEFAULT, the default value, the innodb_stats_sample_pages\nvalue is used.
See InnoDB Persistent
Statistics.\n\nTRANSACTIONAL\n-------------\n\nTRANSACTIONAL is only
applicable for Aria tables. In future Aria tables\ncreated with this option
will be fully transactional, but currently this\nprovides a form of crash
protection. See Aria Storage Engine for more
details.\n\nUNION\n-----\n\nUNION must be specified when you create a MERGE
table. This option contains a\ncomma-separated list of MyISAM tables which
are accessed by the new table. The\nlist is enclosed between parenthesis.
Example: UNION = (t1,t2)\n\nWITH SYSTEM
VERSIONING\n----------------------\n\nWITH SYSTEM VERSIONING is used for
creating System-versioned
tables.\n\nPartitions\n----------\n\npartition_options:\n PARTITION BY\n
{ [LINEAR] HASH(expr)\n | [LINEAR] KEY(column_list)\n |
RANGE(expr)\n | LIST(expr)\n | SYSTEM_TIME [INTERVAL time_quantity
time_unit] [LIMIT num] }\n [PARTITIONS num]\n [SUBPARTITION BY\n {
[LINEAR] HASH(expr)\n | [LINEAR] KEY(column_list) }\n [SUBPARTITIONS
num]\n ]\n [(partition_definition [, partition_definition]
...)]\npartition_definition:\n PARTITION partition_name\n [VALUES {LESS
THAN {(expr) | MAXVALUE} | IN (value_list)}]\n [[STORAGE] ENGINE [=]
engine_name]\n [COMMENT [=] \'comment_text\' ]\n [DATA
DIRECTORY [=] \'data_dir\']\n [INDEX DIRECTORY [=]
\'index_dir\']\n [MAX_ROWS [=] max_number_of_rows]\n
[MIN_ROWS [=] min_number_of_rows]\n [TABLESPACE [=] tablespace_name]\n
[NODEGROUP [=] node_group_id]\n [(subpartition_definition [,
subpartition_definition] ...)]\nsubpartition_definition:\n SUBPARTITION
logical_name\n [[STORAGE] ENGINE [=] engine_name]\n [COMMENT [=]
\'comment_text\' ]\n [DATA DIRECTORY [=]
\'data_dir\']\n [INDEX DIRECTORY [=]
\'index_dir\']\n [MAX_ROWS [=] max_number_of_rows]\n
[MIN_ROWS [=] min_number_of_rows]\n [TABLESPACE [=] tablespace_name]\n
[NODEGROUP [=] node_group_id]\nIf the PARTITION BY clause is used, the
table will be partitioned. A partition\nmethod must be explicitly indicated
for partitions and subpartitions.\nPartition methods are:\n\n* [LINEAR]
HASH creates a hash key which will be used to read and write rows.\nThe
partition function can be any valid SQL expression which returns
an\nINTEGER number. Thus, it is possible to use the HASH method on an
integer\ncolumn, or on functions which accept integer columns as an
argument. However,\nVALUES LESS THAN and VALUES IN clauses can not be used
with HASH. An example:\n\nCREATE TABLE t1 (a INT, b CHAR(5), c DATETIME)\n
PARTITION BY HASH ( YEAR(c) );\n\n[LINEAR] HASH can be used for
subpartitions, too.\n\n* [LINEAR] KEY is similar to HASH, but the index has
an even distribution of\ndata. Also, the expression can only be a column or
a list of columns. VALUES\nLESS THAN and VALUES IN clauses can not be used
with KEY.\n* RANGE partitions the rows using on a range of values, using
the VALUES LESS\nTHAN operator. VALUES IN is not allowed with RANGE. The
partition function can\nbe any valid SQL expression which returns a single
value.\n* LIST assigns partitions based on a table\'s column with a
restricted set of\npossible values. It is similar to RANGE, but VALUES IN
must be used for at\nleast 1 columns, and VALUES LESS THAN is
disallowed.\n* SYSTEM_TIME partitioning is used for System-versioned tables
to store\nhistorical data separately from current data.\n\nOnly HASH and
KEY can be used for subpartitions, and they can be [LINEAR].\n\nIt is
possible to define up to 1024 partitions and subpartitions.\n\nThe number
of defined partitions can be optionally specified as PARTITION\ncount. This
can be done to avoid specifying all partitions individually. But\nyou can
also declare each individual partition and, additionally, specify
a\nPARTITIONS count clause; in the case, the number of PARTITIONs must
equal\ncount.\n\nAlso see Partitioning Types
Overview.\n\nSequences\n---------\n\nMariaDB starting with
10.3\n--------------------------\nCREATE TABLE can also be used to create a
SEQUENCE. See CREATE SEQUENCE and\nSequence Overview.\n\nAtomic
DDL\n----------\n\nMariaDB starting with
10.6.1\n----------------------------\nMariaDB 10.6.1 supports Atomic DDL.
CREATE TABLE is atomic, except for CREATE\nOR REPLACE, which is only crash
safe.\n\nExamples\n--------\n\ncreate table if not exists test (\na bigint
auto_increment primary key,\nname varchar(128) charset utf8,\nkey name
(name(32))\n) engine=InnoDB default charset latin1;\n\nThis example shows a
couple of things:\n\n* Usage of IF NOT EXISTS; If the table already
existed, it will not be\ncreated. There will not be any error for the
client, just a warning.\n* How to create a PRIMARY KEY that is
automatically generated.\n* How to specify a table-specific character set
and another for a column.\n* How to create an index (name) that is only
partly indexed (to save space).\n\nThe following clauses will work from
MariaDB 10.2.1 only.\n\nCREATE TABLE t1(\n a int DEFAULT (1+1),\n b int
DEFAULT (a+1),\n expires DATETIME DEFAULT(NOW() + INTERVAL 1 YEAR),\n x
BLOB DEFAULT USER()\n);\n\nURL:
https://mariadb.com/kb/en/create-table/') WHERE help_topic_id = 700;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(701,38,'DROP TABLE','Syntax\n------\n\nDROP [TEMPORARY]
TABLE [IF EXISTS] [/*COMMENT TO SAVE*/]\n tbl_name [, tbl_name] ...\n
[WAIT n|NOWAIT]\n [RESTRICT | CASCADE]\n\nDescription\n-----------\n\nDROP
TABLE removes one or more tables. You must have the DROP privilege
for\neach table. All table data and the table definition are removed, as
well as\ntriggers associated to the table, so be careful with this
statement! If any of\nthe tables named in the argument list do not exist,
MariaDB returns an error\nindicating by name which non-existing tables it
was unable to drop, but it\nalso drops all of the tables in the list that
do exist.\n\nImportant: When a table is dropped, user privileges on the
table are not\nautomatically dropped. See GRANT.\n\nIf another thread is
using the table in an explicit transaction or an\nautocommit transaction,
then the thread acquires a metadata lock (MDL) on the\ntable. The DROP
TABLE statement will wait in the \"Waiting for table
metadata\nlock\" thread state until the MDL is released. MDLs are
released in the\nfollowing cases:\n\n* If an MDL is acquired in an explicit
transaction, then the MDL will be\nreleased when the transaction ends.\n*
If an MDL is acquired in an autocommit transaction, then the MDL will
be\nreleased when the statement ends.\n* Transactional and
non-transactional tables are handled the same.\n\nNote that for a
partitioned table, DROP TABLE permanently removes the table\ndefinition,
all of its partitions, and all of the data which was stored in\nthose
partitions. It also removes the partitioning definition (.par)
file\nassociated with the dropped table.\n\nFor each referenced table, DROP
TABLE drops a temporary table with that name,\nif it exists. If it does not
exist, and the TEMPORARY keyword is not used, it\ndrops a non-temporary
table with the same name, if it exists. The TEMPORARY\nkeyword ensures that
a non-temporary table will not accidentally be dropped.\n\nUse IF EXISTS to
prevent an error from occurring for tables that do not exist.\nA NOTE is
generated for each non-existent table when using IF EXISTS. See
SHOW\nWARNINGS.\n\nIf a foreign key references this table, the table cannot
be dropped. In this\ncase, it is necessary to drop the foreign key
first.\n\nRESTRICT and CASCADE are allowed to make porting from other
database systems\neasier. In MariaDB, they do nothing.\n\nThe comment
before the table names (/*COMMENT TO SAVE*/) is stored in the\nbinary log.
That feature can be used by replication tools to send their\ninternal
messages.\n\nIt is possible to specify table names as db_name.tab_name.
This is useful to\ndelete tables from multiple databases with one
statement. See Identifier\nQualifiers for details.\n\nThe DROP privilege is
required to use DROP TABLE on non-temporary tables. For\ntemporary tables,
no privilege is required, because such tables are only\nvisible for the
current session.\n\nNote: DROP TABLE automatically commits the current
active transaction, unless\nyou use the TEMPORARY keyword.\n\nMariaDB
starting with 10.5.4\n----------------------------\nFrom MariaDB 10.5.4,
DROP TABLE reliably deletes table remnants inside a\nstorage engine even if
the .frm file is missing. Before then, a missing .frm\nfile would result in
the statement failing.\n\nMariaDB starting with
10.3.1\n----------------------------\n\nWAIT/NOWAIT\n-----------\n\nSet the
lock wait timeout. See WAIT and NOWAIT.\n\nDROP TABLE in
replication\n-------------------------\n\nDROP TABLE has the following
characteristics in replication:\n\n* DROP TABLE IF EXISTS are always
logged.\n* DROP TABLE without IF EXISTS for tables that don\'t exist
are not written to\nthe binary log.\n* Dropping of TEMPORARY tables are
prefixed in the log with TEMPORARY. These\ndrops are only logged when
running statement or mixed mode replication.\n* One DROP TABLE statement
can be logged with up to 3 different DROP\nstatements:\nDROP TEMPORARY
TABLE list_of_non_transactional_temporary_tables\nDROP TEMPORARY TABLE
list_of_transactional_temporary_tables\nDROP TABLE
list_of_normal_tables\n\nDROP TABLE on the primary is treated on the
replica as DROP TABLE IF EXISTS.\nYou can change that by setting
slave-ddl-exec-mode to STRICT.\n\nDropping an Internal #sql-...
Table\n-----------------------------------\n\nFrom MariaDB 10.6, DROP TABLE
is atomic and the following does not apply.\nUntil MariaDB 10.5, if the
mariadbd/mysqld process is killed during an ALTER\nTABLE you may find a
table named #sql-... in your data directory. In MariaDB\n10.3, InnoDB
tables with this prefix will be deleted automatically during\nstartup. From
MariaDB 10.4, these temporary tables will always be
deleted\nautomatically.\n\nIf you want to delete one of these tables
explicitly you can do so by using\nthe following syntax:\n\nDROP TABLE
`#mysql50##sql-...`;\n\nWhen running an ALTER TABLE…ALGORITHM=INPLACE
that rebuilds the table, InnoDB\nwill create an internal #sql-ib table.
Until MariaDB 10.3.2, for these tables,\nthe .frm file will be called
something else. In order to drop such a table\nafter a server crash, you
must rename the #sql*.frm file to match the\n#sql-ib*.ibd file.\n\nFrom
MariaDB 10.3.3, the same name as the .frm file is used for
the\nintermediate copy of the table. The #sql-ib names are used by TRUNCATE
and\ndelayed DROP.\n\nFrom MariaDB 10.2.19 and MariaDB 10.3.10, the #sql-ib
tables will be deleted\nautomatically.\n\nDropping All Tables in a
Database\n---------------------------------\n\nThe best way to drop all
tables in a database is by executing DROP DATABASE,\nwhich will drop the
database itself, and all tables in it.\n\nHowever, if you want to drop all
tables in the database, but you also want to\nkeep the database itself and
any other non-table objects in it, then you would\nneed to execute DROP
TABLE to drop each individual table. You can construct\nthese DROP TABLE
commands by querying the TABLES table in the\ninformation_schema database.
For example:\n\nSELECT CONCAT(\'DROP TABLE IF EXISTS `\',
TABLE_SCHEMA, \'`.`\', TABLE_NAME, \'`;\')\nFROM
information_schema.TABLES\nWHERE TABLE_SCHEMA =
\'mydb\';\n\nAtomic DROP TABLE\n-----------------\n\nMariaDB
starting with 10.6.1\n----------------------------\nFrom MariaDB 10.6, DROP
TABLE for a single table is atomic (MDEV-25180) for\nmost engines,
including InnoDB, MyRocks, MyISAM and Aria.\n\nThis means that if there is
a crash (server down or power outage) during DROP\nTABLE, all tables that
have been processed so far will be completely dropped,\nincluding related
trigger files and status entries, and the binary log will\ninclude a DROP
TABLE statement for the dropped tables. Tables for which the\ndrop had not
started will be left intact.\n\nIn older MariaDB versions, there was a
small chance that, during a server\ncrash happening in the middle of DROP
TABLE, some storage engines that were\nusing multiple storage files, like
MyISAM, could have only a part of its\ninternal files dropped.\n\nIn
MariaDB 10.5, DROP TABLE was extended to be able to delete a table that
was\nonly partly dropped (MDEV-11412) as explained above. Atomic DROP TABLE
is the\nfinal piece to make DROP TABLE fully reliable.\n\nDropping multiple
tables is crash-safe.\n\nSee Atomic DDL for more
information.\n\nExamples\n--------\n\nDROP TABLE Employees,
Customers;\n\nNotes\n-----\n\nBeware that DROP TABLE can drop both tables
and sequences. This is mainly done\nto allow old tools like mysqldump to
work with sequences.\n\nURL:
https://mariadb.com/kb/en/drop-table/','','https://mariadb.com/kb/en/drop-table/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(702,38,'RENAME TABLE','Syntax\n------\n\nRENAME TABLE[S]
[IF EXISTS] tbl_name \n [WAIT n | NOWAIT]\n TO new_tbl_name\n [, tbl_name2
TO new_tbl_name2] ...\n\nDescription\n-----------\n\nThis statement renames
one or more tables or views, but not the privileges\nassociated with
them.\n\nIF EXISTS\n---------\n\nMariaDB starting with
10.5.2\n----------------------------\nIf this directive is used, one will
not get an error if the table to be\nrenamed doesn\'t exist.\n\nThe
rename operation is done atomically, which means that no other session
can\naccess any of the tables while the rename is running. For example, if
you have\nan existing table old_table, you can create another table
new_table that has\nthe same structure but is empty, and then replace the
existing table with the\nempty one as follows (assuming that backup_table
does not already exist):\n\nCREATE TABLE new_table (...);\nRENAME TABLE
old_table TO backup_table, new_table TO old_table;\n\ntbl_name can
optionally be specified as db_name.tbl_name. See Identifier\nQualifiers.
This allows to use RENAME to move a table from a database to\nanother (as
long as they are on the same filesystem):\n\nRENAME TABLE db1.t TO
db2.t;\n\nNote that moving a table to another database is not possible if
it has some\ntriggers. Trying to do so produces the following
error:\n\nERROR 1435 (HY000): Trigger in wrong schema\n\nAlso, views cannot
be moved to another database:\n\nERROR 1450 (HY000): Changing schema from
\'old_db\' to \'new_db\' is not allowed.\n\nMultiple
tables can be renamed in a single statement. The presence or absence\nof
the optional S (RENAME TABLE or RENAME TABLES) has no impact, whether
a\nsingle or multiple tables are being renamed.\n\nIf a RENAME TABLE
renames more than one table and one renaming fails, all\nrenames executed
by the same statement are rolled back.\n\nRenames are always executed in
the specified order. Knowing this, it is also\npossible to swap two
tables\' names:\n\nRENAME TABLE t1 TO tmp_table,\n t2 TO t1,\n
tmp_table TO t2;\n\nWAIT/NOWAIT\n-----------\n\nMariaDB starting with
10.3.0\n----------------------------\nSet the lock wait timeout. See WAIT
and NOWAIT.\n\nPrivileges\n----------\n\nExecuting the RENAME TABLE
statement requires the DROP, CREATE and INSERT\nprivileges for the table or
the database.\n\nAtomic RENAME TABLE\n-------------------\n\nMariaDB
starting with 10.6.1\n----------------------------\nFrom MariaDB 10.6,
RENAME TABLE is atomic for most engines, including InnoDB,\nMyRocks, MyISAM
and Aria (MDEV-23842). This means that if there is a crash\n(server down or
power outage) during RENAME TABLE, all tables will revert to\ntheir
original names and any changes to trigger files will be reverted.\n\nIn
older MariaDB version there was a small chance that, during a server
crash\nhappening in the middle of RENAME TABLE, some tables could have been
renamed\n(in the worst case partly) while others would not be
renamed.\n\nSee Atomic DDL for more information.\n\nURL:
https://mariadb.com/kb/en/rename-table/','','https://mariadb.com/kb/en/rename-table/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(703,38,'TRUNCATE TABLE','Syntax\n------\n\nTRUNCATE [TABLE]
tbl_name\n [WAIT n | NOWAIT]\n\nDescription\n-----------\n\nTRUNCATE TABLE
empties a table completely. It requires the DROP privilege.
See\nGRANT.\n\ntbl_name can also be specified in the form db_name.tbl_name
(see Identifier\nQualifiers).\n\nLogically, TRUNCATE TABLE is equivalent to
a DELETE statement that deletes all\nrows, but there are practical
differences under some circumstances.\n\nTRUNCATE TABLE will fail for an
InnoDB table if any FOREIGN KEY constraints\nfrom other tables reference
the table, returning the error:\n\nERROR 1701 (42000): Cannot truncate a
table referenced in a foreign key\nconstraint\n\nForeign Key constraints
between columns in the same table are permitted.\n\nFor an InnoDB table, if
there are no FOREIGN KEY constraints, InnoDB performs\nfast truncation by
dropping the original table and creating an empty one with\nthe same
definition, which is much faster than deleting rows one by one.
The\nAUTO_INCREMENT counter is reset by TRUNCATE TABLE, regardless of
whether there\nis a FOREIGN KEY constraint.\n\nThe count of rows affected
by TRUNCATE TABLE is accurate only when it is\nmapped to a DELETE
statement.\n\nFor other storage engines, TRUNCATE TABLE differs from DELETE
in the following\nways:\n\n* Truncate operations drop and re-create the
table, which is much\n faster than deleting rows one by one, particularly
for large tables.\n* Truncate operations cause an implicit commit.\n*
Truncation operations cannot be performed if the session holds an\n active
table lock.\n* Truncation operations do not return a meaningful value for
the number\n of deleted rows. The usual result is \"0 rows
affected,\" which should\n be interpreted as \"no
information.\"\n* As long as the table format file tbl_name.frm is
valid, the\n table can be re-created as an empty table\n with TRUNCATE
TABLE, even if the data or index files have become\n corrupted.\n* The
table handler does not remember the last\n used AUTO_INCREMENT value, but
starts counting\n from the beginning. This is true even for MyISAM and
InnoDB, which normally\n do not reuse sequence values.\n* When used with
partitioned tables, TRUNCATE TABLE preserves\n the partitioning; that is,
the data and index files are dropped and\n re-created, while the partition
definitions (.par) file is\n unaffected.\n* Since truncation of a table
does not make any use of DELETE,\n the TRUNCATE statement does not invoke
ON DELETE triggers.\n* TRUNCATE TABLE will only reset the values in the
Performance Schema summary\ntables to zero or null, and will not remove the
rows.\n\nFor the purposes of binary logging and replication, TRUNCATE TABLE
is treated\nas DROP TABLE followed by CREATE TABLE (DDL rather than
DML).\n\nTRUNCATE TABLE does not work on views. Currently, TRUNCATE TABLE
drops all\nhistorical records from a system-versioned table.\n\nMariaDB
starting with
10.3.0\n----------------------------\n\nWAIT/NOWAIT\n-----------\n\nSet the
lock wait timeout. See WAIT and
NOWAIT.\n\nOracle-mode\n-----------\n\nOracle-mode from MariaDB 10.3
permits the optional keywords REUSE STORAGE or\nDROP STORAGE to be
used.\n\nTRUNCATE [TABLE] tbl_name [{DROP | REUSE} STORAGE] [WAIT n |
NOWAIT]\n\nThese have no effect on the
operation.\n\nPerformance\n-----------\n\nTRUNCATE TABLE is faster than
DELETE, because it drops and re-creates a table.\n\nWith InnoDB, TRUNCATE
TABLE is slower if innodb_file_per_table=ON is set (the\ndefault). This is
because TRUNCATE TABLE unlinks the underlying tablespace\nfile, which can
be an expensive operation. See MDEV-8069 for more details.\n\nThe
performance issues with innodb_file_per_table=ON can be exacerbated
in\ncases where the InnoDB buffer pool is very large
and\ninnodb_adaptive_hash_index=ON is set. In that case, using DROP TABLE
followed\nby CREATE TABLE instead of TRUNCATE TABLE may perform better.
Setting\ninnodb_adaptive_hash_index=OFF (it defaults to ON before MariaDB
10.5) can\nalso help. In MariaDB 10.2 only, from MariaDB 10.2.19, this
performance can\nalso be improved by setting innodb_safe_truncate=OFF. See
MDEV-9459 for more\ndetails.\n\nSetting innodb_adaptive_hash_index=OFF can
also improve TRUNCATE TABLE\nperformance in general. See MDEV-16796 for
more details.\n\nURL:
https://mariadb.com/kb/en/truncate-table/','','https://mariadb.com/kb/en/truncate-table/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(704,38,'CREATE DATABASE','Syntax\n------\n\nCREATE [OR
REPLACE] {DATABASE | SCHEMA} [IF NOT EXISTS] db_name\n
[create_specification] ...\n\ncreate_specification:\n [DEFAULT] CHARACTER
SET [=] charset_name\n | [DEFAULT] COLLATE [=] collation_name\n | COMMENT
[=] \'comment\'\n\nDescription\n-----------\n\nCREATE DATABASE
creates a database with the given name. To use this statement,\nyou need
the CREATE privilege for the database. CREATE SCHEMA is a synonym
for\nCREATE DATABASE.\n\nFor valid identifiers to use as database names,
see Identifier Names.\n\nOR REPLACE\n----------\n\nMariaDB starting with
10.1.3\n----------------------------\nThe OR REPLACE clause was added in
MariaDB 10.1.3\n\nIf the optional OR REPLACE clause is used, it acts as a
shortcut for:\n\nDROP DATABASE IF EXISTS db_name;\nCREATE DATABASE db_name
...;\n\nIF NOT EXISTS\n-------------\n\nWhen the IF NOT EXISTS clause is
used, MariaDB will return a warning instead\nof an error if the specified
database already exists.\n\nCOMMENT\n-------\n\nMariaDB starting with
10.5.0\n----------------------------\nFrom MariaDB 10.5.0, it is possible
to add a comment of a maximum of 1024\nbytes. If the comment length exceeds
this length, a error/warning code 4144 is\nthrown. The database comment is
also added to the db.opt file, as well as to\nthe
information_schema.schemata table.\n\nExamples\n--------\n\nCREATE DATABASE
db1;\nQuery OK, 1 row affected (0.18 sec)\n\nCREATE DATABASE db1;\nERROR
1007 (HY000): Can\'t create database \'db1\'; database
exists\n\nCREATE OR REPLACE DATABASE db1;\nQuery OK, 2 rows affected (0.00
sec)\n\nCREATE DATABASE IF NOT EXISTS db1;\nQuery OK, 1 row affected, 1
warning (0.01 sec)\n\nSHOW
WARNINGS;\n+-------+------+----------------------------------------------+\n|
Level | Code | Message
|\n+-------+------+----------------------------------------------+\n| Note
| 1007 | Can\'t create database \'db1\'; database exists
|\n+-------+------+----------------------------------------------+\n\nSetting
the character sets and collation. See Setting Character Sets
and\nCollations for more details.\n\nCREATE DATABASE czech_slovak_names \n
CHARACTER SET = \'keybcs2\'\n COLLATE =
\'keybcs2_bin\';\n\nComments, from MariaDB 10.5.0:\n\nCREATE
DATABASE presentations COMMENT \'Presentations for
conferences\';\n\nURL:
https://mariadb.com/kb/en/create-database/','','https://mariadb.com/kb/en/create-database/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(705,38,'CREATE EVENT','Syntax\n------\n\nCREATE [OR
REPLACE]\n [DEFINER = { user | CURRENT_USER | role | CURRENT_ROLE }]\n
EVENT\n [IF NOT EXISTS]\n event_name\n ON SCHEDULE schedule\n [ON
COMPLETION [NOT] PRESERVE]\n [ENABLE | DISABLE | DISABLE ON SLAVE]\n
[COMMENT \'comment\']\n DO sql_statement;\n\nschedule:\n AT
timestamp [+ INTERVAL interval] ...\n | EVERY interval\n [STARTS timestamp
[+ INTERVAL interval] ...]\n [ENDS timestamp [+ INTERVAL interval]
...]\n\ninterval:\n quantity {YEAR | QUARTER | MONTH | DAY | HOUR | MINUTE
|\n WEEK | SECOND | YEAR_MONTH | DAY_HOUR | DAY_MINUTE |\n
DAY_SECOND | HOUR_MINUTE | HOUR_SECOND |
MINUTE_SECOND}\n\nDescription\n-----------\n\nThis statement creates and
schedules a new event. It requires the EVENT\nprivilege for the schema in
which the event is to be created.\n\nThe minimum requirements for a valid
CREATE EVENT statement are as follows:\n\n* The keywords CREATE EVENT plus
an event name, which uniquely identifies\n the event in the current schema.
(Prior to MySQL 5.1.12, the event name\n needed to be unique only among
events created by the same user on a given\n database.)\n* An ON SCHEDULE
clause, which determines when and how often the event\n executes.\n* A DO
clause, which contains the SQL statement to be executed by an\n
event.\n\nHere is an example of a minimal CREATE EVENT statement:\n\nCREATE
EVENT myevent\n ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR\n DO\n
UPDATE myschema.mytable SET mycol = mycol + 1;\n\nThe previous statement
creates an event named myevent. This event executes\nonce — one hour
following its creation — by running an SQL statement that\nincrements the
value of the myschema.mytable table\'s mycol column by 1.\n\nThe
event_name must be a valid MariaDB identifier with a maximum length of
64\ncharacters. It may be delimited using back ticks, and may be qualified
with\nthe name of a database schema. An event is associated with both a
MariaDB user\n(the definer) and a schema, and its name must be unique among
names of events\nwithin that schema. In general, the rules governing event
names are the same\nas those for names of stored routines. See Identifier
Names.\n\nIf no schema is indicated as part of event_name, the default
(current) schema\nis assumed.\n\nFor valid identifiers to use as event
names, see Identifier Names.\n\nOR REPLACE\n----------\n\nThe OR REPLACE
clause was included in MariaDB 10.1.4. If used and the event\nalready
exists, instead of an error being returned, the existing event will
be\ndropped and replaced by the newly defined event.\n\nIF NOT
EXISTS\n-------------\n\nIf the IF NOT EXISTS clause is used, MariaDB will
return a warning instead of\nan error if the event already exists. Cannot
be used together with OR REPLACE.\n\nON SCHEDULE\n-----------\n\nThe ON
SCHEDULE clause can be used to specify when the event must be
triggered.\n\nAT\n--\n\nIf you want to execute the event only once (one
time event), you can use the\nAT keyword, followed by a timestamp. If you
use CURRENT_TIMESTAMP, the event\nacts as soon as it is created. As a
convenience, you can add one or more\nintervals to that timestamp. You can
also specify a timestamp in the past, so\nthat the event is stored but not
triggered, until you modify it via ALTER\nEVENT.\n\nThe following example
shows how to create an event that will be triggered\ntomorrow at a certain
time:\n\nCREATE EVENT example\nON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL
1 DAY + INTERVAL 3 HOUR\nDO something;\n\nYou can also specify that an
event must be triggered at a regular interval\n(recurring event). In such
cases, use the EVERY clause followed by the\ninterval.\n\nIf an event is
recurring, you can specify when the first execution must happen\nvia the
STARTS clause and a maximum time for the last execution via the
ENDS\nclause. STARTS and ENDS clauses are followed by a timestamp and,
optionally,\none or more intervals. The ENDS clause can specify a timestamp
in the past, so\nthat the event is stored but not executed until you modify
it via ALTER EVENT.\n\nIn the following example, next month a recurring
event will be triggered\nhourly for a week:\n\nCREATE EVENT example\nON
SCHEDULE EVERY 1 HOUR\nSTARTS CURRENT_TIMESTAMP + INTERVAL 1 MONTH\nENDS
CURRENT_TIMESTAMP + INTERVAL 1 MONTH + INTERVAL 1 WEEK\nDO
some_task;\n\nIntervals consist of a quantity and a time unit. The time
units are the same\nused for other staments and time functions, except that
you can\'t use\nmicroseconds for events. For simple time units, like
HOUR or MINUTE, the\nquantity is an integer number, for example \'10
MINUTE\'. For composite time\nunits, like HOUR_MINUTE or HOUR_SECOND,
the quantity must be a string with all\ninvolved simple values and their
separators, for example \'2:30\' or \'2:30:30\'.\n\nON
COMPLETION [NOT] PRESERVE\n----------------------------\n\nThe ON
COMPLETION clause can be used to specify if the event must be
deleted\nafter its last execution (that is, after its AT or ENDS timestamp
is past). By\ndefault, events are dropped when they are expired. To
explicitly state that\nthis is the desired behaviour, you can use ON
COMPLETION NOT PRESERVE.\nInstead, if you want the event to be preserved,
you can use ON COMPLETION\nPRESERVE.\n\nIn you specify ON COMPLETION NOT
PRESERVE, and you specify a timestamp in the\npast for AT or ENDS clause,
the event will be immediatly dropped. In such\ncases, you will get a Note
1558: \"Event execution time is in the past and ON\nCOMPLETION NOT
PRESERVE is set. The event was dropped immediately
after\ncreation\".\n\nENABLE/DISABLE/DISABLE ON
SLAVE\n-------------------------------\n\nEvents are ENABLEd by default. If
you want to stop MariaDB from executing an\nevent, you may specify DISABLE.
When it is ready to be activated, you may\nenable it using ALTER EVENT.
Another option is DISABLE ON SLAVE, which\nindicates that an event was
created on a master and has been replicated to the\nslave, which is
prevented from executing the event. If DISABLE ON SLAVE is\nspecifically
set, the event will be disabled everywhere. It will not be\nexecuted on the
mater or the slaves.\n\nCOMMENT\n-------\n\nThe COMMENT clause may be used
to set a comment for the event. Maximum length\nfor comments is 64
characters. The comment is a string, so it must be quoted.\nTo see events
comments, you can query the INFORMATION_SCHEMA.EVENTS table (the\ncolumn is
named EVENT_COMMENT).\n\nExamples\n--------\n\nMinimal CREATE EVENT
statement:\n\nCREATE EVENT myevent\n ON SCHEDULE AT CURRENT_TIMESTAMP +
INTERVAL 1 HOUR\n DO\n UPDATE myschema.mytable SET mycol = mycol +
1;\n\nAn event that will be triggered tomorrow at a certain time:\n\nCREATE
EVENT example\nON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 DAY + INTERVAL
3 HOUR\nDO something;\n\nNext month a recurring event will be triggered
hourly for a week:\n\nCREATE EVENT example\nON SCHEDULE EVERY 1
HOUR\nSTARTS CURRENT_TIMESTAMP + INTERVAL 1 MONTH\nENDS CURRENT_TIMESTAMP +
INTERVAL 1 MONTH + INTERVAL 1 WEEK\nDO some_task;\n\nOR REPLACE and IF NOT
EXISTS:\n\nCREATE EVENT myevent\n ON SCHEDULE AT CURRENT_TIMESTAMP +
INTERVAL 1 HOUR\n DO\n UPDATE myschema.mytable SET mycol = mycol +
1;\nERROR 1537 (HY000): Event \'myevent\' already
exists\n\nCREATE OR REPLACE EVENT myevent\n ON SCHEDULE AT
CURRENT_TIMESTAMP + INTERVAL 1 HOUR\n DO\n UPDATE myschema.mytable SET
mycol = mycol + 1;;\nQuery OK, 0 rows affected (0.00 sec)\n\nCREATE EVENT
IF NOT EXISTS myevent\n ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1
HOUR\n DO\n UPDATE myschema.mytable SET mycol = mycol + 1;\nQuery OK, 0
rows affected, 1 warning (0.00 sec)\n\nSHOW
WARNINGS;\n+-------+------+--------------------------------+\n| Level |
Code | Message
|\n+-------+------+--------------------------------+\n| Note | 1537 |
Event \'myevent\' already exists
|\n+-------+------+--------------------------------+\n\nURL:
https://mariadb.com/kb/en/create-event/','','https://mariadb.com/kb/en/create-event/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(706,38,'CREATE FUNCTION','Syntax\n------\n\nCREATE [OR
REPLACE]\n [DEFINER = {user | CURRENT_USER | role | CURRENT_ROLE }]\n
[AGGREGATE] FUNCTION [IF NOT EXISTS] func_name ([func_parameter[,...]])\n
RETURNS type\n [characteristic ...]\n RETURN func_body\nfunc_parameter:\n
[ IN | OUT | INOUT | IN OUT ] param_name type\ntype:\n Any valid MariaDB
data type\ncharacteristic:\n LANGUAGE SQL\n | [NOT] DETERMINISTIC\n | {
CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES SQL DATA }\n | SQL
SECURITY { DEFINER | INVOKER }\n | COMMENT
\'string\'\nfunc_body:\n Valid SQL procedure
statement\n\nDescription\n-----------\n\nUse the CREATE FUNCTION statement
to create a new stored function. You must\nhave the CREATE ROUTINE database
privilege to use CREATE FUNCTION. A function\ntakes any number of arguments
and returns a value from the function body. The\nfunction body can be any
valid SQL expression as you would use, for example,\nin any select
expression. If you have the appropriate privileges, you can call\nthe
function exactly as you would any built-in function. See Security
below\nfor details on privileges.\n\nYou can also use a variant of the
CREATE FUNCTION statement to install a\nuser-defined function (UDF) defined
by a plugin. See CREATE FUNCTION (UDF) for\ndetails.\n\nYou can use a
SELECT statement for the function body by enclosing it in\nparentheses,
exactly as you would to use a subselect for any other expression.\nThe
SELECT statement must return a single value. If more than one column
is\nreturned when the function is called, error 1241 results. If more than
one row\nis returned when the function is called, error 1242 results. Use a
LIMIT\nclause to ensure only one row is returned.\n\nYou can also replace
the RETURN clause with a BEGIN...END compound statement.\nThe compound
statement must contain a RETURN statement. When the function is\ncalled,
the RETURN statement immediately returns its result, and any\nstatements
after RETURN are effectively ignored.\n\nBy default, a function is
associated with the current database. To associate\nthe function explicitly
with a given database, specify the fully-qualified\nname as
db_name.func_name when you create it. If the function name is the same\nas
the name of a built-in function, you must use the fully qualified name
when\nyou call it.\n\nThe parameter list enclosed within parentheses must
always be present. If\nthere are no parameters, an empty parameter list of
() should be used.\nParameter names are not case sensitive.\n\nEach
parameter can be declared to use any valid data type, except that
the\nCOLLATE attribute cannot be used.\n\nFor valid identifiers to use as
function names, see Identifier Names.\n\nIN | OUT | INOUT | IN
OUT\n-------------------------\n\nMariaDB starting with
10.8.0\n----------------------------\nThe function parameter qualifiers for
IN, OUT, INOUT, and IN OUT were added in\na 10.8.0 preview release. Prior
to 10.8.0 quantifiers were supported only in\nprocedures.\n\nOUT, INOUT and
its equivalent IN OUT, are only valid if called from SET and\nnot SELECT.
These quantifiers are especially useful for creating functions\nwith more
than one return value. This allows functions to be more complex
and\nnested.\n\nDELIMITER $$\nCREATE FUNCTION add_func3(IN a INT, IN b INT,
OUT c INT) RETURNS INT\nBEGIN\n SET c = 100;\n RETURN a +
b;\nEND;\n$$\nDELIMITER ;\n\nSET @a = 2;\nSET @b = 3;\nSET @c = 0;\nSET
@res= add_func3(@a, @b, @c);\n\nSELECT add_func3(@a, @b, @c);\nERROR 4186
(HY000): OUT or INOUT argument 3 for function add_func3 is not\nallowed
here\n\nDELIMITER $$\nCREATE FUNCTION add_func4(IN a INT, IN b INT, d INT)
RETURNS INT\nBEGIN\n DECLARE c, res INT;\n SET res = add_func3(a, b, c) +
d;\n if (c > 99) then\n return 3;\n else\n return res;\n end
if;\nEND;\n$$\n\nDELIMITER ;\n\nSELECT
add_func4(1,2,3);\n+------------------+\n| add_func4(1,2,3)
|\n+------------------+\n| 3
|\n+------------------+\n\nAGGREGATE\n---------\n\nMariaDB starting with
10.3.3\n----------------------------\nFrom MariaDB 10.3.3, it is possible
to create stored aggregate functions as\nwell. See Stored Aggregate
Functions for details.\n\nRETURNS\n-------\n\nThe RETURNS clause specifies
the return type of the function. NULL values are\npermitted with all return
types.\n\nWhat happens if the RETURN clause returns a value of a different
type? It\ndepends on the SQL_MODE in effect at the moment of the function
creation.\n\nIf the SQL_MODE is strict (STRICT_ALL_TABLES or
STRICT_TRANS_TABLES flags are\nspecified), a 1366 error will be
produced.\n\nOtherwise, the value is coerced to the proper type. For
example, if a function\nspecifies an ENUM or SET value in the RETURNS
clause, but the RETURN clause\nreturns an integer, the value returned from
the function is the string for the\ncorresponding ENUM member of set of SET
members.\n\nMariaDB stores the SQL_MODE system variable setting that is in
effect at the\ntime a routine is created, and always executes the routine
with this setting\nin force, regardless of the server SQL mode in effect
when the routine is\ninvoked.\n\nLANGUAGE SQL\n------------\n\nLANGUAGE SQL
is a standard SQL clause, and it can be used in MariaDB for\nportability.
However that clause has no meaning, because SQL is the only\nsupported
language for stored functions.\n\nA function is deterministic if it can
produce only one result for a given list\nof parameters. If the result may
be affected by stored data, server variables,\nrandom numbers or any value
that is not explicitly passed, then the function\nis not deterministic.
Also, a function is non-deterministic if it uses\nnon-deterministic
functions like NOW() or CURRENT_TIMESTAMP(). The optimizer\nmay choose a
faster execution plan if it known that the function is\ndeterministic. In
such cases, you should declare the routine using the\nDETERMINISTIC
keyword. If you want to explicitly state that the function is\nnot
deterministic (which is the default) you can use the NOT
DETERMINISTIC\nkeywords.\n\nIf you declare a non-deterministic function as
DETERMINISTIC, you may get\nincorrect results. If you declare a
deterministic function as NOT\nDETERMINISTIC, in some cases the queries
will be slower.\n\nOR REPLACE\n----------\n\nMariaDB starting with
10.1.3\n----------------------------\nIf the optional OR REPLACE clause is
used, it acts as a shortcut for:\n\nDROP FUNCTION IF EXISTS
function_name;\nCREATE FUNCTION function_name ...;\n\nwith the exception
that any existing privileges for the function are not\ndropped.\n\nIF NOT
EXISTS\n-------------\n\nMariaDB starting with
10.1.3\n----------------------------\nIf the IF NOT EXISTS clause is used,
MariaDB will return a warning instead of\nan error if the function already
exists. Cannot be used together with OR\nREPLACE.\n\n[NOT]
DETERMINISTIC\n-------------------\n\nThe [NOT] DETERMINISTIC clause also
affects binary logging, because the\nSTATEMENT format can not be used to
store or replicate non-deterministic\nstatements.\n\nCONTAINS SQL, NO SQL,
READS SQL DATA, and MODIFIES SQL DATA are informative\nclauses that tell
the server what the function does. MariaDB does not check in\nany way
whether the specified clause is correct. If none of these clauses
are\nspecified, CONTAINS SQL is used by default.\n\nMODIFIES SQL
DATA\n-----------------\n\nMODIFIES SQL DATA means that the function
contains statements that may modify\ndata stored in databases. This happens
if the function contains statements\nlike DELETE, UPDATE, INSERT, REPLACE
or DDL.\n\nREADS SQL DATA\n--------------\n\nREADS SQL DATA means that the
function reads data stored in databases, but\ndoes not modify any data.
This happens if SELECT statements are used, but\nthere no write operations
are executed.\n\nCONTAINS SQL\n------------\n\nCONTAINS SQL means that the
function contains at least one SQL statement, but\nit does not read or
write any data stored in a database. Examples include SET\nor DO.\n\nNO
SQL\n------\n\nNO SQL means nothing, because MariaDB does not currently
support any language\nother than SQL.\n\nOracle
Mode\n-----------\n\nMariaDB starting with
10.3\n--------------------------\nFrom MariaDB 10.3, a subset of
Oracle\'s PL/SQL language has been supported in\naddition to the
traditional SQL/PSM-based MariaDB syntax. See Oracle mode from\nMariaDB
10.3 for details on changes when running Oracle
mode.\n\nSecurity\n--------\n\nYou must have the EXECUTE privilege on a
function to call it. MariaDB\nautomatically grants the EXECUTE and ALTER
ROUTINE privileges to the account\nthat called CREATE FUNCTION, even if the
DEFINER clause was used.\n\nEach function has an account associated as the
definer. By default, the\ndefiner is the account that created the function.
Use the DEFINER clause to\nspecify a different account as the definer. You
must have the SUPER privilege,\nor, from MariaDB 10.5.2, the SET USER
privilege, to use the DEFINER clause.\nSee Account Names for details on
specifying accounts.\n\nThe SQL SECURITY clause specifies what privileges
are used when a function is\ncalled. If SQL SECURITY is INVOKER, the
function body will be evaluated using\nthe privileges of the user calling
the function. If SQL SECURITY is DEFINER,\nthe function body is always
evaluated using the privileges of the definer\naccount. DEFINER is the
default.\n\nThis allows you to create functions that grant limited access
to certain data.\nFor example, say you have a table that stores some
employee information, and\nthat you\'ve granted SELECT privileges only
on certain columns to the user\naccount roger.\n\nCREATE TABLE employees
(name TINYTEXT, dept TINYTEXT, salary INT);\nGRANT SELECT (name, dept) ON
employees TO roger;\n\nTo allow the user the get the maximum salary for a
department, define a\nfunction and grant the EXECUTE privilege:\n\nCREATE
FUNCTION max_salary (dept TINYTEXT) RETURNS INT RETURN\n (SELECT
MAX(salary) FROM employees WHERE employees.dept = dept);\nGRANT EXECUTE ON
FUNCTION max_salary TO roger;\n\nSince SQL SECURITY defaults to DEFINER,
whenever the user roger calls this\nfunction, the subselect will execute
with your privileges. As long as you have\nprivileges to select the salary
of each employee, the caller of the function\nwill be able to get the
maximum salary for each department without being able\nto see individual
salaries.\n\nCharacter sets and
collations\n-----------------------------\n\nFunction return types can be
declared to use any valid character set and\ncollation. If used, the
COLLATE attribute needs to be preceded by a CHARACTER\nSET attribute.\n\nIf
the character set and collation are not specifically set in the
statement,\nthe database defaults at the time of creation will be used. If
the database\ndefaults change at a later stage, the stored function
character set/collation\nwill not be changed at the same time; the stored
function needs to be dropped\nand recreated to ensure the same character
set/collation as the database is\nused.\n\nExamples\n--------\n\nThe
following example function takes a parameter, performs an operation
using\nan SQL function, and returns the result.\n\nCREATE FUNCTION hello (s
CHAR(20))\n RETURNS CHAR(50) DETERMINISTIC\n RETURN CONCAT(\'Hello,
\',s,\'!\');\n\nSELECT
hello(\'world\');\n+----------------+\n|
hello(\'world\') |\n+----------------+\n| Hello, world!
|\n+----------------+\n\nYou can use a compound statement in a function to
manipulate data with\nstatements like INSERT and UPDATE. The following
example creates a counter\nfunction that uses a temporary table to store
the current value. Because the\ncompound statement contains statements
terminated with semicolons, you have to\nfirst change the statement
delimiter with the DELIMITER statement to allow the\nsemicolon to be used
in the function body. See Delimiters in the mysql client\nfor
more.\n\nCREATE TEMPORARY TABLE counter (c INT);\nINSERT INTO counter
VALUES (0);\nDELIMITER //\nCREATE FUNCTION counter () RETURNS INT\n BEGIN\n
UPDATE counter SET c = c + 1;\n RETURN (SELECT c FROM counter LIMIT 1);\n
END //\nDELIMITER ;\n\nCharacter set and collation:\n\nCREATE FUNCTION
hello2 (s CHAR(20))\n RETURNS CHAR(50) CHARACTER SET \'utf8\'
COLLATE \'utf8_bin\' DETERMINISTIC\n RETURN CONCAT(\'Hello,
\',s,\'!\');\n\nURL:
https://mariadb.com/kb/en/create-function/','','https://mariadb.com/kb/en/create-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(707,38,'CREATE INDEX','Syntax\n------\n\nCREATE [OR
REPLACE] [UNIQUE|FULLTEXT|SPATIAL] INDEX \n [IF NOT EXISTS] index_name\n
[index_type]\n ON tbl_name (index_col_name,...)\n [WAIT n | NOWAIT]\n
[index_option]\n [algorithm_option | lock_option] ...\n\nindex_col_name:\n
col_name [(length)] [ASC | DESC]\n\nindex_type:\n USING {BTREE | HASH |
RTREE}\n\nindex_option:\n [ KEY_BLOCK_SIZE [=] value\n | index_type\n |
WITH PARSER parser_name\n | COMMENT \'string\'\n |
CLUSTERING={YES| NO} ]\n [ IGNORED | NOT IGNORED ]\n\nalgorithm_option:\n
ALGORITHM [=] {DEFAULT|INPLACE|COPY|NOCOPY|INSTANT}\n\nlock_option:\n LOCK
[=] {DEFAULT|NONE|SHARED|EXCLUSIVE}\n\nDescription\n-----------\n\nCREATE
INDEX is mapped to an ALTER TABLE statement to create indexes. See\nALTER
TABLE. CREATE INDEX cannot be used to create a PRIMARY KEY; use
ALTER\nTABLE instead.\n\nIf another connection is using the table, a
metadata lock is active, and this\nstatement will wait until the lock is
released. This is also true for\nnon-transactional tables.\n\nAnother
shortcut, DROP INDEX, allows the removal of an index.\n\nFor valid
identifiers to use as index names, see Identifier Names.\n\nNote that
KEY_BLOCK_SIZE is currently ignored in CREATE INDEX, although it
is\nincluded in the output of SHOW CREATE
TABLE.\n\nPrivileges\n----------\n\nExecuting the CREATE INDEX statement
requires the INDEX privilege for the\ntable or the database.\n\nOnline
DDL\n----------\n\nOnline DDL is supported with the ALGORITHM and LOCK
clauses.\n\nSee InnoDB Online DDL Overview for more information on online
DDL with InnoDB.\n\nCREATE OR REPLACE INDEX\n-----------------------\n\nIf
the OR REPLACE clause is used and if the index already exists, then
instead\nof returning an error, the server will drop the existing index and
replace it\nwith the newly defined index.\n\nCREATE INDEX IF NOT
EXISTS\n--------------------------\n\nIf the IF NOT EXISTS clause is used,
then the index will only be created if an\nindex with the same name does
not already exist. If the index already exists,\nthen a warning will be
triggered by default.\n\nIndex Definitions\n-----------------\n\nSee CREATE
TABLE: Index Definitions for information about index
definitions.\n\nWAIT/NOWAIT\n-----------\n\nSet the lock wait timeout. See
WAIT and NOWAIT.\n\nALGORITHM\n---------\n\nSee ALTER TABLE: ALGORITHM for
more information.\n\nLOCK\n----\n\nSee ALTER TABLE: LOCK for more
information.\n\nProgress Reporting\n------------------\n\nMariaDB provides
progress reporting for CREATE INDEX statement for clients\nthat support the
new progress reporting protocol. For example, if you were\nusing the mysql
client, then the progress report might look like this::\n\nCREATE INDEX i
ON tab (num);\nStage: 1 of 2 \'copy to tmp table\' 46% of
stage\n\nThe progress report is also shown in the output of the SHOW
PROCESSLIST\nstatement and in the contents of the
information_schema.PROCESSLIST table.\n\nSee Progress Reporting for more
information.\n\nWITHOUT OVERLAPS\n----------------\n\nMariaDB starting with
10.5.3\n----------------------------\nThe WITHOUT OVERLAPS clause allows
one to constrain a primary or unique index\nsuch that application-time
periods cannot overlap.\n\nExamples\n--------\n\nCreating a unique
index:\n\nCREATE UNIQUE INDEX HomePhone ON Employees(Home_Phone);\n\nOR
REPLACE and IF NOT EXISTS:\n\nCREATE INDEX xi ON xx5 (x);\nQuery OK, 0 rows
affected (0.03 sec)\n\nCREATE INDEX xi ON xx5 (x);\nERROR 1061 (42000):
Duplicate key name \'xi\'\n\nCREATE OR REPLACE INDEX xi ON xx5
(x);\nQuery OK, 0 rows affected (0.03 sec)\n\nCREATE INDEX IF NOT EXISTS xi
ON xx5 (x);\nQuery OK, 0 rows affected, 1 warning (0.00 sec)\n\nSHOW
WARNINGS;\n+-------+------+-------------------------+\n| Level | Code |
Message |\n+-------+------+-------------------------+\n|
Note | 1061 | Duplicate key name \'xi\'
|\n+-------+------+-------------------------+\n\nFrom MariaDB 10.5.3,
creating a unique index for an application-time period\ntable with a
WITHOUT OVERLAPS constraint:\n\nCREATE UNIQUE INDEX u ON rooms
(room_number, p WITHOUT OVERLAPS);\n\nURL:
https://mariadb.com/kb/en/create-index/','','https://mariadb.com/kb/en/create-index/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(708,38,'CREATE PACKAGE','MariaDB starting with
10.3.5\n----------------------------\nOracle-style packages were introduced
in MariaDB 10.3.5.\n\nSyntax\n------\n\nCREATE\n [ OR REPLACE]\n [DEFINER
= { user | CURRENT_USER | role | CURRENT_ROLE }]\n PACKAGE [ IF NOT EXISTS
]\n [ db_name . ] package_name\n [ package_characteristic ... ]\n{ AS |
IS }\n [ package_specification_element ... ]\nEND [ package_name
]\n\npackage_characteristic:\n COMMENT \'string\'\n | SQL
SECURITY { DEFINER | INVOKER }\n\npackage_specification_element:\n
FUNCTION_SYM package_specification_function ;\n | PROCEDURE_SYM
package_specification_procedure ;\n\npackage_specification_function:\n
func_name [ ( func_param [, func_param]... ) ]\n RETURNS
func_return_type\n [ package_routine_characteristic...
]\n\npackage_specification_procedure:\n proc_name [ ( proc_param [,
proc_param]... ) ]\n [ package_routine_characteristic...
]\n\nfunc_return_type:\n type\n\nfunc_param:\n param_name [ IN | OUT |
INOUT | IN OUT ] type\n\nproc_param:\n param_name [ IN | OUT | INOUT | IN
OUT ] type\n\ntype:\n Any valid MariaDB explicit or anchored data
type\n\npackage_routine_characteristic:\n COMMENT \'string\'\n
| LANGUAGE SQL\n | { CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES
SQL DATA }\n | SQL SECURITY { DEFINER | INVOKER
}\n\nDescription\n-----------\n\nThe CREATE PACKAGE statement can be used
when Oracle SQL_MODE is set.\n\nThe CREATE PACKAGE creates the
specification for a stored package (a\ncollection of logically related
stored objects). A stored package\nspecification declares public routines
(procedures and functions) of the\npackage, but does not implement these
routines.\n\nA package whose specification was created by the CREATE
PACKAGE statement,\nshould later be implemented using the CREATE PACKAGE
BODY statement.\n\nFunction parameter quantifiers IN | OUT | INOUT | IN
OUT\n--------------------------------------------------------\n\nMariaDB
starting with 10.8.0\n----------------------------\nThe function parameter
quantifiers for IN, OUT, INOUT, and IN OUT where added\nin a 10.8.0 preview
release. Prior to 10.8.0 quantifiers were supported only\nin
procedures.\n\nOUT, INOUT and its equivalent IN OUT, are only valid if
called from SET and\nnot SELECT. These quantifiers are especially useful
for creating functions and\nprocedures with more than one return value.
This allows functions and\nprocedures to be more complex and
nested.\n\nExamples\n--------\n\nSET sql_mode=ORACLE;\nDELIMITER $$\nCREATE
OR REPLACE PACKAGE employee_tools AS\n FUNCTION getSalary(eid INT) RETURN
DECIMAL(10,2);\n PROCEDURE raiseSalary(eid INT, amount DECIMAL(10,2));\n
PROCEDURE raiseSalaryStd(eid INT);\n PROCEDURE hire(ename TEXT, esalary
DECIMAL(10,2));\nEND;\n$$\nDELIMITER ;\n\nURL:
https://mariadb.com/kb/en/create-package/','','https://mariadb.com/kb/en/create-package/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(709,38,'CREATE PACKAGE BODY','MariaDB starting with
10.3.5\n----------------------------\nOracle-style packages were introduced
in MariaDB 10.3.5.\n\nSyntax\n------\n\nCREATE [ OR REPLACE ]\n [DEFINER =
{ user | CURRENT_USER | role | CURRENT_ROLE }]\n PACKAGE BODY\n [ IF NOT
EXISTS ]\n [ db_name . ] package_name\n [ package_characteristic... ]\n{
AS | IS }\n package_implementation_declare_section\n
package_implementation_executable_section\nEND [
package_name]\n\npackage_implementation_declare_section:\n
package_implementation_item_declaration\n [
package_implementation_item_declaration... ]\n [
package_implementation_routine_definition... ]\n |
package_implementation_routine_definition\n [
package_implementation_routine_definition...]\n\npackage_implementation_item_declaration:\n
variable_declaration ;\n\nvariable_declaration:\n variable_name[,...]
type [:= expr ]\n\npackage_implementation_routine_definition:\n FUNCTION
package_specification_function\n [ package_implementation_function_body ]
;\n | PROCEDURE package_specification_procedure\n [
package_implementation_procedure_body ]
;\n\npackage_implementation_function_body:\n { AS | IS }
package_routine_body
[func_name]\n\npackage_implementation_procedure_body:\n { AS | IS }
package_routine_body [proc_name]\n\npackage_routine_body:\n [
package_routine_declarations ]\n BEGIN\n statements [ EXCEPTION
exception_handlers ]\n END\n\npackage_routine_declarations:\n
package_routine_declaration \';\' [package_routine_declaration
\';\']...\n\npackage_routine_declaration:\n
variable_declaration\n | condition_name CONDITION FOR condition_value\n
| user_exception_name EXCEPTION\n | CURSOR_SYM cursor_name\n [ (
cursor_formal_parameters ) ]\n IS select_statement\n
;\n\npackage_implementation_executable_section:\n END\n | BEGIN\n
statement ; [statement ; ]...\n [EXCEPTION exception_handlers]\n
END\n\nexception_handlers:\n exception_handler
[exception_handler...]\n\nexception_handler:\n WHEN_SYM condition_value
[, condition_value]...\n THEN_SYM statement ; [statement
;]...\n\ncondition_value:\n condition_name\n | user_exception_name\n
| SQLWARNING\n | SQLEXCEPTION\n | NOT FOUND\n | OTHERS_SYM\n
| SQLSTATE [VALUE] sqlstate_value\n |
mariadb_error_code\n\nDescription\n-----------\n\nThe CREATE PACKAGE BODY
statement can be used when Oracle SQL_MODE is set.\n\nThe CREATE PACKAGE
BODY statement creates the package body for a stored\npackage. The package
specification must be previously created using the CREATE\nPACKAGE
statement.\n\nA package body provides implementations of the package public
routines and can\noptionally have:\n\n* package-wide private variables\n*
package private routines\n* forward declarations for private routines\n* an
executable initialization section\n\nExamples\n--------\n\nSET
sql_mode=ORACLE;\nDELIMITER $$\nCREATE OR REPLACE PACKAGE employee_tools
AS\n FUNCTION getSalary(eid INT) RETURN DECIMAL(10,2);\n PROCEDURE
raiseSalary(eid INT, amount DECIMAL(10,2));\n PROCEDURE raiseSalaryStd(eid
INT);\n PROCEDURE hire(ename TEXT, esalary
DECIMAL(10,2));\nEND;\n$$\nCREATE PACKAGE BODY employee_tools AS\n --
package body variables\n stdRaiseAmount DECIMAL(10,2):=500;\n\n-- private
routines\n PROCEDURE log (eid INT, ecmnt TEXT) AS\n BEGIN\n INSERT INTO
employee_log (id, cmnt) VALUES (eid, ecmnt);\n END;\n\n-- public routines\n
PROCEDURE hire(ename TEXT, esalary DECIMAL(10,2)) AS\n eid INT;\n BEGIN\n
INSERT INTO employee (name, salary) VALUES (ename, esalary);\n eid:=
last_insert_id();\n log(eid, \'hire \' || ename);\n
END;\n\nFUNCTION getSalary(eid INT) RETURN DECIMAL(10,2) AS\n nSalary
DECIMAL(10,2);\n BEGIN\n SELECT salary INTO nSalary FROM employee WHERE
id=eid;\n log(eid, \'getSalary id=\' || eid || \'
salary=\' || nSalary);\n RETURN nSalary;\n END;\n\nPROCEDURE
raiseSalary(eid INT, amount DECIMAL(10,2)) AS\n BEGIN\n UPDATE employee
SET salary=salary+amount WHERE id=eid;\n log(eid, \'raiseSalary
id=\' || eid || \' amount=\' || amount);\n END;\n\nPROCEDURE
raiseSalaryStd(eid INT) AS\n BEGIN\n raiseSalary(eid, stdRaiseAmount);\n
log(eid, \'raiseSalaryStd id=\' || eid);\n END;\n\nBEGIN\n --
This code is executed when the current session\n -- accesses any of the
package routines for the first time\n log(0, \'Session \' ||
connection_id() || \' \' || current_user || \'
started\');\nEND;\n$$\n\nDELIMITER ;\n\nURL:
https://mariadb.com/kb/en/create-package-body/','','https://mariadb.com/kb/en/create-package-body/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(710,38,'CREATE PROCEDURE','Syntax\n------\n\nCREATE\n [OR
REPLACE]\n [DEFINER = { user | CURRENT_USER | role | CURRENT_ROLE }]\n
PROCEDURE [IF NOT EXISTS] sp_name ([proc_parameter[,...]])\n
[characteristic ...] routine_body\n\nproc_parameter:\n [ IN | OUT | INOUT
] param_name type\n\ntype:\n Any valid MariaDB data
type\n\ncharacteristic:\n LANGUAGE SQL\n | [NOT] DETERMINISTIC\n | {
CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES SQL DATA }\n | SQL
SECURITY { DEFINER | INVOKER }\n | COMMENT
\'string\'\n\nroutine_body:\n Valid SQL procedure
statement\n\nDescription\n-----------\n\nCreates a stored procedure. By
default, a routine is associated with the\ndefault database. To associate
the routine explicitly with a given database,\nspecify the name as
db_name.sp_name when you create it.\n\nWhen the routine is invoked, an
implicit USE db_name is performed (and undone\nwhen the routine
terminates). The causes the routine to have the given default\ndatabase
while it executes. USE statements within stored routines
are\ndisallowed.\n\nWhen a stored procedure has been created, you invoke it
by using the CALL\nstatement (see CALL).\n\nTo execute the CREATE PROCEDURE
statement, it is necessary to have the CREATE\nROUTINE privilege. By
default, MariaDB automatically grants the ALTER ROUTINE\nand EXECUTE
privileges to the routine creator. See also Stored
Routine\nPrivileges.\n\nThe DEFINER and SQL SECURITY clauses specify the
security context to be used\nwhen checking access privileges at routine
execution time, as described here.\nRequires the SUPER privilege, or, from
MariaDB 10.5.2, the SET USER privilege.\n\nIf the routine name is the same
as the name of a built-in SQL function, you\nmust use a space between the
name and the following parenthesis when defining\nthe routine, or a syntax
error occurs. This is also true when you invoke the\nroutine later. For
this reason, we suggest that it is better to avoid re-using\nthe names of
existing SQL functions for your own stored routines.\n\nThe IGNORE_SPACE
SQL mode applies to built-in functions, not to stored\nroutines. It is
always allowable to have spaces after a routine name,\nregardless of
whether IGNORE_SPACE is enabled.\n\nThe parameter list enclosed within
parentheses must always be present. If\nthere are no parameters, an empty
parameter list of () should be used.\nParameter names are not case
sensitive.\n\nEach parameter can be declared to use any valid data type,
except that the\nCOLLATE attribute cannot be used.\n\nFor valid identifiers
to use as procedure names, see Identifier Names.\n\nThings to be Aware of
With CREATE OR REPLACE\n--------------------------------------------\n\n*
One can\'t use OR REPLACE together with IF EXISTS.\n\nCREATE PROCEDURE
IF NOT EXISTS\n------------------------------\n\nIf the IF NOT EXISTS
clause is used, then the procedure will only be created\nif a procedure
with the same name does not already exist. If the procedure\nalready
exists, then a warning will be triggered by
default.\n\nIN/OUT/INOUT\n------------\n\nEach parameter is an IN parameter
by default. To specify otherwise for a\nparameter, use the keyword OUT or
INOUT before the parameter name.\n\nAn IN parameter passes a value into a
procedure. The procedure might modify\nthe value, but the modification is
not visible to the caller when the\nprocedure returns. An OUT parameter
passes a value from the procedure back to\nthe caller. Its initial value is
NULL within the procedure, and its value is\nvisible to the caller when the
procedure returns. An INOUT parameter is\ninitialized by the caller, can be
modified by the procedure, and any change\nmade by the procedure is visible
to the caller when the procedure returns.\n\nFor each OUT or INOUT
parameter, pass a user-defined variable in the CALL\nstatement that invokes
the procedure so that you can obtain its value when the\nprocedure returns.
If you are calling the procedure from within another stored\nprocedure or
function, you can also pass a routine parameter or local routine\nvariable
as an IN or INOUT parameter.\n\nDETERMINISTIC/NOT
DETERMINISTIC\n-------------------------------\n\nDETERMINISTIC and NOT
DETERMINISTIC apply only to functions. Specifying\nDETERMINISTC or
NON-DETERMINISTIC in procedures has no effect. The default\nvalue is NOT
DETERMINISTIC. Functions are DETERMINISTIC when they always\nreturn the
same value for the same input. For example, a truncate or
substring\nfunction. Any function involving data, therefore, is always NOT
DETERMINISTIC.\n\nCONTAINS SQL/NO SQL/READS SQL DATA/MODIFIES SQL
DATA\n----------------------------------------------------\n\nCONTAINS SQL,
NO SQL, READS SQL DATA, and MODIFIES SQL DATA are informative\nclauses that
tell the server what the function does. MariaDB does not check in\nany way
whether the specified clause is correct. If none of these clauses
are\nspecified, CONTAINS SQL is used by default.\n\nMODIFIES SQL DATA means
that the function contains statements that may modify\ndata stored in
databases. This happens if the function contains statements\nlike DELETE,
UPDATE, INSERT, REPLACE or DDL.\n\nREADS SQL DATA means that the function
reads data stored in databases, but\ndoes not modify any data. This happens
if SELECT statements are used, but\nthere no write operations are
executed.\n\nCONTAINS SQL means that the function contains at least one SQL
statement, but\nit does not read or write any data stored in a database.
Examples include SET\nor DO.\n\nNO SQL means nothing, because MariaDB does
not currently support any language\nother than SQL.\n\nThe routine_body
consists of a valid SQL procedure statement. This can be a\nsimple
statement such as SELECT or INSERT, or it can be a compound
statement\nwritten using BEGIN and END. Compound statements can contain
declarations,\nloops, and other control structure statements. See
Programmatic and Compound\nStatements for syntax details.\n\nMariaDB allows
routines to contain DDL statements, such as CREATE and DROP.\nMariaDB also
allows stored procedures (but not stored functions) to contain\nSQL
transaction statements such as COMMIT.\n\nFor additional information about
statements that are not allowed in stored\nroutines, see Stored Routine
Limitations.\n\nInvoking stored procedure from within
programs\n----------------------------------------------\n\nFor information
about invoking stored procedures from within programs written\nin a
language that has a MariaDB/MySQL interface, see CALL.\n\nOR
REPLACE\n----------\n\nIf the optional OR REPLACE clause is used, it acts
as a shortcut for:\n\nDROP PROCEDURE IF EXISTS name;\nCREATE PROCEDURE name
...;\n\nwith the exception that any existing privileges for the procedure
are not\ndropped.\n\nsql_mode\n--------\n\nMariaDB stores the sql_mode
system variable setting that is in effect at the\ntime a routine is
created, and always executes the routine with this setting\nin force,
regardless of the server SQL mode in effect when the routine
is\ninvoked.\n\nCharacter Sets and
Collations\n-----------------------------\n\nProcedure parameters can be
declared with any character set/collation. If the\ncharacter set and
collation are not specifically set, the database defaults at\nthe time of
creation will be used. If the database defaults change at a later\nstage,
the stored procedure character set/collation will not be changed at
the\nsame time; the stored procedure needs to be dropped and recreated to
ensure\nthe same character set/collation as the database is used.\n\nOracle
Mode\n-----------\n\nMariaDB starting with
10.3\n--------------------------\nFrom MariaDB 10.3, a subset of
Oracle\'s PL/SQL language has been supported in\naddition to the
traditional SQL/PSM-based MariaDB syntax. See Oracle mode from\nMariaDB
10.3 for details on changes when running Oracle
mode.\n\nExamples\n--------\n\nThe following example shows a simple stored
procedure that uses an OUT\nparameter. It uses the DELIMITER command to set
a new delimiter for the\nduration of the process — see Delimiters in the
mysql client.\n\nDELIMITER //\n\nCREATE PROCEDURE simpleproc (OUT param1
INT)\n BEGIN\n SELECT COUNT(*) INTO param1 FROM t;\n END;\n//\n\nDELIMITER
;\n\nCALL simpleproc(@a);\n\nSELECT @a;\n+------+\n| @a |\n+------+\n|
1 |\n+------+\n\nCharacter set and collation:\n\nDELIMITER //\n\nCREATE
PROCEDURE simpleproc2 (\n OUT param1 CHAR(10) CHARACTER SET
\'utf8\' COLLATE \'utf8_bin\'\n)\n BEGIN\n SELECT
CONCAT(\'a\'),f1 INTO param1 FROM t;\n END;\n//\n\nDELIMITER
;\n\nCREATE OR REPLACE:\n\nDELIMITER //\n\nCREATE PROCEDURE simpleproc2 (\n
OUT param1 CHAR(10) CHARACTER SET \'utf8\' COLLATE
\'utf8_bin\'\n)\n BEGIN\n SELECT CONCAT(\'a\'),f1 INTO
param1 FROM t;\n END;\n//\nERROR 1304 (42000): PROCEDURE simpleproc2
already exists\n\nDELIMITER ;\n\nDELIMITER //\n\nCREATE OR REPLACE
PROCEDURE simpleproc2 (\n OUT param1 CHAR(10) CHARACTER SET
\'utf8\' COLLATE \'utf8_bin\'\n)\n BEGIN\n SELECT
CONCAT(\'a\'),f1 INTO param1 FROM t;\n END;\n//\nERROR 1304
(42000): PROCEDURE simpleproc2 already exists\n\nDELIMITER ;\nQuery OK, 0
rows affected (0.03 sec)\n\nURL:
https://mariadb.com/kb/en/create-procedure/','','https://mariadb.com/kb/en/create-procedure/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(711,38,'CREATE SERVER','Syntax\n------\n\nCREATE [OR
REPLACE] SERVER [IF NOT EXISTS] server_name\n FOREIGN DATA WRAPPER
wrapper_name\n OPTIONS (option [, option] ...)\n\noption:\n { HOST
character-literal\n | DATABASE character-literal\n | USER
character-literal\n | PASSWORD character-literal\n | SOCKET
character-literal\n | OWNER character-literal\n | PORT numeric-literal
}\n\nDescription\n-----------\n\nThis statement creates the definition of a
server for use with the Spider,\nConnect, FEDERATED or FederatedX storage
engine. The CREATE SERVER statement\ncreates a new row within the servers
table within the mysql database. This\nstatement requires the SUPER
privilege or, from MariaDB 10.5.2, the FEDERATED\nADMIN privilege.\n\nThe
server_name should be a unique reference to the server. Server
definitions\nare global within the scope of the server, it is not possible
to qualify the\nserver definition to a specific database. server_name has a
maximum length of\n64 characters (names longer than 64 characters are
silently truncated), and is\ncase insensitive. You may specify the name as
a quoted string.\n\nThe wrapper_name may be quoted with single quotes.
Supported values are:\n\n* mysql\n* mariadb (in MariaDB 10.3 and
later)\n\nFor each option you must specify either a character literal or
numeric\nliteral. Character literals are UTF-8, support a maximum length of
64\ncharacters and default to a blank (empty) string. String literals are
silently\ntruncated to 64 characters. Numeric literals must be a number
between 0 and\n9999, default value is 0.\n\nNote: The OWNER option is
currently not applied, and has no effect on the\nownership or operation of
the server connection that is created.\n\nThe CREATE SERVER statement
creates an entry in the mysql.servers table that\ncan later be used with
the CREATE TABLE statement when creating a Spider,\nConnect, FederatedX or
FEDERATED table. The options that you specify will be\nused to populate the
columns in the mysql.servers table. The table columns are\nServer_name,
Host, Db, Username, Password, Port and Socket.\n\nDROP SERVER removes a
previously created server definition.\n\nCREATE SERVER is not written to
the binary log, irrespective of the binary log\nformat being used. From
MariaDB 10.1.13, Galera replicates the CREATE SERVER,\nALTER SERVER and
DROP SERVER statements.\n\nFor valid identifiers to use as server names,
see Identifier Names.\n\nOR REPLACE\n----------\n\nIf the optional OR
REPLACE clause is used, it acts as a shortcut for:\n\nDROP SERVER IF EXISTS
name;\nCREATE SERVER server_name ...;\n\nIF NOT EXISTS\n-------------\n\nIf
the IF NOT EXISTS clause is used, MariaDB will return a warning instead
of\nan error if the server already exists. Cannot be used together with OR
REPLACE.\n\nExamples\n--------\n\nCREATE SERVER s\nFOREIGN DATA WRAPPER
mysql\nOPTIONS (USER \'Remote\', HOST
\'192.168.1.106\', DATABASE \'test\');\n\nOR REPLACE
and IF NOT EXISTS:\n\nCREATE SERVER s \nFOREIGN DATA WRAPPER mysql
\nOPTIONS (USER \'Remote\', HOST \'192.168.1.106\',
DATABASE \'test\');\nERROR 1476 (HY000): The foreign server, s,
you are trying to create already\nexists\n\nCREATE OR REPLACE SERVER s
\nFOREIGN DATA WRAPPER mysql \nOPTIONS (USER \'Remote\', HOST
\'192.168.1.106\', DATABASE \'test\');\nQuery OK, 0
rows affected (0.00 sec)\n\nCREATE SERVER IF NOT EXISTS s \nFOREIGN DATA
WRAPPER mysql \nOPTIONS (USER \'Remote\', HOST
\'192.168.1.106\', DATABASE \'test\');\nQuery OK, 0
rows affected, 1 warning (0.00 sec)\n\nSHOW
WARNINGS;\n+-------+------+---------------------------------------------------------------\n+\n|
Level | Code | Message
\n
|\n+-------+------+---------------------------------------------------------------\n+\n|
Note | 1476 | The foreign server, s, you are trying to create
already\nexists
|\n+-------+------+---------------------------------------------------------------\n+\n\nURL:
https://mariadb.com/kb/en/create-server/','','https://mariadb.com/kb/en/create-server/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(712,38,'CREATE TABLESPACE','The CREATE TABLESPACE statement
is not supported by MariaDB. It was originally\ninherited from MySQL NDB
Cluster. In MySQL 5.7 and later, the statement is\nalso supported for
InnoDB. However, MariaDB has chosen not to include that\nspecific feature.
See MDEV-19294 for more information.\n\nURL:
https://mariadb.com/kb/en/create-tablespace/','','https://mariadb.com/kb/en/create-tablespace/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(713,38,'CREATE TRIGGER','Syntax\n------\n\nCREATE [OR
REPLACE]\n [DEFINER = { user | CURRENT_USER | role | CURRENT_ROLE }]\n
TRIGGER [IF NOT EXISTS] trigger_name trigger_time trigger_event\n ON
tbl_name FOR EACH ROW\n [{ FOLLOWS | PRECEDES } other_trigger_name ]\n
trigger_stmt;\n\nDescription\n-----------\n\nThis statement creates a new
trigger. A trigger is a named database object\nthat is associated with a
table, and that activates when a particular event\noccurs for the table.
The trigger becomes associated with the table named\ntbl_name, which must
refer to a permanent table. You cannot associate a\ntrigger with a
TEMPORARY table or a view.\n\nCREATE TRIGGER requires the TRIGGER privilege
for the table associated with\nthe trigger.\n\nMariaDB starting with
10.2.3\n----------------------------\nYou can have multiple triggers for
the same trigger_time and trigger_event.\n\nFor valid identifiers to use as
trigger names, see Identifier Names.\n\nOR REPLACE\n----------\n\nMariaDB
starting with 10.1.4\n----------------------------\nIf used and the trigger
already exists, instead of an error being returned,\nthe existing trigger
will be dropped and replaced by the newly defined
trigger.\n\nDEFINER\n-------\n\nThe DEFINER clause determines the security
context to be used when checking\naccess privileges at trigger activation
time. Usage requires the SUPER\nprivilege, or, from MariaDB 10.5.2, the SET
USER privilege.\n\nIF NOT EXISTS\n-------------\n\nMariaDB starting with
10.1.4\n----------------------------\nIf the IF NOT EXISTS clause is used,
the trigger will only be created if a\ntrigger of the same name does not
exist. If the trigger already exists, by\ndefault a warning will be
returned.\n\ntrigger_time\n------------\n\ntrigger_time is the trigger
action time. It can be BEFORE or AFTER to indicate\nthat the trigger
activates before or after each row to be
modified.\n\ntrigger_event\n-------------\n\ntrigger_event indicates the
kind of statement that activates the trigger. The\ntrigger_event can be one
of the following:\n\n* INSERT: The trigger is activated whenever a new row
is inserted into the\ntable; for example, through INSERT, LOAD DATA, and
REPLACE statements.\n* UPDATE: The trigger is activated whenever a row is
modified; for example,\nthrough UPDATE statements.\n* DELETE: The trigger
is activated whenever a row is deleted from the table;\nfor example,
through DELETE and REPLACE statements. However, DROP TABLE and\nTRUNCATE
statements on the table do not activate this trigger, because they do\nnot
use DELETE. Dropping a partition does not activate DELETE triggers,
either.\n\nFOLLOWS/PRECEDES
other_trigger_name\n-----------------------------------\n\nMariaDB starting
with 10.2.3\n----------------------------\nThe FOLLOWS other_trigger_name
and PRECEDES other_trigger_name options were\nadded in MariaDB 10.2.3 as
part of supporting multiple triggers per action\ntime. This is the same
syntax used by MySQL 5.7, although MySQL 5.7 does not\nhave multi-trigger
support.\n\nFOLLOWS adds the new trigger after another trigger while
PRECEDES adds the new\ntrigger before another trigger. If neither option is
used, the new trigger is\nadded last for the given action and
time.\n\nFOLLOWS and PRECEDES are not stored in the trigger definition.
However the\ntrigger order is guaranteed to not change over time.
mariadb-dump/mysqldump\nand other backup methods will not change trigger
order. You can verify the\ntrigger order from the ACTION_ORDER column in
INFORMATION_SCHEMA.TRIGGERS\ntable.\n\nSELECT trigger_name, action_order
FROM information_schema.triggers \n WHERE
event_object_table=\'t1\';\n\nAtomic DDL\n----------\n\nMariaDB
starting with 10.6.1\n----------------------------\nMariaDB 10.6.1 supports
Atomic DDL and CREATE TRIGGER is atomic.\n\nExamples\n--------\n\nCREATE
DEFINER=`root`@`localhost` TRIGGER increment_animal\n AFTER INSERT ON
animals FOR EACH ROW\n UPDATE animal_count SET animal_count.animals =
animal_count.animals+1;\n\nOR REPLACE and IF NOT EXISTS\n\nCREATE
DEFINER=`root`@`localhost` TRIGGER increment_animal\n AFTER INSERT ON
animals FOR EACH ROW\n UPDATE animal_count SET animal_count.animals =
animal_count.animals+1;\nERROR 1359 (HY000): Trigger already
exists\n\nCREATE OR REPLACE DEFINER=`root`@`localhost` TRIGGER
increment_animal\n AFTER INSERT ON animals FOR EACH ROW\n UPDATE
animal_count SET animal_count.animals = animal_count.animals+1;\nQuery OK,
0 rows affected (0.12 sec)\n\nCREATE DEFINER=`root`@`localhost` TRIGGER IF
NOT EXISTS increment_animal\n AFTER INSERT ON animals FOR EACH ROW\n
UPDATE animal_count SET animal_count.animals =
animal_count.animals+1;\nQuery OK, 0 rows affected, 1 warning (0.00
sec)\n\nSHOW WARNINGS;\n+-------+------+------------------------+\n| Level
| Code | Message
|\n+-------+------+------------------------+\n| Note | 1359 | Trigger
already exists |\n+-------+------+------------------------+\n1 row in set
(0.00 sec)\n\nURL:
https://mariadb.com/kb/en/create-trigger/','','https://mariadb.com/kb/en/create-trigger/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(714,38,'CREATE VIEW','Syntax\n------\n\nCREATE\n [OR
REPLACE]\n [ALGORITHM = {UNDEFINED | MERGE | TEMPTABLE}]\n [DEFINER = {
user | CURRENT_USER | role | CURRENT_ROLE }]\n [SQL SECURITY { DEFINER |
INVOKER }]\n VIEW [IF NOT EXISTS] view_name [(column_list)]\n AS
select_statement\n [WITH [CASCADED | LOCAL] CHECK
OPTION]\n\nDescription\n-----------\n\nThe CREATE VIEW statement creates a
new view, or replaces an existing one if\nthe OR REPLACE clause is given.
If the view does not exist, CREATE OR REPLACE\nVIEW is the same as CREATE
VIEW. If the view does exist, CREATE OR REPLACE\nVIEW is the same as ALTER
VIEW.\n\nThe select_statement is a SELECT statement that provides the
definition of the\nview. (When you select from the view, you select in
effect using the SELECT\nstatement.) select_statement can select from base
tables or other views.\n\nThe view definition is \"frozen\" at
creation time, so changes to the underlying\ntables afterwards do not
affect the view definition. For example, if a view is\ndefined as SELECT *
on a table, new columns added to the table later do not\nbecome part of the
view. A SHOW CREATE VIEW shows that such queries are\nrewritten and column
names are included in the view definition.\n\nThe view definition must be a
query that does not return errors at view\ncreation times. However, the
base tables used by the views might be altered\nlater and the query may not
be valid anymore. In this case, querying the view\nwill result in an error.
CHECK TABLE helps in finding this kind of problems.\n\nThe ALGORITHM clause
affects how MariaDB processes the view. The DEFINER and\nSQL SECURITY
clauses specify the security context to be used when checking\naccess
privileges at view invocation time. The WITH CHECK OPTION clause can
be\ngiven to constrain inserts or updates to rows in tables referenced by
the\nview. These clauses are described later in this section.\n\nThe CREATE
VIEW statement requires the CREATE VIEW privilege for the view, and\nsome
privilege for each column selected by the SELECT statement. For
columns\nused elsewhere in the SELECT statement you must have the SELECT
privilege. If\nthe OR REPLACE clause is present, you must also have the
DROP privilege for\nthe view.\n\nA view belongs to a database. By default,
a new view is created in the default\ndatabase. To create the view
explicitly in a given database, specify the name\nas db_name.view_name when
you create it.\n\nCREATE VIEW test.v AS SELECT * FROM t;\n\nBase tables and
views share the same namespace within a database, so a\ndatabase cannot
contain a base table and a view that have the same name.\n\nViews must have
unique column names with no duplicates, just like base tables.\nBy default,
the names of the columns retrieved by the SELECT statement are\nused for
the view column names. To define explicit names for the view columns,\nthe
optional column_list clause can be given as a list of
comma-separated\nidentifiers. The number of names in column_list must be
the same as the number\nof columns retrieved by the SELECT
statement.\n\nMySQL until 5.1.28\n------------------\nPrior to MySQL
5.1.29, When you modify an existing view, the current view\ndefinition is
backed up and saved. It is stored in that table\'s
database\ndirectory, in a subdirectory named arc. The backup file for a
view v is named\nv.frm-00001. If you alter the view again, the next backup
is named\nv.frm-00002. The three latest view backup definitions are stored.
Backed up\nview definitions are not preserved by mysqldump, or any other
such programs,\nbut you can retain them using a file copy operation.
However, they are not\nneeded for anything but to provide you with a backup
of your previous view\ndefinition. It is safe to remove these backup
definitions, but only while\nmysqld is not running. If you delete the arc
subdirectory or its files while\nmysqld is running, you will receive an
error the next time you try to alter\nthe view:\n\nMariaDB [test]> ALTER
VIEW v AS SELECT * FROM t; \nERROR 6 (HY000): Error on delete of
\'.\\test\\arc/v.frm-0004\' (Errcode: 2)\n\nColumns retrieved by
the SELECT statement can be simple references to table\ncolumns. They can
also be expressions that use functions, constant values,\noperators, and so
forth.\n\nUnqualified table or view names in the SELECT statement are
interpreted with\nrespect to the default database. A view can refer to
tables or views in other\ndatabases by qualifying the table or view name
with the proper database name.\n\nA view can be created from many kinds of
SELECT statements. It can refer to\nbase tables or other views. It can use
joins, UNION, and subqueries. The\nSELECT need not even refer to any
tables. The following example defines a view\nthat selects two columns from
another table, as well as an expression\ncalculated from those
columns:\n\nCREATE TABLE t (qty INT, price INT);\n\nINSERT INTO t VALUES(3,
50);\n\nCREATE VIEW v AS SELECT qty, price, qty*price AS value FROM
t;\n\nSELECT * FROM v;\n+------+-------+-------+\n| qty | price | value
|\n+------+-------+-------+\n| 3 | 50 | 150
|\n+------+-------+-------+\n\nA view definition is subject to the
following restrictions:\n\n* The SELECT statement cannot contain a subquery
in the FROM clause.\n* The SELECT statement cannot refer to system or user
variables.\n* Within a stored program, the definition cannot refer to
program parameters\nor local variables.\n* The SELECT statement cannot
refer to prepared statement parameters.\n* Any table or view referred to in
the definition must exist. However, after a\nview has been created, it is
possible to drop a table or view that the\ndefinition refers to. In this
case, use of the view results in an error. To\ncheck a view definition for
problems of this kind, use the CHECK TABLE\nstatement.\n* The definition
cannot refer to a TEMPORARY table, and you cannot create a\nTEMPORARY
view.\n* Any tables named in the view definition must exist at definition
time.\n* You cannot associate a trigger with a view.\n* For valid
identifiers to use as view names, see Identifier Names.\n\nORDER BY is
allowed in a view definition, but it is ignored if you select from\na view
using a statement that has its own ORDER BY.\n\nFor other options or
clauses in the definition, they are added to the options\nor clauses of the
statement that references the view, but the effect is\nundefined. For
example, if a view definition includes a LIMIT clause, and you\nselect from
the view using a statement that has its own LIMIT clause, it is\nundefined
which limit applies. This same principle applies to options such as\nALL,
DISTINCT, or SQL_SMALL_RESULT that follow the SELECT keyword, and
to\nclauses such as INTO, FOR UPDATE, and LOCK IN SHARE MODE.\n\nThe
PROCEDURE clause cannot be used in a view definition, and it cannot
be\nused if a view is referenced in the FROM clause.\n\nIf you create a
view and then change the query processing environment by\nchanging system
variables, that may affect the results that you get from
the\nview:\n\nCREATE VIEW v (mycol) AS SELECT \'abc\';\n\nSET
sql_mode = \'\';\n\nSELECT \"mycol\" FROM
v;\n+-------+\n| mycol |\n+-------+\n| mycol | \n+-------+\n\nSET sql_mode
= \'ANSI_QUOTES\';\n\nSELECT \"mycol\" FROM
v;\n+-------+\n| mycol |\n+-------+\n| abc | \n+-------+\n\nThe DEFINER
and SQL SECURITY clauses determine which MariaDB account to use\nwhen
checking access privileges for the view when a statement is executed
that\nreferences the view. They were added in MySQL 5.1.2. The legal SQL
SECURITY\ncharacteristic values are DEFINER and INVOKER. These indicate
that the\nrequired privileges must be held by the user who defined or
invoked the view,\nrespectively. The default SQL SECURITY value is
DEFINER.\n\nIf a user value is given for the DEFINER clause, it should be a
MariaDB\naccount in \'user_name\'@\'host_name\' format
(the same format used in the GRANT\nstatement). The user_name and host_name
values both are required. The definer\ncan also be given as CURRENT_USER or
CURRENT_USER(). The default DEFINER value\nis the user who executes the
CREATE VIEW statement. This is the same as\nspecifying DEFINER =
CURRENT_USER explicitly.\n\nIf you specify the DEFINER clause, these rules
determine the legal DEFINER\nuser values:\n\n* If you do not have the SUPER
privilege, or, from MariaDB 10.5.2, the SET\nUSER privilege, the only legal
user value is your own account, either\nspecified literally or by using
CURRENT_USER. You cannot set the definer to\nsome other account.\n* If you
have the SUPER privilege, or, from MariaDB 10.5.2, the SET USER\nprivilege,
you can specify any syntactically legal account name. If the\naccount does
not actually exist, a warning is generated.\n* If the SQL SECURITY value is
DEFINER but the definer account does not exist\nwhen the view is
referenced, an error occurs.\n\nWithin a view definition, CURRENT_USER
returns the view\'s DEFINER value by\ndefault. For views defined with
the SQL SECURITY INVOKER characteristic,\nCURRENT_USER returns the account
for the view\'s invoker. For information about\nuser auditing within
views,
see\nhttp://dev.mysql.com/doc/refman/5.1/en/account-activity-auditing.html.\n\nWithin
a stored routine that is defined with the SQL SECURITY
DEFINER\ncharacteristic, CURRENT_USER returns the routine\'s DEFINER
value. This also\naffects a view defined within such a program, if the view
definition contains\na DEFINER value of CURRENT_USER.\n\nView privileges
are checked like this:\n\n* At view definition time, the view creator must
have the privileges needed to\nuse the top-level objects accessed by the
view. For example, if the view\ndefinition refers to table columns, the
creator must have privileges for the\ncolumns, as described previously. If
the definition refers to a stored\nfunction, only the privileges needed to
invoke the function can be checked.\nThe privileges required when the
function runs can be checked only as it\nexecutes: For different
invocations of the function, different execution paths\nwithin the function
might be taken.\n* When a view is referenced, privileges for objects
accessed by the view are\nchecked against the privileges held by the view
creator or invoker, depending\non whether the SQL SECURITY characteristic
is DEFINER or INVOKER, respectively.\n* If reference to a view causes
execution of a stored function, privilege\nchecking for statements executed
within the function depend on whether the\nfunction is defined with a SQL
SECURITY characteristic of DEFINER or INVOKER.\nIf the security
characteristic is DEFINER, the function runs with the\nprivileges of its
creator. If the characteristic is INVOKER, the function runs\nwith the
privileges determined by the view\'s SQL SECURITY
characteristic.\n\nExample: A view might depend on a stored function, and
that function might\ninvoke other stored routines. For example, the
following view invokes a stored\nfunction f():\n\nCREATE VIEW v AS SELECT *
FROM t WHERE t.id = f(t.name);\n\nSuppose that f() contains a statement
such as this:\n\nIF name IS NULL then\n CALL p1();\nELSE\n CALL p2();\nEND
IF;\n\nThe privileges required for executing statements within f() need to
be checked\nwhen f() executes. This might mean that privileges are needed
for p1() or\np2(), depending on the execution path within f(). Those
privileges must be\nchecked at runtime, and the user who must possess the
privileges is determined\nby the SQL SECURITY values of the view v and the
function f().\n\nThe DEFINER and SQL SECURITY clauses for views are
extensions to standard SQL.\nIn standard SQL, views are handled using the
rules for SQL SECURITY INVOKER.\n\nIf you invoke a view that was created
before MySQL 5.1.2, it is treated as\nthough it was created with a SQL
SECURITY DEFINER clause and with a DEFINER\nvalue that is the same as your
account. However, because the actual definer is\nunknown, MySQL issues a
warning. To make the warning go away, it is sufficient\nto re-create the
view so that the view definition includes a DEFINER clause.\n\nThe optional
ALGORITHM clause is an extension to standard SQL. It affects how\nMariaDB
processes the view. ALGORITHM takes three values: MERGE, TEMPTABLE,
or\nUNDEFINED. The default algorithm is UNDEFINED if no ALGORITHM clause
is\npresent. See View Algorithms for more information.\n\nSome views are
updatable. That is, you can use them in statements such as\nUPDATE, DELETE,
or INSERT to update the contents of the underlying table. For\na view to be
updatable, there must be a one-to-one relationship between the\nrows in the
view and the rows in the underlying table. There are also certain\nother
constructs that make a view non-updatable. See Inserting and Updating\nwith
Views.\n\nWITH CHECK OPTION\n-----------------\n\nThe WITH CHECK OPTION
clause can be given for an updatable view to prevent\ninserts or updates to
rows except those for which the WHERE clause in the\nselect_statement is
true.\n\nIn a WITH CHECK OPTION clause for an updatable view, the LOCAL and
CASCADED\nkeywords determine the scope of check testing when the view is
defined in\nterms of another view. The LOCAL keyword restricts the CHECK
OPTION only to\nthe view being defined. CASCADED causes the checks for
underlying views to be\nevaluated as well. When neither keyword is given,
the default is CASCADED.\n\nFor more information about updatable views and
the WITH CHECK OPTION clause,\nsee Inserting and Updating with Views.\n\nIF
NOT EXISTS\n-------------\n\nMariaDB starting with
10.1.3\n----------------------------\nThe IF NOT EXISTS clause was added in
MariaDB 10.1.3\n\nWhen the IF NOT EXISTS clause is used, MariaDB will
return a warning instead\nof an error if the specified view already exists.
Cannot be used together with\nthe OR REPLACE clause.\n\nAtomic
DDL\n----------\n\nMariaDB starting with
10.6.1\n----------------------------\nMariaDB 10.6.1 supports Atomic DDL
and CREATE VIEW is atomic.\n\nExamples\n--------\n\nCREATE TABLE t (a INT,
b INT) ENGINE = InnoDB;\n\nINSERT INTO t VALUES (1,1), (2,2),
(3,3);\n\nCREATE VIEW v AS SELECT a, a*2 AS a2 FROM t;\n\nSELECT * FROM
v;\n+------+------+\n| a | a2 |\n+------+------+\n| 1 | 2 |\n|
2 | 4 |\n| 3 | 6 |\n+------+------+\n\nOR REPLACE and IF NOT
EXISTS:\n\nCREATE VIEW v AS SELECT a, a*2 AS a2 FROM t;\nERROR 1050
(42S01): Table \'v\' already exists\n\nCREATE OR REPLACE VIEW v
AS SELECT a, a*2 AS a2 FROM t;\nQuery OK, 0 rows affected (0.04
sec)\n\nCREATE VIEW IF NOT EXISTS v AS SELECT a, a*2 AS a2 FROM t;\nQuery
OK, 0 rows affected, 1 warning (0.01
sec)\n','','https://mariadb.com/kb/en/create-view/');
update help_topic set description = CONCAT(description, '\nSHOW
WARNINGS;\n+-------+------+--------------------------+\n| Level | Code |
Message |\n+-------+------+--------------------------+\n|
Note | 1050 | Table \'v\' already exists
|\n+-------+------+--------------------------+\n\nURL:
https://mariadb.com/kb/en/create-view/') WHERE help_topic_id = 714;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(715,38,'Generated (Virtual and Persistent/Stored)
Columns','Syntax\n------\n\n<type> [GENERATED ALWAYS] AS
( <expression> )\n[VIRTUAL | PERSISTENT | STORED] [UNIQUE] [UNIQUE
KEY] [COMMENT <text>]\n\nMariaDB\'s generated columns syntax is
designed to be similar to the syntax for\nMicrosoft SQL Server\'s
computed columns and Oracle Database\'s virtual columns.\nIn MariaDB
10.2 and later, the syntax is also compatible with the syntax
for\nMySQL\'s generated columns.\n\nDescription\n-----------\n\nA
generated column is a column in a table that cannot explicitly be set to
a\nspecific value in a DML query. Instead, its value is automatically
generated\nbased on an expression. This expression might generate the value
based on the\nvalues of other columns in the table, or it might generate
the value by\ncalling built-in functions or user-defined functions
(UDFs).\n\nThere are two types of generated columns:\n\n* PERSISTENT
(a.k.a. STORED): This type\'s value is actually stored in
the\ntable.\n* VIRTUAL: This type\'s value is not stored at all.
Instead, the value is\ngenerated dynamically when the table is queried.
This type is the default.\n\nGenerated columns are also sometimes called
computed columns or virtual\ncolumns.\n\nSupported
Features\n------------------\n\nStorage Engine
Support\n----------------------\n\n* Generated columns can only be used
with storage engines which support them.\nIf you try to use a storage
engine that does not support them, then you will\nsee an error similar to
the following:\n\nERROR 1910 (HY000): TokuDB storage engine does not
support computed columns\n\n* InnoDB, Aria, MyISAM and CONNECT support
generated columns.\n\n* A column in a MERGE table can be built on a
PERSISTENT generated column.\nHowever, a column in a MERGE table can not be
defined as a VIRTUAL and\nPERSISTENT generated column.\n\nData Type
Support\n-----------------\n\n* All data types are supported when defining
generated columns.\n\n* Using the ZEROFILL column option is supported when
defining generated\ncolumns.\n\n* Using the AUTO_INCREMENT column option is
not supported when defining\ngenerated columns. Until MariaDB 10.2.25, it
was supported, but this support\nwas removed, because it would not work
correctly. See MDEV-11117.\n\nIndex Support\n-------------\n\n* Using a
generated column as a table\'s primary key is not supported.
See\nMDEV-5590 for more information. If you try to use one as a primary
key, then\nyou will see an error similar to the following:\n\nERROR 1903
(HY000): Primary key cannot be defined upon a computed column\n\n* Using
PERSISTENT generated columns as part of a foreign key is supported.\n\n*
Referencing PERSISTENT generated columns as part of a foreign key is
also\nsupported.\nHowever, using the ON UPDATE CASCADE, ON UPDATE SET NULL,
or ON DELETE SET\nNULL clauses is not supported. If you try to use an
unsupported clause, then\nyou will see an error similar to the
following:\n\nERROR 1905 (HY000): Cannot define foreign key with ON UPDATE
SET NULL clause\non a computed column\n\n* Defining indexes on both VIRTUAL
and PERSISTENT generated columns is\nsupported.\nIf an index is defined on
a generated column, then the optimizer considers\nusing it in the same way
as indexes based on \"real\" columns.\n\nStatement
Support\n-----------------\n\n* Generated columns are used in DML queries
just as if they were \"real\"\ncolumns.\nHowever, VIRTUAL and
PERSISTENT generated columns differ in how their data is\nstored.\nValues
for PERSISTENT generated columns are generated whenever a DML
queries\ninserts or updates the row with the special DEFAULT value. This
generates the\ncolumns value, and it is stored in the table like the other
\"real\" columns.\nThis value can be read by other DML queries
just like the other \"real\" columns.\nValues for VIRTUAL
generated columns are not stored in the table. Instead, the\nvalue is
generated dynamically whenever the column is queried. If other\ncolumns in
a row are queried, but the VIRTUAL generated column is not one of\nthe
queried columns, then the column\'s value is not generated.\n\n* The
SELECT statement supports generated columns.\n\n* Generated columns can be
referenced in the INSERT, UPDATE, and DELETE\nstatements.\nHowever, VIRTUAL
or PERSISTENT generated columns cannot be explicitly set to\nany other
values than NULL or DEFAULT. If a generated column is explicitly set\nto
any other value, then the outcome depends on whether strict mode is
enabled\nin sql_mode. If it is not enabled, then a warning will be raised
and the\ndefault generated value will be used instead. If it is enabled,
then an error\nwill be raised instead.\n\n* The CREATE TABLE statement has
limited support for generated columns.\nIt supports defining generated
columns in a new table.\nIt supports using generated columns to partition
tables.\nIt does not support using the versioning clauses with generated
columns.\n\n* The ALTER TABLE statement has limited support for generated
columns.\nIt supports the MODIFY and CHANGE clauses for PERSISTENT
generated columns.\nIt does not support the MODIFY clause for VIRTUAL
generated columns if\nALGORITHM is not set to COPY. See MDEV-15476 for more
information.\nIt does not support the CHANGE clause for VIRTUAL generated
columns if\nALGORITHM is not set to COPY. See MDEV-17035 for more
information.\nIt does not support altering a table if ALGORITHM is not set
to COPY if the\ntable has a VIRTUAL generated column that is indexed. See
MDEV-14046 for more\ninformation.\nIt does not support adding a VIRTUAL
generated column with the ADD clause if\nthe same statement is also adding
other columns if ALGORITHM is not set to\nCOPY. See MDEV-17468 for more
information.\nIt also does not support altering an existing column into a
VIRTUAL generated\ncolumn.\nIt supports using generated columns to
partition tables.\nIt does not support using the versioning clauses with
generated columns.\n\n* The SHOW CREATE TABLE statement supports generated
columns.\n\n* The DESCRIBE statement can be used to check whether a table
has generated\ncolumns.\nYou can tell which columns are generated by
looking for the ones where the\nExtra column is set to either VIRTUAL or
PERSISTENT. For example:\n\nDESCRIBE
table1;\n+-------+-------------+------+-----+---------+------------+\n|
Field | Type | Null | Key | Default | Extra
|\n+-------+-------------+------+-----+---------+------------+\n| a |
int(11) | NO | | NULL | |\n| b | varchar(32) |
YES | | NULL | |\n| c | int(11) | YES | |
NULL | VIRTUAL |\n| d | varchar(5) | YES | | NULL |
PERSISTENT
|\n+-------+-------------+------+-----+---------+------------+\n\n*
Generated columns can be properly referenced in the NEW and OLD rows
in\ntriggers.\n\n* Stored procedures support generated columns.\n\n* The
HANDLER statement supports generated columns.\n\nExpression
Support\n------------------\n\n* Most legal, deterministic expressions
which can be calculated are supported\nin expressions for generated
columns.\n\n* Most built-in functions are supported in expressions for
generated columns.\nHowever, some built-in functions can\'t be
supported for technical reasons. For\nexample, If you try to use an
unsupported function in an expression, an error\nis generated similar to
the following:\n\nERROR 1901 (HY000): Function or expression
\'dayname()\' cannot be used in the\nGENERATED ALWAYS AS clause
of `v`\n\n* Subqueries are not supported in expressions for generated
columns because\nthe underlying data can change.\n\n* Using anything that
depends on data outside the row is not supported in\nexpressions for
generated columns.\n\n* Stored functions are not supported in expressions
for generated columns. See\nMDEV-17587 for more information.\n\n*
Non-deterministic built-in functions are supported in expressions for
not\nindexed VIRTUAL generated columns.\n\n* Non-deterministic built-in
functions are not supported in expressions for\nPERSISTENT or indexed
VIRTUAL generated columns.\n\n* User-defined functions (UDFs) are supported
in expressions for generated\ncolumns.\nHowever, MariaDB can\'t check
whether a UDF is deterministic, so it is up to\nthe user to be sure that
they do not use non-deterministic UDFs with VIRTUAL\ngenerated
columns.\n\n* Defining a generated column based on other generated columns
defined before\nit in the table definition is supported. For
example:\n\nCREATE TABLE t1 (a int as (1), b int as (a));\n\n* However,
defining a generated column based on other generated columns\ndefined after
in the table definition is not supported in expressions for\ngeneration
columns because generated columns are calculated in the order they\nare
defined.\n\n* Using an expression that exceeds 255 characters in length is
supported in\nexpressions for generated columns. The new limit for the
entire table\ndefinition, including all expressions for generated columns,
is 65,535 bytes.\n\n* Using constant expressions is supported in
expressions for generated\ncolumns. For example:\n\nCREATE TABLE t1 (a int
as (1));\n\nMaking Stored Values
Consistent\n-------------------------------\n\nWhen a generated column is
PERSISTENT or indexed, the value of the expression\nneeds to be consistent
regardless of the SQL Mode flags in the current\nsession. If it is not,
then the table will be seen as corrupted when the value\nthat should
actually be returned by the computed expression and the value that\nwas
previously stored and/or indexed using a different sql_mode
setting\ndisagree.\n\nThere are currently two affected classes of
inconsistencies: character padding\nand unsigned subtraction:\n\n* For a
VARCHAR or TEXT generated column the length of the value returned can\nvary
depending on the PAD_CHAR_TO_FULL_LENGTH sql_mode flag. To make the\nvalue
consistent, create the generated column using an RTRIM() or
RPAD()\nfunction. Alternately, create the generated column as a CHAR
column so that\nits data is always fully padded.\n\n* If a SIGNED generated
column is based on the subtraction of an UNSIGNED\nvalue, the resulting
value can vary depending on how large the value is and\nthe
NO_UNSIGNED_SUBTRACTION sql_mode flag. To make the value consistent,
use\nCAST() to ensure that each UNSIGNED operand is SIGNED before the
subtraction.\n\nMariaDB starting with
10.5\n--------------------------\nBeginning in MariaDB 10.5, there is a
fatal error generated when trying to\ncreate a generated column whose value
can change depending on the SQL Mode\nwhen its data is PERSISTENT or
indexed.\n\nFor an existing generated column that has a potentially
inconsistent value, a\nwarning about a bad expression is generated the
first time it is used (if\nwarnings are enabled).\n\nBeginning in MariaDB
10.4.8, MariaDB 10.3.18, and MariaDB 10.2.27 a\npotentially inconsistent
generated column outputs a warning when created or\nfirst used (without
restricting their creation).\n\nHere is an example of two tables that would
be rejected in MariaDB 10.5 and\nwarned about in the other listed
versions:\n\nCREATE TABLE bad_pad (\n txt CHAR(5),\n -- CHAR -> VARCHAR
or CHAR -> TEXT can\'t be persistent or indexed:\n vtxt VARCHAR(5)
AS (txt) PERSISTENT\n);\n\nCREATE TABLE bad_sub (\n num1 BIGINT UNSIGNED,\n
num2 BIGINT UNSIGNED,\n -- The resulting value can vary for some large
values\n vnum BIGINT AS (num1 - num2) VIRTUAL,\n KEY(vnum)\n);\n\nThe
warnings for the above tables look like this:\n\nWarning (Code 1901):
Function or expression \'`txt`\' cannot be used in the\nGENERATED
ALWAYS AS clause of `vtxt`\nWarning (Code 1105): Expression depends on the
@@sql_mode value\nPAD_CHAR_TO_FULL_LENGTH\n\nWarning (Code 1901): Function
or expression \'`num1` - `num2`\' cannot be used\nin the
GENERATED ALWAYS AS clause of `vnum`\nWarning (Code 1105): Expression
depends on the @@sql_mode value\nNO_UNSIGNED_SUBTRACTION\n\nTo work around
the issue, force the padding or type to make the generated\ncolumn\'s
expression return a consistent value. For example:\n\nCREATE TABLE good_pad
(\n txt CHAR(5),\n -- Using RTRIM() or RPAD() makes the value consistent:\n
vtxt VARCHAR(5) AS (RTRIM(txt)) PERSISTENT,\n -- When not persistent or
indexed, it is OK for the value to vary by mode:\n vtxt2 VARCHAR(5) AS
(txt) VIRTUAL,\n -- CHAR -> CHAR is always OK:\n txt2 CHAR(5) AS (txt)
PERSISTENT\n);\n\nCREATE TABLE good_sub (\n num1 BIGINT UNSIGNED,\n num2
BIGINT UNSIGNED,\n -- The indexed value will always be consistent in this
expression:\n vnum BIGINT AS (CAST(num1 AS SIGNED) - CAST(num2 AS SIGNED))
VIRTUAL,\n KEY(vnum)\n);\n\nMySQL Compatibility
Support\n---------------------------\n\n* The STORED keyword is supported
as an alias for the PERSISTENT keyword.\n\n* Tables created with MySQL 5.7
or later that contain MySQL\'s generated\ncolumns can be imported into
MariaDB without a dump and restore.\n\nImplementation
Differences\n--------------------------\n\nGenerated columns are subject to
various constraints in other DBMSs that are\nnot present in MariaDB\'s
implementation. Generated columns may also be called\ncomputed columns or
virtual columns in different implementations. The various\ndetails for a
specific implementation can be found in the documentation for\neach
specific DBMS.\n\nImplementation Differences Compared to Microsoft SQL
Server\n-----------------------------------------------------------\n\nMariaDB\'s
generated columns implementation does not enforce the
following\nrestrictions that are present in Microsoft SQL Server\'s
computed columns\nimplementation:\n\n* MariaDB allows server variables in
generated column expressions, including\nthose that change dynamically,
such as warning_count.\n* MariaDB allows the CONVERT_TZ() function to be
called with a named time zone\nas an argument, even though time zone names
and time offsets are configurable.\n* MariaDB allows the CAST() function to
be used with non-unicode character\nsets, even though character sets are
configurable and differ between\nbinaries/versions.\n* MariaDB allows FLOAT
expressions to be used in generated columns. Microsoft\nSQL Server
considers these expressions to be \"imprecise\" due to
potential\ncross-platform differences in floating-point implementations and
precision.\n* Microsoft SQL Server requires the ARITHABORT mode to be set,
so that\ndivision by zero returns an error, and not a NULL.\n* Microsoft
SQL Server requires QUOTED_IDENTIFIER to be set in sql_mode. In\nMariaDB,
if data is inserted without ANSI_QUOTES set in sql_mode, then it
will','','https://mariadb.com/kb/en/generated-columns/');
update help_topic set description = CONCAT(description, '\nbe
processed and stored differently in a generated column that contains
quoted\nidentifiers.\n\nMicrosoft SQL Server enforces the above
restrictions by doing one of the\nfollowing things:\n\n* Refusing to create
computed columns.\n* Refusing to allow updates to a table containing
them.\n* Refusing to use an index over such a column if it can not be
guaranteed that\nthe expression is fully deterministic.\n\nIn MariaDB, as
long as the sql_mode, language, and other settings that were in\neffect
during the CREATE TABLE remain unchanged, the generated column\nexpression
will always be evaluated the same. If any of these things change,\nthen
please be aware that the generated column expression might not
be\nevaluated the same way as it previously was.\n\nIf you try to update a
virtual column, you will get an error if the default\nstrict mode is
enabled in sql_mode, or a warning otherwise.\n\nDevelopment
History\n-------------------\n\nGenerated columns was originally developed
by Andrey Zhakov. It was then\nmodified by Sanja Byelkin and Igor Babaev at
Monty Program for inclusion in\nMariaDB. Monty did the work on MariaDB 10.2
to lift a some of the old\nlimitations.\n\nExamples\n--------\n\nHere is an
example table that uses both VIRTUAL and PERSISTENT virtual columns:\n\nUSE
TEST;\n\nCREATE TABLE table1 (\n a INT NOT NULL,\n b VARCHAR(32),\n c
INT AS (a mod 10) VIRTUAL,\n d VARCHAR(5) AS (left(b,5))
PERSISTENT);\n\nIf you describe the table, you can easily see which columns
are virtual by\nlooking in the \"Extra\" column:\n\nDESCRIBE
table1;\n+-------+-------------+------+-----+---------+------------+\n|
Field | Type | Null | Key | Default | Extra
|\n+-------+-------------+------+-----+---------+------------+\n| a |
int(11) | NO | | NULL | |\n| b | varchar(32) |
YES | | NULL | |\n| c | int(11) | YES | |
NULL | VIRTUAL |\n| d | varchar(5) | YES | | NULL |
PERSISTENT
|\n+-------+-------------+------+-----+---------+------------+\n\nTo find
out what function(s) generate the value of the virtual column you can\nuse
SHOW CREATE TABLE:\n\nSHOW CREATE TABLE table1;\n\n| table1 | CREATE TABLE
`table1` (\n `a` int(11) NOT NULL,\n `b` varchar(32) DEFAULT NULL,\n `c`
int(11) AS (a mod 10) VIRTUAL,\n `d` varchar(5) AS (left(b,5))
PERSISTENT\n) ENGINE=MyISAM DEFAULT CHARSET=latin1 |\n\nIf you try to
insert non-default values into a virtual column, you will\nreceive a
warning and what you tried to insert will be ignored and the derived\nvalue
inserted instead:\n\nWARNINGS;\nShow warnings enabled.\n\nINSERT INTO
table1 VALUES (1, \'some text\',default,default);\nQuery OK, 1
row affected (0.00 sec)\n\nINSERT INTO table1 VALUES (2, \'more
text\',5,default);\nQuery OK, 1 row affected, 1 warning (0.00
sec)\n\nWarning (Code 1645): The value specified for computed column
\'c\' in table\n\'table1\' has been ignored.\n\nINSERT
INTO table1 VALUES (123, \'even more
text\',default,\'something\');\nQuery OK, 1 row affected, 2
warnings (0.00 sec)\n\nWarning (Code 1645): The value specified for
computed column \'d\' in table\n\'table1\' has been
ignored.\nWarning (Code 1265): Data truncated for column \'d\' at
row 1\n\nSELECT * FROM table1;\n+-----+----------------+------+-------+\n|
a | b | c | d
|\n+-----+----------------+------+-------+\n| 1 | some text | 1 |
some |\n| 2 | more text | 2 | more |\n| 123 | even more text |
3 | even |\n+-----+----------------+------+-------+\n3 rows in set (0.00
sec)\n\nIf the ZEROFILL clause is specified, it should be placed directly
after the\ntype definition, before the AS (<expression>):\n\nCREATE
TABLE table2 (a INT, b INT ZEROFILL AS (a*2) VIRTUAL);\nINSERT INTO table2
(a) VALUES (1);\n\nSELECT * FROM table2;\n+------+------------+\n| a | b
|\n+------+------------+\n| 1 | 0000000002
|\n+------+------------+\n1 row in set (0.00 sec)\n\nYou can also use
virtual columns to implement a \"poor man\'s partial
index\".\nSee example at the end of Unique Index.\n\nURL:
https://mariadb.com/kb/en/generated-columns/') WHERE help_topic_id =
715;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(716,38,'Invisible Columns','MariaDB starting with
10.3.3\n----------------------------\nInvisible columns (sometimes also
called hidden columns) first appeared in\nMariaDB 10.3.3.\n\nColumns can be
given an INVISIBLE attribute in a CREATE TABLE or ALTER TABLE\nstatement.
These columns will then not be listed in the results of a SELECT
*\nstatement, nor do they need to be assigned a value in an INSERT
statement,\nunless INSERT explicitly mentions them by name.\n\nSince SELECT
* does not return the invisible columns, new tables or views\ncreated in
this manner will have no trace of the invisible columns. If\nspecifically
referenced in the SELECT statement, the columns will be brought\ninto the
view/new table, but the INVISIBLE attribute will not.\n\nInvisible columns
can be declared as NOT NULL, but then require a DEFAULT\nvalue.\n\nIt is
not possible for all columns in a table to be
invisible.\n\nExamples\n--------\n\nCREATE TABLE t (x INT
INVISIBLE);\nERROR 1113 (42000): A table must have at least 1
column\n\nCREATE TABLE t (x INT, y INT INVISIBLE, z INT INVISIBLE NOT
NULL);\nERROR 4106 (HY000): Invisible column `z` must have a default
value\n\nCREATE TABLE t (x INT, y INT INVISIBLE, z INT INVISIBLE NOT NULL
DEFAULT 4);\n\nINSERT INTO t VALUES (1),(2);\n\nINSERT INTO t (x,y) VALUES
(3,33);\n\nSELECT * FROM t;\n+------+\n| x |\n+------+\n| 1 |\n| 2
|\n| 3 |\n+------+\n\nSELECT x,y,z FROM t;\n+------+------+---+\n| x
| y | z |\n+------+------+---+\n| 1 | NULL | 4 |\n| 2 | NULL | 4
|\n| 3 | 33 | 4 |\n+------+------+---+\n\nDESC
t;\n+-------+---------+------+-----+---------+-----------+\n| Field | Type
| Null | Key | Default | Extra
|\n+-------+---------+------+-----+---------+-----------+\n| x |
int(11) | YES | | NULL | |\n| y | int(11) | YES |
| NULL | INVISIBLE |\n| z | int(11) | NO | | 4 |
INVISIBLE
|\n+-------+---------+------+-----+---------+-----------+\n\nALTER TABLE t
MODIFY x INT INVISIBLE, MODIFY y INT, MODIFY z INT NOT NULL\nDEFAULT
4;\n\nDESC t;\n+-------+---------+------+-----+---------+-----------+\n|
Field | Type | Null | Key | Default | Extra
|\n+-------+---------+------+-----+---------+-----------+\n| x |
int(11) | YES | | NULL | INVISIBLE |\n| y | int(11) | YES |
| NULL | |\n| z | int(11) | NO | | 4 |
|\n+-------+---------+------+-----+---------+-----------+\n\nCreating a
view from a table with hidden columns:\n\nCREATE VIEW v1 AS SELECT * FROM
t;\n\nDESC v1;\n+-------+---------+------+-----+---------+-------+\n| Field
| Type | Null | Key | Default | Extra
|\n+-------+---------+------+-----+---------+-------+\n| y | int(11) |
YES | | NULL | |\n| z | int(11) | NO | | 4 |
|\n+-------+---------+------+-----+---------+-------+\n\nCREATE VIEW
v2 AS SELECT x,y,z FROM t;\n\nDESC
v2;\n+-------+---------+------+-----+---------+-------+\n| Field | Type
| Null | Key | Default | Extra
|\n+-------+---------+------+-----+---------+-------+\n| x | int(11) |
YES | | NULL | |\n| y | int(11) | YES | | NULL |
|\n| z | int(11) | NO | | 4 |
|\n+-------+---------+------+-----+---------+-------+\n\nAdding a Surrogate
Primary Key:\n\ncreate table t1 (x bigint unsigned not null, y varchar(16),
z text);\n\ninsert into t1 values (123, \'qq11\',
\'ipsum\');\n\ninsert into t1 values (123, \'qq22\',
\'lorem\');\n\nalter table t1 add pkid serial primary key
invisible first;\n\ninsert into t1 values (123, \'qq33\',
\'amet\');\n\nselect * from t1;\n+-----+------+-------+\n| x |
y | z |\n+-----+------+-------+\n| 123 | qq11 | ipsum |\n| 123 |
qq22 | lorem |\n| 123 | qq33 | amet |\n+-----+------+-------+\n\nselect
pkid, z from t1;\n+------+-------+\n| pkid | z |\n+------+-------+\n|
1 | ipsum |\n| 2 | lorem |\n| 3 | amet |\n+------+-------+\n\nURL:
https://mariadb.com/kb/en/invisible-columns/','','https://mariadb.com/kb/en/invisible-columns/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(717,38,'DROP DATABASE','Syntax\n------\n\nDROP {DATABASE |
SCHEMA} [IF EXISTS] db_name\n\nDescription\n-----------\n\nDROP DATABASE
drops all tables in the database and deletes the database. Be\nvery careful
with this statement! To use DROP DATABASE, you need the DROP\nprivilege on
the database. DROP SCHEMA is a synonym for DROP DATABASE.\n\nImportant:
When a database is dropped, user privileges on the database are
not\nautomatically dropped. See GRANT.\n\nIF EXISTS\n---------\n\nUse IF
EXISTS to prevent an error from occurring for databases that do not\nexist.
A NOTE is generated for each non-existent database when using IF\nEXISTS.
See SHOW WARNINGS.\n\nAtomic DDL\n----------\n\nMariaDB starting with
10.6.1\n----------------------------\nMariaDB 10.6.1 supports Atomic
DDL.\n\nDROP DATABASE is implemented as\n\nloop over all tables\n DROP
TABLE table\n\nEach individual DROP TABLE is atomic while DROP DATABASE as
a whole is\ncrash-safe.\n\nExamples\n--------\n\nDROP DATABASE bufg;\nQuery
OK, 0 rows affected (0.39 sec)\n\nDROP DATABASE bufg;\nERROR 1008 (HY000):
Can\'t drop database \'bufg\'; database doesn\'t
exist\n\n\\W\nShow warnings enabled.\n\nDROP DATABASE IF EXISTS
bufg;\nQuery OK, 0 rows affected, 1 warning (0.00 sec)\nNote (Code 1008):
Can\'t drop database \'bufg\'; database doesn\'t
exist\n\nURL:
https://mariadb.com/kb/en/drop-database/','','https://mariadb.com/kb/en/drop-database/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(718,38,'DROP EVENT','Syntax\n------\n\nDROP EVENT [IF
EXISTS] event_name\n\nDescription\n-----------\n\nThis statement drops the
event named event_name. The event immediately ceases\nbeing active, and is
deleted completely from the server.\n\nIf the event does not exist, the
error ERROR 1517 (HY000): Unknown event\n\'event_name\' results.
You can override this and cause the statement to\ngenerate a NOTE for
non-existent events instead by using IF EXISTS. See SHOW\nWARNINGS.\n\nThis
statement requires the EVENT privilege. In MySQL 5.1.11 and earlier,
an\nevent could be dropped only by its definer, or by a user having the
SUPER\nprivilege.\n\nExamples\n--------\n\nDROP EVENT myevent3;\n\nUsing
the IF EXISTS clause:\n\nDROP EVENT IF EXISTS myevent3;\nQuery OK, 0 rows
affected, 1 warning (0.01 sec)\n\nSHOW
WARNINGS;\n+-------+------+-------------------------------+\n| Level | Code
| Message
|\n+-------+------+-------------------------------+\n| Note | 1305 | Event
myevent3 does not exist
|\n+-------+------+-------------------------------+\n\nURL:
https://mariadb.com/kb/en/drop-event/','','https://mariadb.com/kb/en/drop-event/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(719,38,'DROP FUNCTION','Syntax\n------\n\nDROP FUNCTION [IF
EXISTS] f_name\n\nDescription\n-----------\n\nThe DROP FUNCTION statement
is used to drop a stored function or a\nuser-defined function (UDF). That
is, the specified routine is removed from\nthe server, along with all
privileges specific to the function. You must have\nthe ALTER ROUTINE
privilege for the routine in order to drop it. If
the\nautomatic_sp_privileges server system variable is set, both the ALTER
ROUTINE\nand EXECUTE privileges are granted automatically to the routine
creator - see\nStored Routine Privileges.\n\nIF EXISTS\n---------\n\nThe IF
EXISTS clause is a MySQL/MariaDB extension. It prevents an error
from\noccurring if the function does not exist. A NOTE is produced that can
be\nviewed with SHOW WARNINGS.\n\nFor dropping a user-defined functions
(UDF), see DROP FUNCTION UDF.\n\nExamples\n--------\n\nDROP FUNCTION
hello;\nQuery OK, 0 rows affected (0.042 sec)\n\nDROP FUNCTION
hello;\nERROR 1305 (42000): FUNCTION test.hello does not exist\n\nDROP
FUNCTION IF EXISTS hello;\nQuery OK, 0 rows affected, 1 warning (0.000
sec)\n\nSHOW
WARNINGS;\n+-------+------+------------------------------------+\n| Level |
Code | Message
|\n+-------+------+------------------------------------+\n| Note | 1305 |
FUNCTION test.hello does not exist
|\n+-------+------+------------------------------------+\n\nURL:
https://mariadb.com/kb/en/drop-function/','','https://mariadb.com/kb/en/drop-function/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(720,38,'DROP INDEX','Syntax\n------\n\nDROP INDEX [IF
EXISTS] index_name ON tbl_name \n [WAIT n
|NOWAIT]\n\nDescription\n-----------\n\nDROP INDEX drops the index named
index_name from the table tbl_name. This\nstatement is mapped to an ALTER
TABLE statement to drop the index.\n\nIf another connection is using the
table, a metadata lock is active, and this\nstatement will wait until the
lock is released. This is also true for\nnon-transactional tables.\n\nSee
ALTER TABLE.\n\nAnother shortcut, CREATE INDEX, allows the creation of an
index.\n\nTo remove the primary key, `PRIMARY` must be specified as
index_name. Note\nthat the quotes are necessary, because PRIMARY is a
keyword.\n\nPrivileges\n----------\n\nExecuting the DROP INDEX statement
requires the INDEX privilege for the table\nor the database.\n\nOnline
DDL\n----------\n\nOnline DDL is used by default with InnoDB, when the drop
index operation\nsupports it.\n\nSee InnoDB Online DDL Overview for more
information on online DDL with InnoDB.\n\nDROP INDEX IF EXISTS
...\n------------------------\n\nIf the IF EXISTS clause is used, then
MariaDB will return a warning instead of\nan error if the index does not
exist.\n\nWAIT/NOWAIT\n-----------\n\nMariaDB starting with
10.3.0\n----------------------------\nSet the lock wait timeout. See WAIT
and NOWAIT.\n\nProgress Reporting\n------------------\n\nMariaDB provides
progress reporting for DROP INDEX statement for clients that\nsupport the
new progress reporting protocol. For example, if you were using\nthe mysql
client, then the progress report might look like this::\n\nURL:
https://mariadb.com/kb/en/drop-index/','','https://mariadb.com/kb/en/drop-index/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(721,38,'DROP PACKAGE','MariaDB starting with
10.3.5\n----------------------------\nOracle-style packages were introduced
in MariaDB 10.3.5.\n\nSyntax\n------\n\nDROP PACKAGE [IF EXISTS] [ db_name
. ] package_name\n\nDescription\n-----------\n\nThe DROP PACKAGE statement
can be used when Oracle SQL_MODE is set.\n\nThe DROP PACKAGE statement
drops a stored package entirely:\n\n* Drops the package specification
(earlier created using the CREATE PACKAGE\nstatement).\n* Drops the package
implementation, if the implementation was already created\nusing the CREATE
PACKAGE BODY statement.\n\nURL:
https://mariadb.com/kb/en/drop-package/','','https://mariadb.com/kb/en/drop-package/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(722,38,'DROP PACKAGE BODY','MariaDB starting with
10.3.5\n----------------------------\nOracle-style packages were introduced
in MariaDB 10.3.5.\n\nSyntax\n------\n\nDROP PACKAGE BODY [IF EXISTS] [
db_name . ] package_name\n\nDescription\n-----------\n\nThe DROP PACKAGE
BODY statement can be used when Oracle SQL_MODE is set.\n\nThe DROP PACKAGE
BODY statement drops the package body (i.e the\nimplementation), previously
created using the CREATE PACKAGE BODY statement.\n\nNote, DROP PACKAGE BODY
drops only the package implementation, but does not\ndrop the package
specification. Use DROP PACKAGE to drop the package entirely\n(i.e. both
implementation and specification).\n\nURL:
https://mariadb.com/kb/en/drop-package-body/','','https://mariadb.com/kb/en/drop-package-body/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(723,38,'DROP PROCEDURE','Syntax\n------\n\nDROP PROCEDURE
[IF EXISTS] sp_name\n\nDescription\n-----------\n\nThis statement is used
to drop a stored procedure. That is, the specified\nroutine is removed from
the server along with all privileges specific to the\nprocedure. You must
have the ALTER ROUTINE privilege for the routine. If
the\nautomatic_sp_privileges server system variable is set, that privilege
and\nEXECUTE are granted automatically to the routine creator - see Stored
Routine\nPrivileges.\n\nThe IF EXISTS clause is a MySQL/MariaDB extension.
It prevents an error from\noccurring if the procedure or function does not
exist. A NOTE is produced that\ncan be viewed with SHOW WARNINGS.\n\nWhile
this statement takes effect immediately, threads which are executing
a\nprocedure can continue execution.\n\nExamples\n--------\n\nDROP
PROCEDURE simpleproc;\n\nIF EXISTS:\n\nDROP PROCEDURE simpleproc;\nERROR
1305 (42000): PROCEDURE test.simpleproc does not exist\n\nDROP PROCEDURE IF
EXISTS simpleproc;\nQuery OK, 0 rows affected, 1 warning (0.00 sec)\n\nSHOW
WARNINGS;\n+-------+------+------------------------------------------+\n|
Level | Code | Message
|\n+-------+------+------------------------------------------+\n| Note |
1305 | PROCEDURE test.simpleproc does not exist
|\n+-------+------+------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/drop-procedure/','','https://mariadb.com/kb/en/drop-procedure/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(724,38,'DROP SERVER','Syntax\n------\n\nDROP SERVER [ IF
EXISTS ] server_name\n\nDescription\n-----------\n\nDrops the server
definition for the server named server_name. The\ncorresponding row within
the mysql.servers table will be deleted. This\nstatement requires the SUPER
privilege or, from MariaDB 10.5.2, the FEDERATED\nADMIN
privilege.\n\nDropping a server for a table does not affect any FederatedX,
FEDERATED,\nConnect or Spider tables that used this connection information
when they were\ncreated.\n\nDROP SERVER is not written to the binary log,
irrespective of the binary log\nformat being used. From MariaDB 10.1.13,
Galera replicates the CREATE SERVER,\nALTER SERVER and DROP SERVER
statements.\n\nIF EXISTS\n---------\n\nIf the IF EXISTS clause is used,
MariaDB will not return an error if the\nserver does not exist. Unlike all
other statements, DROP SERVER IF EXISTS does\nnot issue a note if the
server does not exist. See MDEV-9400.\n\nExamples\n--------\n\nDROP SERVER
s;\n\nIF EXISTS:\n\nDROP SERVER s;\nERROR 1477 (HY000): The foreign server
name you are trying to reference \n does not exist. Data source error:
s\n\nDROP SERVER IF EXISTS s;\nQuery OK, 0 rows affected (0.00 sec)\n\nURL:
https://mariadb.com/kb/en/drop-server/','','https://mariadb.com/kb/en/drop-server/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(725,38,'DROP TABLESPACE','The DROP TABLESPACE statement is
not supported by MariaDB. It was originally\ninherited from MySQL NDB
Cluster. In MySQL 5.7 and later, the statement is\nalso supported for
InnoDB. However, MariaDB has chosen not to include that\nspecific feature.
See MDEV-19294 for more information.\n\nURL:
https://mariadb.com/kb/en/drop-tablespace/','','https://mariadb.com/kb/en/drop-tablespace/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(726,38,'DROP TRIGGER','Syntax\n------\n\nDROP TRIGGER [IF
EXISTS] [schema_name.]trigger_name\n\nDescription\n-----------\n\nThis
statement drops a trigger. The schema (database) name is optional. If
the\nschema is omitted, the trigger is dropped from the default schema. Its
use\nrequires the TRIGGER privilege for the table associated with the
trigger.\n\nUse IF EXISTS to prevent an error from occurring for a trigger
that does not\nexist. A NOTE is generated for a non-existent trigger when
using IF EXISTS.\nSee SHOW WARNINGS.\n\nNote: Triggers for a table are also
dropped if you drop the table.\n\nAtomic DDL\n----------\n\nMariaDB
starting with 10.6.1\n----------------------------\nMariaDB 10.6.1 supports
Atomic DDL and DROP TRIGGER is atomic.\n\nExamples\n--------\n\nDROP
TRIGGER test.example_trigger;\n\nUsing the IF EXISTS clause:\n\nDROP
TRIGGER IF EXISTS test.example_trigger;\nQuery OK, 0 rows affected, 1
warning (0.01 sec)\n\nSHOW
WARNINGS;\n+-------+------+------------------------+\n| Level | Code |
Message |\n+-------+------+------------------------+\n| Note
| 1360 | Trigger does not exist
|\n+-------+------+------------------------+\n\nURL:
https://mariadb.com/kb/en/drop-trigger/','','https://mariadb.com/kb/en/drop-trigger/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(727,38,'DROP VIEW','Syntax\n------\n\nDROP VIEW [IF
EXISTS]\n view_name [, view_name] ...\n [RESTRICT |
CASCADE]\n\nDescription\n-----------\n\nDROP VIEW removes one or more
views. You must have the DROP privilege for each\nview. If any of the views
named in the argument list do not exist, MariaDB\nreturns an error
indicating by name which non-existing views it was unable to\ndrop, but it
also drops all of the views in the list that do exist.\n\nThe IF EXISTS
clause prevents an error from occurring for views that don\'t\nexist.
When this clause is given, a NOTE is generated for each non-existent\nview.
See SHOW WARNINGS.\n\nRESTRICT and CASCADE, if given, are parsed and
ignored.\n\nIt is possible to specify view names as db_name.view_name. This
is useful to\ndelete views from multiple databases with one statement. See
Identifier\nQualifiers for details.\n\nThe DROP privilege is required to
use DROP TABLE on non-temporary tables. For\ntemporary tables, no privilege
is required, because such tables are only\nvisible for the current
session.\n\nIf a view references another view, it will be possible to drop
the referenced\nview. However, the other view will reference a view which
does not exist any\nmore. Thus, querying it will produce an error similar
to the following:\n\nERROR 1356 (HY000): View
\'db_name.view_name\' references invalid table(s) or \ncolumn(s)
or function(s) or definer/invoker of view lack rights to use them\n\nThis
problem is reported in the output of CHECK TABLE.\n\nNote that it is not
necessary to use DROP VIEW to replace an existing view,\nbecause CREATE
VIEW has an OR REPLACE clause.\n\nAtomic DDL\n----------\n\nMariaDB
starting with 10.6.1\n----------------------------\nMariaDB 10.6.1 supports
Atomic DDL and DROP VIEW for a singular view is\natomic. Dropping multiple
views is crash-safe.\n\nExamples\n--------\n\nDROP VIEW v,v2;\n\nGiven
views v and v2, but no view v3\n\nDROP VIEW v,v2,v3;\nERROR 1051 (42S02):
Unknown table \'v3\'\n\nDROP VIEW IF EXISTS v,v2,v3;\nQuery OK, 0
rows affected, 1 warning (0.01 sec)\n\nSHOW
WARNINGS;\n+-------+------+-------------------------+\n| Level | Code |
Message |\n+-------+------+-------------------------+\n|
Note | 1051 | Unknown table \'test.v3\'
|\n+-------+------+-------------------------+\n\nURL:
https://mariadb.com/kb/en/drop-view/','','https://mariadb.com/kb/en/drop-view/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(728,38,'CONSTRAINT','MariaDB supports the implementation of
constraints at the table-level using\neither CREATE TABLE or ALTER TABLE
statements. A table constraint restricts\nthe data you can add to the
table. If you attempt to insert invalid data on a\ncolumn, MariaDB throws
an error.\n\nSyntax\n------\n\n[CONSTRAINT [symbol]]
constraint_expression\n\nconstraint_expression:\n | PRIMARY KEY
[index_type] (index_col_name, ...) [index_option] ...\n | FOREIGN KEY
[index_name] (index_col_name, ...)\n REFERENCES tbl_name (index_col_name,
...)\n [ON DELETE reference_option]\n [ON UPDATE reference_option]\n |
UNIQUE [INDEX|KEY] [index_name]\n [index_type] (index_col_name, ...)
[index_option] ...\n | CHECK (check_constraints)\n\nindex_type:\n USING
{BTREE | HASH | RTREE}\n\nindex_col_name:\n col_name [(length)] [ASC |
DESC]\n\nindex_option:\n | KEY_BLOCK_SIZE [=] value\n | index_type\n | WITH
PARSER parser_name\n | COMMENT \'string\'\n |
CLUSTERING={YES|NO}\n\nreference_option:\n RESTRICT | CASCADE | SET NULL |
NO ACTION | SET DEFAULT\n\nDescription\n-----------\n\nConstraints provide
restrictions on the data you can add to a table. This\nallows you to
enforce data integrity from MariaDB, rather than through\napplication
logic. When a statement violates a constraint, MariaDB throws
an\nerror.\n\nThere are four types of table
constraints:\n\n+------------------------------------+---------------------------------------+\n|
Constraint | Description
|\n+------------------------------------+---------------------------------------+\n|
PRIMARY KEY | Sets the column for referencing
|\n| | rows. Values must be unique and
not |\n| | null.
|\n+------------------------------------+---------------------------------------+\n|
FOREIGN KEY | Sets the column to reference the
|\n| | primary key on another table.
|\n+------------------------------------+---------------------------------------+\n|
UNIQUE | Requires values in column or columns
|\n| | only occur once in the table.
|\n+------------------------------------+---------------------------------------+\n|
CHECK | Checks whether the data meets the
|\n| | given condition.
|\n+------------------------------------+---------------------------------------+\n\nThe
Information Schema TABLE_CONSTRAINTS Table contains information
about\ntables that have constraints.\n\nFOREIGN KEY
Constraints\n-----------------------\n\nInnoDB supports foreign key
constraints. The syntax for a foreign key\nconstraint definition in InnoDB
looks like this:\n\n[CONSTRAINT [symbol]] FOREIGN KEY\n [index_name]
(index_col_name, ...)\n REFERENCES tbl_name (index_col_name,...)\n [ON
DELETE reference_option]\n [ON UPDATE
reference_option]\n\nreference_option:\n RESTRICT | CASCADE | SET NULL |
NO ACTION\n\nThe Information Schema REFERENTIAL_CONSTRAINTS table has more
information\nabout foreign keys.\n\nCHECK
Constraints\n-----------------\n\nMariaDB starting with
10.2.1\n----------------------------\nFrom MariaDB 10.2.1, constraints are
enforced. Before MariaDB 10.2.1\nconstraint expressions were accepted in
the syntax but ignored.\n\nIn MariaDB 10.2.1 you can define constraints in
2 different ways:\n\n* CHECK(expression) given as part of a column
definition.\n* CONSTRAINT [constraint_name] CHECK (expression)\n\nBefore a
row is inserted or updated, all constraints are evaluated in the\norder
they are defined. If any constraint expression returns false, then the\nrow
will not be inserted or updated. One can use most deterministic
functions\nin a constraint, including UDFs.\n\nCREATE TABLE t1 (a INT CHECK
(a>2), b INT CHECK (b>2), CONSTRAINT a_greater\nCHECK
(a>b));\n\nIf you use the second format and you don\'t give a name
to the constraint, then\nthe constraint will get an automatically generated
name. This is done so that\nyou can later delete the constraint with ALTER
TABLE DROP constraint_name.\n\nOne can disable all constraint expression
checks by setting the\ncheck_constraint_checks variable to OFF. This is
useful for example when\nloading a table that violates some constraints
that you want to later find and\nfix in
SQL.\n\nReplication\n-----------\n\nIn row-based replication, only the
master checks constraints, and failed\nstatements will not be replicated.
In statement-based replication, the slaves\nwill also check constraints.
Constraints should therefore be identical, as\nwell as deterministic, in a
replication environment.\n\nAuto_increment\n--------------\n\nMariaDB
starting with 10.2.6\n----------------------------\n* From MariaDB 10.2.6,
auto_increment columns are no longer permitted in check\nconstraints.
Previously they were permitted, but would not work correctly.
See\nMDEV-11117.\n\nExamples\n--------\n\nCREATE TABLE product (category
INT NOT NULL, id INT NOT NULL,\n price DECIMAL,\n
PRIMARY KEY(category, id)) ENGINE=INNODB;\nCREATE TABLE customer (id INT
NOT NULL,\n PRIMARY KEY (id)) ENGINE=INNODB;\nCREATE TABLE
product_order (no INT NOT NULL AUTO_INCREMENT,\n
product_category INT NOT NULL,\n product_id INT NOT NULL,\n
customer_id INT NOT NULL,\n PRIMARY KEY(no),\n
INDEX (product_category, product_id),\n FOREIGN KEY
(product_category, product_id)\n REFERENCES product(category,
id)\n ON UPDATE CASCADE ON DELETE RESTRICT,\n
INDEX (customer_id),\n FOREIGN KEY (customer_id)\n
REFERENCES customer(id)) ENGINE=INNODB;\n\nMariaDB starting with
10.2.1\n----------------------------\nThe following examples will work from
MariaDB 10.2.1 onwards.\n\nNumeric constraints and comparisons:\n\nCREATE
TABLE t1 (a INT CHECK (a>2), b INT CHECK (b>2), CONSTRAINT
a_greater\nCHECK (a>b));\n\nINSERT INTO t1(a) VALUES (1);\nERROR 4022
(23000): CONSTRAINT `a` failed for `test`.`t1`\n\nINSERT INTO t1(a,b)
VALUES (3,4);\nERROR 4022 (23000): CONSTRAINT `a_greater` failed for
`test`.`t1`\n\nINSERT INTO t1(a,b) VALUES (4,3);\nQuery OK, 1 row affected
(0.04 sec)\n\nDropping a constraint:\n\nALTER TABLE t1 DROP CONSTRAINT
a_greater;\n\nAdding a constraint:\n\nALTER TABLE t1 ADD CONSTRAINT
a_greater CHECK (a>b);\n\nDate comparisons and character
length:\n\nCREATE TABLE t2 (name VARCHAR(30) CHECK
(CHAR_LENGTH(name)>2), start_date\nDATE, \n end_date DATE CHECK
(start_date IS NULL OR end_date IS NULL
OR\nstart_date<end_date));\n\nINSERT INTO t2(name, start_date, end_date)
VALUES(\'Ione\',
\'2003-12-15\',\n\'2014-11-09\');\nQuery OK, 1 row
affected (0.04 sec)\n\nINSERT INTO t2(name, start_date, end_date)
VALUES(\'Io\',
\'2003-12-15\',\n\'2014-11-09\');\nERROR 4022 (23000):
CONSTRAINT `name` failed for `test`.`t2`\n\nINSERT INTO t2(name,
start_date, end_date) VALUES(\'Ione\', NULL,
\'2014-11-09\');\nQuery OK, 1 row affected (0.04 sec)\n\nINSERT
INTO t2(name, start_date, end_date) VALUES(\'Ione\',
\'2015-12-15\',\n\'2014-11-09\');\nERROR 4022 (23000):
CONSTRAINT `end_date` failed for `test`.`t2`\n\nA misplaced
parenthesis:\n\nCREATE TABLE t3 (name VARCHAR(30) CHECK
(CHAR_LENGTH(name>2)), start_date\nDATE, \n end_date DATE CHECK
(start_date IS NULL OR end_date IS NULL
OR\nstart_date<end_date));\nQuery OK, 0 rows affected (0.32
sec)\n\nINSERT INTO t3(name, start_date, end_date) VALUES(\'Io\',
\'2003-12-15\',\n\'2014-11-09\');\nQuery OK, 1 row
affected, 1 warning (0.04 sec)\n\nSHOW
WARNINGS;\n+---------+------+----------------------------------------+\n|
Level | Code | Message
|\n+---------+------+----------------------------------------+\n| Warning |
1292 | Truncated incorrect DOUBLE value: \'Io\'
|\n+---------+------+----------------------------------------+\n\nCompare
the definition of table t2 to table t3. CHAR_LENGTH(name)>2 is
very\ndifferent to CHAR_LENGTH(name>2) as the latter mistakenly performs
a numeric\ncomparison on the name field, leading to unexpected
results.\n\nURL:
https://mariadb.com/kb/en/constraint/','','https://mariadb.com/kb/en/constraint/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(729,38,'Dynamic Columns','Dynamic columns allow one to
store different sets of columns for each row in a\ntable. It works by
storing a set of columns in a blob and having a small set\nof functions to
manipulate it. Dynamic columns should be used when it is not\npossible to
use regular columns. A typical use case is when one needs to store\nitems
that may have many different attributes (like size, color, weight,
etc),\nand the set of possible attributes is very large and/or unknown in
advance. In\nthat case, attributes can be put into dynamic
columns.\n\nDynamic Columns Basics\n----------------------\n\nThe table
should have a blob column which will be used as storage for
dynamic\ncolumns:\n\ncreate table assets (\n item_name varchar(32) primary
key, -- A common attribute for all items\n dynamic_cols blob -- Dynamic
columns will be stored here\n);\n\nOnce created, one can access dynamic
columns via dynamic column functions:\n\nInsert a row with two dynamic
columns: color=blue, size=XL\n\nINSERT INTO assets VALUES \n
(\'MariaDB T-shirt\', COLUMN_CREATE(\'color\',
\'blue\', \'size\', \'XL\'));\n\nInsert
another row with dynamic columns: color=black, price=500\n\nINSERT INTO
assets VALUES\n (\'Thinkpad Laptop\',
COLUMN_CREATE(\'color\', \'black\',
\'price\', 500));\n\nSelect dynamic column \'color\'
for all items:\n\nSELECT item_name, COLUMN_GET(dynamic_cols,
\'color\' as char) \n AS color FROM
assets;\n+-----------------+-------+\n| item_name | color
|\n+-----------------+-------+\n| MariaDB T-shirt | blue |\n| Thinkpad
Laptop | black |\n+-----------------+-------+\n\nIt is possible to add and
remove dynamic columns from a row:\n\n-- Remove a column:\nUPDATE assets
SET dynamic_cols=COLUMN_DELETE(dynamic_cols, \"price\") \nWHERE
COLUMN_GET(dynamic_cols, \'color\' as
char)=\'black\';\n\n-- Add a column:\nUPDATE assets SET
dynamic_cols=COLUMN_ADD(dynamic_cols, \'warranty\', \'3
years\')\nWHERE item_name=\'Thinkpad Laptop\';\n\nYou can
also list all columns, or get them together with their values in
JSON\nformat:\n\nSELECT item_name, column_list(dynamic_cols) FROM
assets;\n+-----------------+---------------------------+\n| item_name
| column_list(dynamic_cols)
|\n+-----------------+---------------------------+\n| MariaDB T-shirt |
`size`,`color` |\n| Thinkpad Laptop | `color`,`warranty`
|\n+-----------------+---------------------------+\n\nSELECT item_name,
COLUMN_JSON(dynamic_cols) FROM
assets;\n+-----------------+----------------------------------------+\n|
item_name | COLUMN_JSON(dynamic_cols)
|\n+-----------------+----------------------------------------+\n| MariaDB
T-shirt |
{\"size\":\"XL\",\"color\":\"blue\"}
|\n| Thinkpad Laptop |
{\"color\":\"black\",\"warranty\":\"3
years\"}
|\n+-----------------+----------------------------------------+\n\nDynamic
Columns Reference\n-------------------------\n\nThe rest of this page is a
complete reference of dynamic columns in MariaDB\n\nDynamic Columns
Functions\n-------------------------\n\nCOLUMN_CREATE\n-------------\n\nCOLUMN_CREATE(column_nr,
value [as type], [column_nr, value \n [as
type]]...);\nCOLUMN_CREATE(column_name, value [as type], [column_name,
value \n [as type]]...);\n\nReturn a dynamic columns blob that stores the
specified columns with values.\n\nThe return value is suitable for\n\n*
\nstoring in a table\nfurther modification with other dynamic columns
functions\n\nThe as type part allows one to specify the value type. In most
cases, this is\nredundant because MariaDB will be able to deduce the type
of the value.\nExplicit type specification may be needed when the type of
the value is not\napparent. For example, a literal \'2012-12-01\'
has a CHAR type by default, one\nwill need to specify
\'2012-12-01\' AS DATE to have it stored as a date. See
the\nDatatypes section for further details. Note also MDEV-597.\n\nTypical
usage:\n\n-- MariaDB 5.3+:\nINSERT INTO tbl SET dyncol_blob=COLUMN_CREATE(1
/*column id*/, \"value\");\n-- MariaDB 10.0.1+:\nINSERT INTO tbl
SET dyncol_blob=COLUMN_CREATE(\"column_name\",
\"value\");\n\nCOLUMN_ADD\n----------\n\nCOLUMN_ADD(dyncol_blob,
column_nr, value [as type], \n [column_nr, value [as
type]]...);\nCOLUMN_ADD(dyncol_blob, column_name, value [as type], \n
[column_name, value [as type]]...);\n\nAdds or updates dynamic
columns.\n\n* \ndyncol_blob must be either a valid dynamic columns blob
(for example,\nCOLUMN_CREATE returns such blob), or an empty
string.\ncolumn_name specifies the name of the column to be added. If
dyncol_blob\nalready has a column with this name, it will be
overwritten.\nvalue specifies the new value for the column. Passing a NULL
value will cause\nthe column to be deleted.\nas type is optional. See
#datatypes section for a discussion about types.\n\nThe return value is a
dynamic column blob after the modifications.\n\nTypical usage:\n\n--
MariaDB 5.3+:\nUPDATE tbl SET dyncol_blob=COLUMN_ADD(dyncol_blob, 1
/*column id*/, \"value\") \n WHERE id=1;\n-- MariaDB
10.0.1+:\nUPDATE t1 SET dyncol_blob=COLUMN_ADD(dyncol_blob,
\"column_name\", \"value\") \n WHERE id=1;\n\nNote:
COLUMN_ADD() is a regular function (just like CONCAT()), hence, in
order\nto update the value in the table you have to use the UPDATE ...
SET\ndynamic_col=COLUMN_ADD(dynamic_col, ....)
pattern.\n\nCOLUMN_GET\n----------\n\nCOLUMN_GET(dyncol_blob, column_nr as
type);\nCOLUMN_GET(dyncol_blob, column_name as type);\n\nGet the value of a
dynamic column by its name. If no column with the given\nname exists, NULL
will be returned.\n\ncolumn_name as type requires that one specify the
datatype of the dynamic\ncolumn they are reading.\n\nThis may seem
counter-intuitive: why would one need to specify which
datatype\nthey\'re retrieving? Can\'t the dynamic columns system
figure the datatype from\nthe data being stored?\n\nThe answer is: SQL is a
statically-typed language. The SQL interpreter needs\nto know the datatypes
of all expressions before the query is run (for example,\nwhen one is using
prepared statements and runs \"select COLUMN_GET(...)\",
the\nprepared statement API requires the server to inform the client about
the\ndatatype of the column being read before the query is executed and the
server\ncan see what datatype the column actually has).\n\nSee the
Datatypes section for more information about
datatypes.\n\nCOLUMN_DELETE\n-------------\n\nCOLUMN_DELETE(dyncol_blob,
column_nr, column_nr...);\nCOLUMN_DELETE(dyncol_blob, column_name,
column_name...);\n\nDelete a dynamic column with the specified name.
Multiple names can be given.\n\nThe return value is a dynamic column blob
after the
modification.\n\nCOLUMN_EXISTS\n-------------\n\nCOLUMN_EXISTS(dyncol_blob,
column_nr);\nCOLUMN_EXISTS(dyncol_blob, column_name);\n\nCheck if a column
with name column_name exists in dyncol_blob. If yes, return\n1, otherwise
return
0.\n\nCOLUMN_LIST\n-----------\n\nCOLUMN_LIST(dyncol_blob);\n\nReturn a
comma-separated list of column names. The names are quoted
with\nbackticks.\n\nSELECT
column_list(column_create(\'col1\',\'val1\',\'col2\',\'val2\'));\n+---------------------------------------------------------+\n|
column_list(column_create(\'col1\',\'val1\',\'col2\',\'val2\'))
|\n+---------------------------------------------------------+\n|
`col1`,`col2`
|\n+---------------------------------------------------------+\n\nCOLUMN_CHECK\n------------\n\nCOLUMN_CHECK(dyncol_blob);\n\nCheck
if dyncol_blob is a valid packed dynamic columns blob. Return value of
1\nmeans the blob is valid, return value of 0 means it is
not.\n\nRationale: Normally, one works with valid dynamic column blobs.
Functions like\nCOLUMN_CREATE, COLUMN_ADD, COLUMN_DELETE always return
valid dynamic column\nblobs. However, if a dynamic column blob is
accidentally truncated, or\ntranscoded from one character set to another,
it will be corrupted. This\nfunction can be used to check if a value in a
blob field is a valid dynamic\ncolumn blob.\n\nNote: It is possible that a
truncation cut a Dynamic Column \"clearly\" so that\nCOLUMN_CHECK
will not notice the corruption, but in any case of truncation a\nwarning is
issued during value
storing.\n\nCOLUMN_JSON\n-----------\n\nCOLUMN_JSON(dyncol_blob);\n\nReturn
a JSON representation of data in dyncol_blob.\n\nExample:\n\nSELECT
item_name, COLUMN_JSON(dynamic_cols) FROM
assets;\n+-----------------+----------------------------------------+\n|
item_name | COLUMN_JSON(dynamic_cols)
|\n+-----------------+----------------------------------------+\n| MariaDB
T-shirt |
{\"size\":\"XL\",\"color\":\"blue\"}
|\n| Thinkpad Laptop |
{\"color\":\"black\",\"warranty\":\"3
years\"}
|\n+-----------------+----------------------------------------+\n\nLimitation:
COLUMN_JSON will decode nested dynamic columns at a nesting level\nof not
more than 10 levels deep. Dynamic columns that are nested deeper than\n10
levels will be shown as BINARY string, without encoding.\n\nNesting Dynamic
Columns\n-----------------------\n\nIt is possible to use nested dynamic
columns by putting one dynamic column\nblob inside another. The COLUMN_JSON
function will display nested columns.\n\nSET @tmp=
column_create(\'parent_column\', \n
column_create(\'child_column\', 12345));\nQuery OK, 0 rows
affected (0.00 sec)\n\nSELECT
column_json(@tmp);\n+------------------------------------------+\n|
column_json(@tmp)
|\n+------------------------------------------+\n|
{\"parent_column\":{\"child_column\":12345}}
|\n+------------------------------------------+\n\nSELECT
column_get(column_get(@tmp, \'parent_column\' AS char), \n
\'child_column\' AS
int);\n+------------------------------------------------------------------------------\n\n|
column_get(column_get(@tmp, \'parent_column\' as char),
\'child_column\' as
int)\n|\n+------------------------------------------------------------------------------\n\n|
12345\n|\n+------------------------------------------------------------------------------\n\nIf
you are trying to get a nested dynamic column as a string use \'as
BINARY\'\nas the last argument of COLUMN_GET (otherwise problems with
character set\nconversion and illegal symbols are possible):\n\nselect
column_json( column_get(\n column_create(\'test1\',\n
column_create(\'key1\',\'value1\',\'key2\',\'value2\',\'key3\',\'value3\')),\n
\'test1\' as BINARY));\n\nDatatypes\n---------\n\nIn SQL, one
needs to define the type of each column in a table. Dynamic\ncolumns do not
provide any way to declare a type in advance (\"whenever there\nis a
column \'weight\', it should be integer\" is not possible).
However, each\nparticular dynamic column value is stored together with its
datatype.\n\nThe set of possible datatypes is mostly the same as that used
by the SQL CAST\nand CONVERT functions. However, note that there are
currently some differences\n- see
MDEV-597.\n\n+--------+----------------------------------------------+-------------------+\n|
type | dynamic column internal type | description
|\n+--------+----------------------------------------------+-------------------+\n|
BINARY | DYN_COL_STRING | (variable length
|\n| (N)] | | string with
|\n| | | binary
charset)
|\n+--------+----------------------------------------------+-------------------+\n|
CHAR[( | DYN_COL_STRING | (variable length
|\n| )] | | string with
|\n| | | charset)
|\n+--------+----------------------------------------------+-------------------+\n|
DATE | DYN_COL_DATE | (date - 3 bytes)
|\n+--------+----------------------------------------------+-------------------+\n|
DATETI | DYN_COL_DATETIME | (date and time
|\n| E[(D)] | | (with
|\n| | |
microseconds) - |\n| |
| 9 bytes)
|\n+--------+----------------------------------------------+-------------------+\n|
DECIMA | DYN_COL_DECIMAL | (variable length
|\n| [(M[,D | | binary decimal
|\n| )] | |
representation |\n| |
| with MariaDB |\n| |
| limitation)
|\n+--------+----------------------------------------------+-------------------+\n|
DOUBLE | DYN_COL_DOUBLE | (64 bit
|\n| (M,D)] | |
double-precision |\n| |
| floating point)
|\n+--------+----------------------------------------------+-------------------+\n|
INTEGE | DYN_COL_INT | (variable
|\n| | | length, up to
64 |\n| | | bit signed
|\n| | |
integer)
|\n+--------+----------------------------------------------+-------------------+\n|
SIGNED | DYN_COL_INT | (variable
|\n| [INTEG | | length, up to
64 |\n| R] | | bit signed
|\n| | |
integer)
|\n+--------+----------------------------------------------+-------------------+\n|
TIME[( | DYN_COL_TIME | (time (with
|\n| )] | | microseconds,
|\n| | | may be
negative) |\n| | | - 6
bytes)
|\n+--------+----------------------------------------------+-------------------+\n|
UNSIGN | DYN_COL_UINT | (variable
|\n| D | | length, up to
|','','https://mariadb.com/kb/en/dynamic-columns/');
update help_topic set description = CONCAT(description, '\n| [INTEG |
| 64bit unsigned |\n| R]
| | integer)
|\n+--------+----------------------------------------------+-------------------+\n\nA
Note About Lengths\n--------------------\n\nIf you\'re running queries
like\n\nSELECT COLUMN_GET(blob, \'colname\' as CHAR)
...\n\nwithout specifying a maximum length (i.e. using #as CHAR#, not as
CHAR(n)),\nMariaDB will report the maximum length of the resultset column
to be\n53,6870,911 (bytes or characters?) for MariaDB 5.3-10.0.0 and
16,777,216 for\nMariaDB 10.0.1+. This may cause excessive memory usage in
some client\nlibraries, because they try to pre-allocate a buffer of
maximum resultset\nwidth. If you suspect you\'re hitting this problem,
use CHAR(n) whenever you\'re\nusing COLUMN_GET in the select
list.\n\nMariaDB 5.3 vs MariaDB 10.0\n---------------------------\n\nThe
dynamic columns feature was introduced into MariaDB in two steps:\n\n*
MariaDB 5.3 was the first version to support dynamic columns. Only
numbers\n could be used as column names in this version.\n* In MariaDB
10.0.1, column names can be either numbers or strings.\n Also, the
COLUMN_JSON and COLUMN_CHECK functions were added.\n\nSee also Dynamic
Columns in MariaDB 10.\n\nClient-side API\n---------------\n\nIt is also
possible to create or parse dynamic columns blobs on the client\nside.
libmysql client library now includes an API for writing/reading
dynamic\ncolumn blobs. See dynamic-columns-api for
details.\n\nLimitations\n-----------\n\n+---------------------------------------------------+------------------------+\n|
Description | Limit
|\n+---------------------------------------------------+------------------------+\n|
Max number of columns | 65535
|\n+---------------------------------------------------+------------------------+\n|
Max total length of packed dynamic column | max_allowed_packet
|\n| | (1G)
|\n+---------------------------------------------------+------------------------+\n\nURL:
https://mariadb.com/kb/en/dynamic-columns/') WHERE help_topic_id =
729;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(730,38,'Dynamic Columns from MariaDB 10','MariaDB starting
with 10.0.1\n----------------------------\nMariaDB 10.0.1 introduced the
following improvements to the dynamic columns\nfeature.\n\nColumn Name
Support\n-------------------\n\nIt is possible to refer to column by names.
Names can be used everywhere where\nin MariaDB 5.3 one could use only
strings:\n\n* Create a dynamic column
blob:\n\nCOLUMN_CREATE(\'int_col\', 123 as int,
\'double_col\', 3.14 as double,\n\'string_col\',
\'text-data\' as char);\n\n* Set a column
value:\n\nCOLUMN_ADD(dyncol_blob, \'intcol\', 1234);\n\n* Get a
column value:\n\nCOLUMN_GET(dynstr, \'column1\' as
char(10));\n\n* Check whether a column exists\n\nCOLUMN_EXISTS(dyncol_blob,
\'column_name\');\n\nChanges in
Behavior\n-------------------\n\n* Column list output now includes
quoting:\n\nselect column_list(column_create(1, 22, 2,
23));\n+------------------------------------------+\n|
column_list(column_create(1, 22, 2, 23))
|\n+------------------------------------------+\n| `1`,`2`
|\n+------------------------------------------+\nselect
column_list(column_create(\'column1\', 22, \'column2\',
23)); \n+----------------------------------------------------------+\n|
column_list(column_create(\'column1\', 22, \'column2\',
23)) |\n+----------------------------------------------------------+\n|
`column1`,`column2`
|\n+----------------------------------------------------------+\n\n* Column
name interpretation has been changed so that the string now is
not\nconverted to a number. So some \"magic\" tricks will not
work any more, for\nexample, \"1test\" and \"1\" now
become different column names:\n\nselect
column_list(column_add(column_create(\'1a\', 22),
\'1b\',
23));\n+------------------------------------------------------------+\n|
column_list(column_add(column_create(\'1a\', 22),
\'1b\', 23))
|\n+------------------------------------------------------------+\n|
`1a`,`1b`
|\n+------------------------------------------------------------+\n\n* Old
behavior:\n\nselect column_list(column_add(column_create(\'1a\',
22), \'1b\',
23));\n+------------------------------------------------------------+\n|
column_list(column_add(column_create(\'1a\', 22),
\'1b\', 23))
|\n+------------------------------------------------------------+\n| 1
|\n+------------------------------------------------------------+\n\nNew
Functions\n-------------\n\nThe following new functions have been added to
dynamic columns in MariaDB 10\n\nCOLUMN_CHECK\n------------\n\nCOLUMN_CHECK
is used to check a column\'s integrity. When it encounters an\nerror
it does not return illegal format errors but returns false instead.
It\nalso checks integrity more thoroughly and finds errors in the dynamic
column\ninternal structures which might not be found by other
functions.\n\nselect column_check(column_create(\'column1\',
22));\n+--------------------------------------------+\n|
column_check(column_create(\'column1\', 22))
|\n+--------------------------------------------+\n|
1
|\n+--------------------------------------------+\nselect
column_check(\'abracadabra\');\n+-----------------------------+\n|
column_check(\'abracadabra\')
|\n+-----------------------------+\n| 0
|\n+-----------------------------+\n\nCOLUMN_JSON\n-----------\n\nCOLUMN_JSON
converts all dynamic column record content to a JSON object.\n\nselect
column_json(column_create(\'column1\', 1, \'column2\',
\"two\"));\n+------------------------------------------------------------+\n|
column_json(column_create(\'column1\', 1, \'column2\',
\"two\"))
|\n+------------------------------------------------------------+\n|
{\"column1\":1,\"column2\":\"two\"}
|\n+------------------------------------------------------------+\n\nOther
Changes\n-------------\n\n* All API functions has prefix mariadb_dyncol_
(old prefix dynamic_column_ is\ndepricated\n* API changed to be able to
work with the new format (*_named functions).\n* Removed
\'delete\' function because deleting could be done by adding
NULL\nvalue.\n* \'Time\' and \'datetime\' in the new
format are stored without microseconds if\nthey are 0.\n* New function
added to API (except that two which are representing SQL
level\nfunctions):\n\'Unpack\' the dynamic columns content to an
arrays of values and names.\n3 functions to get any column value as string,
integer (long long) or floating\npoint (double).\n\n* New type of
\"dynamic column\" row added on the API level (in SQL level
output\nit is a string but if you use dynamic column functions to construct
object it\nwill be added as dynamic column value) which allow to add
dynamic columns\ninside dynamic columns. JSON function represent such
recursive constructions\ncorrectly but limit depth of representation as
current implementation limit\n(internally depth of dynamic columns
embedding is not limited).\n\nInterface with
Cassandra\n------------------------\n\nCassandraSE is no longer actively
being developed and has been removed in\nMariaDB 10.6. See
MDEV-23024.\n\nSome internal changes were added to dynamic columns to allow
them to serve as\nan interface to Apache Cassandra dynamic columns. The
Cassandra engine may\npack all columns which were not mentioned in the
MariaDB interface table\ndefinition and even bring changes in the dynamic
column contents back to the\ncassandra columns family (the table analog in
cassandra).\n\nURL:
https://mariadb.com/kb/en/dynamic-columns-from-mariadb-10/','','https://mariadb.com/kb/en/dynamic-columns-from-mariadb-10/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(731,38,'MERGE','Description\n-----------\n\nThe MERGE
storage engine, also known as the MRG_MyISAM engine, is a collection\nof
identical MyISAM tables that can be used as one. \"Identical\"
means that all\ntables have identical column and index information. You
cannot merge MyISAM\ntables in which the columns are listed in a different
order, do not have\nexactly the same columns, or have the indexes in
different order. However, any\nor all of the MyISAM tables can be
compressed with myisampack. Columns names\nand indexes names can be
different, as long as data types and NULL/NOT NULL\nclauses are the same.
Differences in table options such as AVG_ROW_LENGTH,\nMAX_ROWS, or
PACK_KEYS do not matter.\n\nEach index in a MERGE table must match an index
in underlying MyISAM tables,\nbut the opposite is not true. Also, a MERGE
table cannot have a PRIMARY KEY or\nUNIQUE indexes, because it cannot
enforce uniqueness over all underlying\ntables.\n\nThe following options
are meaningful for MERGE tables:\n\n* UNION. This option specifies the list
of the underlying MyISAM tables. The\nlist is enclosed between parentheses
and separated with commas.\n* INSERT_METHOD. This options specifies
whether, and how, INSERTs are allowed\nfor the table. Allowed values are:
NO (INSERTs are not allowed), FIRST (new\nrows will be written into the
first table specified in the UNION list), LAST\n(new rows will be written
into the last table specified in the UNION list).\nThe default value is
NO.\n\nIf you define a MERGE table with a definition which is different
from the\nunderlying MyISAM tables, or one of the underlying tables is not
MyISAM, the\nCREATE TABLE statement will not return any error. But any
statement which\ninvolves the table will produce an error like the
following:\n\nERROR 1168 (HY000): Unable to open underlying table which is
differently\ndefined \n or of non-MyISAM type or doesn\'t exist\n\nA
CHECK TABLE will show more information about the problem.\n\nThe error is
also produced if the table is properly define, but an
underlying\ntable\'s definition changes at some point in time.\n\nIf
you try to insert a new row into a MERGE table with INSERT_METHOD=NO,
you\nwill get an error like the following:\n\nERROR 1036 (HY000): Table
\'tbl_name\' is read only\n\nIt is possible to build a MERGE
table on MyISAM tables which have one or more\nvirtual columns. MERGE
itself does not support virtual columns, thus such\ncolumns will be seen as
regular columns. The data types and sizes will still\nneed to be identical,
and they cannot be NOT NULL.\n\nExamples\n--------\n\nCREATE TABLE t1 (\n
a INT NOT NULL AUTO_INCREMENT PRIMARY KEY,\n message CHAR(20))
ENGINE=MyISAM;\n\nCREATE TABLE t2 (\n a INT NOT NULL AUTO_INCREMENT
PRIMARY KEY,\n message CHAR(20)) ENGINE=MyISAM;\n\nINSERT INTO t1
(message) VALUES
(\'Testing\'),(\'table\'),(\'t1\');\n\nINSERT
INTO t2 (message) VALUES
(\'Testing\'),(\'table\'),(\'t2\');\n\nCREATE
TABLE total (\n a INT NOT NULL AUTO_INCREMENT,\n message CHAR(20),
INDEX(a))\n ENGINE=MERGE UNION=(t1,t2) INSERT_METHOD=LAST;\n\nSELECT *
FROM total;\n+---+---------+\n| a | message |\n+---+---------+\n| 1 |
Testing |\n| 2 | table |\n| 3 | t1 |\n| 1 | Testing |\n| 2 | table
|\n| 3 | t2 |\n+---+---------+\n\nIn the following example,
we\'ll create three MyISAM tables, and then a MERGE\ntable on them.
However, one of them uses a different data type for the column\nb, so a
SELECT will produce an error:\n\nCREATE TABLE t1 (\n a INT,\n b INT\n)
ENGINE = MyISAM;\n\nCREATE TABLE t2 (\n a INT,\n b INT\n) ENGINE =
MyISAM;\n\nCREATE TABLE t3 (\n a INT,\n b TINYINT\n) ENGINE =
MyISAM;\n\nCREATE TABLE t_mrg (\n a INT,\n b INT\n) ENGINE =
MERGE,UNION=(t1,t2,t3);\n\nSELECT * FROM t_mrg;\nERROR 1168 (HY000): Unable
to open underlying table which is differently\ndefined\n or of non-MyISAM
type or doesn\'t exist\n\nTo find out what\'s wrong, we\'ll
use a CHECK TABLE:\n\nCHECK TABLE t_mrg\\G\n*************************** 1.
row ***************************\n Table: test.t_mrg\n Op:
check\nMsg_type: Error\nMsg_text: Table \'test.t3\' is
differently defined or of non-MyISAM type or\ndoesn\'t
exist\n*************************** 2. row ***************************\n
Table: test.t_mrg\n Op: check\nMsg_type: Error\nMsg_text: Unable to open
underlying table which is differently defined or of\nnon-MyISAM type or
doesn\'t exist\n*************************** 3. row
***************************\n Table: test.t_mrg\n Op: check\nMsg_type:
error\nMsg_text: Corrupt\n\nNow, we know that the problem is in t3\'s
definition.\n\nURL:
https://mariadb.com/kb/en/merge/','','https://mariadb.com/kb/en/merge/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(732,39,'Sequence Overview','MariaDB starting with
10.3\n--------------------------\nSequences were introduced in MariaDB
10.3.\n\nIntroduction\n------------\n\nA sequence is an object that
generates a sequence of numeric values, as\nspecified by the CREATE
SEQUENCE statement.\n\nCREATE SEQUENCE will create a sequence that
generates new values when called\nwith NEXT VALUE FOR sequence_name.
It\'s an alternative to AUTO INCREMENT when\none wants to have more
control of how the numbers are generated. As the\nSEQUENCE caches values
(up to the CACHE value in the CREATE SEQUENCE\nstatement, by default 1000)
it can in some cases be much faster than AUTO\nINCREMENT. Another benefit
is that one can access the last value generated by\nall used sequences,
which solves one of the limitations with LAST_INSERT_ID().\n\nCreating a
Sequence\n-------------------\n\nThe CREATE SEQUENCE statement is used to
create a sequence. Here is an example\nof a sequence starting at 100,
incrementing by 10 each time:\n\nCREATE SEQUENCE s START WITH 100 INCREMENT
BY 10;\n\nThe CREATE SEQUENCE statement, along with defaults, can be viewd
with the SHOW\nCREATE SEQUENCE STATEMENT, for example:\n\nSHOW CREATE
SEQUENCE s\\G\n*************************** 1. row
***************************\n Table: s\nCreate Table: CREATE SEQUENCE `s`
start with 100 minvalue 1 maxvalue\n9223372036854775806 \n increment by 10
cache 1000 nocycle ENGINE=InnoDB\n\nUsing Sequence
Objects\n----------------------\n\nTo get the next value from a sequence,
use\n\nNEXT VALUE FOR sequence_name\n\nor\n\nNEXTVAL(sequence_name)\n\nor
in Oracle mode (SQL_MODE=ORACLE)\n\nsequence_name.nextval\n\nFor retrieving
the last value used by the current connection from a
sequence\nuse:\n\nPREVIOUS VALUE FOR
sequence_name\n\nor\n\nLASTVAL(sequence_name)\n\nor in Oracle mode
(SQL_MODE=ORACLE)\n\nsequence_name.currval\n\nFor example:\n\nSELECT
NEXTVAL(s);\n+------------+\n| NEXTVAL(s) |\n+------------+\n| 100
|\n+------------+\n\nSELECT NEXTVAL(s);\n+------------+\n| NEXTVAL(s)
|\n+------------+\n| 110 |\n+------------+\n\nSELECT
LASTVAL(s);\n+------------+\n| LASTVAL(s) |\n+------------+\n| 110
|\n+------------+\n\nUsing Sequences in
DEFAULT\n--------------------------\n\nMariaDB starting with
10.3.3\n----------------------------\nStarting from 10.3.3 you can use
Sequences in DEFAULT:\n\ncreate sequence s1;\ncreate table t1 (a int
primary key default (next value for s1), b int);\ninsert into t1 (b) values
(1),(2);\nselect * from t1;\n+---+------+\n| a | b |\n+---+------+\n| 1
| 1 |\n| 2 | 2 |\n+---+------+\n\nChanging a
Sequence\n-------------------\n\nThe ALTER SEQUENCE statement is used for
changing sequences. For example, to\nrestart the sequence at another
value:\n\nALTER SEQUENCE s RESTART 50;\n\nSELECT
NEXTVAL(s);\n+------------+\n| NEXTVAL(s) |\n+------------+\n| 50
|\n+------------+\n\nThe SETVAL function can also be used to set the next
value to be returned for\na SEQUENCE, for example:\n\nSELECT SETVAL(s,
100);\n+----------------+\n| SETVAL(s, 100) |\n+----------------+\n|
100 |\n+----------------+\n\nSETVAL can only be used to increase the
sequence value. Attempting to set a\nlower value will fail, returning
NULL:\n\nSELECT SETVAL(s, 50);\n+---------------+\n| SETVAL(s, 50)
|\n+---------------+\n| NULL |\n+---------------+\n\nDropping a
Sequence\n-------------------\n\nThe DROP SEQUENCE statement is used to
drop a sequence, for example:\n\nDROP SEQUENCE
s;\n\nReplication\n-----------\n\nIf one wants to use Sequences in a
master-master setup or with Galera one\nshould use INCREMENT=0. This will
tell the Sequence to use\nauto_increment_increment and
auto_increment_offset to generate unique values\nfor each
server.\n\nStandards Compliance\n--------------------\n\nMariaDB 10.3
supports both ANSI SQL and Oracle syntax for sequences.\n\nHowever as
SEQUENCE is implemented as a special kind of table, it uses the\nsame
namespace as tables. The benefits are that sequences show up in
SHOW\nTABLES, and one can also create a sequence with CREATE TABLE and drop
it with\nDROP TABLE. One can SELECT from it as from any other table. This
ensures that\nall old tools that work with tables should work with
sequences.\n\nSince sequence objects act as regular tables in many
contexts, they will be\naffected by LOCK TABLES. This is not the case in
other DBMS, such as Oracle,\nwhere LOCK TABLE does not affect
sequences.\n\nNotes\n-----\n\nOne of the goals with the Sequence
implementation is that all old tools, such\nas mysqldump, should work
unchanged, while still keeping the normal usage of\nsequence standard
compatibly.\n\nTo make this possible, sequence is currently implemented as
a table with a few\nexclusive properties.\n\nThe special properties for
sequence tables are:\n\n* A sequence table has always one row.\n* When one
creates a sequence, either with CREATE TABLE or CREATE SEQUENCE,\none row
will be inserted.\n* If one tries to insert into a sequence table, the
single row will be\nupdated. This allows mysqldump to work but also gives
the additional benefit\nthat one can change all properties of a sequence
with a single insert. New\napplications should of course also use ALTER
SEQUENCE.\n* UPDATE or DELETE can\'t be performed on Sequence
objects.\n* Doing a select on the sequence shows the current state of the
sequence,\nexcept the values that are reserved in the cache. The
next_value column shows\nthe next value not reserved by the cache.\n* FLUSH
TABLES will close the sequence and the next sequence number generated\nwill
be according to what\'s stored in the Sequence object. In effect,
this\nwill discard the cached values.\n* A number of normal table
operations work on Sequence tables. See next\nsection.\n\nTable Operations
that Work with Sequences\n-----------------------------------------\n\n*
SHOW CREATE TABLE sequence_name. This shows the table structure that
is\nbehind the SEQUENCE including the field names that can be used with
SELECT or\neven CREATE TABLE.\n* CREATE TABLE sequence-structure ...
SEQUENCE=1\n* ALTER TABLE sequence RENAME TO sequence2\n* RENAME TABLE
sequence_name TO new_sequence_name\n* DROP TABLE sequence_name. This is
allowed mainly to get old tools like\nmysqldump to work with sequence
tables.\n* SHOW TABLES\n\nImplementation\n--------------\n\nInternally,
sequence tables are created as a normal table without rollback\n(the
InnoDB, Aria and MySAM engines support this), wrapped by a sequence\nengine
object. This allowed us to create sequences with almost no
performance\nimpact for normal tables. (The cost is one \'if\'
per insert if the binary log\nis enabled).\n\nUnderlying Table
Structure\n--------------------------\n\nThe following example shows the
table structure of sequences and how it can be\nused as a table. (Output of
results are slightly edited to make them easier to\nread)\n\ncreate
sequence t1;\nshow create sequence t1\\G\n*************************** 1.
row ***************************\n CREATE SEQUENCE `t1` start with 1
minvalue 1 maxvalue 9223372036854775806\n increment by 1 cache 1000 nocycle
ENGINE=InnoDB\n\nshow create table t1\\G\n*************************** 1.
row ***************************\nCreate Table: CREATE TABLE `t1` (\n
`next_not_cached_value` bigint(21) NOT NULL,\n `minimum_value` bigint(21)
NOT NULL,\n `maximum_value` bigint(21) NOT NULL,\n `start_value` bigint(21)
NOT NULL COMMENT \'start value when sequences is\ncreated or value if
RESTART is used\',\n `increment` bigint(21) NOT NULL COMMENT
\'increment value\',\n `cache_size` bigint(21) unsigned NOT
NULL,\n `cycle_option` tinyint(1) unsigned NOT NULL COMMENT \'0 if no
cycles are\nallowed, 1 if the sequence should begin a new cycle when
maximum_value is\npassed\',\n `cycle_count` bigint(21) NOT NULL
COMMENT \'How many cycles have been done\'\n) ENGINE=InnoDB
SEQUENCE=1\n\nselect * from t1\\G\nnext_not_cached_value: 1\n
minimum_value: 1\n maximum_value: 9223372036854775806\n start_value: 1\n
increment: 1\n cache_size: 1000\n cycle_option: 0\n cycle_count: 0\n\nThe
cycle_count column is incremented every time the sequence wraps
around.\n\nCredits\n-------\n\n* Thanks to Jianwe Zhao from Aliyun for his
work on SEQUENCE in AliSQL, which\ngave ideas and inspiration for this
work.\n* Thanks to Peter Gulutzan,who helped test and gave useful comments
about the\nimplementation.\n\nURL:
https://mariadb.com/kb/en/sequence-overview/','','https://mariadb.com/kb/en/sequence-overview/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(733,39,'CREATE SEQUENCE','MariaDB starting with
10.3\n--------------------------\nCREATE SEQUENCE was introduced in MariaDB
10.3.\n\nSyntax\n------\n\nCREATE [OR REPLACE] [TEMPORARY] SEQUENCE [IF NOT
EXISTS] sequence_name\n[ INCREMENT [ BY | = ] increment ]\n[ MINVALUE [=]
minvalue | NO MINVALUE | NOMINVALUE ]\n[ MAXVALUE [=] maxvalue | NO
MAXVALUE | NOMAXVALUE ]\n[ START [ WITH | = ] start ] \n[ CACHE [=] cache |
NOCACHE ] [ CYCLE | NOCYCLE] \n[table_options]\nThe options for CREATE
SEQUENCE can be given in any order, optionally followed\nby
table_options.\n\ntable_options can be any of the normal table options in
CREATE TABLE but the\nmost usable ones are ENGINE=... and
COMMENT=.\n\nNOMAXVALUE and NOMINVALUE are there to allow one to create
SEQUENCEs using the\nOracle syntax.\n\nDescription\n-----------\n\nCREATE
SEQUENCE will create a sequence that generates new values when called\nwith
NEXT VALUE FOR sequence_name. It\'s an alternative to AUTO INCREMENT
when\none wants to have more control of how the numbers are generated. As
the\nSEQUENCE caches values (up to CACHE) it can in some cases be much
faster than\nAUTO INCREMENT. Another benefit is that one can access the
last value\ngenerated by all used sequences, which solves one of the
limitations with\nLAST_INSERT_ID().\n\nCREATE SEQUENCE requires the CREATE
privilege.\n\nDROP SEQUENCE can be used to drop a sequence, and ALTER
SEQUENCE to change it.\n\nArguments to Create\n-------------------\n\nThe
following options may be
used:\n\n+---------------+------------------------------+----------------------------+\n|
Option | Default value | Description
|\n+---------------+------------------------------+----------------------------+\n|
INCREMENT | 1 | Increment to use for
|\n| | | values. May be
negative. |\n| | | Setting an
increment of 0 |\n| | | causes
the sequence to |\n| | | use
the value of the |\n| | |
auto_increment_increment |\n| |
| system variable at the |\n| |
| time of creation, which |\n| |
| is always a positive |\n| |
| number. (see MDEV-16035).
|\n+---------------+------------------------------+----------------------------+\n|
MINVALUE | 1 if INCREMENT > 0 and | Minimum value for the
|\n| | -9223372036854775807 if | sequence
|\n| | INCREMENT < 0 |
|\n+---------------+------------------------------+----------------------------+\n|
MAXVALUE | 9223372036854775806 if | Max value for sequence
|\n| | INCREMENT > 0 and -1 if |
|\n| | INCREMENT < 0 |
|\n+---------------+------------------------------+----------------------------+\n|
START | MINVALUE if INCREMENT > 0 | First value that the
|\n| | and MAX_VALUE if INCREMENT< | sequence will
generate |\n| | 0 |
|\n+---------------+------------------------------+----------------------------+\n|
CACHE | 1000 | Number of values that
|\n| | | should be cached. 0 if
no |\n| | | CACHE. The
underlying |\n| | | table
will be updated |\n| | |
first time a new sequence |\n| |
| number is generated and |\n| |
| each time the cache runs |\n| |
| out.
|\n+---------------+------------------------------+----------------------------+\n\nIf
CYCLE is used then the sequence should start again from MINVALUE after
it\nhas run out of values. Default value is NOCYCLE.\n\nConstraints on
Create Arguments\n-------------------------------\n\nTo be able to create a
legal sequence, the following must hold:\n\n* MAXVALUE >= start\n*
MAXVALUE > MINVALUE\n* START >= MINVALUE\n* MAXVALUE <=
9223372036854775806 (LONGLONG_MAX-1)\n* MINVALUE >=
-9223372036854775807 (LONGLONG_MIN+1)\n\nNote that sequences can\'t
generate the maximum/minimum 64 bit number because\nof the constraint of
MINVALUE and MAXVALUE.\n\nAtomic DDL\n----------\n\nMariaDB starting with
10.6.1\n----------------------------\nMariaDB 10.6.1 supports Atomic DDL
and CREATE SEQUENCE is atomic.\n\nExamples\n--------\n\nCREATE SEQUENCE s
START WITH 100 INCREMENT BY 10;\n\nCREATE SEQUENCE s2 START WITH -100
INCREMENT BY -10;\n\nThe following statement fails, as the increment
conflicts with the defaults\n\nCREATE SEQUENCE s3 START WITH -100 INCREMENT
BY 10;\nERROR 4082 (HY000): Sequence \'test.s3\' values are
conflicting\n\nThe sequence can be created by specifying workable minimum
and maximum values:\n\nCREATE SEQUENCE s3 START WITH -100 INCREMENT BY 10
MINVALUE=-100 MAXVALUE=1000;\n\nURL:
https://mariadb.com/kb/en/create-sequence/','','https://mariadb.com/kb/en/create-sequence/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(734,39,'ALTER SEQUENCE','MariaDB starting with
10.3.1\n----------------------------\nALTER SEQUENCE was introduced in
MariaDB 10.3.\n\nSyntax\n------\n\nALTER SEQUENCE [IF EXISTS]
sequence_name\n[ INCREMENT [ BY | = ] increment ]\n[ MINVALUE [=] minvalue
| NO MINVALUE | NOMINVALUE ]\n[ MAXVALUE [=] maxvalue | NO MAXVALUE |
NOMAXVALUE ]\n[ START [ WITH | = ] start ] [ CACHE [=] cache ] [ [ NO ]
CYCLE ]\n[ RESTART [[WITH | =] restart]\n\nALTER SEQUENCE allows one to
change any values for a SEQUENCE created with\nCREATE SEQUENCE.\n\nThe
options for ALTER SEQUENCE can be given in any
order.\n\nDescription\n-----------\n\nALTER SEQUENCE changes the parameters
of an existing sequence generator. Any\nparameters not specifically set in
the ALTER SEQUENCE command retain their\nprior settings.\n\nALTER SEQUENCE
requires the ALTER privilege.\n\nArguments to ALTER
SEQUENCE\n---------------------------\n\nThe following options may be
used:\n\n+---------------+-------------------------------+---------------------------+\n|
Option | Default value | Description
|\n+---------------+-------------------------------+---------------------------+\n|
INCREMENT | 1 | Increment to use for
|\n| | | values. May be
negative.
|\n+---------------+-------------------------------+---------------------------+\n|
MINVALUE | 1 if INCREMENT > 0 and | Minimum value for the
|\n| | -9223372036854775807 if | sequence.
|\n| | INCREMENT < 0 |
|\n+---------------+-------------------------------+---------------------------+\n|
MAXVALUE | 9223372036854775806 if | Max value for sequence.
|\n| | INCREMENT > 0 and -1 if |
|\n| | INCREMENT < 0 |
|\n+---------------+-------------------------------+---------------------------+\n|
START | MINVALUE if INCREMENT > 0 | First value that the
|\n| | and MAX_VALUE if INCREMENT< 0 | sequence will
generate.
|\n+---------------+-------------------------------+---------------------------+\n|
CACHE | 1000 | Number of values that
|\n| | | should be cached. 0 if
|\n| | | no CACHE. The
|\n| | | underlying table
will be |\n| | | updated first
time a new |\n| | | sequence
number is |\n| | |
generated and each time |\n| |
| the cache runs out.
|\n+---------------+-------------------------------+---------------------------+\n|
CYCLE | 0 (= NO CYCLE) | 1 if the sequence should
|\n| | | start again from
|\n| | | MINVALUE# after it
has |\n| | | run out of
values.
|\n+---------------+-------------------------------+---------------------------+\n|
RESTART | START if restart value not | If RESTART option is
|\n| | is given | used, NEXT VALUE will
|\n| | | return the restart
value.
|\n+---------------+-------------------------------+---------------------------+\n\nThe
optional clause RESTART [ WITH restart ] sets the next value for
the\nsequence. This is equivalent to calling the SETVAL() function with the
is_used\nargument as 0. The specified value will be returned by the next
call of\nnextval. Using RESTART with no restart value is equivalent to
supplying the\nstart value that was recorded by CREATE SEQUENCE or last set
by ALTER SEQUENCE\nSTART WITH.\n\nALTER SEQUENCE will not allow you to
change the sequence so that it\'s\ninconsistent. For
example:\n\nCREATE SEQUENCE s1;\nALTER SEQUENCE s1 MINVALUE 10;\nERROR 4061
(HY000): Sequence \'test.t1\' values are conflicting\n\nALTER
SEQUENCE s1 MINVALUE 10 RESTART 10;\nERROR 4061 (HY000): Sequence
\'test.t1\' values are conflicting\n\nALTER SEQUENCE s1 MINVALUE
10 START 10 RESTART 10;\n\nINSERT\n------\n\nTo allow SEQUENCE objects to
be backed up by old tools, like mysqldump, one\ncan use SELECT to read the
current state of a SEQUENCE object and use an\nINSERT to update the
SEQUENCE object. INSERT is only allowed if all fields
are\nspecified:\n\nCREATE SEQUENCE s1;\nINSERT INTO s1
VALUES(1000,10,2000,1005,1,1000,0,0);\nSELECT * FROM
s1;\n\n+------------+-----------+-----------+-------+-----------+-------+-------+-----\n-+\n|
next_value | min_value | max_value | start | increment | cache | cycle
|\nround
|\n+------------+-----------+-----------+-------+-----------+-------+-------+-----\n-+\n|
1000 | 10 | 2000 | 1005 | 1 | 1000 | 0 |
\n0
|\n+------------+-----------+-----------+-------+-----------+-------+-------+-----\n-+\n\nSHOW
CREATE SEQUENCE
s1;\n+-------+----------------------------------------------------------------------\n---------------------------------------+\n|
Table | Create Table
\n
|\n+-------+----------------------------------------------------------------------\n---------------------------------------+\n|
s1 | CREATE SEQUENCE `s1` start with 1005 minvalue 10 maxvalue
2000\nincrement by 1 cache 1000 nocycle ENGINE=Aria
|\n+-------+----------------------------------------------------------------------\n---------------------------------------+\n\nNotes\n-----\n\nALTER
SEQUENCE will instantly affect all future SEQUENCE operations. This is\nin
contrast to some other databases where the changes requested by
ALTER\nSEQUENCE will not be seen until the sequence cache has run
out.\n\nALTER SEQUENCE will take a full table lock of the sequence object
during its\n(brief) operation. This ensures that ALTER SEQUENCE is
replicated correctly.\nIf you only want to set the next sequence value to a
higher value than\ncurrent, then you should use SETVAL() instead, as this
is not blocking.\n\nIf you want to change storage engine, sequence comment
or rename the sequence,\nyou can use ALTER TABLE for this.\n\nURL:
https://mariadb.com/kb/en/alter-sequence/','','https://mariadb.com/kb/en/alter-sequence/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(735,39,'DROP SEQUENCE','MariaDB starting with
10.3\n--------------------------\nDROP SEQUENCE was introduced in MariaDB
10.3.\n\nSyntax\n------\n\nDROP [TEMPORARY] SEQUENCE [IF EXISTS] [/*COMMENT
TO SAVE*/]\n sequence_name [, sequence_name]
...\n\nDescription\n-----------\n\nDROP SEQUENCE removes one or more
sequences created with CREATE SEQUENCE. You\nmust have the DROP privilege
for each sequence. MariaDB returns an error\nindicating by name which
non-existing tables it was unable to drop, but it\nalso drops all of the
tables in the list that do exist.\n\nImportant: When a table is dropped,
user privileges on the table are not\nautomatically dropped. See
GRANT.\n\nIf another connection is using the sequence, a metadata lock is
active, and\nthis statement will wait until the lock is released. This is
also true for\nnon-transactional tables.\n\nFor each referenced sequence,
DROP SEQUENCE drops a temporary sequence with\nthat name, if it exists. If
it does not exist, and the TEMPORARY keyword is\nnot used, it drops a
non-temporary sequence with the same name, if it exists.\nThe TEMPORARY
keyword ensures that a non-temporary sequence will not\naccidentally be
dropped.\n\nUse IF EXISTS to prevent an error from occurring for sequences
that do not\nexist. A NOTE is generated for each non-existent sequence when
using IF\nEXISTS. See SHOW WARNINGS.\n\nDROP SEQUENCE requires the DROP
privilege.\n\nNotes\n-----\n\nDROP SEQUENCE only removes sequences, not
tables. However, DROP TABLE can\nremove both sequences and tables.\n\nURL:
https://mariadb.com/kb/en/drop-sequence/','','https://mariadb.com/kb/en/drop-sequence/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(736,39,'NEXT VALUE for sequence_name','MariaDB starting
with 10.3\n--------------------------\nSEQUENCEs were introduced in MariaDB
10.3\n\nSyntax\n------\n\nNEXT VALUE FOR
sequence\n\nor\n\nNEXTVAL(sequence_name)\n\nor in Oracle mode
(SQL_MODE=ORACLE)\n\nsequence_name.nextval\n\nNEXT VALUE FOR is ANSI SQL
syntax while NEXTVAL() is PostgreSQL
syntax.\n\nDescription\n-----------\n\nGenerate next value for a
SEQUENCE.\n\n* You can greatly speed up NEXT VALUE by creating the sequence
with the CACHE\noption. If not, every NEXT VALUE usage will cause changes
in the stored\nSEQUENCE table.\n* When using NEXT VALUE the value will be
reserved at once and will not be\nreused, except if the SEQUENCE was
created with CYCLE. This means that when\nyou are using SEQUENCEs you have
to expect gaps in the generated sequence\nnumbers.\n* If one updates the
SEQUENCE with SETVAL() or ALTER SEQUENCE ... RESTART,\nNEXT VALUE FOR will
notice this and start from the next requested value.\n* FLUSH TABLES will
close the sequence and the next sequence number generated\nwill be
according to what\'s stored in the SEQUENCE object. In effect,
this\nwill discard the cached values.\n* A server restart (or closing the
current connection) also causes a drop of\nall cached values. The cached
sequence numbers are reserved only for the\ncurrent connection.\n* NEXT
VALUE requires the INSERT privilege.\n\nMariaDB starting with
10.3.3\n----------------------------\n* You can also use NEXT VALUE FOR
sequence for column DEFAULT.\n\nURL:
https://mariadb.com/kb/en/next-value-for-sequence_name/','','https://mariadb.com/kb/en/next-value-for-sequence_name/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(737,39,'PREVIOUS VALUE FOR sequence_name','MariaDB starting
with 10.3\n--------------------------\nSEQUENCEs were introduced in MariaDB
10.3.\n\nSyntax\n------\n\nPREVIOUS VALUE FOR
sequence_name\n\nor\n\nLASTVAL(sequence_name)\n\nor in Oracle mode
(SQL_MODE=ORACLE)\n\nsequence_name.currval\n\nPREVIOUS VALUE FOR is IBM DB2
syntax while LASTVAL() is PostgreSQL
syntax.\n\nDescription\n-----------\n\nGet last value in the current
connection generated from a sequence.\n\n* If the sequence has not yet been
used by the connection, PREVIOUS VALUE FOR\nreturns NULL (the same thing
applies with a new connection which doesn\'t see a\nlast value for an
existing sequence).\n* If a SEQUENCE has been dropped and re-created then
it\'s treated as a new\nSEQUENCE and PREVIOUS VALUE FOR will return
NULL.\n* FLUSH TABLES has no effect on PREVIOUS VALUE FOR.\n* Previous
values for all used sequences are stored per connection until\nconnection
ends.\n* PREVIOUS VALUE FOR requires the SELECT
privilege.\n\nExample\n-------\n\nCREATE SEQUENCE s START WITH 100
INCREMENT BY 10;\n\nSELECT PREVIOUS VALUE FOR
s;\n+----------------------+\n| PREVIOUS VALUE FOR s
|\n+----------------------+\n| NULL
|\n+----------------------+\n\n# The function works for sequences only, if
the table is used an error is\ngenerated\nSELECT PREVIOUS VALUE FOR
t;\nERROR 4089 (42S02): \'test.t\' is not a SEQUENCE\n\n# Call
the NEXT VALUE FOR s:\nSELECT NEXT VALUE FOR s;\n+------------------+\n|
NEXT VALUE FOR s |\n+------------------+\n| 100
|\n+------------------+\n\nSELECT PREVIOUS VALUE FOR
s;\n+----------------------+\n| PREVIOUS VALUE FOR s
|\n+----------------------+\n| 100
|\n+----------------------+\n\nNow try to start the new connection and
check that the last value is still\nNULL, before updating the value in the
new connection after the output of the\nnew connection gets current value
(110 in the example below). Note that first\nconnection cannot see this
change and the result of last value still remains\nthe same (100 in the
example above).\n\n$ .mysql -uroot test -e\"SELECT PREVIOUS VALUE FOR
s; SELECT NEXT VALUE FOR s;\nSELECT PREVIOUS VALUE FOR
s;\"\n+----------------------+\n| PREVIOUS VALUE FOR s
|\n+----------------------+\n| NULL
|\n+----------------------+\n+------------------+\n| NEXT VALUE FOR s
|\n+------------------+\n| 110
|\n+------------------+\n+----------------------+\n| PREVIOUS VALUE FOR s
|\n+----------------------+\n| 110
|\n+----------------------+\n\nURL:
https://mariadb.com/kb/en/previous-value-for-sequence_name/','','https://mariadb.com/kb/en/previous-value-for-sequence_name/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(738,39,'SETVAL','MariaDB starting with
10.3.1\n----------------------------\nSEQUENCEs were introduced in MariaDB
10.3.\n\nSyntax\n------\n\nSETVAL(sequence_name, next_value, [is_used,
[round]])\n\nDescription\n-----------\n\nSet the next value to be returned
for a SEQUENCE.\n\nThis function is compatible with PostgreSQL syntax,
extended with the round\nargument.\n\nIf the is_used argument is not given
or is 1 or true, then the next used value\nwill one after the given value.
If is_used is 0 or false then the next\ngenerated value will be the given
value.\n\nIf round is used then it will set the round value (or the
internal cycle\ncount, starting at zero) for the sequence. If round is not
used, it\'s assumed\nto be 0.\n\nnext_value must be an integer
literal.\n\nFor SEQUENCE tables defined with CYCLE (see CREATE SEQUENCE)
one should use\nboth next_value and round to define the next value. In this
case the current\nsequence value is defined to be round, next_value.\n\nThe
result returned by SETVAL() is next_value or NULL if the given
next_value\nand round is smaller than the current value.\n\nSETVAL() will
not set the SEQUENCE value to a something that is less than its\ncurrent
value. This is needed to ensure that SETVAL() is replication safe. If\nyou
want to set the SEQUENCE to a smaller number use ALTER SEQUENCE.\n\nIf
CYCLE is used, first round and then next_value are compared to see if
the\nvalue is bigger than the current value.\n\nInternally, in the MariaDB
server, SETVAL() is used to inform slaves that a\nSEQUENCE has changed
value. The slave may get SETVAL() statements out of\norder, but this is ok
as only the biggest one will have an effect.\n\nSETVAL requires the INSERT
privilege.\n\nExamples\n--------\n\nSELECT setval(foo, 42); --
Next nextval will return 43\nSELECT setval(foo, 42, true); -- Same as
above\nSELECT setval(foo, 42, false); -- Next nextval will return
42\n\nSETVAL setting higher and lower values on a sequence with an
increment of 10:\n\nSELECT NEXTVAL(s);\n+------------+\n| NEXTVAL(s)
|\n+------------+\n| 50 |\n+------------+\n\nSELECT SETVAL(s,
100);\n+----------------+\n| SETVAL(s, 100) |\n+----------------+\n|
100 |\n+----------------+\n\nSELECT NEXTVAL(s);\n+------------+\n|
NEXTVAL(s) |\n+------------+\n| 110 |\n+------------+\n\nSELECT
SETVAL(s, 50);\n+---------------+\n| SETVAL(s, 50) |\n+---------------+\n|
NULL |\n+---------------+\n\nSELECT NEXTVAL(s);\n+------------+\n|
NEXTVAL(s) |\n+------------+\n| 120 |\n+------------+\n\nExample
demonstrating round:\n\nCREATE OR REPLACE SEQUENCE s1\n START WITH 1\n
MINVALUE 1\n MAXVALUE 99\n INCREMENT BY 1\n CACHE 20\n CYCLE;\n\nSELECT
SETVAL(s1, 99, 1, 0);\n+----------------------+\n| SETVAL(s1, 99, 1, 0)
|\n+----------------------+\n| 99
|\n+----------------------+\n\nSELECT NEXTVAL(s1);\n+-------------+\n|
NEXTVAL(s1) |\n+-------------+\n| 1 |\n+-------------+\n\nThe
following statement returns NULL, as the given next_value and round
is\nsmaller than the current value.\n\nSELECT SETVAL(s1, 99, 1,
0);\n+----------------------+\n| SETVAL(s1, 99, 1, 0)
|\n+----------------------+\n| NULL
|\n+----------------------+\n\nSELECT NEXTVAL(s1);\n+-------------+\n|
NEXTVAL(s1) |\n+-------------+\n| 2
|\n+-------------+\n\nIncreasing the round from zero to 1 will allow
next_value to be returned.\n\nSELECT SETVAL(s1, 99, 1,
1);\n+----------------------+\n| SETVAL(s1, 99, 1, 1)
|\n+----------------------+\n| 99
|\n+----------------------+\n\nSELECT NEXTVAL(s1);\n+-------------+\n|
NEXTVAL(s1) |\n+-------------+\n| 1 |\n+-------------+\n\nURL:
https://mariadb.com/kb/en/setval/','','https://mariadb.com/kb/en/setval/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(739,40,'JSON_ARRAYAGG','MariaDB starting with
10.5.0\n----------------------------\nJSON_ARRAYAGG was added in MariaDB
10.5.0.\n\nSyntax\n------\n\nJSON_ARRAYAGG(column_or_expression)\n\nDescription\n-----------\n\nJSON_ARRAYAGG
returns a JSON array containing an element for each value in a\ngiven set
of JSON or SQL values. It acts on a column or an expression that\nevaluates
to a single value.\n\nReturns NULL in the case of an error, or if the
result contains no rows.\n\nJSON_ARRAYAGG cannot currently be used as a
window function.\n\nThe full syntax is as
follows:\n\nJSON_ARRAYAGG([DISTINCT] expr [,expr ...]\n [ORDER BY
{unsigned_integer | col_name | expr}\n [ASC | DESC] [,col_name
...]]\n [LIMIT {[offset,] row_count | row_count OFFSET
offset}])\n\nExamples\n--------\n\nCREATE TABLE t1 (a INT, b
INT);\n\nINSERT INTO t1 VALUES (1, 1),(2, 1), (1, 1),(2, 1), (3, 2),(2,
2),(2, 2),(2,\n2);\n\nSELECT JSON_ARRAYAGG(a), JSON_ARRAYAGG(b) FROM
t1;\n+-------------------+-------------------+\n| JSON_ARRAYAGG(a) |
JSON_ARRAYAGG(b) |\n+-------------------+-------------------+\n|
[1,2,1,2,3,2,2,2] | [1,1,1,1,2,2,2,2]
|\n+-------------------+-------------------+\n\nSELECT JSON_ARRAYAGG(a),
JSON_ARRAYAGG(b) FROM t1 GROUP BY
b;\n+------------------+------------------+\n| JSON_ARRAYAGG(a) |
JSON_ARRAYAGG(b) |\n+------------------+------------------+\n| [1,2,1,2]
| [1,1,1,1] |\n| [3,2,2,2] | [2,2,2,2]
|\n+------------------+------------------+\n\nURL:
https://mariadb.com/kb/en/json_arrayagg/','','https://mariadb.com/kb/en/json_arrayagg/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(740,40,'JSON_OBJECTAGG','MariaDB starting with
10.5.0\n----------------------------\nJSON_OBJECTAGG was added in MariaDB
10.5.0.\n\nSyntax\n------\n\nJSON_OBJECTAGG(key,
value)\n\nDescription\n-----------\n\nJSON_OBJECTAGG returns a JSON object
containing key-value pairs. It takes two\nexpressions that evaluate to a
single value, or two column names, as\narguments, the first used as a key,
and the second as a value.\n\nReturns NULL in the case of an error, or if
the result contains no rows.\n\nJSON_OBJECTAGG cannot currently be used as
a window function.\n\nExamples\n--------\n\nselect * from
t1;\n+------+-------+\n| a | b |\n+------+-------+\n| 1 | Hello
|\n| 1 | World |\n| 2 | This |\n+------+-------+\n\nSELECT
JSON_OBJECTAGG(a, b) FROM
t1;\n+----------------------------------------+\n| JSON_OBJECTAGG(a, b)
|\n+----------------------------------------+\n|
{\"1\":\"Hello\", \"1\":\"World\",
\"2\":\"This\"}
|\n+----------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_objectagg/','','https://mariadb.com/kb/en/json_objectagg/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(741,40,'JSONPath Expressions','A number of JSON functions
accept JSON Path expressions. MariaDB defines this\npath as
follows:\n\nJSON Path Syntax\n----------------\n\npath :
[\'lax\'] \'$\' [step]*\n\nThe path starts with an
optional path mode. At the moment, MariaDB supports\nonly the
\"lax\" mode, which is also the mode that is used when it is
not\nexplicitly specified.\n\nThe $ symbol represents the context item. The
search always starts from the\ncontext item; because of that, the path
always starts with $.\n\nThen, it is followed by zero or more steps, which
select element(s) in the\nJSON document. A step may be one of the
following:\n\n* Object member selector\n* Array element selector\n*
Wildcard selector\n\nObject Member Selector\n----------------------\n\nTo
select member(s) in a JSON object, one can use one of the following:\n\n*
.memberName selects the value of the member with name memberName.\n*
.\"memberName\" - the same as above but allows one to select a
member with a\nname that\'s not a valid identifier (that is, has
space, dot, and/or other\ncharacters)\n* .* - selects the values of all
members of the object.\n\nIf the current item is an array (instead of an
object), nothing will be\nselected.\n\nArray Element
Selector\n----------------------\n\nTo select elements of an array, one can
use one of the following:\n\n* [N] selects element number N in the array.
The elements are counted from\nzero.\n* [*] selects all elements in the
array.\n\nIf the current item is an object (instead of an array), nothing
will be\nselected.\n\nStarting from MariaDB server 10.9, JSON path also
supports negative index in\narray, \'last\' keyword and range
notation (\'to\' keyword) for accessing array\nelements. Negative
index starts from -1.\n\n* [-N] selects n th element from end.\n* [last-N]
selects n th element from the last element.\n* [M to N] selects range of
elements starting from index M to N.\n\nExample:\n\nSET @json=\'{\n
\"A\": [0,\n [1, 2, 3],\n [4, 5, 6],\n
\"seven\",\n 0.8,\n true,\n false,\n
\"eleven\",\n [12, [13, 14],
{\"key1\":\"value1\"},[15]],\n true],\n
\"B\": {\"C\": 1},\n \"D\": 2\n
}\';\nSELECT JSON_EXTRACT(@json,
\'$.A[-8][1]\');\n+--------------------------------------------------+\n|
JSON_EXTRACT(@json, \'$.A[-8][1]\')
|\n+--------------------------------------------------+\n| 5
|\n+--------------------------------------------------+\n\nSELECT
JSON_EXTRACT(@json,
\'$.A[last-7][1]\');\n+-----------------------------------------------+\n|
SELECT JSON_EXTRACT(@json, \'$.A[last-7][1]\');
|\n+-----------------------------------------------+\n| 5
|\n+-----------------------------------------------+\n\nSET @json=
\'[\n [1, {\"key1\": \"value1\"}, 3],\n
[false, 5, 6],\n [7, 8, [9, {\"key2\": 2}, 11]],\n [15,
1.34, [14], [\"string1\", [16,
{\"key1\":[1,2,3,[4,5,6]]}, 18]]],\n [19, 20],\n 21,
22\n ]\';\n\nSELECT JSON_EXTRACT(@json, \'$[0 to
3][2]\');\n+-----------------------------------------------+\n|
JSON_EXTRACT(@json, \'$[0 to 3][2]\')
|\n+-----------------------------------------------+\n| [3, 6, [9,
{\"key2\": 2}, 11], [14]]
|\n+-----------------------------------------------+\n\nThis will produce
output for first index of eighth from last element of a two\ndimensional
array.\n\nNote: In range notation, when M > N ( when M,N are greater
than or equal to 0)\nor (size of array - M or size of array - N when M, N
are less than 0), then it\nis treated as an impossible range and NULL is
returned.\n\nSET @json= \'[1, 2, 3, 4, 5]\';\nSELECT
JSON_EXTRACT(@json, \'$[4 to
2]\');\n+-----------------------------------+\n| JSON_EXTRACT(@json,
\'$[4 to 2]\') |\n+-----------------------------------+\n| NULL
|\n+-----------------------------------+\n\nWildcard\n--------\n\nThe
wildcard step, **, recursively selects all child elements of the
current\nelement. Both array elements and object members are
selected.\n\nThe wildcard step must not be the last step in the JSONPath
expression. It\nmust be followed by an array or object member selector
step.\n\nFor example:\n\nselect json_extract(@json_doc,
\'$**.price\');\n\nwill select all object members in the document
that are named price, while\n\nselect json_extract(@json_doc,
\'$**[2]\');\n\nwill select the second element in each of the
arrays present in the
document.\n\nCompatibility\n-------------\n\nMariaDB\'s JSONPath
syntax supports a subset of JSON Path\'s definition in the\nSQL
Standard. The most notable things not supported are the strict mode
and\nfilters.\n\nMariaDB\'s JSONPath is close to MySQL\'s
JSONPath. The wildcard step ( ** ) is a\nnon-standard extension that has
the same meaning as in MySQL. The differences\nbetween MariaDB and
MySQL\'s JSONPath are: MySQL supports [last] and [M to N]\nas array
element selectors; MySQL doesn\'t allow one to specify the
mode\nexplicitly (but uses lax mode implicitly).\n\nURL:
https://mariadb.com/kb/en/jsonpath-expressions/','','https://mariadb.com/kb/en/jsonpath-expressions/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(742,40,'JSON_ARRAY','Syntax\n------\n\nJSON_ARRAY([value[,
value2] ...])\n\nDescription\n-----------\n\nReturns a JSON array
containing the listed values. The list can be
empty.\n\nExample\n-------\n\nSELECT Json_Array(56, 3.1416, \'My name
is \"Foo\"\',
NULL);\n+--------------------------------------------------+\n|
Json_Array(56, 3.1416, \'My name is \"Foo\"\', NULL)
|\n+--------------------------------------------------+\n| [56, 3.1416,
\"My name is \\\"Foo\\\"\", null]
|\n+--------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_array/','','https://mariadb.com/kb/en/json_array/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(743,40,'JSON_ARRAY_APPEND','Syntax\n------\n\nJSON_ARRAY_APPEND(json_doc,
path, value[, path, value] ...)\n\nDescription\n-----------\n\nAppends
values to the end of the specified arrays within a JSON
document,\nreturning the result, or NULL if any of the arguments are
NULL.\n\nEvaluation is performed from left to right, with the resulting
document from\nthe previous pair becoming the new value against which the
next pair is\nevaluated.\n\nIf the json_doc is not a valid JSON document,
or if any of the paths are not\nvalid, or contain a * or ** wildcard, an
error is returned.\n\nExamples\n--------\n\nSET @json = \'[1, 2, [3,
4]]\';\n\nSELECT JSON_ARRAY_APPEND(@json, \'$[0]\',
5)\n+-------------------------------------+\n| JSON_ARRAY_APPEND(@json,
\'$[0]\', 5) |\n+-------------------------------------+\n| [[1,
5], 2, [3, 4]]
|\n+-------------------------------------+\n\nSELECT
JSON_ARRAY_APPEND(@json, \'$[1]\',
6);\n+-------------------------------------+\n| JSON_ARRAY_APPEND(@json,
\'$[1]\', 6) |\n+-------------------------------------+\n| [1,
[2, 6], [3, 4]]
|\n+-------------------------------------+\n\nSELECT
JSON_ARRAY_APPEND(@json, \'$[1]\', 6, \'$[2]\',
7);\n+------------------------------------------------+\n|
JSON_ARRAY_APPEND(@json, \'$[1]\', 6, \'$[2]\', 7)
|\n+------------------------------------------------+\n| [1, [2, 6], [3, 4,
7]]
|\n+------------------------------------------------+\n\nSELECT
JSON_ARRAY_APPEND(@json, \'$\',
5);\n+----------------------------------+\n| JSON_ARRAY_APPEND(@json,
\'$\', 5) |\n+----------------------------------+\n| [1, 2, [3,
4], 5] |\n+----------------------------------+\n\nSET @json
= \'{\"A\": 1, \"B\": [2], \"C\": [3,
4]}\';\n\nSELECT JSON_ARRAY_APPEND(@json, \'$.B\',
5);\n+------------------------------------+\n| JSON_ARRAY_APPEND(@json,
\'$.B\', 5) |\n+------------------------------------+\n|
{\"A\": 1, \"B\": [2, 5], \"C\": [3, 4]}
|\n+------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_array_append/','','https://mariadb.com/kb/en/json_array_append/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(744,40,'JSON_ARRAY_INSERT','Syntax\n------\n\nJSON_ARRAY_INSERT(json_doc,
path, value[, path, value] ...)\n\nDescription\n-----------\n\nInserts a
value into a JSON document, returning the modified document, or NULL\nif
any of the arguments are NULL.\n\nEvaluation is performed from left to
right, with the resulting document from\nthe previous pair becoming the new
value against which the next pair is\nevaluated.\n\nIf the json_doc is not
a valid JSON document, or if any of the paths are not\nvalid, or contain a
* or ** wildcard, an error is returned.\n\nExamples\n--------\n\nSET @json
= \'[1, 2, [3, 4]]\';\n\nSELECT JSON_ARRAY_INSERT(@json,
\'$[0]\', 5);\n+-------------------------------------+\n|
JSON_ARRAY_INSERT(@json, \'$[0]\', 5)
|\n+-------------------------------------+\n| [5, 1, 2, [3, 4]]
|\n+-------------------------------------+\n\nSELECT
JSON_ARRAY_INSERT(@json, \'$[1]\',
6);\n+-------------------------------------+\n| JSON_ARRAY_INSERT(@json,
\'$[1]\', 6) |\n+-------------------------------------+\n| [1, 6,
2, [3, 4]]
|\n+-------------------------------------+\n\nSELECT
JSON_ARRAY_INSERT(@json, \'$[1]\', 6, \'$[2]\',
7);\n+------------------------------------------------+\n|
JSON_ARRAY_INSERT(@json, \'$[1]\', 6, \'$[2]\', 7)
|\n+------------------------------------------------+\n| [1, 6, 7, 2, [3,
4]]
|\n+------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_array_insert/','','https://mariadb.com/kb/en/json_array_insert/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(745,40,'JSON_COMPACT','Syntax\n------\n\nJSON_COMPACT(json_doc)\n\nDescription\n-----------\n\nRemoves
all unnecessary spaces so the json document is as short as
possible.\n\nExample\n-------\n\nSET @j = \'{ \"A\": 1,
\"B\": [2, 3]}\';\n\nSELECT JSON_COMPACT(@j),
@j;\n+-------------------+------------------------+\n| JSON_COMPACT(@j) |
@j |\n+-------------------+------------------------+\n|
{\"A\":1,\"B\":[2,3]} | { \"A\": 1,
\"B\": [2, 3]}
|\n+-------------------+------------------------+\n\nURL:
https://mariadb.com/kb/en/json_compact/','','https://mariadb.com/kb/en/json_compact/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(746,40,'JSON_CONTAINS','Syntax\n------\n\nJSON_CONTAINS(json_doc,
val[, path])\n\nDescription\n-----------\n\nReturns whether or not the
specified value is found in the given JSON document\nor, optionally, at the
specified path within the document. Returns 1 if it\ndoes, 0 if not and
NULL if any of the arguments are null. An error occurs if\nthe document or
path is not valid, or contains the * or **
wildcards.\n\nExamples\n--------\n\nSET @json = \'{\"A\": 0,
\"B\": {\"C\": 1}, \"D\":
2}\';\n\nSELECT JSON_CONTAINS(@json, \'2\',
\'$.A\');\n+----------------------------------+\n|
JSON_CONTAINS(@json, \'2\', \'$.A\')
|\n+----------------------------------+\n| 0
|\n+----------------------------------+\n\nSELECT JSON_CONTAINS(@json,
\'2\',
\'$.D\');\n+----------------------------------+\n|
JSON_CONTAINS(@json, \'2\', \'$.D\')
|\n+----------------------------------+\n| 1
|\n+----------------------------------+\n\nSELECT JSON_CONTAINS(@json,
\'{\"C\": 1}\',
\'$.A\');\n+-----------------------------------------+\n|
JSON_CONTAINS(@json, \'{\"C\": 1}\', \'$.A\')
|\n+-----------------------------------------+\n|
0 |\n+-----------------------------------------+\n\nSELECT
JSON_CONTAINS(@json, \'{\"C\": 1}\',
\'$.B\');\n+-----------------------------------------+\n|
JSON_CONTAINS(@json, \'{\"C\": 1}\', \'$.B\')
|\n+-----------------------------------------+\n|
1 |\n+-----------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_contains/','','https://mariadb.com/kb/en/json_contains/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(747,40,'JSON_CONTAINS_PATH','Syntax\n------\n\nJSON_CONTAINS_PATH(json_doc,
return_arg, path[, path] ...)\n\nDescription\n-----------\n\nIndicates
whether the given JSON document contains data at the specified path\nor
paths. Returns 1 if it does, 0 if not and NULL if any of the arguments
are\nnull.\n\nThe return_arg can be one or all:\n\n* one - Returns 1 if at
least one path exists within the JSON document. \n* all - Returns 1 only if
all paths exist within the JSON document.\n\nExamples\n--------\n\nSET
@json = \'{\"A\": 1, \"B\": [2], \"C\":
[3, 4]}\';\n\nSELECT JSON_CONTAINS_PATH(@json, \'one\',
\'$.A\',
\'$.D\');\n+------------------------------------------------+\n|
JSON_CONTAINS_PATH(@json, \'one\', \'$.A\',
\'$.D\') |\n+------------------------------------------------+\n|
1
|\n+------------------------------------------------+\n1 row in set (0.00
sec)\n\nSELECT JSON_CONTAINS_PATH(@json, \'all\',
\'$.A\',
\'$.D\');\n+------------------------------------------------+\n|
JSON_CONTAINS_PATH(@json, \'all\', \'$.A\',
\'$.D\') |\n+------------------------------------------------+\n|
0
|\n+------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_contains_path/','','https://mariadb.com/kb/en/json_contains_path/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(748,40,'JSON_DEPTH','Syntax\n------\n\nJSON_DEPTH(json_doc)\n\nDescription\n-----------\n\nReturns
the maximum depth of the given JSON document, or NULL if the argument\nis
null. An error will occur if the argument is an invalid JSON document.\n\n*
Scalar values or empty arrays or objects have a depth of 1.\n* Arrays or
objects that are not empty but contain only elements or member\nvalues of
depth 1 will have a depth of 2.\n* In other cases, the depth will be
greater than 2.\n\nExamples\n--------\n\nSELECT
JSON_DEPTH(\'[]\'), JSON_DEPTH(\'true\'),
JSON_DEPTH(\'{}\');\n+------------------+--------------------+------------------+\n|
JSON_DEPTH(\'[]\') | JSON_DEPTH(\'true\') |
JSON_DEPTH(\'{}\')
|\n+------------------+--------------------+------------------+\n|
1 | 1 | 1
|\n+------------------+--------------------+------------------+\n\nSELECT
JSON_DEPTH(\'[1, 2, 3]\'), JSON_DEPTH(\'[[], {},
[]]\');\n+-------------------------+----------------------------+\n|
JSON_DEPTH(\'[1, 2, 3]\') | JSON_DEPTH(\'[[], {},
[]]\') |\n+-------------------------+----------------------------+\n|
2 | 2
|\n+-------------------------+----------------------------+\n\nSELECT
JSON_DEPTH(\'[1, 2, [3, 4, 5, 6],
7]\');\n+---------------------------------------+\n|
JSON_DEPTH(\'[1, 2, [3, 4, 5, 6], 7]\')
|\n+---------------------------------------+\n|
3 |\n+---------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_depth/','','https://mariadb.com/kb/en/json_depth/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(749,40,'JSON_DETAILED','Syntax\n------\n\nJSON_DETAILED(json_doc[,
tab_size])\n\nDescription\n-----------\n\nRepresents JSON in the most
understandable way emphasizing nested
structures.\n\nExample\n-------\n\nSET @j = \'{
\"A\":1,\"B\":[2,3]}\';\n\nSELECT
@j;\n+--------------------+\n| @j
|\n+--------------------+\n| { \"A\":1,\"B\":[2,3]}
|\n+--------------------+\n\nSELECT
JSON_DETAILED(@j);\n+------------------------------------------------------------+\n|
JSON_DETAILED(@j)
|\n+------------------------------------------------------------+\n| {\n
\"A\": 1,\n \"B\":\n [\n 2,\n 3\n ]\n}
|\n+------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_detailed/','','https://mariadb.com/kb/en/json_detailed/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(750,40,'JSON_EXISTS','Syntax\n------\n\nDescription\n-----------\n\nDetermines
whether a specified JSON value exists in the given data. Returns 1\nif
found, 0 if not, or NULL if any of the inputs were
NULL.\n\nExamples\n--------\n\nSELECT
JSON_EXISTS(\'{\"key1\":\"xxxx\",
\"key2\":[1, 2, 3]}\',
\"$.key2\");\n+------------------------------------------------------------+\n|
JSON_EXISTS(\'{\"key1\":\"xxxx\",
\"key2\":[1, 2, 3]}\', \"$.key2\")
|\n+------------------------------------------------------------+\n|
1
|\n+------------------------------------------------------------+\n\nSELECT
JSON_EXISTS(\'{\"key1\":\"xxxx\",
\"key2\":[1, 2, 3]}\',
\"$.key3\");\n+------------------------------------------------------------+\n|
JSON_EXISTS(\'{\"key1\":\"xxxx\",
\"key2\":[1, 2, 3]}\', \"$.key3\")
|\n+------------------------------------------------------------+\n|
0
|\n+------------------------------------------------------------+\n\nSELECT
JSON_EXISTS(\'{\"key1\":\"xxxx\",
\"key2\":[1, 2, 3]}\',
\"$.key2[1]\");\n+---------------------------------------------------------------+\n|
JSON_EXISTS(\'{\"key1\":\"xxxx\",
\"key2\":[1, 2, 3]}\', \"$.key2[1]\")
|\n+---------------------------------------------------------------+\n|
1
|\n+---------------------------------------------------------------+\n\nSELECT
JSON_EXISTS(\'{\"key1\":\"xxxx\",
\"key2\":[1, 2, 3]}\',
\"$.key2[10]\");\n+----------------------------------------------------------------+\n|
JSON_EXISTS(\'{\"key1\":\"xxxx\",
\"key2\":[1, 2, 3]}\', \"$.key2[10]\")
|\n+----------------------------------------------------------------+\n|
0
|\n+----------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_exists/','','https://mariadb.com/kb/en/json_exists/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(751,40,'JSON_EXTRACT','Syntax\n------\n\nJSON_EXTRACT(json_doc,
path[, path] ...)\n\nDescription\n-----------\n\nExtracts data from a JSON
document. The extracted data is selected from the\nparts matching the path
arguments. Returns all matched values; either as a\nsingle matched value,
or, if the arguments could return multiple values, a\nresult autowrapped as
an array in the matching order.\n\nReturns NULL if no paths match or if any
of the arguments are NULL.\n\nAn error will occur if any path argument is
not a valid path, or if the\njson_doc argument is not a valid JSON
document.\n\nThe path expression be a JSONPath expression as supported by
MariaDB\n\nExamples\n--------\n\nSET @json = \'[1, 2, [3,
4]]\';\n\nSELECT JSON_EXTRACT(@json,
\'$[1]\');\n+-----------------------------+\n|
JSON_EXTRACT(@json, \'$[1]\')
|\n+-----------------------------+\n| 2
|\n+-----------------------------+\n\nSELECT JSON_EXTRACT(@json,
\'$[2]\');\n+-----------------------------+\n|
JSON_EXTRACT(@json, \'$[2]\')
|\n+-----------------------------+\n| [3, 4]
|\n+-----------------------------+\n\nSELECT JSON_EXTRACT(@json,
\'$[2][1]\');\n+--------------------------------+\n|
JSON_EXTRACT(@json, \'$[2][1]\')
|\n+--------------------------------+\n| 4
|\n+--------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_extract/','','https://mariadb.com/kb/en/json_extract/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(752,40,'JSON_INSERT','Syntax\n------\n\nJSON_INSERT(json_doc,
path, val[, path, val] ...)\n\nDescription\n-----------\n\nInserts data
into a JSON document, returning the resulting document or NULL if\nany
argument is null.\n\nAn error will occur if the JSON document is not
invalid, or if any of the\npaths are invalid or contain a * or **
wildcard.\n\nJSON_INSERT can only insert data while JSON_REPLACE can only
update. JSON_SET\ncan update or insert data.\n\nExamples\n--------\n\nSET
@json = \'{ \"A\": 0, \"B\": [1,
2]}\';\n\nSELECT JSON_INSERT(@json, \'$.C\', \'[3,
4]\');\n+--------------------------------------+\n| JSON_INSERT(@json,
\'$.C\', \'[3, 4]\')
|\n+--------------------------------------+\n| { \"A\": 0,
\"B\": [1, 2], \"C\":\"[3, 4]\"}
|\n+--------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_insert/','','https://mariadb.com/kb/en/json_insert/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(753,40,'JSON_KEYS','Syntax\n------\n\nJSON_KEYS(json_doc[,
path])\n\nDescription\n-----------\n\nReturns the keys as a JSON array from
the top-level value of a JSON object or,\nif the optional path argument is
provided, the top-level keys from the path.\n\nExcludes keys from nested
sub-objects in the top level value. The resulting\narray will be empty if
the selected object is empty.\n\nReturns NULL if any of the arguments are
null, a given path does not locate an\nobject, or if the json_doc argument
is not an object.\n\nAn error will occur if JSON document is invalid, the
path is invalid or if the\npath contains a * or **
wildcard.\n\nExamples\n--------\n\nSELECT
JSON_KEYS(\'{\"A\": 1, \"B\": {\"C\":
2}}\');\n+--------------------------------------+\n|
JSON_KEYS(\'{\"A\": 1, \"B\": {\"C\":
2}}\') |\n+--------------------------------------+\n|
[\"A\", \"B\"]
|\n+--------------------------------------+\n\nSELECT
JSON_KEYS(\'{\"A\": 1, \"B\": 2, \"C\":
{\"D\": 3}}\',
\'$.C\');\n+-----------------------------------------------------+\n|
JSON_KEYS(\'{\"A\": 1, \"B\": 2, \"C\":
{\"D\": 3}}\', \'$.C\')
|\n+-----------------------------------------------------+\n|
[\"D\"]
|\n+-----------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_keys/','','https://mariadb.com/kb/en/json_keys/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(754,40,'JSON_LENGTH','Syntax\n------\n\nJSON_LENGTH(json_doc[,
path])\n\nDescription\n-----------\n\nReturns the length of a JSON
document, or, if the optional path argument is\ngiven, the length of the
value within the document specified by the path.\n\nReturns NULL if any of
the arguments argument are null or the path argument\ndoes not identify a
value in the document.\n\nAn error will occur if the JSON document is
invalid, the path is invalid or if\nthe path contains a * or **
wildcard.\n\nLength will be determined as follow:\n\n* A scalar\'s
length is always 1.\n* If an array, the number of elements in the array.\n*
If an object, the number of members in the object.\n\nThe length of nested
arrays or objects are not counted.\n\nExamples\n--------\n\nURL:
https://mariadb.com/kb/en/json_length/','','https://mariadb.com/kb/en/json_length/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(755,40,'JSON_LOOSE','Syntax\n------\n\nJSON_LOOSE(json_doc)\n\nDescription\n-----------\n\nAdds
spaces to a JSON document to make it look more
readable.\n\nExample\n-------\n\nSET @j = \'{
\"A\":1,\"B\":[2,3]}\';\n\nSELECT JSON_LOOSE(@j),
@j;\n+-----------------------+--------------------+\n| JSON_LOOSE(@j)
| @j |\n+-----------------------+--------------------+\n|
{\"A\": 1, \"B\": [2, 3]} | {
\"A\":1,\"B\":[2,3]}
|\n+-----------------------+--------------------+\n\nURL:
https://mariadb.com/kb/en/json_loose/','','https://mariadb.com/kb/en/json_loose/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(756,40,'JSON_MERGE','Syntax\n------\n\nJSON_MERGE(json_doc,
json_doc[, json_doc] ...)\n\nDescription\n-----------\n\nMerges the given
JSON documents.\n\nReturns the merged result,or NULL if any argument is
NULL.\n\nAn error occurs if any of the arguments are not valid JSON
documents.\n\nJSON_MERGE has been deprecated since MariaDB 10.2.25, MariaDB
10.3.16 and\nMariaDB 10.4.5. JSON_MERGE_PATCH is an RFC 7396-compliant
replacement, and\nJSON_MERGE_PRESERVE is a
synonym.\n\nExample\n-------\n\nSET @json1 = \'[1, 2]\';\nSET
@json2 = \'[3, 4]\';\n\nSELECT
JSON_MERGE(@json1,@json2);\n+---------------------------+\n|
JSON_MERGE(@json1,@json2) |\n+---------------------------+\n| [1, 2, 3, 4]
|\n+---------------------------+\n\nURL:
https://mariadb.com/kb/en/json_merge/','','https://mariadb.com/kb/en/json_merge/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(757,40,'JSON_MERGE_PATCH','MariaDB starting with
10.2.25\n-----------------------------\nJSON_MERGE_PATCH was introduced in
MariaDB 10.2.25, MariaDB 10.3.16 and\nMariaDB
10.4.5.\n\nSyntax\n------\n\nJSON_MERGE_PATCH(json_doc, json_doc[,
json_doc] ...)\n\nDescription\n-----------\n\nMerges the given JSON
documents, returning the merged result, or NULL if any\nargument is
NULL.\n\nJSON_MERGE_PATCH is an RFC 7396-compliant replacement for
JSON_MERGE, which\nhas been deprecated.\n\nExample\n-------\n\nSET @json1 =
\'[1, 2]\';\nSET @json2 = \'[2, 3]\';\nSELECT
JSON_MERGE_PATCH(@json1,@json2),JSON_MERGE_PRESERVE(@json1,@json2);\n+---------------------------------+------------------------------------+\n|
JSON_MERGE_PATCH(@json1,@json2) | JSON_MERGE_PRESERVE(@json1,@json2)
|\n+---------------------------------+------------------------------------+\n|
[2, 3] | [1, 2, 2, 3]
|\n+---------------------------------+------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_merge_patch/','','https://mariadb.com/kb/en/json_merge_patch/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(758,40,'JSON_MERGE_PRESERVE','MariaDB starting with
10.2.25\n-----------------------------\nJSON_MERGE_PRESERVE was introduced
in MariaDB 10.2.25, MariaDB 10.3.16 and\nMariaDB
10.4.5.\n\nSyntax\n------\n\nJSON_MERGE_PRESERVE(json_doc, json_doc[,
json_doc] ...)\n\nDescription\n-----------\n\nMerges the given JSON
documents, returning the merged result, or NULL if any\nargument is
NULL.\n\nJSON_MERGE_PRESERVE was introduced in MariaDB 10.2.25, MariaDB
10.3.16 and\nMariaDB 10.4.5 as a synonym for JSON_MERGE, which has been
deprecated.\n\nExample\n-------\n\nSET @json1 = \'[1, 2]\';\nSET
@json2 = \'[2, 3]\';\nSELECT
JSON_MERGE_PATCH(@json1,@json2),JSON_MERGE_PRESERVE(@json1,@json2);\n+---------------------------------+------------------------------------+\n|
JSON_MERGE_PATCH(@json1,@json2) | JSON_MERGE_PRESERVE(@json1,@json2)
|\n+---------------------------------+------------------------------------+\n|
[2, 3] | [1, 2, 2, 3]
|\n+---------------------------------+------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_merge_preserve/','','https://mariadb.com/kb/en/json_merge_preserve/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(759,40,'JSON_OBJECT','Syntax\n------\n\nJSON_OBJECT([key,
value[, key, value] ...])\n\nDescription\n-----------\n\nReturns a JSON
object containing the given key/value pairs. The key/value list\ncan be
empty.\n\nAn error will occur if there are an odd number of arguments, or
any key name\nis NULL.\n\nExample\n-------\n\nSELECT
JSON_OBJECT(\"id\", 1, \"name\",
\"Monty\");\n+---------------------------------------+\n|
JSON_OBJECT(\"id\", 1, \"name\", \"Monty\")
|\n+---------------------------------------+\n| {\"id\": 1,
\"name\": \"Monty\"}
|\n+---------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_object/','','https://mariadb.com/kb/en/json_object/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(760,40,'JSON_QUERY','Syntax\n------\n\nJSON_QUERY(json_doc,
path)\n\nDescription\n-----------\n\nGiven a JSON document, returns an
object or array specified by the path.\nReturns NULL if not given a valid
JSON document, or if there is no match.\n\nExamples\n--------\n\nselect
json_query(\'{\"key1\":{\"a\":1,
\"b\":[1,2]}}\',
\'$.key1\');\n+-----------------------------------------------------+\n|
json_query(\'{\"key1\":{\"a\":1,
\"b\":[1,2]}}\', \'$.key1\')
|\n+-----------------------------------------------------+\n|
{\"a\":1, \"b\":[1,2]}
|\n+-----------------------------------------------------+\n\nselect
json_query(\'{\"key1\":123, \"key1\":
[1,2,3]}\',
\'$.key1\');\n+-------------------------------------------------------+\n|
json_query(\'{\"key1\":123, \"key1\":
[1,2,3]}\', \'$.key1\')
|\n+-------------------------------------------------------+\n| [1,2,3]
|\n+-------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_query/','','https://mariadb.com/kb/en/json_query/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(761,40,'JSON_QUOTE','Syntax\n------\n\nJSON_QUOTE(json_value)\n\nDescription\n-----------\n\nQuotes
a string as a JSON value, usually for producing valid JSON string\nliterals
for inclusion in JSON documents. Wraps the string with double
quote\ncharacters and escapes interior quotes and other special characters,
returning\na utf8mb4 string.\n\nReturns NULL if the argument is
NULL.\n\nExamples\n--------\n\nSELECT JSON_QUOTE(\'A\'),
JSON_QUOTE(\"B\"),
JSON_QUOTE(\'\"C\"\');\n+-----------------+-----------------+-------------------+\n|
JSON_QUOTE(\'A\') | JSON_QUOTE(\"B\") |
JSON_QUOTE(\'\"C\"\')
|\n+-----------------+-----------------+-------------------+\n|
\"A\" | \"B\" |
\"\\\"C\\\"\"
|\n+-----------------+-----------------+-------------------+\n\nURL:
https://mariadb.com/kb/en/json_quote/','','https://mariadb.com/kb/en/json_quote/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(762,40,'JSON_REMOVE','Syntax\n------\n\nJSON_REMOVE(json_doc,
path[, path] ...)\n\nDescription\n-----------\n\nRemoves data from a JSON
document returning the result, or NULL if any of the\narguments are null.
If the element does not exist in the document, no changes\nare made.\n\nAn
error will occur if JSON document is invalid, the path is invalid or if
the\npath contains a * or ** wildcard.\n\nPath arguments are evaluated from
left to right, with the result from the\nearlier evaluation being used as
the value for the next.\n\nExamples\n--------\n\nSELECT
JSON_REMOVE(\'{\"A\": 1, \"B\": 2,
\"C\": {\"D\": 3}}\',
\'$.C\');\n+-------------------------------------------------------+\n|
JSON_REMOVE(\'{\"A\": 1, \"B\": 2,
\"C\": {\"D\": 3}}\', \'$.C\')
|\n+-------------------------------------------------------+\n|
{\"A\": 1, \"B\": 2}
|\n+-------------------------------------------------------+\n\nSELECT
JSON_REMOVE(\'[\"A\", \"B\", [\"C\",
\"D\"], \"E\"]\',
\'$[1]\');\n+----------------------------------------------------+\n|
JSON_REMOVE(\'[\"A\", \"B\", [\"C\",
\"D\"], \"E\"]\', \'$[1]\')
|\n+----------------------------------------------------+\n|
[\"A\", [\"C\", \"D\"], \"E\"]
|\n+----------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_remove/','','https://mariadb.com/kb/en/json_remove/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(763,40,'JSON_REPLACE','Syntax\n------\n\nJSON_REPLACE(json_doc,
path, val[, path, val] ...)\n\nDescription\n-----------\n\nReplaces
existing values in a JSON document, returning the result, or NULL if\nany
of the arguments are NULL.\n\nAn error will occur if the JSON document is
invalid, the path is invalid or if\nthe path contains a * or **
wildcard.\n\nPaths and values are evaluated from left to right, with the
result from the\nearlier evaluation being used as the value for the
next.\n\nJSON_REPLACE can only update data, while JSON_INSERT can only
insert. JSON_SET\ncan update or insert
data.\n\nExamples\n--------\n\nSELECT JSON_REPLACE(\'{
\"A\": 1, \"B\": [2, 3]}\', \'$.B[1]\',
4);\n+-----------------------------------------------------+\n|
JSON_REPLACE(\'{ \"A\": 1, \"B\": [2, 3]}\',
\'$.B[1]\', 4)
|\n+-----------------------------------------------------+\n| {
\"A\": 1, \"B\": [2, 4]}
|\n+-----------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_replace/','','https://mariadb.com/kb/en/json_replace/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(764,40,'JSON_SEARCH','Syntax\n------\n\nJSON_SEARCH(json_doc,
return_arg, search_str[, escape_char[, path]
...])\n\nDescription\n-----------\n\nReturns the path to the given string
within a JSON document, or NULL if any of\njson_doc, search_str or a path
argument is NULL; if the search string is not\nfound, or if no path exists
within the document.\n\nA warning will occur if the JSON document is not
valid, any of the path\narguments are not valid, if return_arg is neither
one nor all, or if the\nescape character is not a constant. NULL will be
returned.\n\nreturn_arg can be one of two values:\n\n* \'one:
Terminates after finding the first match, so will return one path\nstring.
If there is more than one match, it is undefined which is
considered\nfirst.\n* all: Returns all matching path strings, without
duplicates. Multiple strings\nare autowrapped as an array. The order is
undefined.\n\nExamples\n--------\n\nSET @json = \'[\"A\",
[{\"B\": \"1\"}], {\"C\":\"AB\"},
{\"D\":\"BC\"}]\';\n\nSELECT JSON_SEARCH(@json,
\'one\',
\'AB\');\n+---------------------------------+\n|
JSON_SEARCH(@json, \'one\', \'AB\')
|\n+---------------------------------+\n| \"$[2].C\"
|\n+---------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_search/','','https://mariadb.com/kb/en/json_search/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(765,40,'JSON_SET','Syntax\n------\n\nJSON_SET(json_doc,
path, val[, path, val] ...)\n\nDescription\n-----------\n\nUpdates or
inserts data into a JSON document, returning the result, or NULL if\nany of
the arguments are NULL or the optional path fails to find an object.\n\nAn
error will occur if the JSON document is invalid, the path is invalid or
if\nthe path contains a * or wildcard.\n\nJSON_SET can update or insert
data, while JSON_REPLACE can only update, and\nJSON_INSERT only
insert.\n\nExamples\n--------\n\nSELECT JSON_SET(Priv,
\'$.locked\', \'true\') FROM mysql.global_priv\n\nURL:
https://mariadb.com/kb/en/json_set/','','https://mariadb.com/kb/en/json_set/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(766,40,'JSON_TABLE','MariaDB starting with
10.6.0\n----------------------------\nJSON_TABLE was added in MariaDB
10.6.0.\n\nJSON_TABLE is a table function that converts JSON data into a
relational form.\n\nSyntax\n------\n\nJSON_TABLE(json_doc, \n
context_path COLUMNS (column_list)\n) [AS] alias\n\ncolumn_list:\n
column[, column][, ...]\n\ncolumn:\n name FOR ORDINALITY\n | name type
PATH path_str [on_empty] [on_error]\n | name type EXISTS PATH path_str\n
| NESTED PATH path_str COLUMNS (column_list)\n\non_empty:\n {NULL |
DEFAULT string | ERROR} ON EMPTY\n\non_error:\n {NULL | DEFAULT string |
ERROR} ON ERROR\n\nDescription\n-----------\n\nJSON_TABLE can be used in
contexts where a table reference can be used; in the\nFROM clause of a
SELECT statement, and in multi-table UPDATE/DELETE statements.\n\njson_doc
is the JSON document to extract data from. In the simplest case, it\nis a
string literal containing JSON. In more complex cases it can be
an\narbitrary expression returning JSON. The expression may have references
to\ncolumns of other tables. However, one can only refer to tables that
precede\nthis JSON_TABLE invocation. For RIGHT JOIN, it is assumed that its
outer side\nprecedes the inner. All tables in outer selects are also
considered preceding.\n\ncontext_path is a JSON Path expression pointing to
a collection of nodes in\njson_doc that will be used as the source of
rows.\n\nThe COLUMNS clause declares the names and types of the columns
that JSON_TABLE\nreturns, as well as how the values of the columns are
produced.\n\nColumn Definitions\n------------------\n\nThe following types
of columns are supported:\n\nPath Columns\n------------\n\nname type PATH
path_str [on_empty] [on_error]\n\nLocates the JSON node pointed to by
path_str and returns its value. The\npath_str is evaluated using the
current row source node as the context node.\n\nset @json=\'\n[\n
{\"name\":\"Laptop\",
\"color\":\"black\",
\"price\":\"1000\"},\n
{\"name\":\"Jeans\",
\"color\":\"blue\"}\n]\';\n\nselect * from
json_table(@json, \'$[*]\' \n columns(\n name varchar(10) path
\'$.name\',\n color varchar(10) path \'$.color\',\n
price decimal(8,2) path \'$.price\' )\n) as
jt;\n+--------+-------+---------+\n| name | color | price
|\n+--------+-------+---------+\n| Laptop | black | 1000.00 |\n| Jeans |
blue | NULL |\n+--------+-------+---------+\n\nThe on_empty and
on_error clauses specify the actions to be performed when the\nvalue was
not found or there was an error condition. See the ON EMPTY and ON\nERROR
clauses section for details.\n\nORDINALITY
Columns\n------------------\n\nname FOR ORDINALITY\n\nCounts the rows,
starting from 1.\n\nExample:\n\nset @json=\'\n[\n
{\"name\":\"Laptop\",
\"color\":\"black\"},\n
{\"name\":\"Jeans\",
\"color\":\"blue\"}\n]\';\n\nselect * from
json_table(@json, \'$[*]\' \n columns(\n id for ordinality,\n
name varchar(10) path \'$.name\')\n) as
jt;\n+------+--------+\n| id | name |\n+------+--------+\n| 1 |
Laptop |\n| 2 | Jeans |\n+------+--------+\n\nEXISTS PATH
Columns\n-------------------\n\nname type EXISTS PATH path_str\n\nChecks
whether the node pointed to by value_path exists. The value_path
is\nevaluated using the current row source node as the context node.\n\nset
@json=\'\n[\n {\"name\":\"Laptop\",
\"color\":\"black\", \"price\":1000},\n
{\"name\":\"Jeans\",
\"color\":\"blue\"}\n]\';\n\nselect * from
json_table(@json, \'$[*]\' \n columns(\n name varchar(10) path
\'$.name\',\n has_price integer exists path
\'$.price\')\n) as jt;\n+--------+-----------+\n| name |
has_price |\n+--------+-----------+\n| Laptop | 1 |\n| Jeans |
0 |\n+--------+-----------+\n\nNESTED PATHs\n------------\n\nNESTED
PATH converts nested JSON structures into multiple rows.\n\nNESTED PATH
path COLUMNS (column_list)\n\nIt finds the sequence of JSON nodes pointed
to by path and uses it to produce\nrows. For each found node, a row is
generated with column values as specified\nby the NESTED PATH\'s
COLUMNS clause. If path finds no nodes, only one row is\ngenerated with all
columns having NULL values.\n\nFor example, consider a JSON document that
contains an array of items, and\neach item, in turn, is expected to have an
array of its available sizes:\n\nset @json=\'\n[\n
{\"name\":\"Jeans\", \"sizes\": [32, 34,
36]},\n {\"name\":\"T-Shirt\",
\"sizes\":[\"Medium\", \"Large\"]},\n
{\"name\":\"Cellphone\"}\n]\';\n\nNESTED PATH
allows one to produce a separate row for each size each item has:\n\nselect
* from json_table(@json, \'$[*]\' \n columns(\n name
varchar(10) path \'$.name\',\n nested path
\'$.sizes[*]\' columns (\n size varchar(32) path
\'$\'\n )\n )\n) as jt;\n+-----------+--------+\n| name |
size |\n+-----------+--------+\n| Jeans | 32 |\n| Jeans | 34
|\n| Jeans | 36 |\n| T-Shirt | Medium |\n| T-Shirt | Large
|\n| Cellphone | NULL |\n+-----------+--------+\n\nNESTED PATH clauses
can be nested within one another. They can also be located\nnext to each
other. In that case, the nested path clauses will produce records\none at a
time. The ones that are not producing records will have all columns\nset to
NULL.\n\nExample:\n\nset @json=\'\n[\n
{\"name\":\"Jeans\", \"sizes\": [32, 34,
36], \"colors\":[\"black\",
\"blue\"]}\n]\';\n\nselect * from json_table(@json,
\'$[*]\' \n columns(\n name varchar(10) path
\'$.name\',\n nested path \'$.sizes[*]\' columns (\n
size varchar(32) path \'$\'\n ),\n nested path
\'$.colors[*]\' columns (\n color varchar(32) path
\'$\'\n )\n )\n) as jt;\n\n+-------+------+-------+\n| name |
size | color |\n+-------+------+-------+\n| Jeans | 32 | NULL |\n| Jeans
| 34 | NULL |\n| Jeans | 36 | NULL |\n| Jeans | NULL | black |\n|
Jeans | NULL | blue |\n+-------+------+-------+\n\nON EMPTY and ON ERROR
Clauses\n-----------------------------\n\nThe ON EMPTY clause specifies
what will be done when the element specified by\nthe search path is missing
in the JSON document.\n\non_empty:\n {NULL | DEFAULT string | ERROR} ON
EMPTY\n\nWhen ON EMPTY clause is not present, NULL ON EMPTY is
implied.\n\non_error:\n {NULL | DEFAULT string | ERROR} ON ERROR\n\nThe ON
ERROR clause specifies what should be done if a JSON structure
error\noccurs when trying to extract the value pointed to by the path
expression. A\nJSON structure error here occurs only when one attempts to
convert a JSON\nnon-scalar (array or object) into a scalar value. When the
ON ERROR clause is\nnot present, NULL ON ERROR is implied.\n\nNote: A
datatype conversion error (e.g. attempt to store a non-integer value\ninto
an integer field, or a varchar column being truncated) is not considered\na
JSON error and so will not trigger the ON ERROR behavior. It will
produce\nwarnings, in the same way as CAST(value AS datatype)
would.\n\nReplication\n-----------\n\nIn the current code, evaluation of
JSON_TABLE is deterministic, that is, for a\ngiven input string JSON_TABLE
will always produce the same set of rows in the\nsame order. However, one
can think of JSON documents that one can consider\nidentical which will
produce different output. In order to be future-proof and\nwithstand
changes like:\n\n* sorting JSON object members by name (like MySQL does)\n*
changing the way duplicate object members are handled\nthe function is
marked as unsafe for statement-based replication.\n\nExtracting a
Subdocument into a
Column\n--------------------------------------\n\nMariaDB starting with
10.6.9\n----------------------------\nPrior to MariaDB 10.6.9, JSON_TABLE
did not allow one to extract a JSON\n\"subdocument\" into a JSON
column.\n\nSELECT * FROM JSON_TABLE(\'{\"foo\":
[1,2,3,4]}\',\'$\' columns( jscol json
path\n\'$.foo\') ) AS T;\n+-------+\n| jscol |\n+-------+\n| NULL
|\n+-------+\n\nThis is supported from MariaDB 10.6.9:\n\nSELECT * FROM
JSON_TABLE(\'{\"foo\": [1,2,3,4]}\',\'$\'
columns( jscol json path\n\'$.foo\') ) AS T;\n+-----------+\n|
jscol |\n+-----------+\n| [1,2,3,4] |\n+-----------+\n\nURL:
https://mariadb.com/kb/en/json_table/','','https://mariadb.com/kb/en/json_table/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(767,40,'JSON_TYPE','Syntax\n------\n\nJSON_TYPE(json_val)\n\nDescription\n-----------\n\nReturns
the type of a JSON value (as a string), or NULL if the argument
is\nnull.\n\nAn error will occur if the argument is an invalid JSON
value.\n\nThe following is a complete list of the possible return
types:\n\n+-----------------------------------+-----------------+-----------------------+\n|
Return type | Value | Example
|\n+-----------------------------------+-----------------+-----------------------+\n|
ARRAY | JSON array | [1, 2,
{\"key\": |\n| |
| \"value\"}]
|\n+-----------------------------------+-----------------+-----------------------+\n|
OBJECT | JSON object |
{\"key\":\"value\"}
|\n+-----------------------------------+-----------------+-----------------------+\n|
BOOLEAN | JSON | true, false
|\n| | true/false |
|\n| | literals |
|\n+-----------------------------------+-----------------+-----------------------+\n|
DOUBLE | A number with | 1.2
|\n| | at least one |
|\n| | floating point |
|\n| | decimal. |
|\n+-----------------------------------+-----------------+-----------------------+\n|
INTEGER | A number | 1
|\n| | without a |
|\n| | floating point |
|\n| | decimal. |
|\n+-----------------------------------+-----------------+-----------------------+\n|
NULL | JSON null | null
|\n| | literal (this |
|\n| | is returned as |
|\n| | a string, not |
|\n| | to be confused |
|\n| | with the SQL
| |\n| | NULL
value!) |
|\n+-----------------------------------+-----------------+-----------------------+\n|
STRING | JSON String | \"a sample
string\"
|\n+-----------------------------------+-----------------+-----------------------+\n\nExamples\n--------\n\nSELECT
JSON_TYPE(\'{\"A\": 1, \"B\": 2, \"C\":
3}\');\n+---------------------------------------+\n|
JSON_TYPE(\'{\"A\": 1, \"B\": 2, \"C\":
3}\') |\n+---------------------------------------+\n| OBJECT
|\n+---------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_type/','','https://mariadb.com/kb/en/json_type/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(768,40,'JSON_UNQUOTE','Syntax\n------\n\nJSON_UNQUOTE(val)\n\nDescription\n-----------\n\nUnquotes
a JSON value, returning a string, or NULL if the argument is null.\n\nAn
error will occur if the given value begins and ends with double quotes
and\nis an invalid JSON string literal.\n\nIf the given value is not a JSON
string, value is passed through unmodified.\n\nCertain character sequences
have special meanings within a string. Usually, a\nbackslash is ignored,
but the escape sequences in the table below are\nrecognised by MariaDB,
unless the SQL Mode is set to NO_BACKSLASH_ESCAPES
SQL.\n\n+-----------------------------------------------+-----------------------------+\n|
Escape sequence | Character
|\n+-----------------------------------------------+-----------------------------+\n|
\\\" | Double quote
(\")
|\n+-----------------------------------------------+-----------------------------+\n|
\\b | Backslash
|\n+-----------------------------------------------+-----------------------------+\n|
\\f | Formfeed
|\n+-----------------------------------------------+-----------------------------+\n|
\\n | Newline (linefeed)
|\n+-----------------------------------------------+-----------------------------+\n|
\\r | Carriage return
|\n+-----------------------------------------------+-----------------------------+\n|
\\t | Tab
|\n+-----------------------------------------------+-----------------------------+\n|
\\\\ | Backslash (\\)
|\n+-----------------------------------------------+-----------------------------+\n|
\\uXXXX | UTF-8 bytes for Unicode
|\n| | value XXXX
|\n+-----------------------------------------------+-----------------------------+\n\nExamples\n--------\n\nSELECT
JSON_UNQUOTE(\'\"Monty\"\');\n+-------------------------+\n|
JSON_UNQUOTE(\'\"Monty\"\')
|\n+-------------------------+\n| Monty
|\n+-------------------------+\n\nWith the default SQL Mode:\n\nSELECT
JSON_UNQUOTE(\'Si\\bng\\ting\');\n+-----------------------------+\n|
JSON_UNQUOTE(\'Si\\bng\\ting\')
|\n+-----------------------------+\n| Sng ing
|\n+-----------------------------+\n\nSetting NO_BACKSLASH_ESCAPES:\n\nSET
@@sql_mode = \'NO_BACKSLASH_ESCAPES\';\n\nSELECT
JSON_UNQUOTE(\'Si\\bng\\ting\');\n+-----------------------------+\n|
JSON_UNQUOTE(\'Si\\bng\\ting\')
|\n+-----------------------------+\n| Si\\bng\\ting
|\n+-----------------------------+\n\nURL:
https://mariadb.com/kb/en/json_unquote/','','https://mariadb.com/kb/en/json_unquote/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(769,40,'JSON_VALID','Syntax\n------\n\nJSON_VALID(value)\n\nDescription\n-----------\n\nIndicates
whether the given value is a valid JSON document or not. Returns 1\nif
valid, 0 if not, and NULL if the argument is NULL.\n\nFrom MariaDB 10.4.3,
the JSON_VALID function is automatically used as a CHECK\nconstraint for
the JSON data type alias in order to ensure that a valid json\ndocument is
inserted.\n\nExamples\n--------\n\nSELECT
JSON_VALID(\'{\"id\": 1, \"name\":
\"Monty\"}\');\n+------------------------------------------+\n|
JSON_VALID(\'{\"id\": 1, \"name\":
\"Monty\"}\')
|\n+------------------------------------------+\n|
1 |\n+------------------------------------------+\n\nSELECT
JSON_VALID(\'{\"id\": 1, \"name\":
\"Monty\",
\"oddfield\"}\');\n+------------------------------------------------------+\n|
JSON_VALID(\'{\"id\": 1, \"name\":
\"Monty\", \"oddfield\"}\')
|\n+------------------------------------------------------+\n|
0
|\n+------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/json_valid/','','https://mariadb.com/kb/en/json_valid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(770,40,'JSON_VALUE','Syntax\n------\n\nJSON_VALUE(json_doc,
path)\n\nDescription\n-----------\n\nGiven a JSON document, returns the
scalar specified by the path. Returns NULL\nif not given a valid JSON
document, or if there is no match.\n\nExamples\n--------\n\nselect
json_value(\'{\"key1\":123}\',
\'$.key1\');\n+--------------------------------------+\n|
json_value(\'{\"key1\":123}\', \'$.key1\')
|\n+--------------------------------------+\n| 123
|\n+--------------------------------------+\n\nselect
json_value(\'{\"key1\": [1,2,3],
\"key1\":123}\',
\'$.key1\');\n+-------------------------------------------------------+\n|
json_value(\'{\"key1\": [1,2,3],
\"key1\":123}\', \'$.key1\')
|\n+-------------------------------------------------------+\n| 123
|\n+-------------------------------------------------------+\n\nIn the SET
statement below, two escape characters are needed, as a single\nescape
character would be applied by the SQL parser in the SET statement, and\nthe
escaped character would not form part of the saved value.\n\nSET @json =
\'{\"key1\":\"60\\\\\" Table\",
\"key2\":\"1\"}\';\n\nSELECT
JSON_VALUE(@json,\'$.key1\') AS Name ,
json_value(@json,\'$.key2\') as ID;\n+-----------+------+\n| Name
| ID |\n+-----------+------+\n| 60\" Table | 1
|\n+-----------+------+\n\nURL:
https://mariadb.com/kb/en/json_value/','','https://mariadb.com/kb/en/json_value/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(771,41,'Window Functions
Overview','Introduction\n------------\n\nWindow functions allow
calculations to be performed across a set of rows\nrelated to the current
row.\n\nSyntax\n------\n\nfunction (expression) OVER (\n [ PARTITION BY
expression_list ]\n [ ORDER BY order_list [ frame_clause ] ]
)\n\nfunction:\n A valid window function\n\nexpression_list:\n expression |
column_name [, expr_list ]\n\norder_list:\n expression | column_name [ ASC
| DESC ]\n [, ... ]\n\nframe_clause:\n {ROWS | RANGE} {frame_border |
BETWEEN frame_border AND frame_border}\n\nframe_border:\n | UNBOUNDED
PRECEDING\n | UNBOUNDED FOLLOWING\n | CURRENT ROW\n | expr PRECEDING\n |
expr FOLLOWING\n\nDescription\n-----------\n\nIn some ways, window
functions are similar to aggregate functions in that they\nperform
calculations across a set of rows. However, unlike aggregate\nfunctions,
the output is not grouped into a single row.\n\nNon-aggregate window
functions include\n\n* CUME_DIST\n* DENSE_RANK\n* FIRST_VALUE\n* LAG\n*
LAST_VALUE\n* LEAD\n* MEDIAN\n* NTH_VALUE\n* NTILE\n* PERCENT_RANK\n*
PERCENTILE_CONT\n* PERCENTILE_DISC\n* RANK, ROW_NUMBER\n\nAggregate
functions that can also be used as window functions include\n\n* AVG\n*
BIT_AND\n* BIT_OR\n* BIT_XOR\n* COUNT\n* MAX\n* MIN\n* STD\n* STDDEV\n*
STDDEV_POP\n* STDDEV_SAMP\n* SUM\n* VAR_POP\n* VAR_SAMP\n*
VARIANCE\n\nWindow function queries are characterised by the OVER keyword,
following which\nthe set of rows used for the calculation is specified. By
default, the set of\nrows used for the calculation (the \"window) is
the entire dataset, which can\nbe ordered with the ORDER BY clause. The
PARTITION BY clause is used to reduce\nthe window to a particular group
within the dataset.\n\nFor example, given the following data:\n\nCREATE
TABLE student (name CHAR(10), test CHAR(10), score TINYINT);\n\nINSERT INTO
student VALUES \n (\'Chun\', \'SQL\', 75),
(\'Chun\', \'Tuning\', 73),\n (\'Esben\',
\'SQL\', 43), (\'Esben\', \'Tuning\', 31),\n
(\'Kaolin\', \'SQL\', 56), (\'Kaolin\',
\'Tuning\', 88),\n (\'Tatiana\', \'SQL\',
87), (\'Tatiana\', \'Tuning\', 83);\n\nthe following
two queries return the average partitioned by test and by
name\nrespectively:\n\nSELECT name, test, score, AVG(score) OVER (PARTITION
BY test) \n AS average_by_test FROM
student;\n+---------+--------+-------+-----------------+\n| name | test
| score | average_by_test
|\n+---------+--------+-------+-----------------+\n| Chun | SQL |
75 | 65.2500 |\n| Chun | Tuning | 73 | 68.7500 |\n|
Esben | SQL | 43 | 65.2500 |\n| Esben | Tuning | 31 |
68.7500 |\n| Kaolin | SQL | 56 | 65.2500 |\n| Kaolin
| Tuning | 88 | 68.7500 |\n| Tatiana | SQL | 87 |
65.2500 |\n| Tatiana | Tuning | 83 | 68.7500
|\n+---------+--------+-------+-----------------+\n\nSELECT name, test,
score, AVG(score) OVER (PARTITION BY name) \n AS average_by_name FROM
student;\n+---------+--------+-------+-----------------+\n| name | test
| score | average_by_name
|\n+---------+--------+-------+-----------------+\n| Chun | SQL |
75 | 74.0000 |\n| Chun | Tuning | 73 | 74.0000 |\n|
Esben | SQL | 43 | 37.0000 |\n| Esben | Tuning | 31 |
37.0000 |\n| Kaolin | SQL | 56 | 72.0000 |\n| Kaolin
| Tuning | 88 | 72.0000 |\n| Tatiana | SQL | 87 |
85.0000 |\n| Tatiana | Tuning | 83 | 85.0000
|\n+---------+--------+-------+-----------------+\n\nIt is also possible to
specify which rows to include for the window function\n(for example, the
current row and all preceding rows). See Window Frames for\nmore
details.\n\nScope\n-----\n\nWindow functions were introduced in SQL:2003,
and their definition was\nexpanded in subsequent versions of the standard.
The last expansion was in the\nlatest version of the standard,
SQL:2011.\n\nMost database products support a subset of the standard, they
implement some\nfunctions defined as late as in SQL:2011, and at the same
time leave some\nparts of SQL:2008 unimplemented.\n\nMariaDB:\n\n* Supports
ROWS and RANGE-type frames\nAll kinds of frame bounds are supported,
including RANGE PRECEDING|FOLLOWING n\nframe bounds (unlike PostgreSQL or
MS SQL Server)\nDoes not yet support DATE[TIME] datatype and arithmetic for
RANGE-type frames\n(MDEV-9727)\n\n* Does not support GROUPS-type frames (it
seems that no popular database\nsupports it, either)\n\n* Does not support
frame exclusion (no other database seems to support it,\neither)
(MDEV-9724)\n* Does not support explicit NULLS FIRST or NULLS LAST.\n* Does
not support nested navigation in window functions (this is\nVALUE_OF(expr
AT row_marker [, default_value) syntax)\n\n* The following window functions
are supported:\n\"Streamable\" window functions: ROW_NUMBER,
RANK, DENSE_RANK, \nWindow functions that can be streamed once the number
of rows in partition is\nknown: PERCENT_RANK, CUME_DIST, NTILE\n\n*
Aggregate functions that are currently supported as window functions
are:\nCOUNT, SUM, AVG, BIT_OR, BIT_AND, BIT_XOR.\n* Aggregate functions
with the DISTINCT specifier (e.g. COUNT( DISTINCT x))\nare not supported as
window functions.\n\nLinks\n-----\n\n* MDEV-6115 is the main jira task for
window functions development. Other\ntasks are are attached as sub-tasks\n*
bb-10.2-mdev9543 is the feature tree for window functions. Development
is\nongoing, and this tree has the newest changes.\n* Testcases are in
mysql-test/t/win*.test\n\nExamples\n--------\n\nGiven the following sample
data:\n\nCREATE TABLE users (\n email VARCHAR(30),\n first_name
VARCHAR(30),\n last_name VARCHAR(30),\n account_type
VARCHAR(30)\n);\n\nINSERT INTO users VALUES \n
(\'admin@boss.org\', \'Admin\', \'Boss\',
\'admin\'),\n (\'bob.carlsen@foo.bar\',
\'Bob\', \'Carlsen\', \'regular\'),\n
(\'eddie.stevens@data.org\', \'Eddie\',
\'Stevens\', \'regular\'),\n
(\'john.smith@xyz.org\', \'John\', \'Smith\',
\'regular\'),\n (\'root@boss.org\', \'Root\',
\'Chief\', \'admin\')\n\nFirst, let\'s order the
records by email alphabetically, giving each an\nascending rnum value
starting with 1. This will make use of the ROW_NUMBER\nwindow
function:\n\nSELECT row_number() OVER (ORDER BY email) AS rnum,\n email,
first_name, last_name, account_type\nFROM users ORDER BY
email;\n+------+------------------------+------------+-----------+--------------+\n|
rnum | email | first_name | last_name | account_type
|\n+------+------------------------+------------+-----------+--------------+\n|
1 | admin@boss.org | Admin | Boss | admin |\n|
2 | bob.carlsen@foo.bar | Bob | Carlsen | regular |\n|
3 | eddie.stevens@data.org | Eddie | Stevens | regular |\n|
4 | john.smith@xyz.org | John | Smith | regular |\n|
5 | root@boss.org | Root | Chief | admin
|\n+------+------------------------+------------+-----------+--------------\n\nWe
can generate separate sequences based on account type, using the
PARTITION\nBY clause:\n\nSELECT row_number() OVER (PARTITION BY
account_type ORDER BY email) AS rnum, \n email, first_name, last_name,
account_type\nFROM users ORDER BY
account_type,email;\n+------+------------------------+------------+-----------+--------------+\n|
rnum | email | first_name | last_name | account_type
|\n+------+------------------------+------------+-----------+--------------+\n|
1 | admin@boss.org | Admin | Boss | admin |\n|
2 | root@boss.org | Root | Chief | admin |\n|
1 | bob.carlsen@foo.bar | Bob | Carlsen | regular |\n|
2 | eddie.stevens@data.org | Eddie | Stevens | regular |\n|
3 | john.smith@xyz.org | John | Smith | regular
|\n+------+------------------------+------------+-----------+--------------+\n\nGiven
the following structure and data, we want to find the top 5 salaries\nfrom
each department.\n\nCREATE TABLE employee_salaries (dept VARCHAR(20), name
VARCHAR(20), salary\nINT(11));\n\nINSERT INTO employee_salaries
VALUES\n(\'Engineering\', \'Dharma\',
3500),\n(\'Engineering\', \'Binh\',
3000),\n(\'Engineering\', \'Adalynn\',
2800),\n(\'Engineering\', \'Samuel\',
2500),\n(\'Engineering\', \'Cveta\',
2200),\n(\'Engineering\', \'Ebele\',
1800),\n(\'Sales\', \'Carbry\',
500),\n(\'Sales\', \'Clytemnestra\',
400),\n(\'Sales\', \'Juraj\',
300),\n(\'Sales\', \'Kalpana\',
300),\n(\'Sales\', \'Svantepolk\',
250),\n(\'Sales\', \'Angelo\', 200);\n\nWe could do
this without using window functions, as follows:\n\nselect dept, name,
salary\nfrom employee_salaries as t1\nwhere (select count(t2.salary)\n
from employee_salaries as t2\n where t1.name != t2.name and\n
t1.dept = t2.dept and\n t2.salary > t1.salary) < 5\norder by
dept, salary desc;\n\n+-------------+--------------+--------+\n| dept
| name | salary |\n+-------------+--------------+--------+\n|
Engineering | Dharma | 3500 |\n| Engineering | Binh |
3000 |\n| Engineering | Adalynn | 2800 |\n| Engineering | Samuel
| 2500 |\n| Engineering | Cveta | 2200 |\n| Sales |
Carbry | 500 |\n| Sales | Clytemnestra | 400 |\n| Sales
| Juraj | 300 |\n| Sales | Kalpana | 300 |\n|
Sales | Svantepolk | 250
|\n+-------------+--------------+--------+\n\nThis has a number of
disadvantages:\n\n* if there is no index, the query could take a long time
if the\nemployee_salary_table is large\n* Adding and maintaining indexes
adds overhead, and even with indexes on dept\nand salary, each subquery
execution adds overhead by performing a lookup\nthrough the
index.\n\nLet\'s try achieve the same with window functions. First,
generate a rank for\nall employees, using the RANK function.\n\nselect
rank() over (partition by dept order by salary desc) as ranking,\n dept,
name, salary\n from employee_salaries\n order by dept,
ranking;\n+---------+-------------+--------------+--------+\n| ranking |
dept | name | salary
|\n+---------+-------------+--------------+--------+\n| 1 |
Engineering | Dharma | 3500 |\n| 2 | Engineering | Binh
| 3000 |\n| 3 | Engineering | Adalynn | 2800 |\n| 4
| Engineering | Samuel | 2500 |\n| 5 | Engineering | Cveta
| 2200 |\n| 6 | Engineering | Ebele | 1800 |\n|
1 | Sales | Carbry | 500 |\n| 2 | Sales |
Clytemnestra | 400 |\n| 3 | Sales | Juraj | 300
|\n| 3 | Sales | Kalpana | 300 |\n| 5 | Sales
| Svantepolk | 250 |\n| 6 | Sales | Angelo |
200 |\n+---------+-------------+--------------+--------+\n\nEach department
has a separate sequence of ranks due to the PARTITION BY\nclause. This
particular sequence of values for rank() is given by the ORDER BY\nclause
inside the window function’s OVER clause. Finally, to get our results\nin
a readable format we order the data by dept and the newly generated
ranking\ncolumn.\n\nNow, we need to reduce the results to find only the top
5 per department. Here\nis a common mistake:\n\nselect\nrank() over
(partition by dept order by salary desc) as ranking,\ndept, name,
salary\nfrom employee_salaries\nwhere ranking <= 5\norder by dept,
ranking;\n\nERROR 1054 (42S22): Unknown column \'ranking\' in
\'where clause\'\n\nTrying to filter only the first 5 values per
department by putting a where\nclause in the statement does not work, due
to the way window functions are\ncomputed. The computation of window
functions happens after all WHERE, GROUP\nBY and HAVING clauses have been
completed, right before ORDER BY, so the WHERE\nclause has no idea that the
ranking column exists. It is only present after we\nhave filtered and
grouped all the rows.\n\nTo counteract this problem, we need to wrap our
query into a derived table. We\ncan then attach a where clause to
it:\n\nselect *from (select rank() over (partition by dept order by salary
desc) as\nranking,\n dept, name, salary\nfrom employee_salaries) as
salary_ranks\nwhere (salary_ranks.ranking <= 5)\n order by dept,
ranking;\n+---------+-------------+--------------+--------+\n| ranking |
dept | name | salary
|\n+---------+-------------+--------------+--------+\n| 1 |
Engineering | Dharma | 3500 |\n| 2 | Engineering | Binh
| 3000 |\n| 3 | Engineering | Adalynn | 2800 |\n| 4
| Engineering | Samuel | 2500 |\n| 5 | Engineering | Cveta
| 2200 |\n| 1 | Sales | Carbry | 500 |\n|
2 | Sales | Clytemnestra | 400 |\n| 3 | Sales | Juraj
| 300 |\n| 3 | Sales | Kalpana | 300 |\n|
5 | Sales | Svantepolk | 250
|\n+---------+-------------+--------------+--------+\n\nURL:
https://mariadb.com/kb/en/window-functions-overview/','','https://mariadb.com/kb/en/window-functions-overview/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(772,41,'CUME_DIST','Syntax\n------\n\nCUME_DIST() OVER ( \n
[ PARTITION BY partition_expression ]\n [ ORDER BY order_list
]\n)\n\nDescription\n-----------\n\nCUME_DIST() is a window function that
returns the cumulative distribution of a\ngiven row. The following formula
is used to calculate the value:\n\n(number of rows <= current row) /
(total rows)\n\nExamples\n--------\n\ncreate table t1 (\n pk int primary
key,\n a int,\n b int\n);\n\ninsert into t1 values\n( 1 , 0, 10),\n( 2 , 0,
10),\n( 3 , 1, 10),\n( 4 , 1, 10),\n( 8 , 2, 10),\n( 5 , 2, 20),\n( 6 , 2,
20),\n( 7 , 2, 20),\n( 9 , 4, 20),\n(10 , 4, 20);\n\nselect pk, a, b,\n
rank() over (order by a) as rank,\n percent_rank() over (order by a) as
pct_rank,\n cume_dist() over (order by a) as cume_dist\nfrom
t1;\n+----+------+------+------+--------------+--------------+\n| pk | a
| b | rank | pct_rank | cume_dist
|\n+----+------+------+------+--------------+--------------+\n| 1 | 0 |
10 | 1 | 0.0000000000 | 0.2000000000 |\n| 2 | 0 | 10 | 1 |
0.0000000000 | 0.2000000000 |\n| 3 | 1 | 10 | 3 | 0.2222222222 |
0.4000000000 |\n| 4 | 1 | 10 | 3 | 0.2222222222 | 0.4000000000
|\n| 5 | 2 | 20 | 5 | 0.4444444444 | 0.8000000000 |\n| 6 | 2 |
20 | 5 | 0.4444444444 | 0.8000000000 |\n| 7 | 2 | 20 | 5 |
0.4444444444 | 0.8000000000 |\n| 8 | 2 | 10 | 5 | 0.4444444444 |
0.8000000000 |\n| 9 | 4 | 20 | 9 | 0.8888888889 | 1.0000000000
|\n| 10 | 4 | 20 | 9 | 0.8888888889 | 1.0000000000
|\n+----+------+------+------+--------------+--------------+\n\nselect pk,
a, b,\n percent_rank() over (order by pk) as pct_rank,\n cume_dist()
over (order by pk) as cume_dist\nfrom t1 order by
pk;\n+----+------+------+--------------+--------------+\n| pk | a | b
| pct_rank | cume_dist
|\n+----+------+------+--------------+--------------+\n| 1 | 0 | 10 |
0.0000000000 | 0.1000000000 |\n| 2 | 0 | 10 | 0.1111111111 |
0.2000000000 |\n| 3 | 1 | 10 | 0.2222222222 | 0.3000000000 |\n| 4 |
1 | 10 | 0.3333333333 | 0.4000000000 |\n| 5 | 2 | 20 |
0.4444444444 | 0.5000000000 |\n| 6 | 2 | 20 | 0.5555555556 |
0.6000000000 |\n| 7 | 2 | 20 | 0.6666666667 | 0.7000000000 |\n| 8 |
2 | 10 | 0.7777777778 | 0.8000000000 |\n| 9 | 4 | 20 |
0.8888888889 | 0.9000000000 |\n| 10 | 4 | 20 | 1.0000000000 |
1.0000000000
|\n+----+------+------+--------------+--------------+\n\nselect pk, a, b,\n
percent_rank() over (partition by a order by a) as pct_rank,\n
cume_dist() over (partition by a order by a) as cume_dist\nfrom
t1;\n+----+------+------+--------------+--------------+\n| pk | a | b
| pct_rank | cume_dist
|\n+----+------+------+--------------+--------------+\n| 1 | 0 | 10 |
0.0000000000 | 1.0000000000 |\n| 2 | 0 | 10 | 0.0000000000 |
1.0000000000 |\n| 3 | 1 | 10 | 0.0000000000 | 1.0000000000 |\n| 4 |
1 | 10 | 0.0000000000 | 1.0000000000 |\n| 5 | 2 | 20 |
0.0000000000 | 1.0000000000 |\n| 6 | 2 | 20 | 0.0000000000 |
1.0000000000 |\n| 7 | 2 | 20 | 0.0000000000 | 1.0000000000 |\n| 8 |
2 | 10 | 0.0000000000 | 1.0000000000 |\n| 9 | 4 | 20 |
0.0000000000 | 1.0000000000 |\n| 10 | 4 | 20 | 0.0000000000 |
1.0000000000 |\n+----+------+------+--------------+--------------+\n\nURL:
https://mariadb.com/kb/en/cume_dist/','','https://mariadb.com/kb/en/cume_dist/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(773,41,'DENSE_RANK','Syntax\n------\n\nDENSE_RANK() OVER
(\n [ PARTITION BY partition_expression ]\n [ ORDER BY order_list
]\n)\n\nDescription\n-----------\n\nDENSE_RANK() is a window function that
displays the number of a given row,\nstarting at one and following the
ORDER BY sequence of the window function,\nwith identical values receiving
the same result. Unlike the RANK() function,\nthere are no skipped values
if the preceding results are identical. It is also\nsimilar to the
ROW_NUMBER() function except that in that function, identical\nvalues will
receive a different row number for each
result.\n\nExamples\n--------\n\nThe distinction between DENSE_RANK(),
RANK() and ROW_NUMBER():\n\nCREATE TABLE student(course VARCHAR(10), mark
int, name varchar(10));\n\nINSERT INTO student VALUES \n
(\'Maths\', 60, \'Thulile\'),\n (\'Maths\',
60, \'Pritha\'),\n (\'Maths\', 70,
\'Voitto\'),\n (\'Maths\', 55, \'Chun\'),\n
(\'Biology\', 60, \'Bilal\'),\n (\'Biology\',
70, \'Roger\');\n\nSELECT \n RANK() OVER (PARTITION BY course
ORDER BY mark DESC) AS rank,\n DENSE_RANK() OVER (PARTITION BY course ORDER
BY mark DESC) AS dense_rank,\n ROW_NUMBER() OVER (PARTITION BY course ORDER
BY mark DESC) AS row_num,\n course, mark, name\nFROM student ORDER BY
course, mark
DESC;\n+------+------------+---------+---------+------+---------+\n| rank |
dense_rank | row_num | course | mark | name
|\n+------+------------+---------+---------+------+---------+\n| 1 |
1 | 1 | Biology | 70 | Roger |\n| 2 | 2 |
2 | Biology | 60 | Bilal |\n| 1 | 1 | 1 | Maths |
70 | Voitto |\n| 2 | 2 | 2 | Maths | 60 | Thulile
|\n| 2 | 2 | 3 | Maths | 60 | Pritha |\n| 4 |
3 | 4 | Maths | 55 | Chun
|\n+------+------------+---------+---------+------+---------+\n\nURL:
https://mariadb.com/kb/en/dense_rank/','','https://mariadb.com/kb/en/dense_rank/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(774,41,'FIRST_VALUE','Syntax\n------\n\nFIRST_VALUE(expr)
OVER (\n [ PARTITION BY partition_expression ]\n [ ORDER BY order_list
]\n)\n\nDescription\n-----------\n\nFIRST_VALUE returns the first result
from an ordered set, or NULL if no such\nresult
exists.\n\nExamples\n--------\n\nCREATE TABLE t1 (\n pk int primary key,\n
a int,\n b int,\n c char(10),\n d decimal(10, 3),\n e real\n);\n\nINSERT
INTO t1 VALUES\n( 1, 0, 1, \'one\', 0.1, 0.001),\n( 2, 0,
2, \'two\', 0.2, 0.002),\n( 3, 0, 3,
\'three\', 0.3, 0.003),\n( 4, 1, 2, \'three\',
0.4, 0.004),\n( 5, 1, 1, \'two\', 0.5, 0.005),\n( 6, 1,
1, \'one\', 0.6, 0.006),\n( 7, 2, NULL,
\'n_one\', 0.5, 0.007),\n( 8, 2, 1, \'n_two\',
NULL, 0.008),\n( 9, 2, 2, NULL, 0.7, 0.009),\n(10, 2, 0,
\'n_four\', 0.8, 0.010),\n(11, 2, 10, NULL, 0.9,
NULL);\n\nSELECT pk, FIRST_VALUE(pk) OVER (ORDER BY pk) AS first_asc,\n
LAST_VALUE(pk) OVER (ORDER BY pk) AS last_asc,\n FIRST_VALUE(pk) OVER
(ORDER BY pk DESC) AS first_desc,\n LAST_VALUE(pk) OVER (ORDER BY pk
DESC) AS last_desc\nFROM t1\nORDER BY pk
DESC;\n\n+----+-----------+----------+------------+-----------+\n| pk |
first_asc | last_asc | first_desc | last_desc
|\n+----+-----------+----------+------------+-----------+\n| 11 | 1
| 11 | 11 | 11 |\n| 10 | 1 | 10 |
11 | 10 |\n| 9 | 1 | 9 | 11 | 9
|\n| 8 | 1 | 8 | 11 | 8 |\n| 7 | 1
| 7 | 11 | 7 |\n| 6 | 1 | 6 |
11 | 6 |\n| 5 | 1 | 5 | 11 | 5
|\n| 4 | 1 | 4 | 11 | 4 |\n| 3 | 1
| 3 | 11 | 3 |\n| 2 | 1 | 2 |
11 | 2 |\n| 1 | 1 | 1 | 11 | 1
|\n+----+-----------+----------+------------+-----------+\n\nCREATE OR
REPLACE TABLE t1 (i int);\nINSERT INTO t1 VALUES
(1),(2),(3),(4),(5),(6),(7),(8),(9),(10);\n\nSELECT i,\n FIRST_VALUE(i)
OVER (ORDER BY i ROWS BETWEEN CURRENT ROW and 1 FOLLOWING) AS\nf_1f,\n
LAST_VALUE(i) OVER (ORDER BY i ROWS BETWEEN CURRENT ROW and 1 FOLLOWING)
AS\nl_1f,\n FIRST_VALUE(i) OVER (ORDER BY i ROWS BETWEEN 1 PRECEDING AND 1
FOLLOWING) AS\nf_1p1f,\n LAST_VALUE(i) OVER (ORDER BY i ROWS BETWEEN 1
PRECEDING AND 1 FOLLOWING) AS\nf_1p1f,\n FIRST_VALUE(i) OVER (ORDER BY i
ROWS BETWEEN 2 PRECEDING AND 1 PRECEDING) AS\nf_2p1p,\n LAST_VALUE(i) OVER
(ORDER BY i ROWS BETWEEN 2 PRECEDING AND 1 PRECEDING) AS\nf_2p1p,\n
FIRST_VALUE(i) OVER (ORDER BY i ROWS BETWEEN 1 FOLLOWING AND 2 FOLLOWING)
AS\nf_1f2f,\n LAST_VALUE(i) OVER (ORDER BY i ROWS BETWEEN 1 FOLLOWING AND 2
FOLLOWING) AS\nf_1f2f\nFROM
t1;\n\n+------+------+------+--------+--------+--------+--------+--------+--------+\n|
i | f_1f | l_1f | f_1p1f | f_1p1f | f_2p1p | f_2p1p | f_1f2f | f_1f2f
|\n+------+------+------+--------+--------+--------+--------+--------+--------+\n|
1 | 1 | 2 | 1 | 2 | NULL | NULL | 2 | 3
|\n| 2 | 2 | 3 | 1 | 3 | 1 | 1 | 3 |
4 |\n| 3 | 3 | 4 | 2 | 4 | 1 | 2 | 4 |
5 |\n| 4 | 4 | 5 | 3 | 5 | 2 | 3 | 5 |
6 |\n| 5 | 5 | 6 | 4 | 6 | 3 | 4 | 6
| 7 |\n| 6 | 6 | 7 | 5 | 7 | 4 | 5 |
7 | 8 |\n| 7 | 7 | 8 | 6 | 8 | 5 | 6 |
8 | 9 |\n| 8 | 8 | 9 | 7 | 9 | 6 | 7 |
9 | 10 |\n| 9 | 9 | 10 | 8 | 10 | 7 | 8
| 10 | 10 |\n| 10 | 10 | 10 | 9 | 10 | 8 |
9 | NULL | NULL
|\n+------+------+------+--------+--------+--------+--------+--------+--------+\n\nURL:
https://mariadb.com/kb/en/first_value/','','https://mariadb.com/kb/en/first_value/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(775,41,'LAG','Syntax\n------\n\nLAG (expr[, offset]) OVER (
\n [ PARTITION BY partition_expression ]\n < ORDER BY order_list
>\n)\n\nDescription\n-----------\n\nThe LAG function accesses data from
a previous row according to the ORDER BY\nclause without the need for a
self-join. The specific row is determined by the\noffset (default 1), which
specifies the number of rows behind the current row\nto use. An offset of 0
is the current row.\n\nExamples\n--------\n\nCREATE TABLE t1 (pk int
primary key, a int, b int, c char(10), d decimal(10,\n3), e
real);\n\nINSERT INTO t1 VALUES\n ( 1, 0, 1, \'one\', 0.1,
0.001),\n ( 2, 0, 2, \'two\', 0.2, 0.002),\n ( 3, 0, 3,
\'three\', 0.3, 0.003),\n ( 4, 1, 2, \'three\',
0.4, 0.004),\n ( 5, 1, 1, \'two\', 0.5, 0.005),\n ( 6, 1,
1, \'one\', 0.6, 0.006),\n ( 7, 2, NULL,
\'n_one\', 0.5, 0.007),\n ( 8, 2, 1, \'n_two\',
NULL, 0.008),\n ( 9, 2, 2, NULL, 0.7, 0.009),\n (10, 2, 0,
\'n_four\', 0.8, 0.010),\n (11, 2, 10, NULL, 0.9,
NULL);\n\nSELECT pk, LAG(pk) OVER (ORDER BY pk) AS l,\n LAG(pk,1) OVER
(ORDER BY pk) AS l1,\n LAG(pk,2) OVER (ORDER BY pk) AS l2,\n LAG(pk,0) OVER
(ORDER BY pk) AS l0,\n LAG(pk,-1) OVER (ORDER BY pk) AS lm1,\n LAG(pk,-2)
OVER (ORDER BY pk) AS lm2\nFROM
t1;\n+----+------+------+------+------+------+------+\n| pk | l | l1 |
l2 | l0 | lm1 | lm2
|\n+----+------+------+------+------+------+------+\n| 1 | NULL | NULL |
NULL | 1 | 2 | 3 |\n| 2 | 1 | 1 | NULL | 2 | 3 | 4
|\n| 3 | 2 | 2 | 1 | 3 | 4 | 5 |\n| 4 | 3 | 3 |
2 | 4 | 5 | 6 |\n| 5 | 4 | 4 | 3 | 5 | 6 | 7
|\n| 6 | 5 | 5 | 4 | 6 | 7 | 8 |\n| 7 | 6 | 6 |
5 | 7 | 8 | 9 |\n| 8 | 7 | 7 | 6 | 8 | 9 | 10
|\n| 9 | 8 | 8 | 7 | 9 | 10 | 11 |\n| 10 | 9 | 9 |
8 | 10 | 11 | NULL |\n| 11 | 10 | 10 | 9 | 11 | NULL | NULL
|\n+----+------+------+------+------+------+------+\n\nURL:
https://mariadb.com/kb/en/lag/','','https://mariadb.com/kb/en/lag/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(776,41,'LEAD','Syntax\n------\n\nLEAD (expr[, offset]) OVER
( \n [ PARTITION BY partition_expression ]\n [ ORDER BY order_list
]\n)\n\nDescription\n-----------\n\nThe LEAD function accesses data from a
following row in the same result set\nwithout the need for a self-join. The
specific row is determined by the offset\n(default 1), which specifies the
number of rows ahead the current row to use.\nAn offset of 0 is the current
row.\n\nExample\n-------\n\nCREATE TABLE t1 (pk int primary key, a int, b
int, c char(10), d decimal(10,\n3), e real);\n\nINSERT INTO t1 VALUES\n (
1, 0, 1, \'one\', 0.1, 0.001),\n ( 2, 0, 2,
\'two\', 0.2, 0.002),\n ( 3, 0, 3, \'three\',
0.3, 0.003),\n ( 4, 1, 2, \'three\', 0.4, 0.004),\n ( 5, 1,
1, \'two\', 0.5, 0.005),\n ( 6, 1, 1,
\'one\', 0.6, 0.006),\n ( 7, 2, NULL, \'n_one\',
0.5, 0.007),\n ( 8, 2, 1, \'n_two\', NULL, 0.008),\n ( 9, 2,
2, NULL, 0.7, 0.009),\n (10, 2, 0, \'n_four\', 0.8,
0.010),\n (11, 2, 10, NULL, 0.9, NULL);\n\nSELECT pk, LEAD(pk) OVER
(ORDER BY pk) AS l,\n LEAD(pk,1) OVER (ORDER BY pk) AS l1,\n LEAD(pk,2)
OVER (ORDER BY pk) AS l2,\n LEAD(pk,0) OVER (ORDER BY pk) AS l0,\n
LEAD(pk,-1) OVER (ORDER BY pk) AS lm1,\n LEAD(pk,-2) OVER (ORDER BY pk) AS
lm2\nFROM t1;\n+----+------+------+------+------+------+------+\n| pk | l
| l1 | l2 | l0 | lm1 | lm2
|\n+----+------+------+------+------+------+------+\n| 1 | 2 | 2 |
3 | 1 | NULL | NULL |\n| 2 | 3 | 3 | 4 | 2 | 1 | NULL
|\n| 3 | 4 | 4 | 5 | 3 | 2 | 1 |\n| 4 | 5 | 5 |
6 | 4 | 3 | 2 |\n| 5 | 6 | 6 | 7 | 5 | 4 | 3
|\n| 6 | 7 | 7 | 8 | 6 | 5 | 4 |\n| 7 | 8 | 8 |
9 | 7 | 6 | 5 |\n| 8 | 9 | 9 | 10 | 8 | 7 | 6
|\n| 9 | 10 | 10 | 11 | 9 | 8 | 7 |\n| 10 | 11 | 11 |
NULL | 10 | 9 | 8 |\n| 11 | NULL | NULL | NULL | 11 | 10 | 9
|\n+----+------+------+------+------+------+------+\n\nURL:
https://mariadb.com/kb/en/lead/','','https://mariadb.com/kb/en/lead/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(777,41,'Median Window Function','MariaDB starting with
10.3.3\n----------------------------\nThe MEDIAN() window function was
first introduced with in MariaDB 10.3.3.\n\nSyntax\n------\n\nMEDIAN(median
expression) OVER (\n [ PARTITION BY partition_expression
]\n)\n\nDescription\n-----------\n\nMEDIAN() is a window function that
returns the median value of a range of\nvalues.\n\nIt is a specific case of
PERCENTILE_CONT, with an argument of 0.5 and the\nORDER BY column the one
in MEDIAN\'s argument.\n\nMEDIAN(<median-arg>) OVER ( [
PARTITION BY partition_expression] )\n\nIs equivalent
to:\n\nPERCENTILE_CONT(0.5) WITHIN \n GROUP (ORDER BY <median-arg>)
OVER ( [ PARTITION BY partition_expression
])\n\nExamples\n--------\n\nCREATE TABLE book_rating (name CHAR(30),
star_rating TINYINT);\n\nINSERT INTO book_rating VALUES (\'Lord of the
Ladybirds\', 5);\nINSERT INTO book_rating VALUES (\'Lord of the
Ladybirds\', 3);\nINSERT INTO book_rating VALUES (\'Lady of the
Flies\', 1);\nINSERT INTO book_rating VALUES (\'Lady of the
Flies\', 2);\nINSERT INTO book_rating VALUES (\'Lady of the
Flies\', 5);\n\nSELECT name, median(star_rating) OVER (PARTITION BY
name) FROM
book_rating;\n+-----------------------+----------------------------------------------+\n|
name | median(star_rating) OVER (PARTITION BY name)
|\n+-----------------------+----------------------------------------------+\n|
Lord of the Ladybirds | 4.0000000000 |\n|
Lord of the Ladybirds | 4.0000000000 |\n|
Lady of the Flies | 2.0000000000 |\n|
Lady of the Flies | 2.0000000000 |\n|
Lady of the Flies | 2.0000000000
|\n+-----------------------+----------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/median/','','https://mariadb.com/kb/en/median/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(778,41,'NTH_VALUE','Syntax\n------\n\nNTH_VALUE (expr[,
num_row]) OVER ( \n [ PARTITION BY partition_expression ]\n [ ORDER BY
order_list ]\n)\n\nDescription\n-----------\n\nThe NTH_VALUE function
returns the value evaluated at row number num_row of\nthe window frame,
starting from 1, or NULL if the row does not exist.\n\nURL:
https://mariadb.com/kb/en/nth_value/','','https://mariadb.com/kb/en/nth_value/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(779,41,'NTILE','Syntax\n------\n\nNTILE (expr) OVER ( \n [
PARTITION BY partition_expression ]\n [ ORDER BY order_list
]\n)\n\nDescription\n-----------\n\nNTILE() is a window function that
returns an integer indicating which group a\ngiven row falls into. The
number of groups is specified in the argument\n(expr), starting at one.
Ordered rows in the partition are divided into the\nspecified number of
groups with as equal a size as possible.\n\nExamples\n--------\n\ncreate
table t1 (\n pk int primary key,\n a int,\n b int\n );\n\ninsert into t1
values\n (11 , 0, 10),\n (12 , 0, 10),\n (13 , 1, 10),\n (14 , 1,
10),\n (18 , 2, 10),\n (15 , 2, 20),\n (16 , 2, 20),\n (17 , 2, 20),\n
(19 , 4, 20),\n (20 , 4, 20);\n\nselect pk, a, b,\n ntile(1) over (order
by pk)\n from t1;\n+----+------+------+-----------------------------+\n| pk
| a | b | ntile(1) over (order by pk)
|\n+----+------+------+-----------------------------+\n| 11 | 0 | 10 |
1 |\n| 12 | 0 | 10 |
1 |\n| 13 | 1 | 10 | 1 |\n| 14 | 1 |
10 | 1 |\n| 15 | 2 | 20 |
1 |\n| 16 | 2 | 20 | 1 |\n| 17 | 2
| 20 | 1 |\n| 18 | 2 | 10 |
1 |\n| 19 | 4 | 20 | 1 |\n| 20 |
4 | 20 | 1
|\n+----+------+------+-----------------------------+\n\nselect pk, a, b,\n
ntile(4) over (order by pk)\n from
t1;\n+----+------+------+-----------------------------+\n| pk | a | b
| ntile(4) over (order by pk)
|\n+----+------+------+-----------------------------+\n| 11 | 0 | 10 |
1 |\n| 12 | 0 | 10 |
1 |\n| 13 | 1 | 10 | 1 |\n| 14 | 1 |
10 | 2 |\n| 15 | 2 | 20 |
2 |\n| 16 | 2 | 20 | 2 |\n| 17 | 2
| 20 | 3 |\n| 18 | 2 | 10 |
3 |\n| 19 | 4 | 20 | 4 |\n| 20 |
4 | 20 | 4
|\n+----+------+------+-----------------------------+\n\nURL:
https://mariadb.com/kb/en/ntile/','','https://mariadb.com/kb/en/ntile/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(780,41,'PERCENT_RANK','Syntax\n------\n\nPERCENT_RANK()
OVER (\n [ PARTITION BY partition_expression ]\n [ ORDER BY order_list
]\n)\n\nDescription\n-----------\n\nPERCENT_RANK() is a window function
that returns the relative percent rank of\na given row. The following
formula is used to calculate the percent rank:\n\n(rank - 1) / (number of
rows in the window or partition - 1)\n\nExamples\n--------\n\ncreate table
t1 (\n pk int primary key,\n a int,\n b int\n);\n\ninsert into t1 values\n(
1 , 0, 10),\n( 2 , 0, 10),\n( 3 , 1, 10),\n( 4 , 1, 10),\n( 8 , 2, 10),\n(
5 , 2, 20),\n( 6 , 2, 20),\n( 7 , 2, 20),\n( 9 , 4, 20),\n(10 , 4,
20);\n\nselect pk, a, b,\n rank() over (order by a) as rank,\n
percent_rank() over (order by a) as pct_rank,\n cume_dist() over (order by
a) as cume_dist\nfrom
t1;\n+----+------+------+------+--------------+--------------+\n| pk | a
| b | rank | pct_rank | cume_dist
|\n+----+------+------+------+--------------+--------------+\n| 1 | 0 |
10 | 1 | 0.0000000000 | 0.2000000000 |\n| 2 | 0 | 10 | 1 |
0.0000000000 | 0.2000000000 |\n| 3 | 1 | 10 | 3 | 0.2222222222 |
0.4000000000 |\n| 4 | 1 | 10 | 3 | 0.2222222222 | 0.4000000000
|\n| 5 | 2 | 20 | 5 | 0.4444444444 | 0.8000000000 |\n| 6 | 2 |
20 | 5 | 0.4444444444 | 0.8000000000 |\n| 7 | 2 | 20 | 5 |
0.4444444444 | 0.8000000000 |\n| 8 | 2 | 10 | 5 | 0.4444444444 |
0.8000000000 |\n| 9 | 4 | 20 | 9 | 0.8888888889 | 1.0000000000
|\n| 10 | 4 | 20 | 9 | 0.8888888889 | 1.0000000000
|\n+----+------+------+------+--------------+--------------+\n\nselect pk,
a, b,\n percent_rank() over (order by pk) as pct_rank,\n cume_dist()
over (order by pk) as cume_dist\nfrom t1 order by
pk;\n+----+------+------+--------------+--------------+\n| pk | a | b
| pct_rank | cume_dist
|\n+----+------+------+--------------+--------------+\n| 1 | 0 | 10 |
0.0000000000 | 0.1000000000 |\n| 2 | 0 | 10 | 0.1111111111 |
0.2000000000 |\n| 3 | 1 | 10 | 0.2222222222 | 0.3000000000 |\n| 4 |
1 | 10 | 0.3333333333 | 0.4000000000 |\n| 5 | 2 | 20 |
0.4444444444 | 0.5000000000 |\n| 6 | 2 | 20 | 0.5555555556 |
0.6000000000 |\n| 7 | 2 | 20 | 0.6666666667 | 0.7000000000 |\n| 8 |
2 | 10 | 0.7777777778 | 0.8000000000 |\n| 9 | 4 | 20 |
0.8888888889 | 0.9000000000 |\n| 10 | 4 | 20 | 1.0000000000 |
1.0000000000
|\n+----+------+------+--------------+--------------+\n\nselect pk, a, b,\n
percent_rank() over (partition by a order by a) as pct_rank,\n
cume_dist() over (partition by a order by a) as cume_dist\nfrom
t1;\n+----+------+------+--------------+--------------+\n| pk | a | b
| pct_rank | cume_dist
|\n+----+------+------+--------------+--------------+\n| 1 | 0 | 10 |
0.0000000000 | 1.0000000000 |\n| 2 | 0 | 10 | 0.0000000000 |
1.0000000000 |\n| 3 | 1 | 10 | 0.0000000000 | 1.0000000000 |\n| 4 |
1 | 10 | 0.0000000000 | 1.0000000000 |\n| 5 | 2 | 20 |
0.0000000000 | 1.0000000000 |\n| 6 | 2 | 20 | 0.0000000000 |
1.0000000000 |\n| 7 | 2 | 20 | 0.0000000000 | 1.0000000000 |\n| 8 |
2 | 10 | 0.0000000000 | 1.0000000000 |\n| 9 | 4 | 20 |
0.0000000000 | 1.0000000000 |\n| 10 | 4 | 20 | 0.0000000000 |
1.0000000000 |\n+----+------+------+--------------+--------------+\n\nURL:
https://mariadb.com/kb/en/percent_rank/','','https://mariadb.com/kb/en/percent_rank/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(781,41,'PERCENTILE_CONT','MariaDB starting with
10.3.3\n----------------------------\nThe PERCENTILE_CONT() window function
was first introduced with in
MariaDB\n10.3.3.\n\nSyntax\n------\n\nDescription\n-----------\n\nPERCENTILE_CONT()
(standing for continuous percentile) is a window function\nwhich returns a
value which corresponds to the given fraction in the sort\norder. If
required, it will interpolate between adjacent input items.\n\nEssentially,
the following process is followed to find the value to return:\n\n* Get the
number of rows in the partition, denoted by N\n* RN = p*(N-1), where p
denotes the argument to the PERCENTILE_CONT function\n* calculate the
FRN(floor row number) and CRN(column row number for the group(\nFRN=
floor(RN) and CRN = ceil(RN))\n* look up rows FRN and CRN\n* If (CRN = FRN
= RN) then the result is (value of expression from row at RN)\n* Otherwise
the result is\n* (CRN - RN) * (value of expression for row at FRN) +\n* (RN
- FRN) * (value of expression for row at CRN)\n\nThe MEDIAN function is a
specific case of PERCENTILE_CONT, equivalent
to\nPERCENTILE_CONT(0.5).\n\nExamples\n--------\n\nCREATE TABLE book_rating
(name CHAR(30), star_rating TINYINT);\n\nINSERT INTO book_rating VALUES
(\'Lord of the Ladybirds\', 5);\nINSERT INTO book_rating VALUES
(\'Lord of the Ladybirds\', 3);\nINSERT INTO book_rating VALUES
(\'Lady of the Flies\', 1);\nINSERT INTO book_rating VALUES
(\'Lady of the Flies\', 2);\nINSERT INTO book_rating VALUES
(\'Lady of the Flies\', 5);\n\nSELECT name, PERCENTILE_CONT(0.5)
WITHIN GROUP (ORDER BY star_rating) \n OVER (PARTITION BY name) AS pc\n
FROM book_rating;\n+-----------------------+--------------+\n| name
| pc |\n+-----------------------+--------------+\n| Lord
of the Ladybirds | 4.0000000000 |\n| Lord of the Ladybirds | 4.0000000000
|\n| Lady of the Flies | 2.0000000000 |\n| Lady of the Flies |
2.0000000000 |\n| Lady of the Flies | 2.0000000000
|\n+-----------------------+--------------+\n\nSELECT name,
PERCENTILE_CONT(1) WITHIN GROUP (ORDER BY star_rating) \n OVER (PARTITION
BY name) AS pc\n FROM
book_rating;\n+-----------------------+--------------+\n| name
| pc |\n+-----------------------+--------------+\n| Lord of
the Ladybirds | 5.0000000000 |\n| Lord of the Ladybirds | 5.0000000000 |\n|
Lady of the Flies | 5.0000000000 |\n| Lady of the Flies |
5.0000000000 |\n| Lady of the Flies | 5.0000000000
|\n+-----------------------+--------------+\n\nSELECT name,
PERCENTILE_CONT(0) WITHIN GROUP (ORDER BY star_rating) \n OVER (PARTITION
BY name) AS pc\n FROM
book_rating;\n+-----------------------+--------------+\n| name
| pc |\n+-----------------------+--------------+\n| Lord of
the Ladybirds | 3.0000000000 |\n| Lord of the Ladybirds | 3.0000000000 |\n|
Lady of the Flies | 1.0000000000 |\n| Lady of the Flies |
1.0000000000 |\n| Lady of the Flies | 1.0000000000
|\n+-----------------------+--------------+\n\nSELECT name,
PERCENTILE_CONT(0.6) WITHIN GROUP (ORDER BY star_rating) \n OVER (PARTITION
BY name) AS pc\n FROM
book_rating;\n+-----------------------+--------------+\n| name
| pc |\n+-----------------------+--------------+\n| Lord of
the Ladybirds | 4.2000000000 |\n| Lord of the Ladybirds | 4.2000000000 |\n|
Lady of the Flies | 2.6000000000 |\n| Lady of the Flies |
2.6000000000 |\n| Lady of the Flies | 2.6000000000
|\n+-----------------------+--------------+\n\nURL:
https://mariadb.com/kb/en/percentile_cont/','','https://mariadb.com/kb/en/percentile_cont/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(782,41,'PERCENTILE_DISC','MariaDB starting with
10.3.3\n----------------------------\nThe PERCENTILE_DISC() window function
was first introduced with in
MariaDB\n10.3.3.\n\nSyntax\n------\n\nDescription\n-----------\n\nPERCENTILE_DISC()
(standing for discrete percentile) is a window function\nwhich returns the
first value in the set whose ordered position is the same or\nmore than the
specified fraction.\n\nEssentially, the following process is followed to
find the value to return:\n\n* Get the number of rows in the partition.\n*
Walk through the partition, in order, until finding the the first row
with\nCUME_DIST() >= function_argument.\n\nExamples\n--------\n\nCREATE
TABLE book_rating (name CHAR(30), star_rating TINYINT);\n\nINSERT INTO
book_rating VALUES (\'Lord of the Ladybirds\', 5);\nINSERT INTO
book_rating VALUES (\'Lord of the Ladybirds\', 3);\nINSERT INTO
book_rating VALUES (\'Lady of the Flies\', 1);\nINSERT INTO
book_rating VALUES (\'Lady of the Flies\', 2);\nINSERT INTO
book_rating VALUES (\'Lady of the Flies\', 5);\n\nSELECT name,
PERCENTILE_DISC(0.5) WITHIN GROUP (ORDER BY star_rating)\n OVER (PARTITION
BY name) AS pc FROM book_rating;\n+-----------------------+------+\n| name
| pc |\n+-----------------------+------+\n| Lord of the
Ladybirds | 3 |\n| Lord of the Ladybirds | 3 |\n| Lady of the Flies
| 2 |\n| Lady of the Flies | 2 |\n| Lady of the Flies |
2 |\n+-----------------------+------+\n5 rows in set (0.000 sec)\n\nSELECT
name, PERCENTILE_DISC(0) WITHIN GROUP (ORDER BY star_rating) \n OVER
(PARTITION BY name) AS pc FROM
book_rating;\n+-----------------------+------+\n| name |
pc |\n+-----------------------+------+\n| Lord of the Ladybirds | 3
|\n| Lord of the Ladybirds | 3 |\n| Lady of the Flies | 1 |\n|
Lady of the Flies | 1 |\n| Lady of the Flies | 1
|\n+-----------------------+------+\n5 rows in set (0.000 sec)\n\nSELECT
name, PERCENTILE_DISC(1) WITHIN GROUP (ORDER BY star_rating) \n OVER
(PARTITION BY name) AS pc FROM
book_rating;\n+-----------------------+------+\n| name |
pc |\n+-----------------------+------+\n| Lord of the Ladybirds | 5
|\n| Lord of the Ladybirds | 5 |\n| Lady of the Flies | 5 |\n|
Lady of the Flies | 5 |\n| Lady of the Flies | 5
|\n+-----------------------+------+\n5 rows in set (0.000 sec)\n\nSELECT
name, PERCENTILE_DISC(0.6) WITHIN GROUP (ORDER BY star_rating) \n OVER
(PARTITION BY name) AS pc FROM
book_rating;\n+-----------------------+------+\n| name |
pc |\n+-----------------------+------+\n| Lord of the Ladybirds | 5
|\n| Lord of the Ladybirds | 5 |\n| Lady of the Flies | 2 |\n|
Lady of the Flies | 2 |\n| Lady of the Flies | 2
|\n+-----------------------+------\n\nURL:
https://mariadb.com/kb/en/percentile_disc/','','https://mariadb.com/kb/en/percentile_disc/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(783,41,'RANK','Syntax\n------\n\nRANK() OVER (\n [
PARTITION BY partition_expression ]\n [ ORDER BY order_list
]\n)\n\nDescription\n-----------\n\nRANK() is a window function that
displays the number of a given row, starting\nat one and following the
ORDER BY sequence of the window function, with\nidentical values receiving
the same result. It is similar to the ROW_NUMBER()\nfunction except that in
that function, identical values will receive a\ndifferent row number for
each result.\n\nExamples\n--------\n\nThe distinction between DENSE_RANK(),
RANK() and ROW_NUMBER():\n\nCREATE TABLE student(course VARCHAR(10), mark
int, name varchar(10));\n\nINSERT INTO student VALUES \n
(\'Maths\', 60, \'Thulile\'),\n (\'Maths\',
60, \'Pritha\'),\n (\'Maths\', 70,
\'Voitto\'),\n (\'Maths\', 55, \'Chun\'),\n
(\'Biology\', 60, \'Bilal\'),\n (\'Biology\',
70, \'Roger\');\n\nSELECT \n RANK() OVER (PARTITION BY course
ORDER BY mark DESC) AS rank,\n DENSE_RANK() OVER (PARTITION BY course ORDER
BY mark DESC) AS dense_rank,\n ROW_NUMBER() OVER (PARTITION BY course ORDER
BY mark DESC) AS row_num,\n course, mark, name\nFROM student ORDER BY
course, mark
DESC;\n+------+------------+---------+---------+------+---------+\n| rank |
dense_rank | row_num | course | mark | name
|\n+------+------------+---------+---------+------+---------+\n| 1 |
1 | 1 | Biology | 70 | Roger |\n| 2 | 2 |
2 | Biology | 60 | Bilal |\n| 1 | 1 | 1 | Maths |
70 | Voitto |\n| 2 | 2 | 2 | Maths | 60 | Thulile
|\n| 2 | 2 | 3 | Maths | 60 | Pritha |\n| 4 |
3 | 4 | Maths | 55 | Chun
|\n+------+------------+---------+---------+------+---------+\n\nURL:
https://mariadb.com/kb/en/rank/','','https://mariadb.com/kb/en/rank/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(784,41,'ROW_NUMBER','Syntax\n------\n\nROW_NUMBER() OVER
(\n [ PARTITION BY partition_expression ]\n [ ORDER BY order_list
]\n)\n\nDescription\n-----------\n\nROW_NUMBER() is a window function that
displays the number of a given row,\nstarting at one and following the
ORDER BY sequence of the window function,\nwith identical values receiving
different row numbers. It is similar to the\nRANK() and DENSE_RANK()
functions except that in that function, identical\nvalues will receive the
same rank for each result.\n\nExamples\n--------\n\nThe distinction between
DENSE_RANK(), RANK() and ROW_NUMBER():\n\nCREATE TABLE student(course
VARCHAR(10), mark int, name varchar(10));\n\nINSERT INTO student VALUES \n
(\'Maths\', 60, \'Thulile\'),\n (\'Maths\',
60, \'Pritha\'),\n (\'Maths\', 70,
\'Voitto\'),\n (\'Maths\', 55, \'Chun\'),\n
(\'Biology\', 60, \'Bilal\'),\n (\'Biology\',
70, \'Roger\');\n\nSELECT \n RANK() OVER (PARTITION BY course
ORDER BY mark DESC) AS rank,\n DENSE_RANK() OVER (PARTITION BY course ORDER
BY mark DESC) AS dense_rank,\n ROW_NUMBER() OVER (PARTITION BY course ORDER
BY mark DESC) AS row_num,\n course, mark, name\nFROM student ORDER BY
course, mark
DESC;\n+------+------------+---------+---------+------+---------+\n| rank |
dense_rank | row_num | course | mark | name
|\n+------+------------+---------+---------+------+---------+\n| 1 |
1 | 1 | Biology | 70 | Roger |\n| 2 | 2 |
2 | Biology | 60 | Bilal |\n| 1 | 1 | 1 | Maths |
70 | Voitto |\n| 2 | 2 | 2 | Maths | 60 | Thulile
|\n| 2 | 2 | 3 | Maths | 60 | Pritha |\n| 4 |
3 | 4 | Maths | 55 | Chun
|\n+------+------------+---------+---------+------+---------+\n\nURL:
https://mariadb.com/kb/en/row_number/','','https://mariadb.com/kb/en/row_number/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(785,41,'Aggregate Functions as Window Functions','It is
possible to use aggregate functions as window functions. An
aggregate\nfunction used as a window function must have the OVER clause.
For example,\nhere\'s COUNT() used as a window function:\n\nselect
COUNT(*) over (order by column) from table;\n\nMariaDB currently allows
these aggregate functions to be used as window\nfunctions:\n\n* AVG\n*
BIT_AND\n* BIT_OR\n* BIT_XOR\n* COUNT\n* JSON_ARRAYAGG\n* JSON_OBJECTAGG\n*
MAX\n* MIN\n* STD\n* STDDEV\n* STDDEV_POP\n* STDDEV_SAMP\n* SUM\n*
VAR_POP\n* VAR_SAMP\n* VARIANCE\n\nURL:
https://mariadb.com/kb/en/aggregate-functions-as-window-functions/','','https://mariadb.com/kb/en/aggregate-functions-as-window-functions/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(786,41,'ColumnStore Window
Functions','Introduction\n------------\n\nMariaDB ColumnStore
provides support for window functions broadly following\nthe SQL 2003
specification. A window function allows for calculations relating\nto a
window of data surrounding the current row in a result set.
This\ncapability provides for simplified queries in support of common
business\nquestions such as cumulative totals, rolling averages, and top 10
lists.\n\nAggregate functions are utilized for window functions however
differ in\nbehavior from a group by query because the rows remain
ungrouped. This\nprovides support for cumulative sums and rolling averages,
for example.\n\nTwo key concepts for window functions are Partition and
Frame:\n\n* A Partition is a group of rows, or window, that have the same
value for a\nspecific column, for example a Partition can be created over a
time period\nsuch as a quarter or lookup values.\n* The Frame for each row
is a subset of the row\'s Partition. The frame\ntypically is dynamic
allowing for a sliding frame of rows within the\nPartition. The Frame
determines the range of rows for the windowing function.\nA Frame could be
defined as the last X rows and next Y rows all the way up to\nthe entire
Partition.\n\nWindow functions are applied after joins, group by, and
having clauses are\ncalculated.\n\nSyntax\n------\n\nA window function is
applied in the select clause using the following syntax:\n\nfunction_name
([expression [, expression ... ]]) OVER ( window_definition )\n\nwhere
window_definition is defined as:\n\n[ PARTITION BY expression [, ...] ]\n[
ORDER BY expression [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] ]\n[
frame_clause ]\n\nPARTITION BY:\n\n* Divides the window result set into
groups based on one or more expressions.\n* An expression may be a
constant, column, and non window function expressions.\n* A query is not
limited to a single partition by clause. Different partition\nclauses can
be used across different window function applications.\n* The partition by
columns do not need to be in the select list but do need to\nbe available
from the query result set.\n* If there is no PARTITION BY clause, all rows
of the result set define the\ngroup.\n\nORDER BY\n\n* Defines the ordering
of values within the partition.\n* Can be ordered by multiple keys which
may be a constant, column or non\nwindow function expression.\n* The order
by columns do not need to be in the select list but need to be\navailable
from the query result set.\n* Use of a select column alias from the query
is not supported.\n* ASC (default) and DESC options allow for ordering
ascending or descending.\n* NULLS FIRST and NULL_LAST options specify
whether null values come first or\nlast in the ordering sequence.
NULLS_FIRST is the default for ASC order, and\nNULLS_LAST is the default
for DESC order.\n\nand the optional frame_clause is defined as:\n\n{ RANGE
| ROWS } frame_start\n{ RANGE | ROWS } BETWEEN frame_start AND
frame_end\n\nand the optional frame_start and frame_end are defined as
(value being a\nnumeric expression):\n\nUNBOUNDED PRECEDING\nvalue
PRECEDING\nCURRENT ROW\nvalue FOLLOWING\nUNBOUNDED
FOLLOWING\n\nRANGE/ROWS:\n\n* Defines the windowing clause for calculating
the set of rows that the\nfunction applies to for calculating a given rows
window function result.\n* Requires an ORDER BY clause to define the row
order for the window.\n* ROWS specify the window in physical units, i.e.
result set rows and must be\na constant or expression evaluating to a
positive numeric value.\n* RANGE specifies the window as a logical offset.
If the the expression\nevaluates to a numeric value then the ORDER BY
expression must be a numeric or\nDATE type. If the expression evaluates to
an interval value then the ORDER BY\nexpression must be a DATE data
type.\n* UNBOUNDED PRECEDING indicates the window starts at the first row
of the\npartition.\n* UNBOUNDED FOLLOWING indicates the window ends at the
last row of the\npartition.\n* CURRENT ROW specifies the window start or
ends at the current row or value.\n* If omitted, the default is ROWS
BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW.\n\nSupported
Functions\n-------------------\n\n+--------------------------------+-------------------------------------------+\n|
Function | Description
|\n+--------------------------------+-------------------------------------------+\n|
AVG() | The average of all input values.
|\n+--------------------------------+-------------------------------------------+\n|
COUNT() | Number of input rows.
|\n+--------------------------------+-------------------------------------------+\n|
CUME_DIST() | Calculates the cumulative distribution,
|\n| | or relative rank, of the current row
to |\n| | other rows in the same
partition. Number |\n| | of peer or
preceding rows / number of |\n| | rows
in partition.
|\n+--------------------------------+-------------------------------------------+\n|
DENSE_RANK() | Ranks items in a group leaving no gaps
|\n| | in ranking sequence when there are
ties.
|\n+--------------------------------+-------------------------------------------+\n|
FIRST_VALUE() | The value evaluated at the row that is
|\n| | the first row of the window frame
|\n| | (counting from 1); null if no
such row.
|\n+--------------------------------+-------------------------------------------+\n|
LAG() | The value evaluated at the row that is
|\n| | offset rows before the current row
|\n| | within the partition; if there is
no |\n| | such row, instead return
default. Both |\n| | offset and default
are evaluated with |\n| | respect to the
current row. If omitted, |\n| | offset
defaults to 1 and default to |\n| |
null. LAG provides access to more than |\n|
| one row of a table at the same time |\n|
| without a self-join. Given a series of |\n|
| rows returned from a query and a |\n|
| position of the cursor, LAG provides |\n|
| access to a row at a given physical |\n|
| offset prior to that position.
|\n+--------------------------------+-------------------------------------------+\n|
LAST_VALUE() | The value evaluated at the row that is
|\n| | the last row of the window frame
|\n| | (counting from 1); null if no
such row.
|\n+--------------------------------+-------------------------------------------+\n|
LEAD() | Provides access to a row at a given
|\n| | physical offset beyond that position.
|\n| | Returns value evaluated at the
row that |\n| | is offset rows after the
current row |\n| | within the
partition; if there is no |\n| | such
row, instead return default. Both |\n| |
offset and default are evaluated with |\n|
| respect to the current row. If omitted, |\n|
| offset defaults to 1 and default to null.
|\n+--------------------------------+-------------------------------------------+\n|
MAX() | Maximum value of expression across all
|\n| | input values.
|\n+--------------------------------+-------------------------------------------+\n|
MEDIAN() | An inverse distribution function that
|\n| | assumes a continuous distribution
model. |\n| | It takes a numeric or
datetime value and |\n| | returns the
middle value or an |\n| |
interpolated value that would be the |\n|
| middle value once the values are sorted. |\n|
| Nulls are ignored in the calculation.
|\n+--------------------------------+-------------------------------------------+\n|
MIN() | Minimum value of expression across all
|\n| | input values.
|\n+--------------------------------+-------------------------------------------+\n|
NTH_VALUE() | The value evaluated at the row that is
|\n| | the nth row of the window frame
|\n| | (counting from 1); null if no
such row.
|\n+--------------------------------+-------------------------------------------+\n|
NTILE() | Divides an ordered data set into a
|\n| | number of buckets indicated by expr
and |\n| | assigns the appropriate bucket
number to |\n| | each row. The buckets are
numbered 1 |\n| | through expr. The
expr value must |\n| | resolve to a
positive constant for each |\n| |
partition. Integer ranging from 1 to the |\n|
| argument value, dividing the partition |\n|
| as equally as possible.
|\n+--------------------------------+-------------------------------------------+\n|
PERCENT_RANK() | relative rank of the current row: (rank
|\n| | - 1) / (total rows - 1).
|\n+--------------------------------+-------------------------------------------+\n|
PERCENTILE_CONT() | An inverse distribution function that
|\n| | assumes a continuous distribution
model. |\n| | It takes a percentile value
and a sort |\n| | specification, and
returns an |\n| | interpolated
value that would fall into |\n| | that
percentile value with respect to |\n| |
the sort specification. Nulls are |\n|
| ignored in the calculation.
|\n+--------------------------------+-------------------------------------------+\n|
PERCENTILE_DISC() | An inverse distribution function that
|\n| | assumes a discrete distribution
model. |\n| | It takes a percentile value
and a sort |\n| | specification and
returns an element |\n| | from the set.
Nulls are ignored in the |\n| |
calculation.
|\n+--------------------------------+-------------------------------------------+\n|
RANK() | rank of the current row with gaps; same
|\n| | as row_number of its first peer.
|\n+--------------------------------+-------------------------------------------+\n|
ROW_NUMBER() | number of the current row within its
|\n| | partition, counting from 1
|\n+--------------------------------+-------------------------------------------+\n|
STDDEV() STDDEV_POP() | Computes the population standard
|\n| | deviation and returns the square root
of |\n| | the population variance.
|\n+--------------------------------+-------------------------------------------+\n|
STDDEV_SAMP() | Computes the cumulative sample standard
|\n| | deviation and returns the square root
of |\n| | the sample variance.
|\n+--------------------------------+-------------------------------------------+\n|
SUM() | Sum of expression across all input
|\n| | values.
|\n+--------------------------------+-------------------------------------------+\n|
VARIANCE() VAR_POP() | Population variance of the input values
|\n| | (square of the population standard
|\n| | deviation).
|\n+--------------------------------+-------------------------------------------+\n|
VAR_SAMP() | Sample variance of the input values
|\n| | (square of the sample standard
|\n| | deviation).
|\n+--------------------------------+-------------------------------------------+\n\nExamples\n--------\n\nExample
Schema\n--------------\n\nThe examples are all based on the following
simplified sales opportunity table:\n\ncreate table opportunities (\nid
int,\naccountName varchar(20),\nname varchar(128),\nowner
varchar(7),\namount decimal(10,2),\ncloseDate date,\nstageName
varchar(11)\n) engine=columnstore;\n\nSome example values are (thanks to
https://www.mockaroo.com for sample
data\ngeneration):\n\n+----+---------------+------+--------+---------+-------------+-------------+\n|
id | accountName | name | owner | amount | closeDate | stageName
|\n+----+---------------+------+--------+---------+-------------+-------------+\n|
1 | Browseblab | Mult | Bob | 26444.8 | 2016-10-20 | Negotiating
|','','https://mariadb.com/kb/en/window-functions-columnstore-window-functions/');
update help_topic set description = CONCAT(description, '\n| |
| -lat | | | | |\n| |
| ral | | | | |\n| |
| exec | | | | |\n|
| | tive | | | | |\n|
| | func | | | |
|\n| | | ion | | | |
|\n+----+---------------+------+--------+---------+-------------+-------------+\n|
2 | Mita | Orga | Maria | 477878. | 2016-11-28 | ClosedWon
|\n| | | ic | | 1 | |
|\n| | | dema | | | |
|\n| | | d-dr | | | |
|\n| | | ven | | | |
|\n| | | benc | | | |
|\n| | | mark | | | |
|\n+----+---------------+------+--------+---------+-------------+-------------+\n|
3 | Miboo | De-e | Olivie | 80181.7 | 2017-01-05 | ClosedWon
|\n| | | gine | | | |
|\n| | | red | | | |
|\n| | | hybr | | | |
|\n| | | d | | | |
|\n| | | grou | | | |
|\n| | | ware | | | |
|\n+----+---------------+------+--------+---------+-------------+-------------+\n|
4 | Youbridge | Ente | Chris | 946245. | 2016-07-02 | ClosedWon
|\n| | | pris | | 9 | |
|\n| | | -wid | | | |
|\n| | | | | | |
|\n| | | bott | | | |
|\n| | | m-li | | | |
|\n| | | e | | | |
|\n| | | Grap | | |
| |\n| | | ic | | |
| |\n| | | Inte | | |
| |\n| | | face | | |
|
|\n+----+---------------+------+--------+---------+-------------+-------------+\n|
5 | Skyba | Reve | Maria | 696241. | 2017-02-17 | Negotiating
|\n| | | se-e | | 2 | |
|\n| | | gine | | | |
|\n| | | red | | | |
|\n| | | fres | | | |
|\n| | | -thi | | | |
|\n| | | king | | | |
|\n| | | stan | | |
| |\n| | | ardi | | |
| |\n| | | atio | | |
| |\n| | | | | |
|
|\n+----+---------------+------+--------+---------+-------------+-------------+\n|
6 | Eayo | Fund | Bob | 765605. | 2016-08-27 | Prospecting
|\n| | | ment | | 2 | |
|\n| | | l | | | |
|\n| | | well | | | |
|\n| | | modu | | | |
|\n| | | ated | | | |
|\n| | | arti | | | |
|\n| | | icia | | |
| |\n| | | | | |
| |\n| | | inte | | |
| |\n| | | lige | | |
| |\n| | | ce | | |
|
|\n+----+---------------+------+--------+---------+-------------+-------------+\n|
7 | Yotz | Exte | Chris | 319624. | 2017-01-06 | ClosedLost
|\n| | | ded | | 0 | |
|\n| | | seco | | | |
|\n| | | dary | | | |
|\n| | | infr | | | |
|\n| | | stru | | | |
|\n| | | ture | | | |
|\n+----+---------------+------+--------+---------+-------------+-------------+\n|
8 | Oloo | Conf | Chris | 321016. | 2017-03-08 | ClosedLost
|\n| | | gura | | 6 | |
|\n| | | le | | | |
|\n| | | web- | | | |
|\n| | | nabl | | | |
|\n| | | d | | | |
|\n| | | data | | | |
|\n| | | ware | | |
| |\n| | | ouse | | |
|
|\n+----+---------------+------+--------+---------+-------------+-------------+\n|
9 | Kaymbo | Mult | Bob | 690881. | 2017-01-02 | Developing
|\n| | | -lat | | 1 | |
|\n| | | ral | | | |
|\n| | | web- | | | |
|\n| | | nabl | | | |
|\n| | | d | | | |
|\n| | | defi | | | |
|\n| | | itio | | |
| |\n| | | | | |
|
|\n+----+---------------+------+--------+---------+-------------+-------------+\n|
10 | Rhyloo | Publ | Chris | 965477. | 2016-11-07 | Prospecting
|\n| | | c-ke | | 4 | |
|\n| | | | | | |
|\n| | | cohe | | | |
|\n| | | ent | | | |
|\n| | | infr | | | |
|\n| | | stru | | | |
|\n| | | ture | | |
|
|\n+----+---------------+------+--------+---------+-------------+-------------+\n\nThe
schema, sample data, and queries are available as an attachment to
this\narticle.\n\nCumulative Sum and Running Max
Example\n--------------------------------------\n\nWindow functions can be
used to achieve cumulative / running calculations on a\ndetail report. In
this case a won opportunity report for a 7 day period adds\ncolumns to show
the accumulated won amount as well as the current highest\nopportunity
amount in preceding rows.\n\nselect owner, \naccountName, \nCloseDate,
\namount, \nsum(amount) over (order by CloseDate rows between unbounded
preceding and\ncurrent row) cumeWon, \nmax(amount) over (order by CloseDate
rows between unbounded preceding and\ncurrent row) runningMax\nfrom
opportunities \nwhere stageName=\'ClosedWon\' \nand closeDate
>= \'2016-10-02\' and closeDate <= \'2016-10-09\'
\norder by CloseDate;\n\nwith example
results:\n\n+--------+---------------+-------------+---------+----------+--------------+\n|
owner | accountName | CloseDate | amount | cumeWon | runningMax
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Bill | Babbleopia | 2016-10-02 | 437636. | 437636.4 | 437636.47
|\n| | | | 7 | |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Bill | Thoughtworks | 2016-10-04 | 146086. | 583722.9 | 437636.47
|\n| | | | 1 | |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Olivie | Devpulse | 2016-10-05 | 834235. | 1417958. | 834235.93
|\n| | | | 3 | 1 |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Chris | Linkbridge | 2016-10-07 | 539977. | 2458738. | 834235.93
|\n| | | | 5 | 5 |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Olivie | Trupe | 2016-10-07 | 500802. | 1918761. | 834235.93
|\n| | | | 9 | 0 |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Bill | Latz | 2016-10-08 | 857254. | 3315993. | 857254.87
|\n| | | | 7 | 2 |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Chris | Avamm | 2016-10-09 | 699566. | 4015560. | 857254.87
|\n| | | | 6 | 8 |
|\n+--------+---------------+-------------+---------+----------+--------------+\n\nPartitioned
Cumulative Sum and Running Max
Example\n--------------------------------------------------\n\nThe above
example can be partitioned, so that the window functions are over
a\nparticular field grouping such as owner and accumulate within that
grouping.\nThis is achieved by adding the syntax \"partition by
<columns>\" in the window\nfunction clause.\n\nselect owner,
\naccountName, \nCloseDate, \namount, \nsum(amount) over (partition by
owner order by CloseDate rows between unbounded\npreceding and current row)
cumeWon, \nmax(amount) over (partition by owner order by CloseDate rows
between unbounded\npreceding and current row) runningMax \nfrom
opportunities \nwhere stageName=\'ClosedWon\' \nand closeDate
>= \'2016-10-02\' and closeDate <= \'2016-10-09\'
\norder by owner, CloseDate;\n\nwith example
results:\n\n+--------+---------------+-------------+---------+----------+--------------+\n|
owner | accountName | CloseDate | amount | cumeWon | runningMax
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Bill | Babbleopia | 2016-10-02 | 437636. | 437636.4 | 437636.47
|\n| | | | 7 | |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Bill | Thoughtworks | 2016-10-04 | 146086. | 583722.9 | 437636.47
|\n| | | | 1 | |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Bill | Latz | 2016-10-08 | 857254. | 1440977. | 857254.87
|\n| | | | 7 | 5 |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Chris | Linkbridge | 2016-10-07 | 539977. | 539977.4 | 539977.45
|\n| | | | 5 | |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Chris | Avamm | 2016-10-09 | 699566. | 1239544. | 699566.86
|\n| | | | 6 | 1 |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Olivie | Devpulse | 2016-10-05 | 834235. | 834235.9 | 834235.93
|\n| | | | 3 | |
|\n+--------+---------------+-------------+---------+----------+--------------+\n|
Olivie | Trupe | 2016-10-07 | 500802. | 1335038. | 834235.93
|\n| | | | 9 | 2 |
|\n+--------+---------------+-------------+---------+----------+--------------+\n\nRanking
/ Top Results\n---------------------\n\nThe rank window function allows for
ranking or assigning a numeric order value\nbased on the window function
definition. Using the Rank() function will result\nin the same value for
ties / equal values and the next rank value skipped. The\nDense_Rank()
function behaves similarly except the next consecutive number is\nused
after a tie rather than skipped. The Row_Number() function will provide
a\nunique ordering value. The example query shows the Rank() function
being\napplied to rank sales reps by the number of opportunities for Q4
2016.\n\nselect owner, \nwonCount, \nrank() over (order by wonCount desc)
rank \nfrom (\n select owner,\n count(*) wonCount\n from opportunities\n
where stageName=\'ClosedWon\'\n and closeDate >=
\'2016-10-01\' and closeDate < \'2016-12-31\'\n
group by owner\n) t\norder by rank;\n\nwith example results (note the query
is technically incorrect by using\ncloseDate < \'2016-12-31\'
however this creates a tie scenario for
illustrative\npurposes):\n\n+----------------------+----------------------------------+------------------+\n|
owner | wonCount | rank
|\n+----------------------+----------------------------------+------------------+\n|
Bill | 19 | 1
|\n+----------------------+----------------------------------+------------------+\n|
Chris | 15 | 2
|') WHERE help_topic_id = 786;
update help_topic set description = CONCAT(description,
'\n+----------------------+----------------------------------+------------------+\n|
Maria | 14 | 3
|\n+----------------------+----------------------------------+------------------+\n|
Bob | 14 | 3
|\n+----------------------+----------------------------------+------------------+\n|
Olivier | 10 | 5
|\n+----------------------+----------------------------------+------------------+\n\nIf
the dense_rank function is used the rank values would be 1,2,3,3,4 and
for\nthe row_number function the values would be 1,2,3,4,5.\n\nFirst and
Last Values\n---------------------\n\nThe first_value and last_value
functions allow determining the first and last\nvalues of a given range.
Combined with a group by this allows summarizing\nopening and closing
values. The example shows a more complex case where\ndetailed information
is presented for first and last opportunity by quarter.\n\nselect a.year,
\na.quarter, \nf.accountName firstAccountName, \nf.owner firstOwner,
\nf.amount firstAmount, \nl.accountName lastAccountName, \nl.owner
lastOwner, \nl.amount lastAmount \nfrom (\n select year,\n quarter,\n
min(firstId) firstId,\n min(lastId) lastId\n from (\n select
year(closeDate) year,\n quarter(closeDate) quarter,\n first_value(id)
over (partition by year(closeDate), quarter(closeDate)\norder by closeDate
rows between unbounded preceding and current row) firstId, \n
last_value(id) over (partition by year(closeDate),
quarter(closeDate)\norder by closeDate rows between current row and
unbounded following) lastId \n from opportunities where
stageName=\'ClosedWon\'\n ) t\n group by year, quarter order by
year,quarter\n) a \njoin opportunities f on a.firstId = f.id \njoin
opportunities l on a.lastId = l.id \norder by year, quarter;\n\nwith
example
results:\n\n+----+------+------------+--------+---------+-----------+-------+--------+\n|
ye | quar | firstAccou | firstO | firstAm | lastAccou | lastO | lastAm |\n|
r | er | tName | ner | unt | tName | ner | unt
|\n+----+------+------------+--------+---------+-----------+-------+--------+\n|
20 | 3 | Skidoo | Bill | 523295. | Skipstorm | Bill | 151420 |\n|
6 | | | | 7 | | | 86
|\n+----+------+------------+--------+---------+-----------+-------+--------+\n|
20 | 4 | Skimia | Chris | 961513. | Avamm | Maria | 112493 |\n|
6 | | | | 9 | | | 65
|\n+----+------+------------+--------+---------+-----------+-------+--------+\n|
20 | 1 | Yombu | Bob | 536875. | Skaboo | Chris | 270273 |\n|
7 | | | | 1 | | | 08
|\n+----+------+------------+--------+---------+-----------+-------+--------+\n\nPrior
and Next Example\n----------------------\n\nSometimes it useful to
understand the previous and next values in the context\nof a given row. The
lag and lead window functions provide this capability. By\ndefault the
offset is one providing the prior or next value but can also be\nprovided
to get a larger offset. The example query is a report of\nopportunities by
account name showing the opportunity amount, and the prior\nand next
opportunity amount for that account by close date.\n\nselect accountName,
\ncloseDate, \namount currentOppAmount, \nlag(amount) over (partition by
accountName order by closeDate) priorAmount,\nlead(amount) over (partition
by accountName order by closeDate) nextAmount \nfrom opportunities \norder
by accountName, closeDate \nlimit 9;\n\nwith example
results:\n\n+--------------+-----------+-------------------+--------------+-------------+\n|
accountName | closeDate | currentOppAmount | priorAmount | nextAmount
|\n+--------------+-----------+-------------------+--------------+-------------+\n|
Abata | 2016-09-1 | 645098.45 | NULL | 161086.82
|\n| | | | |
|\n+--------------+-----------+-------------------+--------------+-------------+\n|
Abata | 2016-10-1 | 161086.82 | 645098.45 | 350235.75
|\n| | | | |
|\n+--------------+-----------+-------------------+--------------+-------------+\n|
Abata | 2016-12-1 | 350235.75 | 161086.82 | 878595.89
|\n| | | | |
|\n+--------------+-----------+-------------------+--------------+-------------+\n|
Abata | 2016-12-3 | 878595.89 | 350235.75 | 922322.39
|\n| | | | |
|\n+--------------+-----------+-------------------+--------------+-------------+\n|
Abata | 2017-01-2 | 922322.39 | 878595.89 | NULL
|\n| | | | |
|\n+--------------+-----------+-------------------+--------------+-------------+\n|
Abatz | 2016-10-1 | 795424.15 | NULL | NULL
|\n| | | | |
|\n+--------------+-----------+-------------------+--------------+-------------+\n|
Agimba | 2016-07-0 | 288974.84 | NULL | 914461.49
|\n| | | | |
|\n+--------------+-----------+-------------------+--------------+-------------+\n|
Agimba | 2016-09-0 | 914461.49 | 288974.84 | 176645.52
|\n| | | | |
|\n+--------------+-----------+-------------------+--------------+-------------+\n|
Agimba | 2016-09-2 | 176645.52 | 914461.49 | NULL
|\n| | | | |
|\n+--------------+-----------+-------------------+--------------+-------------+\n\nQuartiles
Example\n-----------------\n\nThe NTile window function allows for breaking
up a data set into portions\nassigned a numeric value to each portion of
the range. NTile(4) breaks the\ndata up into quartiles (4 sets). The
example query produces a report of all\nopportunities summarizing the
quartile boundaries of amount values.\n\nselect t.quartile, \nmin(t.amount)
min, \nmax(t.amount) max \nfrom (\n select amount,\n ntile(4) over (order
by amount asc) quartile\n from opportunities\n where closeDate >=
\'2016-10-01\' and closeDate <= \'2016-12-31\'\n )
t\ngroup by quartile \norder by quartile;\n\nWith example
results:\n\n+-----------------------------------------+----------------+----------------+\n|
quartile | min | max
|\n+-----------------------------------------+----------------+----------------+\n|
1 | 6337.15 | 287634.01
|\n+-----------------------------------------+----------------+----------------+\n|
2 | 288796.14 | 539977.45
|\n+-----------------------------------------+----------------+----------------+\n|
3 | 540070.04 | 748727.51
|\n+-----------------------------------------+----------------+----------------+\n|
4 | 753670.77 | 998864.47
|\n+-----------------------------------------+----------------+----------------+\n\nPercentile
Example\n------------------\n\nThe percentile functions have a slightly
different syntax from other window\nfunctions as can be seen in the example
below. These functions can be only\napplied against numeric values. The
argument to the function is the percentile\nto evaluate. Following
\'within group\' is the sort expression which indicates\nthe sort
column and optionally order. Finally after \'over\' is an
optional\npartition by clause, for no partition clause use \'over
()\'. The example below\nutilizes the value 0.5 to calculate the
median opportunity amount in the rows.\nThe values differ sometimes because
percentile_cont will return the average of\nthe 2 middle rows for an even
data set while percentile_desc returns the first\nencountered in the
sort.\n\nselect owner, \naccountName, \nCloseDate,
\namount,\npercentile_cont(0.5) within group (order by amount) over
(partition by owner)\npct_cont,\npercentile_disc(0.5) within group (order
by amount) over (partition by owner)\npct_disc\nfrom opportunities \nwhere
stageName=\'ClosedWon\' \nand closeDate >=
\'2016-10-02\' and closeDate <= \'2016-10-09\'
\norder by owner, CloseDate;\n\nWith example
results:\n\n+--------+----------------+-------------+---------+------------+------------+\n|
owner | accountName | CloseDate | amount | pct_cont | pct_disc
|\n+--------+----------------+-------------+---------+------------+------------+\n|
Bill | Babbleopia | 2016-10-02 | 437636. | 437636.470 | 437636.47
|\n| | | | 7 | 000000 |
|\n+--------+----------------+-------------+---------+------------+------------+\n|
Bill | Thoughtworks | 2016-10-04 | 146086. | 437636.470 | 437636.47
|\n| | | | 1 | 000000 |
|\n+--------+----------------+-------------+---------+------------+------------+\n|
Bill | Latz | 2016-10-08 | 857254. | 437636.470 | 437636.47
|\n| | | | 7 | 000000 |
|\n+--------+----------------+-------------+---------+------------+------------+\n|
Chris | Linkbridge | 2016-10-07 | 539977. | 619772.155 | 539977.45
|\n| | | | 5 | 000000 |
|\n+--------+----------------+-------------+---------+------------+------------+\n|
Chris | Avamm | 2016-10-09 | 699566. | 619772.155 | 539977.45
|\n| | | | 6 | 000000 |
|\n+--------+----------------+-------------+---------+------------+------------+\n|
Olivie | Devpulse | 2016-10-05 | 834235. | 667519.110 | 500802.29
|\n| | | | 3 | 000000 |
|\n+--------+----------------+-------------+---------+------------+------------+\n|
Olivie | Trupe | 2016-10-07 | 500802. | 667519.110 | 500802.29
|\n| | | | 9 | 000000 |
|\n+--------+----------------+-------------+---------+------------+------------+\n\nURL:
https://mariadb.com/kb/en/window-functions-columnstore-window-functions/')
WHERE help_topic_id = 786;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(787,41,'Window Frames','Syntax\n------\n\nframe_clause:\n
{ROWS | RANGE} {frame_border | BETWEEN frame_border AND
frame_border}\n\nframe_border:\n | UNBOUNDED PRECEDING\n | UNBOUNDED
FOLLOWING\n | CURRENT ROW\n | expr PRECEDING\n | expr
FOLLOWING\n\nDescription\n-----------\n\nA basic overview of window
functions is described in Window Functions\nOverview. Window frames expand
this functionality by allowing the function to\ninclude a specified a
number of rows around the current row.\n\nThese include:\n\n* All rows
before the current row (UNBOUNDED PRECEDING), for example RANGE\nBETWEEN
UNBOUNDED PRECEDING AND CURRENT ROW\n* All rows after the current row
(UNBOUNDED FOLLOWING), for example RANGE\nBETWEEN CURRENT ROW AND UNBOUNDED
FOLLOWING\n* A set number of rows before the current row (expr PRECEDING)
for example\nRANGE BETWEEN 6 PRECEDING AND CURRENT ROW\n* A set number of
rows after the current row (expr PRECEDING AND expr\nFOLLOWING) for
example RANGE BETWEEN CURRENT ROW AND 2 FOLLOWING\n* A specified number of
rows both before and after the current row, for\nexample RANGE BETWEEN 6
PRECEDING AND 3 FOLLOWING\n\nThe following functions operate on window
frames:\n\n* AVG\n* BIT_AND\n* BIT_OR\n* BIT_XOR\n* COUNT\n* LEAD\n* MAX\n*
MIN\n* NTILE\n* STD\n* STDDEV\n* STDDEV_POP\n* STDDEV_SAMP\n* SUM\n*
VAR_POP\n* VAR_SAMP\n* VARIANCE\n\nWindow frames are determined by the
frame_clause in the window function\nrequest.\n\nTake the following
example:\n\nCREATE TABLE `student_test` (\n name char(10),\n test
char(10),\n score tinyint(4)\n);\n\nINSERT INTO student_test VALUES \n
(\'Chun\', \'SQL\', 75), (\'Chun\',
\'Tuning\', 73),\n (\'Esben\', \'SQL\', 43),
(\'Esben\', \'Tuning\', 31),\n (\'Kaolin\',
\'SQL\', 56), (\'Kaolin\', \'Tuning\', 88),\n
(\'Tatiana\', \'SQL\', 87);\n\nSELECT name, test,
score, SUM(score) \n OVER () AS total_score\n FROM
student_test;\n+---------+--------+-------+-------------+\n| name | test
| score | total_score |\n+---------+--------+-------+-------------+\n|
Chun | SQL | 75 | 453 |\n| Chun | Tuning | 73 |
453 |\n| Esben | SQL | 43 | 453 |\n| Esben | Tuning |
31 | 453 |\n| Kaolin | SQL | 56 | 453 |\n| Kaolin
| Tuning | 88 | 453 |\n| Tatiana | SQL | 87 | 453
|\n+---------+--------+-------+-------------+\n\nBy not specifying an OVER
clause, the SUM function is run over the entire\ndataset. However, if we
specify an ORDER BY condition based on score (and\norder the entire result
in the same way for clarity), the following result is\nreturned:\n\nSELECT
name, test, score, SUM(score) \n OVER (ORDER BY score) AS total_score\n
FROM student_test ORDER BY
score;\n+---------+--------+-------+-------------+\n| name | test |
score | total_score |\n+---------+--------+-------+-------------+\n| Esben
| Tuning | 31 | 31 |\n| Esben | SQL | 43 | 74
|\n| Kaolin | SQL | 56 | 130 |\n| Chun | Tuning | 73 |
203 |\n| Chun | SQL | 75 | 278 |\n| Tatiana | SQL
| 87 | 365 |\n| Kaolin | Tuning | 88 | 453
|\n+---------+--------+-------+-------------+\n\nThe total_score column
represents a running total of the current row, and all\nprevious rows. The
window frame in this example expands as the function\nproceeds.\n\nThe
above query makes use of the default to define the window frame. It
could\nbe written explicitly as follows:\n\nSELECT name, test, score,
SUM(score) \n OVER (ORDER BY score RANGE BETWEEN UNBOUNDED PRECEDING AND
CURRENT ROW) AS\ntotal_score \n FROM student_test ORDER BY
score;\n+---------+--------+-------+-------------+\n| name | test |
score | total_score |\n+---------+--------+-------+-------------+\n| Esben
| Tuning | 31 | 31 |\n| Esben | SQL | 43 | 74
|\n| Kaolin | SQL | 56 | 130 |\n| Chun | Tuning | 73 |
203 |\n| Chun | SQL | 75 | 278 |\n| Tatiana | SQL
| 87 | 365 |\n| Kaolin | Tuning | 88 | 453
|\n+---------+--------+-------+-------------+\n\nLet\'s look at some
alternatives:\n\nFirstly, applying the window function to the current row
and all following\nrows can be done with the use of UNBOUNDED
FOLLOWING:\n\nSELECT name, test, score, SUM(score) \n OVER (ORDER BY score
RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) AS\ntotal_score \n FROM
student_test ORDER BY score;\n+---------+--------+-------+-------------+\n|
name | test | score | total_score
|\n+---------+--------+-------+-------------+\n| Esben | Tuning | 31 |
453 |\n| Esben | SQL | 43 | 422 |\n| Kaolin | SQL
| 56 | 379 |\n| Chun | Tuning | 73 | 323 |\n|
Chun | SQL | 75 | 250 |\n| Tatiana | SQL | 87 |
175 |\n| Kaolin | Tuning | 88 | 88
|\n+---------+--------+-------+-------------+\n\nIt\'s possible to
specify a number of rows, rather than the entire unbounded\nfollowing or
preceding set. The following example takes the current row, as\nwell as the
previous row:\n\nSELECT name, test, score, SUM(score) \n OVER (ORDER BY
score ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) AS\ntotal_score \n FROM
student_test ORDER BY score;\n+---------+--------+-------+-------------+\n|
name | test | score | total_score
|\n+---------+--------+-------+-------------+\n| Esben | Tuning | 31 |
31 |\n| Esben | SQL | 43 | 74 |\n| Kaolin | SQL
| 56 | 99 |\n| Chun | Tuning | 73 | 129 |\n|
Chun | SQL | 75 | 148 |\n| Tatiana | SQL | 87 |
162 |\n| Kaolin | Tuning | 88 | 175
|\n+---------+--------+-------+-------------+\n\nThe current row and the
following row:\n\nSELECT name, test, score, SUM(score) \n OVER (ORDER BY
score ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING) AS\ntotal_score \n FROM
student_test ORDER BY score;\n+---------+--------+-------+-------------+\n|
name | test | score | total_score
|\n+---------+--------+-------+-------------+\n| Esben | Tuning | 31 |
74 |\n| Esben | SQL | 43 | 130 |\n| Kaolin | SQL
| 56 | 172 |\n| Chun | Tuning | 73 | 204 |\n|
Chun | SQL | 75 | 235 |\n| Tatiana | SQL | 87 |
250 |\n| Kaolin | Tuning | 88 | 175
|\n+---------+--------+-------+-------------+\n\nURL:
https://mariadb.com/kb/en/window-frames/','','https://mariadb.com/kb/en/window-frames/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(788,42,'SPIDER_BG_DIRECT_SQL','Syntax\n------\n\nSPIDER_BG_DIRECT_SQL(\'sql\',
\'tmp_table_list\',
\'parameters\')\n\nDescription\n-----------\n\nExecutes the given
SQL statement in the background on the remote server, as\ndefined in the
parameters listing. If the query returns a result-set, it\nsttores the
results in the given temporary table. When the given SQL
statement\nexecutes successfully, this function returns the number of
called UDF\'s. It\nreturns 0 when the given SQL statement
fails.\n\nThis function is a UDF installed with the Spider storage
engine.\n\nExamples\n--------\n\nSELECT SPIDER_BG_DIRECT_SQL(\'SELECT
* FROM example_table\', \'\', \n \'srv
\"node1\", port \"8607\"\') AS \"Direct
Query\";\n+--------------+\n| Direct Query | \n+--------------+\n|
1
|\n+--------------+\n\nParameters\n----------\n\nerror_rw_mode\n-------------\n\n*
Description: Returns empty results on network error.\n0 : Return error on
getting network error.\n1: Return 0 records on getting network error.\n\n*
Default Table Value: 0\n* DSN Parameter Name: erwm\n\nURL:
https://mariadb.com/kb/en/spider_bg_direct_sql/','','https://mariadb.com/kb/en/spider_bg_direct_sql/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(789,42,'SPIDER_COPY_TABLES','Syntax\n------\n\nSPIDER_COPY_TABLES(spider_table_name,
\n source_link_id, destination_link_id_list
[,parameters])\n\nDescription\n-----------\n\nA UDF installed with the
Spider Storage Engine, this function copies table\ndata from source_link_id
to destination_link_id_list. The service does not\nneed to be stopped in
order to copy.\n\nIf the Spider table is partitioned, the name must be of
the format\ntable_name#P#partition_name. The partition name can be viewed
in the\nmysql.spider_tables table, for example:\n\nSELECT table_name FROM
mysql.spider_tables;\n+-------------+\n| table_name |\n+-------------+\n|
spt_a#P#pt1 |\n| spt_a#P#pt2 |\n| spt_a#P#pt3 |\n+-------------+\n\nReturns
1 if the data was copied successfully, or 0 if copying the data
failed.\n\nURL:
https://mariadb.com/kb/en/spider_copy_tables/','','https://mariadb.com/kb/en/spider_copy_tables/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(790,42,'SPIDER_DIRECT_SQL','Syntax\n------\n\nSPIDER_DIRECT_SQL(\'sql\',
\'tmp_table_list\',
\'parameters\')\n\nDescription\n-----------\n\nA UDF installed
with the Spider Storage Engine, this function is used to\nexecute the SQL
string sql on the remote server, as defined in parameters. If\nany
resultsets are returned, they are stored in the tmp_table_list.\n\nThe
function returns 1 if the SQL executes successfully, or 0 if it
fails.\n\nExamples\n--------\n\nSELECT SPIDER_DIRECT_SQL(\'SELECT *
FROM s\', \'\', \'srv \"node1\", port
\"8607\"\');\n+----------------------------------------------------------------------+\n|
SPIDER_DIRECT_SQL(\'SELECT * FROM s\', \'\', \'srv
\"node1\", port \"8607\"\')
|\n+----------------------------------------------------------------------+\n|
1
|\n+----------------------------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/spider_direct_sql/','','https://mariadb.com/kb/en/spider_direct_sql/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(791,42,'SPIDER_FLUSH_TABLE_MON_CACHE','Syntax\n------\n\nSPIDER_FLUSH_TABLE_MON_CACHE()\n\nDescription\n-----------\n\nA
UDF installed with the Spider Storage Engine, this function is used
for\nrefreshing monitoring server information. It returns a value of
1.\n\nExamples\n--------\n\nSELECT
SPIDER_FLUSH_TABLE_MON_CACHE();\n+--------------------------------+\n|
SPIDER_FLUSH_TABLE_MON_CACHE() |\n+--------------------------------+\n|
1 |\n+--------------------------------+\n\nURL:
https://mariadb.com/kb/en/spider_flush_table_mon_cache/','','https://mariadb.com/kb/en/spider_flush_table_mon_cache/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(792,43,'COLUMN_ADD','Syntax\n------\n\nCOLUMN_ADD(dyncol_blob,
column_nr, value [as type], [column_nr, value
[as\ntype]]...);\nCOLUMN_ADD(dyncol_blob, column_name, value [as type],
[column_name, value [as\ntype]]...);\n\nDescription\n-----------\n\nAdds or
updates dynamic columns.\n\n* dyncol_blob must be either a valid dynamic
columns blob (for example,\nCOLUMN_CREATE returns such blob), or an empty
string.\n* column_name specifies the name of the column to be added. If
dyncol_blob\nalready has a column with this name, it will be
overwritten.\n* value specifies the new value for the column. Passing a
NULL value will\ncause the column to be deleted.\n* as type is optional.
See #datatypes section for a discussion about types.\n\nThe return value is
a dynamic column blob after the
modifications.\n\nExamples\n--------\n\nUPDATE t1 SET
dyncol_blob=COLUMN_ADD(dyncol_blob, \"column_name\",
\"value\")\nWHERE id=1;\n\nNote: COLUMN_ADD() is a regular
function (just like CONCAT()), hence, in order\nto update the value in the
table you have to use the UPDATE ...
SET\ndynamic_col=COLUMN_ADD(dynamic_col, ....) pattern.\n\nURL:
https://mariadb.com/kb/en/column_add/','','https://mariadb.com/kb/en/column_add/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(793,43,'COLUMN_CHECK','Syntax\n------\n\nCOLUMN_CHECK(dyncol_blob);\n\nDescription\n-----------\n\nCheck
if dyncol_blob is a valid packed dynamic columns blob. Return value of
1\nmeans the blob is valid, return value of 0 means it is
not.\n\nRationale: Normally, one works with valid dynamic column blobs.
Functions like\nCOLUMN_CREATE, COLUMN_ADD, COLUMN_DELETE always return
valid dynamic column\nblobs. However, if a dynamic column blob is
accidentally truncated, or\ntranscoded from one character set to another,
it will be corrupted. This\nfunction can be used to check if a value in a
blob field is a valid dynamic\ncolumn blob.\n\nURL:
https://mariadb.com/kb/en/column_check/','','https://mariadb.com/kb/en/column_check/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(794,43,'COLUMN_CREATE','Syntax\n------\n\nCOLUMN_CREATE(column_nr,
value [as type], [column_nr, value [as
type]]...);\nCOLUMN_CREATE(column_name, value [as type], [column_name,
value [as type]]...);\n\nDescription\n-----------\n\nReturns a dynamic
columns blob that stores the specified columns with values.\n\nThe return
value is suitable for\n\n* storing in a table\n* further modification with
other dynamic columns functions\n\nThe as type part allows one to specify
the value type. In most cases, this is\nredundant because MariaDB will be
able to deduce the type of the value.\nExplicit type specification may be
needed when the type of the value is not\napparent. For example, a literal
\'2012-12-01\' has a CHAR type by default, one\nwill need to
specify \'2012-12-01\' AS DATE to have it stored as a date.
See\nDynamic Columns:Datatypes for further
details.\n\nExamples\n--------\n\nINSERT INTO tbl SET
dyncol_blob=COLUMN_CREATE(\"column_name\",
\"value\");\n\nURL:
https://mariadb.com/kb/en/column_create/','','https://mariadb.com/kb/en/column_create/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(795,43,'COLUMN_DELETE','Syntax\n------\n\nCOLUMN_DELETE(dyncol_blob,
column_nr, column_nr...);\nCOLUMN_DELETE(dyncol_blob, column_name,
column_name...);\n\nDescription\n-----------\n\nDeletes a dynamic column
with the specified name. Multiple names can be given.\nThe return value is
a dynamic column blob after the modification.\n\nURL:
https://mariadb.com/kb/en/column_delete/','','https://mariadb.com/kb/en/column_delete/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(796,43,'COLUMN_EXISTS','Syntax\n------\n\nCOLUMN_EXISTS(dyncol_blob,
column_nr);\nCOLUMN_EXISTS(dyncol_blob,
column_name);\n\nDescription\n-----------\n\nChecks if a column with name
column_name exists in dyncol_blob. If yes, return\n1, otherwise return 0.
See dynamic columns for more information.\n\nURL:
https://mariadb.com/kb/en/column_exists/','','https://mariadb.com/kb/en/column_exists/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(797,43,'COLUMN_GET','Syntax\n------\n\nCOLUMN_GET(dyncol_blob,
column_nr as type);\nCOLUMN_GET(dyncol_blob, column_name as
type);\n\nDescription\n-----------\n\nGets the value of a dynamic column by
its name. If no column with the given\nname exists, NULL will be
returned.\n\ncolumn_name as type requires that one specify the datatype of
the dynamic\ncolumn they are reading.\n\nThis may seem counter-intuitive:
why would one need to specify which datatype\nthey\'re retrieving?
Can\'t the dynamic columns system figure the datatype from\nthe data
being stored?\n\nThe answer is: SQL is a statically-typed language. The SQL
interpreter needs\nto know the datatypes of all expressions before the
query is run (for example,\nwhen one is using prepared statements and runs
\"select COLUMN_GET(...)\", the\nprepared statement API requires
the server to inform the client about the\ndatatype of the column being
read before the query is executed and the server\ncan see what datatype the
column actually has).\n\nLengths\n-------\n\nIf you\'re running
queries like:\n\nSELECT COLUMN_GET(blob, \'colname\' as CHAR)
...\n\nwithout specifying a maximum length (i.e. using as CHAR, not as
CHAR(n)),\nMariaDB will report the maximum length of the resultset column
to be\n16,777,216. This may cause excessive memory usage in some client
libraries,\nbecause they try to pre-allocate a buffer of maximum resultset
width. To avoid\nthis problem, use CHAR(n) whenever you\'re using
COLUMN_GET in the select list.\n\nSee Dynamic Columns:Datatypes for more
information about datatypes.\n\nURL:
https://mariadb.com/kb/en/column_get/','','https://mariadb.com/kb/en/column_get/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(798,43,'COLUMN_JSON','Syntax\n------\n\nCOLUMN_JSON(dyncol_blob)\n\nDescription\n-----------\n\nReturns
a JSON representation of data in dyncol_blob. Can also be used to\ndisplay
nested columns. See dynamic columns for more
information.\n\nExample\n-------\n\nselect item_name,
COLUMN_JSON(dynamic_cols) from
assets;\n+-----------------+----------------------------------------+\n|
item_name | COLUMN_JSON(dynamic_cols)
|\n+-----------------+----------------------------------------+\n| MariaDB
T-shirt |
{\"size\":\"XL\",\"color\":\"blue\"}
|\n| Thinkpad Laptop |
{\"color\":\"black\",\"warranty\":\"3
years\"}
|\n+-----------------+----------------------------------------+\n\nLimitation:
COLUMN_JSON will decode nested dynamic columns at a nesting level\nof not
more than 10 levels deep. Dynamic columns that are nested deeper than\n10
levels will be shown as BINARY string, without encoding.\n\nURL:
https://mariadb.com/kb/en/column_json/','','https://mariadb.com/kb/en/column_json/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(799,43,'COLUMN_LIST','Syntax\n------\n\nCOLUMN_LIST(dyncol_blob);\n\nDescription\n-----------\n\nReturns
a comma-separated list of column names. The names are quoted
with\nbackticks.\n\nSee dynamic columns for more information.\n\nURL:
https://mariadb.com/kb/en/column_list/','','https://mariadb.com/kb/en/column_list/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(800,44,'WSREP_LAST_SEEN_GTID','MariaDB starting with
10.4.2\n----------------------------\nWSREP_LAST_SEEN_GTID was added as
part of Galera 4 in MariaDB
10.4.2.\n\nSyntax\n------\n\nWSREP_LAST_SEEN_GTID()\n\nDescription\n-----------\n\nReturns
the Global Transaction ID of the most recent write transaction\nobserved by
the client.\n\nThe result can be useful to determine the transaction to
provide to\nWSREP_SYNC_WAIT_UPTO_GTID for waiting and unblocking
purposes.\n\nURL:
https://mariadb.com/kb/en/wsrep_last_seen_gtid/','','https://mariadb.com/kb/en/wsrep_last_seen_gtid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(801,44,'WSREP_LAST_WRITTEN_GTID','MariaDB starting with
10.4.2\n----------------------------\nWSREP_LAST_WRITTEN_GTID was added as
part of Galera 4 in MariaDB
10.4.2.\n\nSyntax\n------\n\nWSREP_LAST_WRITTEN_GTID()\n\nDescription\n-----------\n\nReturns
the Global Transaction ID of the most recent write transaction\nperformed
by the client.\n\nURL:
https://mariadb.com/kb/en/wsrep_last_written_gtid/','','https://mariadb.com/kb/en/wsrep_last_written_gtid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(802,44,'WSREP_SYNC_WAIT_UPTO_GTID','MariaDB starting with
10.4.2\n----------------------------\nWSREP_SYNC_WAIT_UPTO_GTID was added
as part of Galera 4 in MariaDB
10.4.2.\n\nSyntax\n------\n\nWSREP_SYNC_WAIT_UPTO_GTID(gtid[,timeout])\n\nDescription\n-----------\n\nBlocks
the client until the transaction specified by the given Global\nTransaction
ID is applied and committed by the node.\n\nThe optional timeout argument
can be used to specify a block timeout in\nseconds. If not provided, the
timeout will be indefinite.\n\nReturns the node that applied and committed
the Global Transaction ID,\nER_LOCAL_WAIT_TIMEOUT if the function is timed
out before this, or\nER_WRONG_ARGUMENTS if the function is given an invalid
GTID.\n\nThe result from WSREP_LAST_SEEN_GTID can be useful to determine
the\ntransaction to provide to WSREP_SYNC_WAIT_UPTO_GTID for waiting and
unblocking\npurposes.\n\nURL:
https://mariadb.com/kb/en/wsrep_sync_wait_upto_gtid/','','https://mariadb.com/kb/en/wsrep_sync_wait_upto_gtid/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(803,45,'System-Versioned Tables','MariaDB supports temporal
data tables in the form of system-versioning tables\n(allowing you to query
and operate on historic data, discussed below),\napplication-time periods
(allow you to query and operate on a temporal range\nof data), and
bitemporal tables (which combine both system-versioning
and\napplication-time periods).\n\nSystem-Versioned
Tables\n-----------------------\n\nSystem-versioned tables store the
history of all changes, not only data which\nis currently valid. This
allows data analysis for any point in time, auditing\nof changes and
comparison of data from different points in time. Typical uses\ncases
are:\n\n* Forensic analysis & legal requirements to store data for N
years.\n* Data analytics (retrospective, trends etc.), e.g. to get your
staff\ninformation as of one year ago.\n* Point-in-time recovery - recover
a table state as of particular point in\ntime.\n\nSystem-versioned tables
were first introduced in the SQL:2011 standard.\n\nCreating a
System-Versioned Table\n---------------------------------\n\nThe CREATE
TABLE syntax has been extended to permit creating a\nsystem-versioned
table. To be system-versioned, according to SQL:2011, a table\nmust have
two generated columns, a period, and a special table option
clause:\n\nCREATE TABLE t(\n x INT,\n start_timestamp TIMESTAMP(6)
GENERATED ALWAYS AS ROW START,\n end_timestamp TIMESTAMP(6) GENERATED
ALWAYS AS ROW END,\n PERIOD FOR SYSTEM_TIME(start_timestamp,
end_timestamp)\n) WITH SYSTEM VERSIONING;\n\nIn MariaDB one can also use a
simplified syntax:\n\nCREATE TABLE t (\n x INT\n) WITH SYSTEM
VERSIONING;\n\nIn the latter case no extra columns will be created and they
won\'t clutter the\noutput of, say, SELECT * FROM t. The versioning
information will still be\nstored, and it can be accessed via the
pseudo-columns ROW_START and ROW_END:\n\nSELECT x, ROW_START, ROW_END FROM
t;\n\nAdding or Removing System Versioning To/From a
Table\n----------------------------------------------------\n\nAn existing
table can be altered to enable system versioning for it.\n\nCREATE TABLE
t(\n x INT\n);\n\nALTER TABLE t ADD SYSTEM VERSIONING;\n\nSHOW CREATE TABLE
t\\G\n*************************** 1. row ***************************\n
Table: t\nCreate Table: CREATE TABLE `t` (\n `x` int(11) DEFAULT NULL\n)
ENGINE=InnoDB DEFAULT CHARSET=latin1 WITH SYSTEM VERSIONING\n\nSimilarly,
system versioning can be removed from a table:\n\nALTER TABLE t DROP SYSTEM
VERSIONING;\n\nSHOW CREATE TABLE t\\G\n*************************** 1. row
***************************\n Table: t\nCreate Table: CREATE TABLE `t`
(\n `x` int(11) DEFAULT NULL\n) ENGINE=InnoDB DEFAULT CHARSET=latin1\n\nOne
can also add system versioning with all columns created
explicitly:\n\nALTER TABLE t ADD COLUMN ts TIMESTAMP(6) GENERATED ALWAYS AS
ROW START,\n ADD COLUMN te TIMESTAMP(6) GENERATED ALWAYS AS ROW
END,\n ADD PERIOD FOR SYSTEM_TIME(ts, te),\n ADD SYSTEM
VERSIONING;\n\nSHOW CREATE TABLE t\\G\n*************************** 1. row
***************************\n Table: t\nCreate Table: CREATE TABLE `t`
(\n `x` int(11) DEFAULT NULL,\n `ts` timestamp(6) GENERATED ALWAYS AS ROW
START,\n `te` timestamp(6) GENERATED ALWAYS AS ROW END,\n PERIOD FOR
SYSTEM_TIME (`ts`, `te`)\n) ENGINE=InnoDB DEFAULT CHARSET=latin1 WITH
SYSTEM VERSIONING\n\nInserting Data\n--------------\n\nWhen data is
inserted into a system-versioned table, it is given a row_start\nvalue of
the current timestamp, and a row_end value
of\nFROM_UNIXTIME(2147483647.999999). The current timestamp can be adjusted
by\nsetting the timestamp system variable, for example:\n\nSELECT
NOW();\n+---------------------+\n| NOW()
|\n+---------------------+\n| 2022-10-24 23:09:38
|\n+---------------------+\n\nINSERT INTO t VALUES(1);\n\nSET @@timestamp =
UNIX_TIMESTAMP(\'2033-10-24\');\n\nINSERT INTO t
VALUES(2);\n\nSET @@timestamp = default;\n\nINSERT INTO t
VALUES(3);\n\nSELECT a,row_start,row_end FROM
t;\n+------+----------------------------+----------------------------+\n| a
| row_start | row_end
|\n+------+----------------------------+----------------------------+\n|
1 | 2022-10-24 23:09:38.951347 | 2038-01-19 05:14:07.999999 |\n| 2 |
2033-10-24 00:00:00.000000 | 2038-01-19 05:14:07.999999 |\n| 3 |
2022-10-24 23:09:38.961857 | 2038-01-19 05:14:07.999999
|\n+------+----------------------------+----------------------------+\n\nQuerying
Historical Data\n------------------------\n\nSELECT\n------\n\nTo query the
historical data one uses the clause FOR SYSTEM_TIME directly\nafter the
table name (before the table alias, if any). SQL:2011 provides
three\nsyntactic extensions:\n\n* AS OF is used to see the table as it was
at a specific point in time in the\npast:\n\nSELECT * FROM t FOR
SYSTEM_TIME AS OF TIMESTAMP\'2016-10-09 08:07:06\';\n\n* BETWEEN
start AND end will show all rows that were visible at any point\nbetween
two specified points in time. It works inclusively, a row visible\nexactly
at start or exactly at end will be shown too.\n\nSELECT * FROM t FOR
SYSTEM_TIME BETWEEN (NOW() - INTERVAL 1 YEAR) AND NOW();\n\n* FROM start TO
end will also show all rows that were visible at any point\nbetween two
specified points in time, including start, but excluding end.\n\nSELECT *
FROM t FOR SYSTEM_TIME FROM \'2016-01-01 00:00:00\' TO
\'2017-01-01\n00:00:00\';\n\nAdditionally MariaDB implements a
non-standard extension:\n\n* ALL will show all rows, historical and
current.\n\nSELECT * FROM t FOR SYSTEM_TIME ALL;\n\nIf the FOR SYSTEM_TIME
clause is not used, the table will show the current\ndata. This is usually
the same as if one had specified FOR SYSTEM_TIME AS OF\nCURRENT_TIMESTAMP,
unless one has adjusted the row_start value (until MariaDB\n10.11, only
possible by setting the secure_timestamp variable). For example:\n\nCREATE
OR REPLACE TABLE t (a int) WITH SYSTEM VERSIONING;\n\nSELECT
NOW();\n+---------------------+\n| NOW()
|\n+---------------------+\n| 2022-10-24 23:43:37
|\n+---------------------+\n\nINSERT INTO t VALUES (1);\n\nSET @@timestamp
= UNIX_TIMESTAMP(\'2033-03-03\');\n\nINSERT INTO t VALUES
(2);\n\nDELETE FROM t;\n\nSET @@timestamp = default;\n\nSELECT a,
row_start, row_end FROM t FOR SYSTEM_TIME
ALL;\n+------+----------------------------+----------------------------+\n|
a | row_start | row_end
|\n+------+----------------------------+----------------------------+\n|
1 | 2022-10-24 23:43:37.192725 | 2033-03-03 00:00:00.000000 |\n| 2 |
2033-03-03 00:00:00.000000 | 2033-03-03 00:00:00.000000
|\n+------+----------------------------+----------------------------+\n2
rows in set (0.000 sec)\n\nSELECT a, row_start, row_end FROM t FOR
SYSTEM_TIME AS OF
CURRENT_TIMESTAMP;\n+------+----------------------------+----------------------------+\n|
a | row_start | row_end
|\n+------+----------------------------+----------------------------+\n|
1 | 2022-10-24 23:43:37.192725 | 2033-03-03 00:00:00.000000
|\n+------+----------------------------+----------------------------+\n1
row in set (0.000 sec)\n\nSELECT a, row_start, row_end FROM t;\nEmpty set
(0.001 sec)\n\nViews and Subqueries\n--------------------\n\nWhen a
system-versioned tables is used in a view or in a subquery in the
from\nclause, FOR SYSTEM_TIME can be used directly in the view or subquery
body, or\n(non-standard) applied to the whole view when it\'s being
used in a SELECT:\n\nCREATE VIEW v1 AS SELECT * FROM t FOR SYSTEM_TIME AS
OF TIMESTAMP\'2016-10-09\n08:07:06\';\n\nOr\n\nCREATE VIEW v1 AS
SELECT * FROM t;\nSELECT * FROM v1 FOR SYSTEM_TIME AS OF
TIMESTAMP\'2016-10-09 08:07:06\';\n\nUse in Replication and
Binary Logs\n----------------------------------\n\nTables that use
system-versioning implicitly add the row_end column to the\nPrimary Key.
While this is generally not an issue for most use cases, it can\nlead to
problems when re-applying write statements from the binary log or
in\nreplication environments, where a primary retries an SQL statement on
the\nreplica.\n\nSpecifically, these writes include a value on the row_end
column containing\nthe timestamp from when the write was initially made.
The re-occurrence of the\nPrimary Key with the old system-versioning
columns raises an error due to the\nduplication.\n\nTo mitigate this with
MariaDB Replication, set the secure_timestamp system\nvariable to YES on
the replica. When set, the replica uses its own system\nclock when applying
to the row log, meaning that the primary can retry as many\ntimes as needed
without causing a conflict. The retries generate new\nhistorical rows with
new values for the row_start and row_end columns.\n\nTransaction-Precise
History in InnoDB\n-------------------------------------\n\nA point in time
when a row was inserted or deleted does not necessarily mean\nthat a change
became visible at the same moment. With transactional tables, a\nrow might
have been inserted in a long transaction, and became visible hours\nafter
it was inserted.\n\nFor some applications — for example, when doing data
analytics on one-year-old\ndata — this distinction does not matter much.
For others — forensic analysis —\nit might be crucial.\n\nMariaDB
supports transaction-precise history (only for the InnoDB storage\nengine)
that allows seeing the data exactly as it would\'ve been seen by a
new\nconnection doing a SELECT at the specified point in time — rows
inserted\nbefore that point, but committed after will not be shown.\n\nTo
use transaction-precise history, InnoDB needs to remember not
timestamps,\nbut transaction identifier per row. This is done by creating
generated columns\nas BIGINT UNSIGNED, not TIMESTAMP(6):\n\nCREATE TABLE
t(\n x INT,\n start_trxid BIGINT UNSIGNED GENERATED ALWAYS AS ROW START,\n
end_trxid BIGINT UNSIGNED GENERATED ALWAYS AS ROW END,\n PERIOD FOR
SYSTEM_TIME(start_trxid, end_trxid)\n) WITH SYSTEM VERSIONING;\n\nThese
columns must be specified explicitly, but they can be made INVISIBLE
to\navoid cluttering SELECT * output.\n\nWhen one uses transaction-precise
history, one can optionally use transaction\nidentifiers in the FOR
SYSTEM_TIME clause:\n\nSELECT * FROM t FOR SYSTEM_TIME AS OF TRANSACTION
12345;\n\nThis will show the data, exactly as it was seen by the
transaction with the\nidentifier 12345.\n\nStoring the History
Separately\n------------------------------\n\nWhen the history is stored
together with the current data, it increases the\nsize of the table, so
current data queries — table scans and index searches —\nwill take more
time, because they will need to skip over historical data. If\nmost queries
on that table use only current data, it might make sense to store\nthe
history separately, to reduce the overhead from versioning.\n\nThis is done
by partitioning the table by SYSTEM_TIME. Because of the\npartition pruning
optimization, all current data queries will only access one\npartition, the
one that stores current data.\n\nThis example shows how to create such a
partitioned table:\n\nCREATE TABLE t (x INT) WITH SYSTEM VERSIONING\n
PARTITION BY SYSTEM_TIME (\n PARTITION p_hist HISTORY,\n PARTITION p_cur
CURRENT\n );\n\nIn this example all history will be stored in the partition
p_hist while all\ncurrent data will be in the partition p_cur. The table
must have exactly one\ncurrent partition and at least one historical
partition.\n\nPartitioning by SYSTEM_TIME also supports automatic partition
rotation. One\ncan rotate historical partitions by time or by size. This
example shows how to\nrotate partitions by size:\n\nCREATE TABLE t (x INT)
WITH SYSTEM VERSIONING\n PARTITION BY SYSTEM_TIME LIMIT 100000 (\n
PARTITION p0 HISTORY,\n PARTITION p1 HISTORY,\n PARTITION pcur CURRENT\n
);\n\nMariaDB will start writing history rows into partition p0, and when
it reaches\na size of 100000 rows, MariaDB will switch to partition p1.
There are only two\nhistorical partitions, so when p1 overflows, MariaDB
will issue a warning, but\nwill continue writing into it.\n\nSimilarly, one
can rotate partitions by time:\n\nCREATE TABLE t (x INT) WITH SYSTEM
VERSIONING\n PARTITION BY SYSTEM_TIME INTERVAL 1 WEEK (\n PARTITION p0
HISTORY,\n PARTITION p1 HISTORY,\n PARTITION p2 HISTORY,\n PARTITION
pcur CURRENT\n );\n\nThis means that the history for the first week after
the table was created\nwill be stored in p0. The history for the second
week — in p1, and all later\nhistory will go into p2. One can see the
exact rotation time for each\npartition in the
INFORMATION_SCHEMA.PARTITIONS table.\n\nIt is possible to combine
partitioning by SYSTEM_TIME and subpartitions:\n\nCREATE TABLE t (x INT)
WITH SYSTEM VERSIONING\n PARTITION BY SYSTEM_TIME\n SUBPARTITION BY KEY
(x)\n SUBPARTITIONS 4 (\n PARTITION ph HISTORY,\n PARTITION pc CURRENT\n
);\n\nDefault Partitions\n------------------\n\nMariaDB starting with
10.5.0\n----------------------------\nSince partitioning by current and
historical data is such a typical usecase,\nfrom MariaDB 10.5, it is
possible to use a simplified statement to do so. For\nexample, instead
of\n\nCREATE TABLE t (x INT) WITH SYSTEM VERSIONING \n PARTITION BY
SYSTEM_TIME (\n PARTITION p0 HISTORY,\n PARTITION pn CURRENT\n);\n\nyou
can use\n\nCREATE TABLE t (x INT) WITH SYSTEM VERSIONING \n PARTITION BY
SYSTEM_TIME;\n\nYou can also specify the number of partitions, which is
useful if you want to\nrotate history by time, for example:\n\nCREATE TABLE
t (x INT) WITH SYSTEM VERSIONING \n PARTITION BY SYSTEM_TIME\n INTERVAL 1
MONTH\n PARTITIONS 12;\n\nSpecifying the number of partitions without
specifying a rotation condition\nwill result in a warning:\n\nCREATE OR
REPLACE TABLE t (x INT) WITH SYSTEM VERSIONING\n PARTITION BY SYSTEM_TIME
PARTITIONS 12;\nQuery OK, 0 rows affected, 1 warning (0.518 sec)\n\nWarning
(Code 4115): Maybe missing parameters: no rotation condition for\nmultiple
HISTORY partitions.\n\nwhile specifying only 1 partition will result in an
error:\n\nCREATE OR REPLACE TABLE t (x INT) WITH SYSTEM VERSIONING\n
PARTITION BY SYSTEM_TIME PARTITIONS 1;\nERROR 4128 (HY000): Wrong
partitions for `t`: must have at least one HISTORY\nand exactly one last
CURRENT\n\nAutomatically Creating
Partitions\n---------------------------------\n\nMariaDB starting with
10.9.1\n----------------------------\nFrom MariaDB 10.9.1, the AUTO keyword
can be used to automatically create\nhistory partitions.\n\nFor
example\n\nCREATE TABLE t1 (x int) WITH SYSTEM VERSIONING\n PARTITION BY
SYSTEM_TIME INTERVAL 1 HOUR
AUTO;\n','','https://mariadb.com/kb/en/system-versioned-tables/');
update help_topic set description = CONCAT(description, '\nCREATE
TABLE t1 (x int) WITH SYSTEM VERSIONING\n PARTITION BY SYSTEM_TIME INTERVAL
1 MONTH\n STARTS \'2021-01-01 00:00:00\' AUTO PARTITIONS
12;\n\nCREATE TABLE t1 (x int) WITH SYSTEM VERSIONING\n PARTITION BY
SYSTEM_TIME LIMIT 1000 AUTO;\n\nOr with explicit partitions:\n\nCREATE
TABLE t1 (x int) WITH SYSTEM VERSIONING\n PARTITION BY SYSTEM_TIME INTERVAL
1 HOUR AUTO\n (PARTITION p0 HISTORY, PARTITION pn CURRENT);\n\nTo disable
or enable auto-creation one can use ALTER TABLE by adding or\nremoving AUTO
from the partitioning specification:\n\nCREATE TABLE t1 (x int) WITH SYSTEM
VERSIONING\n PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR AUTO;\n\n# Disables
auto-creation:\nALTER TABLE t1 PARTITION BY SYSTEM_TIME INTERVAL 1
HOUR;\n\n# Enables auto-creation:\nALTER TABLE t1 PARTITION BY SYSTEM_TIME
INTERVAL 1 HOUR AUTO;\n\nIf the rest of the partitioning specification is
identical to CREATE TABLE, no\nrepartitioning will be done (for details see
MDEV-27328).\n\nRemoving Old History\n--------------------\n\nBecause it
stores all the history, a system-versioned table might grow very\nlarge
over time. There are many options to trim down the space and remove
the\nold history.\n\nOne can completely drop the versioning from the table
and add it back again,\nthis will delete all the history:\n\nALTER TABLE t
DROP SYSTEM VERSIONING;\nALTER TABLE t ADD SYSTEM VERSIONING;\n\nIt might
be a rather time-consuming operation, though, as the table will need\nto be
rebuilt, possibly twice (depending on the storage engine).\n\nAnother
option would be to use partitioning and drop some of
historical\npartitions:\n\nALTER TABLE t DROP PARTITION p0;\n\nNote, that
one cannot drop a current partition or the only
historical\npartition.\n\nAnd the third option; one can use a variant of
the DELETE statement to prune\nthe history:\n\nDELETE HISTORY FROM t;\n\nor
only old history up to a specific point in time:\n\nDELETE HISTORY FROM t
BEFORE SYSTEM_TIME \'2016-10-09 08:07:06\';\n\nor to a specific
transaction (with BEFORE SYSTEM_TIME TRANSACTION xxx).\n\nTo protect the
integrity of the history, this statement requires a special\nDELETE HISTORY
privilege.\n\nCurrently, using the DELETE HISTORY statement with a BEFORE
SYSTEM_TIME\ngreater than the ROW_END of the active records (as a
TIMESTAMP, this has a\nmaximum value of \'2038-01-19 03:14:07\'
UTC) will result in the historical\nrecords being dropped, and the active
records being deleted and moved to\nhistory. See MDEV-25468.\n\nPrior to
MariaDB 10.4.5, the TRUNCATE TABLE statement drops all historical\nrecords
from a system-versioned-table.\n\nFrom MariaDB 10.4.5, historic data is
protected from TRUNCATE statements, as\nper the SQL standard, and an Error
4137 is instead raised:\n\nTRUNCATE t;\nERROR 4137 (HY000):
System-versioned tables do not support TRUNCATE TABLE\n\nExcluding Columns
From Versioning\n---------------------------------\n\nAnother MariaDB
extension allows to version only a subset of columns in a\ntable. This is
useful, for example, if you have a table with user information\nthat should
be versioned, but one column is, let\'s say, a login counter that\nis
incremented often and is not interesting to version. Such a column can
be\nexcluded from versioning by declaring it WITHOUT VERSIONING\n\nCREATE
TABLE t (\n x INT,\n y INT WITHOUT SYSTEM VERSIONING\n) WITH SYSTEM
VERSIONING;\n\nA column can also be declared WITH VERSIONING, that will
automatically make\nthe table versioned. The statement below is equivalent
to the one above:\n\nCREATE TABLE t (\n x INT WITH SYSTEM VERSIONING,\n y
INT\n);\n\nChanges in other sections:
https://mariadb.com/kb/en/create-table/\nhttps://mariadb.com/kb/en/alter-table/
https://mariadb.com/kb/en/join-syntax/\nhttps://mariadb.com/kb/en/partitioning-types-overview/\nhttps://mariadb.com/kb/en/date-and-time-units/\nhttps://mariadb.com/kb/en/delete/
https://mariadb.com/kb/en/grant/\n\nthey all reference back to this
page\n\nAlso, TODO:\n\n* limitations (size, speed, adding history to unique
not nullable columns)\n\nSystem Variables\n----------------\n\nThere are a
number of system variables related to system-versioned
tables:\n\nsystem_versioning_alter_history\n-------------------------------\n\n*
Description: SQL:2011 does not allow ALTER TABLE on system-versioned
tables.\nWhen this variable is set to ERROR, an attempt to alter a
system-versioned\ntable will result in an error. When this variable is set
to KEEP, ALTER TABLE\nwill be allowed, but the history will become
incorrect — querying historical\ndata will show the new table structure.
This mode is still useful, for\nexample, when adding new columns to a
table. Note that if historical data\ncontains or would contain nulls,
attempting to ALTER these columns to be NOT\nNULL will return an error (or
warning if strict_mode is not set).\n* Commandline:
--system-versioning-alter-history=value\n* Scope: Global, Session\n*
Dynamic: Yes\n* Type: Enum\n* Default Value: ERROR\n* Valid Values: ERROR,
KEEP\n\nsystem_versioning_asof\n----------------------\n\n* Description: If
set to a specific timestamp value, an implicit FOR\nSYSTEM_TIME AS OF
clause will be applied to all queries. This is useful if one\nwants to do
many queries for history at the specific point in time. Set it to\nDEFAULT
to restore the default behavior. Has no effect on DML, so queries such\nas
INSERT .. SELECT and REPLACE .. SELECT need to state AS OF explicitly.\n*
Commandline: None\n* Scope: Global, Session\n* Dynamic: Yes\n* Type:
Varchar\n* Default Value:
DEFAULT\n\nsystem_versioning_innodb_algorithm_simple\n-----------------------------------------\n\n*
Description: Never fully implemented and removed in the following
release.\n* Commandline:
--system-versioning-innodb-algorithm-simple[={0|1}]\n* Scope: Global,
Session\n* Dynamic: Yes\n* Type: Boolean\n* Default Value: ON\n*
Introduced: MariaDB 10.3.4\n* Removed: MariaDB
10.3.5\n\nsystem_versioning_insert_history\n--------------------------------\n\n*
Description: Allows direct inserts into ROW_START and ROW_END columns
if\nsecure_timestamp allows changing timestamp.\n* Commandline:
--system-versioning-insert-history[={0|1}]\n* Scope: Global, Session\n*
Dynamic: Yes\n* Type: Boolean\n* Default Value: OFF\n* Introduced: MariaDB
10.11.0\n\nLimitations\n-----------\n\n* Versioning clauses can not be
applied to generated (virtual and persistent)\ncolumns.\n* Before MariaDB
10.11, mariadb-dump did not read historical rows from\nversioned tables,
and so historical data would not be backed up. Also, a\nrestore of the
timestamps would not be possible as they cannot be defined by\nan insert/a
user. From MariaDB 10.11, use the -H or --dump-history options to\ninclude
the history.\n\nURL:
https://mariadb.com/kb/en/system-versioned-tables/') WHERE
help_topic_id = 803;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(804,45,'Application-Time Periods','MariaDB starting with
10.4.3\n----------------------------\nSupport for application-time
period-versioning was added in MariaDB 10.4.3.\n\nExtending
system-versioned tables, MariaDB 10.4 supports application-time\nperiod
tables. Time periods are defined by a range between two temporal\ncolumns.
The columns must be of the same temporal data type, i.e. DATE,\nTIMESTAMP
or DATETIME (TIME and YEAR are not supported), and of the same
width.\n\nUsing time periods implicitly defines the two columns as NOT
NULL. It also\nadds a constraint to check whether the first value is less
than the second\nvalue. The constraint is invisible to SHOW CREATE TABLE
statements. The name\nof this constraint is prefixed by the time period
name, to avoid conflict with\nother constraints.\n\nCreating Tables with
Time Periods\n---------------------------------\n\nTo create a table with a
time period, use a CREATE TABLE statement with the\nPERIOD table
option.\n\nCREATE TABLE t1(\n name VARCHAR(50),\n date_1 DATE,\n date_2
DATE,\n PERIOD FOR date_period(date_1, date_2));\n\nThis creates a table
with a time_period period and populates the table with\nsome basic temporal
values.\n\nExamples are available in the MariaDB Server source code,
at\nmysql-test/suite/period/r/create.result.\n\nAdding and Removing Time
Periods\n--------------------------------\n\nThe ALTER TABLE statement now
supports syntax for adding and removing time\nperiods from a table. To add
a period, use the ADD PERIOD clause.\n\nFor example:\n\nCREATE OR REPLACE
TABLE rooms (\n room_number INT,\n guest_name VARCHAR(255),\n checkin
DATE,\n checkout DATE\n );\n\nALTER TABLE rooms ADD PERIOD FOR
p(checkin,checkout);\n\nTo remove a period, use the DROP PERIOD
clause:\n\nALTER TABLE rooms DROP PERIOD FOR p;\n\nBoth ADD PERIOD and DROP
PERIOD clauses include an option to handle whether\nthe period already
exists:\n\nALTER TABLE rooms ADD PERIOD IF NOT EXISTS FOR
p(checkin,checkout);\n\nALTER TABLE rooms DROP PERIOD IF EXISTS FOR
p;\n\nDeletion by Portion\n-------------------\n\nYou can also remove rows
that fall within certain time periods.\n\nWhen MariaDB executes a DELETE
FOR PORTION statement, it removes the row:\n\n* When the row period falls
completely within the delete period, it removes\nthe row.\n* When the row
period overlaps the delete period, it shrinks the row, removing\nthe
overlap from the first or second row period value.\n* When the delete
period falls completely within the row period, it splits the\nrow into two
rows. The first row runs from the starting row period to the\nstarting
delete period. The second runs from the ending delete period to
the\nending row period.\n\nTo test this, first populate the table with some
data to operate on:\n\nCREATE TABLE t1(\n name VARCHAR(50),\n date_1
DATE,\n date_2 DATE,\n PERIOD FOR date_period(date_1, date_2));\n\nINSERT
INTO t1 (name, date_1, date_2) VALUES\n (\'a\',
\'1999-01-01\', \'2000-01-01\'),\n (\'b\',
\'1999-01-01\', \'2018-12-12\'),\n (\'c\',
\'1999-01-01\', \'2017-01-01\'),\n (\'d\',
\'2017-01-01\', \'2019-01-01\');\n\nSELECT * FROM
t1;\n+------+------------+------------+\n| name | date_1 | date_2
|\n+------+------------+------------+\n| a | 1999-01-01 | 2000-01-01
|\n| b | 1999-01-01 | 2018-12-12 |\n| c | 1999-01-01 | 2017-01-01
|\n| d | 2017-01-01 | 2019-01-01
|\n+------+------------+------------+\n\nThen, run the DELETE FOR PORTION
statement:\n\nDELETE FROM t1\nFOR PORTION OF date_period\n FROM
\'2001-01-01\' TO \'2018-01-01\';\nQuery OK, 3 rows
affected (0.028 sec)\n\nSELECT * FROM t1 ORDER BY
name;\n+------+------------+------------+\n| name | date_1 | date_2
|\n+------+------------+------------+\n| a | 1999-01-01 | 2000-01-01
|\n| b | 1999-01-01 | 2001-01-01 |\n| b | 2018-01-01 | 2018-12-12
|\n| c | 1999-01-01 | 2001-01-01 |\n| d | 2018-01-01 | 2019-01-01
|\n+------+------------+------------+\n\nHere:\n\n* a is unchanged, as the
range falls entirely out of the specified portion to\nbe deleted.\n* b,
with values ranging from 1999 to 2018, is split into two rows, 1999
to\n2000 and 2018-01 to 2018-12.\n* c, with values ranging from 1999 to
2017, where only the upper value falls\nwithin the portion to be deleted,
has been shrunk to 1999 to 2001.\n* d, with values ranging from 2017 to
2019, where only the lower value falls\nwithin the portion to be deleted,
has been shrunk to 2018 to 2019.\n\nThe DELETE FOR PORTION statement has
the following restrictions\n\n* The FROM...TO clause must be constant\n*
Multi-delete is not supported\n\nIf there are DELETE or INSERT triggers, it
works as follows: any matched row\nis deleted, and then one or two rows are
inserted. If the record is deleted\ncompletely, nothing is
inserted.\n\nUpdating by Portion\n-------------------\n\nThe UPDATE syntax
now supports UPDATE FOR PORTION, which modifies rows based\non their
occurrence in a range:\n\nTo test it, first populate the table with some
data:\n\nTRUNCATE t1;\n\nINSERT INTO t1 (name, date_1, date_2) VALUES\n
(\'a\', \'1999-01-01\', \'2000-01-01\'),\n
(\'b\', \'1999-01-01\', \'2018-12-12\'),\n
(\'c\', \'1999-01-01\', \'2017-01-01\'),\n
(\'d\', \'2017-01-01\',
\'2019-01-01\');\n\nSELECT * FROM
t1;\n+------+------------+------------+\n| name | date_1 | date_2
|\n+------+------------+------------+\n| a | 1999-01-01 | 2000-01-01
|\n| b | 1999-01-01 | 2018-12-12 |\n| c | 1999-01-01 | 2017-01-01
|\n| d | 2017-01-01 | 2019-01-01
|\n+------+------------+------------+\n\nThen run the update:\n\nUPDATE t1
FOR PORTION OF date_period\n FROM \'2000-01-01\' TO
\'2018-01-01\'\nSET name =
CONCAT(name,\'_original\');\n\nSELECT * FROM t1 ORDER BY
name;\n+------------+------------+------------+\n| name | date_1
| date_2 |\n+------------+------------+------------+\n| a |
1999-01-01 | 2000-01-01 |\n| b | 1999-01-01 | 2000-01-01 |\n| b
| 2018-01-01 | 2018-12-12 |\n| b_original | 2000-01-01 | 2018-01-01
|\n| c | 1999-01-01 | 2000-01-01 |\n| c_original | 2000-01-01 |
2017-01-01 |\n| d | 2018-01-01 | 2019-01-01 |\n| d_original |
2017-01-01 | 2018-01-01 |\n+------------+------------+------------+\n\n* a
is unchanged, as the range falls entirely out of the specified portion
to\nbe deleted.\n* b, with values ranging from 1999 to 2018, is split into
two rows, 1999 to\n2000 and 2018-01 to 2018-12.\n* c, with values ranging
from 1999 to 2017, where only the upper value falls\nwithin the portion to
be deleted, has been shrunk to 1999 to 2001.\n* d, with values ranging from
2017 to 2019, where only the lower value falls\nwithin the portion to be
deleted, has been shrunk to 2018 to 2019. \n* Original rows affected by the
update have \"_original\" appended to the name.\n\nThe UPDATE FOR
PORTION statement has the following limitations:\n\n* The operation cannot
modify the two temporal columns used by the time period\n* The operation
cannot reference period values in the SET expression\n* FROM...TO
expressions must be constant\n\nWITHOUT
OVERLAPS\n----------------\n\nMariaDB starting with
10.5.3\n----------------------------\nMariaDB 10.5 introduced a new clause,
WITHOUT OVERLAPS, which allows one to\ncreate an index specifying that
application time periods should not overlap.\n\nAn index constrained by
WITHOUT OVERLAPS is required to be either a primary\nkey or a unique
index.\n\nTake the following example, an application time period table for
a booking\nsystem:\n\nCREATE OR REPLACE TABLE rooms (\n room_number INT,\n
guest_name VARCHAR(255),\n checkin DATE,\n checkout DATE,\n PERIOD FOR
p(checkin,checkout)\n );\n\nINSERT INTO rooms VALUES \n (1,
\'Regina\', \'2020-10-01\',
\'2020-10-03\'),\n (2, \'Cochise\',
\'2020-10-02\', \'2020-10-05\'),\n (1,
\'Nowell\', \'2020-10-03\',
\'2020-10-07\'),\n (2, \'Eusebius\',
\'2020-10-04\', \'2020-10-06\');\n\nOur system is not
intended to permit overlapping bookings, so the fourth\nrecord above should
not have been inserted. Using WITHOUT OVERLAPS in a unique\nindex (in this
case based on a combination of room number and the application\ntime
period) allows us to specify this constraint in the table
definition.\n\nCREATE OR REPLACE TABLE rooms (\n room_number INT,\n
guest_name VARCHAR(255),\n checkin DATE,\n checkout DATE,\n PERIOD FOR
p(checkin,checkout),\n UNIQUE (room_number, p WITHOUT OVERLAPS)\n
);\n\nINSERT INTO rooms VALUES \n (1, \'Regina\',
\'2020-10-01\', \'2020-10-03\'),\n (2,
\'Cochise\', \'2020-10-02\',
\'2020-10-05\'),\n (1, \'Nowell\',
\'2020-10-03\', \'2020-10-07\'),\n (2,
\'Eusebius\', \'2020-10-04\',
\'2020-10-06\');\nERROR 1062 (23000): Duplicate entry
\'2-2020-10-06-2020-10-04\' for
key\n\'room_number\'\n\nFurther Examples\n----------------\n\nThe
implicit change from NULL to NOT NULL:\n\nCREATE TABLE `t2` (\n `id`
int(11) DEFAULT NULL,\n `d1` datetime DEFAULT NULL,\n `d2` datetime DEFAULT
NULL\n) ENGINE=InnoDB DEFAULT CHARSET=latin1;\n\nALTER TABLE t2 ADD PERIOD
FOR p(d1,d2);\n\nSHOW CREATE TABLE t2\\G\n*************************** 1.
row ***************************\n Table: t2\nCreate Table: CREATE TABLE
`t2` (\n `id` int(11) DEFAULT NULL,\n `d1` datetime NOT NULL,\n `d2`
datetime NOT NULL,\n PERIOD FOR `p` (`d1`, `d2`)\n) ENGINE=InnoDB DEFAULT
CHARSET=latin1\n\nDue to this constraint, trying to add a time period where
null data already\nexists will fail.\n\nCREATE OR REPLACE TABLE `t2` (\n
`id` int(11) DEFAULT NULL,\n `d1` datetime DEFAULT NULL,\n `d2` datetime
DEFAULT NULL\n) ENGINE=InnoDB DEFAULT CHARSET=latin1;\n\nINSERT INTO t2(id)
VALUES(1);\n\nALTER TABLE t2 ADD PERIOD FOR p(d1,d2);\nERROR 1265 (01000):
Data truncated for column \'d1\' at row 1\n\nURL:
https://mariadb.com/kb/en/application-time-periods/','','https://mariadb.com/kb/en/application-time-periods/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(805,45,'Bitemporal Tables','MariaDB starting with
10.4.3\n----------------------------\nBitemporal tables are tables that use
versioning both at the system and\napplication-time period levels.\n\nUsing
Bitemporal Tables\n-----------------------\n\nTo create a bitemporal table,
use:\n\nCREATE TABLE test.t3 (\n date_1 DATE,\n date_2 DATE,\n row_start
TIMESTAMP(6) AS ROW START INVISIBLE,\n row_end TIMESTAMP(6) AS ROW END
INVISIBLE,\n PERIOD FOR application_time(date_1, date_2),\n PERIOD FOR
system_time(row_start, row_end))\nWITH SYSTEM VERSIONING;\n\nNote that,
while system_time here is also a time period, it cannot be used in\nDELETE
FOR PORTION or UPDATE FOR PORTION statements.\n\nDELETE FROM test.t3 \nFOR
PORTION OF system_time \n FROM \'2000-01-01\' TO
\'2018-01-01\';\nERROR 42000: You have an error in your SQL
syntax; check the manual that\ncorresponds \n to your MariaDB server
version for the right syntax to use near\n \'of system_time from
\'2000-01-01\' to \'2018-01-01\'\' at line
1\n\nURL:
https://mariadb.com/kb/en/bitemporal-tables/','','https://mariadb.com/kb/en/bitemporal-tables/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(806,46,'ST_AsGeoJSON','Syntax\n------\n\nST_AsGeoJSON(g[,
max_decimals[, options]])\n\nDescription\n-----------\n\nReturns the given
geometry g as a GeoJSON element. The optional max_decimals\nlimits the
maximum number of decimals displayed.\n\nThe optional options flag can be
set to 1 to add a bounding box to the
output.\n\nExamples\n--------\n\nSELECT
ST_AsGeoJSON(ST_GeomFromText(\'POINT(5.3
7.2)\'));\n+-------------------------------------------------+\n|
ST_AsGeoJSON(ST_GeomFromText(\'POINT(5.3 7.2)\'))
|\n+-------------------------------------------------+\n|
{\"type\": \"Point\", \"coordinates\": [5.3,
7.2]} |\n+-------------------------------------------------+\n\nURL:
https://mariadb.com/kb/en/geojson-st_asgeojson/','','https://mariadb.com/kb/en/geojson-st_asgeojson/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(807,46,'ST_GeomFromGeoJSON','MariaDB starting with
10.2.4\n----------------------------\nST_GeomFromGeoJSON was added in
MariaDB 10.2.4\n\nSyntax\n------\n\nST_GeomFromGeoJSON(g[,
option])\n\nDescription\n-----------\n\nGiven a GeoJSON input g, returns a
geometry object. The option specifies what\nto do if g contains geometries
with coordinate dimensions higher than
2.\n\n+---------------------------+------------------------------------------------+\n|
Option | Description
|\n+---------------------------+------------------------------------------------+\n|
1 | Return an error (the default)
|\n+---------------------------+------------------------------------------------+\n|
2 - 4 | The document is accepted, but the coordinates
|\n| | for higher coordinate dimensions are
stripped |\n| | off.
|\n+---------------------------+------------------------------------------------+\n\nNote
that this function did not work correctly before MariaDB 10.2.8 -
see\nMDEV-12180.\n\nExamples\n--------\n\nSET @j = \'{
\"type\": \"Point\", \"coordinates\": [5.3,
15.0]}\';\n\nSELECT
ST_AsText(ST_GeomFromGeoJSON(@j));\n+-----------------------------------+\n|
ST_AsText(ST_GeomFromGeoJSON(@j))
|\n+-----------------------------------+\n| POINT(5.3 15)
|\n+-----------------------------------+\n\nURL:
https://mariadb.com/kb/en/st_geomfromgeojson/','','https://mariadb.com/kb/en/st_geomfromgeojson/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(808,47,'Operator Precedence','The precedence is the order
in which the SQL operators are evaluated.\n\nThe following list shows the
SQL operator precedence. Operators that appear\nfirst in the list have a
higher precedence. Operators which are listed\ntogether have the same
precedence.\n\n* INTERVAL\n* BINARY, COLLATE\n* !\n* - (unary minus),
[[bitwise-not|]] (unary bit inversion)\n* || (string concatenation)\n* ^\n*
*, /, DIV, %, MOD\n* -, +\n* <<, >>\n* &\n* |\n* =
(comparison), <=>, >=, >, <=, <, <>, !=, IS, LIKE,
REGEXP, IN\n* BETWEEN, CASE, WHEN, THEN, ELSE, END\n* NOT\n* &&,
AND\n* XOR\n* || (logical or), OR\n* = (assignment), :=\n\nFunctions
precedence is always higher than operators precedence.\n\nIn this page CASE
refers to the CASE operator, not to the CASE statement.\n\nIf the
HIGH_NOT_PRECEDENCE SQL_MODE is set, NOT has the same precedence as
!.\n\nThe || operator\'s precedence, as well as its meaning, depends
on the\nPIPES_AS_CONCAT SQL_MODE flag: if it is on, || can be used to
concatenate\nstrings (like the CONCAT() function) and has a higher
precedence.\n\nThe = operator\'s precedence depends on the context -
it is higher when = is\nused as a comparison operator.\n\nParenthesis can
be used to modify the operators precedence in an
expression.\n\nShort-circuit evaluation\n------------------------\n\nThe
AND, OR, && and || operators support short-circuit evaluation. This
means\nthat, in some cases, the expression on the right of those operators
is not\nevaluated, because its result cannot affect the result. In the
following\ncases, short-circuit evaluation is used and x() is not
evaluated:\n\n* FALSE AND x()\n* FALSE && x()\n* TRUE OR x()\n*
TRUE || x()\n* NULL BETWEEN x() AND x()\n\nNote however that the
short-circuit evaluation does not apply to NULL AND x().\nAlso,
BETWEEN\'s right operands are not evaluated if the left operand is
NULL,\nbut in all other cases all the operands are evaluated.\n\nThis is a
speed optimization. Also, since functions can have side-effects,\nthis
behavior can be used to choose whether execute them or not using a\nconcise
syntax:\n\nSELECT some_function() OR log_error();\n\nURL:
https://mariadb.com/kb/en/operator-precedence/','','https://mariadb.com/kb/en/operator-precedence/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(809,48,'Addition Operator
(+)','Syntax\n------\n\n+\n\nDescription\n-----------\n\nAddition.\n\nIf
both operands are integers, the result is calculated with BIGINT
precision.\nIf either integer is unsigned, the result is also an unsigned
integer.\n\nFor real or string operands, the operand with the highest
precision determines\nthe result precision.\n\nExamples\n--------\n\nSELECT
3+5;\n+-----+\n| 3+5 |\n+-----+\n| 8 |\n+-----+\n\nURL:
https://mariadb.com/kb/en/addition-operator/','','https://mariadb.com/kb/en/addition-operator/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(810,48,'Division Operator
(/)','Syntax\n------\n\n/\n\nDescription\n-----------\n\nDivision
operator. Dividing by zero will return NULL. By default, returns
four\ndigits after the decimal. This is determined by the server system
variable\ndiv_precision_increment which by default is four. It can be set
from 0 to 30.\n\nDividing by zero returns NULL. If the
ERROR_ON_DIVISION_BY_ZERO SQL_MODE is\nused (the default since MariaDB
10.2.4), a division by zero also produces
a\nwarning.\n\nExamples\n--------\n\nSELECT 4/5;\n+--------+\n| 4/5
|\n+--------+\n| 0.8000 |\n+--------+\n\nSELECT
300/(2-2);\n+-----------+\n| 300/(2-2) |\n+-----------+\n| NULL
|\n+-----------+\n\nSELECT 300/7;\n+---------+\n| 300/7 |\n+---------+\n|
42.8571 |\n+---------+\n\nChanging div_precision_increment for the session
from the default of four to\nsix:\n\nSET div_precision_increment =
6;\n\nSELECT 300/7;\n+-----------+\n| 300/7 |\n+-----------+\n|
42.857143 |\n+-----------+\n\nSELECT 300/7;\n+-----------+\n| 300/7
|\n+-----------+\n| 42.857143 |\n+-----------+\n\nURL:
https://mariadb.com/kb/en/division-operator/','','https://mariadb.com/kb/en/division-operator/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(811,48,'Modulo Operator (%)','Syntax\n------\n\nN %
M\n\nDescription\n-----------\n\nModulo operator. Returns the remainder of
N divided by M. See also MOD.\n\nExamples\n--------\n\nSELECT 1042 %
50;\n+-----------+\n| 1042 % 50 |\n+-----------+\n| 42
|\n+-----------+\n\nURL:
https://mariadb.com/kb/en/modulo-operator/','','https://mariadb.com/kb/en/modulo-operator/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(812,48,'Multiplication Operator
(*)','Syntax\n------\n\n*\n\nDescription\n-----------\n\nMultiplication
operator.\n\nExamples\n--------\n\nSELECT 7*6;\n+-----+\n| 7*6
|\n+-----+\n| 42 |\n+-----+\n\nSELECT
1234567890*9876543210;\n+-----------------------+\n| 1234567890*9876543210
|\n+-----------------------+\n| -6253480962446024716
|\n+-----------------------+\n\nSELECT
18014398509481984*18014398509481984.0;\n+---------------------------------------+\n|
18014398509481984*18014398509481984.0
|\n+---------------------------------------+\n|
324518553658426726783156020576256.0
|\n+---------------------------------------+\n\nSELECT
18014398509481984*18014398509481984;\n+-------------------------------------+\n|
18014398509481984*18014398509481984
|\n+-------------------------------------+\n|
0 |\n+-------------------------------------+\n\nURL:
https://mariadb.com/kb/en/multiplication-operator/','','https://mariadb.com/kb/en/multiplication-operator/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(813,48,'Subtraction Operator
(-)','Syntax\n------\n\n-\n\nDescription\n-----------\n\nSubtraction.
The operator is also used as the unary minus for changing sign.\n\nIf both
operands are integers, the result is calculated with BIGINT precision.\nIf
either integer is unsigned, the result is also an unsigned integer,
unless\nthe NO_UNSIGNED_SUBTRACTION SQL_MODE is enabled, in which case the
result is\nalways signed.\n\nFor real or string operands, the operand with
the highest precision determines\nthe result
precision.\n\nExamples\n--------\n\nSELECT 96-9;\n+------+\n| 96-9
|\n+------+\n| 87 |\n+------+\n\nSELECT 15-17;\n+-------+\n| 15-17
|\n+-------+\n| -2 |\n+-------+\n\nSELECT 3.66 +
1.333;\n+--------------+\n| 3.66 + 1.333 |\n+--------------+\n|
4.993 |\n+--------------+\n\nUnary minus:\n\nSELECT -
(3+5);\n+---------+\n| - (3+5) |\n+---------+\n| -8
|\n+---------+\n\nURL:
https://mariadb.com/kb/en/subtraction-operator-/','','https://mariadb.com/kb/en/subtraction-operator-/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(814,49,'CHANGE MASTER TO','The terms master and slave have
historically been used in replication, but the\nterms terms primary and
replica are now preferred. The old terms are used\nstill used in parts of
the documentation, and in MariaDB commands, although\nMariaDB 10.5 has
begun the process of renaming. The documentation process is\nongoing. See
MDEV-18777 to follow progress on this effort.\n\nSyntax\n------\n\nCHANGE
MASTER [\'connection_name\'] TO master_def [, master_def] ... \n
[FOR CHANNEL \'channel_name\']\n\nmaster_def:\n MASTER_BIND =
\'interface_name\'\n | MASTER_HOST = \'host_name\'\n |
MASTER_USER = \'user_name\'\n | MASTER_PASSWORD =
\'password\'\n | MASTER_PORT = port_num\n | MASTER_CONNECT_RETRY
= interval\n | MASTER_HEARTBEAT_PERIOD = interval\n | MASTER_LOG_FILE =
\'master_log_name\'\n | MASTER_LOG_POS = master_log_pos\n |
RELAY_LOG_FILE = \'relay_log_name\'\n | RELAY_LOG_POS =
relay_log_pos\n | MASTER_DELAY = interval\n | MASTER_SSL = {0|1}\n |
MASTER_SSL_CA = \'ca_file_name\'\n | MASTER_SSL_CAPATH =
\'ca_directory_name\'\n | MASTER_SSL_CERT =
\'cert_file_name\'\n | MASTER_SSL_CRL =
\'crl_file_name\'\n | MASTER_SSL_CRLPATH =
\'crl_directory_name\'\n | MASTER_SSL_KEY =
\'key_file_name\'\n | MASTER_SSL_CIPHER =
\'cipher_list\'\n | MASTER_SSL_VERIFY_SERVER_CERT = {0|1}\n |
MASTER_USE_GTID = {current_pos|slave_pos|no}\n | MASTER_DEMOTE_TO_SLAVE =
bool\n | IGNORE_SERVER_IDS = (server_id_list)\n | DO_DOMAIN_IDS =
([N,..])\n | IGNORE_DOMAIN_IDS =
([N,..])\n\nDescription\n-----------\n\nThe CHANGE MASTER statement sets
the options that a replica uses to connect to\nand replicate from a
primary.\n\nMariaDB starting with 10.7.0\n----------------------------\nThe
FOR CHANNEL keyword was added for MySQL compatibility. This is
identical\nto using the channel_name directly after CHANGE
MASTER.\n\nMulti-Source Replication\n------------------------\n\nIf you are
using multi-source replication, then you need to specify a\nconnection name
when you execute CHANGE MASTER. There are two ways to do this:\n\n* Setting
the default_master_connection system variable prior to executing\nCHANGE
MASTER.\n* Setting the connection_name parameter when executing CHANGE
MASTER.\n\ndefault_master_connection\n-------------------------\n\nSET
default_master_connection = \'gandalf\';\nSTOP SLAVE;\nCHANGE
MASTER TO \n MASTER_PASSWORD=\'new3cret\';\nSTART
SLAVE;\n\nconnection_name\n---------------\n\nSTOP SLAVE
\'gandalf\';\nCHANGE MASTER \'gandalf\' TO \n
MASTER_PASSWORD=\'new3cret\';\nSTART SLAVE
\'gandalf\';\n\nOptions\n-------\n\nConnection
Options\n------------------\n\nMASTER_USER\n-----------\n\nThe MASTER_USER
option for CHANGE MASTER defines the user account that the\nreplica will
use to connect to the primary.\n\nThis user account will need the
REPLICATION SLAVE privilege (or, from MariaDB\n10.5.1, the REPLICATION
REPLICA on the primary.\n\nFor example:\n\nSTOP SLAVE;\nCHANGE MASTER TO\n
MASTER_USER=\'repl\',\n
MASTER_PASSWORD=\'new3cret\';\nSTART SLAVE;\n\nThe maximum length
of the MASTER_USER string is 96 characters until MariaDB\n10.5, and 128
characters from MariaDB 10.6.\n\nMASTER_PASSWORD\n---------------\n\nThe
MASTER_USER option for CHANGE MASTER defines the password that the
replica\nwill use to connect to the primary as the user account defined by
the\nMASTER_USER option.\n\nFor example:\n\nSTOP SLAVE;\nCHANGE MASTER TO
\n MASTER_PASSWORD=\'new3cret\';\nSTART SLAVE;\n\nThe maximum
length of the MASTER_PASSWORD string is 32 characters. The\neffective
maximum length of the string depends on how many bytes are used
per\ncharacter and can be up to 96 characters.\n\nDue to MDEV-29994, the
password can be silently truncated to 41 characters\nwhen MariaDB is
restarted. For this reason it is recommended to use a password\nthat is
shorter than this.\n\nMASTER_HOST\n-----------\n\nThe MASTER_HOST option
for CHANGE MASTER defines the hostname or IP address of\nthe primary.\n\nIf
you set the value of the MASTER_HOST option to the empty string, then
that\nis not the same as not setting the option\'s value at all. If
you set the value\nof the MASTER_HOST option to the empty string, then the
CHANGE MASTER command\nwill fail with an error. In MariaDB 5.3 and before,
if you set the value of\nthe MASTER_HOST option to the empty string, then
the CHANGE MASTER command\nwould succeed, but the subsequent START SLAVE
command would fail.\n\nFor example:\n\nSTOP SLAVE;\nCHANGE MASTER TO\n
MASTER_HOST=\'dbserver1.example.com\',\n
MASTER_USER=\'repl\',\n MASTER_PASSWORD=\'new3cret\',\n
MASTER_USE_GTID=slave_pos;\nSTART SLAVE;\n\nIf you set the value of the
MASTER_HOST option in a CHANGE MASTER command,\nthen the replica assumes
that the primary is different from before, even if\nyou set the value of
this option to the same value it had previously. In this\nscenario, the
replica will consider the old values for the primary\'s binary\nlog
file name and position to be invalid for the new primary. As a
side\neffect, if you do not explicitly set the values of the
MASTER_LOG_FILE and\nMASTER_LOG_POS options in the statement, then the
statement will be implicitly\nappended with MASTER_LOG_FILE=\'\'
and MASTER_LOG_POS=4. However, if you enable\nGTID mode for replication by
setting the MASTER_USE_GTID option to some value\nother than no in the
statement, then these values will effectively be
ignored\nanyway.\n\nReplicas cannot connect to primaries using Unix socket
files or Windows named\npipes. The replica must connect to the primary
using TCP/IP.\n\nThe maximum length of the MASTER_HOST string is 60
characters until MariaDB\n10.5, and 255 characters from MariaDB
10.6.\n\nMASTER_PORT\n-----------\n\nThe MASTER_PORT option for CHANGE
MASTER defines the TCP/IP port of the\nprimary.\n\nFor example:\n\nSTOP
SLAVE;\nCHANGE MASTER TO\n
MASTER_HOST=\'dbserver1.example.com\',\n MASTER_PORT=3307,\n
MASTER_USER=\'repl\',\n MASTER_PASSWORD=\'new3cret\',\n
MASTER_USE_GTID=slave_pos;\nSTART SLAVE;\n\nIf you set the value of the
MASTER_PORT option in a CHANGE MASTER command,\nthen the replica assumes
that the primary is different from before, even if\nyou set the value of
this option to the same value it had previously. In this\nscenario, the
replica will consider the old values for the primary\'s binary\nlog
file name and position to be invalid for the new primary. As a
side\neffect, if you do not explicitly set the values of the
MASTER_LOG_FILE and\nMASTER_LOG_POS options in the statement, then the
statement will be implicitly\nappended with MASTER_LOG_FILE=\'\'
and MASTER_LOG_POS=4. However, if you enable\nGTID mode for replication by
setting the MASTER_USE_GTID option to some value\nother than no in the
statement, then these values will effectively be
ignored\nanyway.\n\nReplicas cannot connect to primaries using Unix socket
files or Windows named\npipes. The replica must connect to the primary
using TCP/IP.\n\nMASTER_CONNECT_RETRY\n--------------------\n\nThe
MASTER_CONNECT_RETRY option for CHANGE MASTER defines how many
seconds\nthat the replica will wait between connection retries. The default
is 60.\n\nSTOP SLAVE;\nCHANGE MASTER TO \n MASTER_CONNECT_RETRY=20;\nSTART
SLAVE;\n\nThe number of connection attempts is limited by the
master_retry_count option.\nIt can be set either on the command-line or in
a server option group in an\noption file prior to starting up the server.
For
example:\n\n[mariadb]\n...\nmaster_retry_count=4294967295\n\nMASTER_BIND\n-----------\n\nThe
MASTER_BIND option for CHANGE MASTER is only supported by MySQL 5.6.2
and\nlater and by MySQL NDB Cluster 7.3.1 and later. This option is not
supported\nby MariaDB. See MDEV-19248 for more information.\n\nThe
MASTER_BIND option for CHANGE MASTER can be used on replicas that
have\nmultiple network interfaces to choose which network interface the
replica will\nuse to connect to the
primary.\n\nMASTER_HEARTBEAT_PERIOD\n-----------------------\n\nThe
MASTER_HEARTBEAT_PERIOD option for CHANGE MASTER can be used to set
the\ninterval in seconds between replication heartbeats. Whenever the
primary\'s\nbinary log is updated with an event, the waiting period
for the next heartbeat\nis reset.\n\nThis option\'s interval argument
has the following characteristics:\n\n* It is a decimal value with a range
of 0 to 4294967 seconds.\n* It has a resolution of hundredths of a
second.\n* Its smallest valid non-zero value is 0.001.\n* Its default value
is the value of the slave_net_timeout system variable\ndivided by 2.\n* If
it\'s set to 0, then heartbeats are disabled.\n\nHeartbeats are sent
by the primary only if there are no unsent events in the\nbinary log file
for a period longer than the interval.\n\nIf the RESET SLAVE statement is
executed, then the heartbeat interval is reset\nto the default.\n\nIf the
slave_net_timeout system variable is set to a value that is lower than\nthe
current heartbeat interval, then a warning will be issued.\n\nTLS
Options\n-----------\n\nThe TLS options are used for providing information
about TLS. The options can\nbe set even on replicas that are compiled
without TLS support. The TLS options\nare saved to either the default
master.info file or the file that is\nconfigured by the master_info_file
option, but these TLS options are ignored\nunless the replica supports
TLS.\n\nSee Replication with Secure Connections for more
information.\n\nMASTER_SSL\n----------\n\nThe MASTER_SSL option for CHANGE
MASTER tells the replica whether to force TLS\nfor the connection. The
valid values are 0 or 1.\n\nFor example:\n\nSTOP SLAVE;\nCHANGE MASTER TO\n
MASTER_SSL=1;\nSTART SLAVE;\n\nMASTER_SSL_CA\n-------------\n\nThe
MASTER_SSL_CA option for CHANGE MASTER defines a path to a PEM file
that\nshould contain one or more X509 certificates for trusted
Certificate\nAuthorities (CAs) to use for TLS. This option requires that
you use the\nabsolute path, not a relative path. This option implies the
MASTER_SSL option.\n\nFor example:\n\nSTOP SLAVE;\nCHANGE MASTER TO\n
MASTER_SSL_CERT=\'/etc/my.cnf.d/certificates/server-cert.pem\',\n
MASTER_SSL_KEY=\'/etc/my.cnf.d/certificates/server-key.pem\',\n
MASTER_SSL_CA=\'/etc/my.cnf.d/certificates/ca.pem\',\n
MASTER_SSL_VERIFY_SERVER_CERT=1;\nSTART SLAVE;\n\nSee Secure Connections
Overview: Certificate Authorities (CAs) for more\ninformation.\n\nThe
maximum length of MASTER_SSL_CA string is 511
characters.\n\nMASTER_SSL_CAPATH\n-----------------\n\nThe
MASTER_SSL_CAPATH option for CHANGE MASTER defines a path to a
directory\nthat contains one or more PEM files that should each contain one
X509\ncertificate for a trusted Certificate Authority (CA) to use for TLS.
This\noption requires that you use the absolute path, not a relative path.
The\ndirectory specified by this option needs to be run through the openssl
rehash\ncommand. This option implies the MASTER_SSL option.\n\nFor
example:\n\nSTOP SLAVE;\nCHANGE MASTER TO\n
MASTER_SSL_CERT=\'/etc/my.cnf.d/certificates/server-cert.pem\',\n
MASTER_SSL_KEY=\'/etc/my.cnf.d/certificates/server-key.pem\',\n
MASTER_SSL_CAPATH=\'/etc/my.cnf.d/certificates/ca/\',\n
MASTER_SSL_VERIFY_SERVER_CERT=1;\nSTART SLAVE;\n\nSee Secure Connections
Overview: Certificate Authorities (CAs) for more\ninformation.\n\nThe
maximum length of MASTER_SSL_CA_PATH string is 511
characters.\n\nMASTER_SSL_CERT\n---------------\n\nThe MASTER_SSL_CERT
option for CHANGE MASTER defines a path to the X509\ncertificate file to
use for TLS. This option requires that you use the\nabsolute path, not a
relative path. This option implies the MASTER_SSL option.\n\nFor
example:\n\nSTOP SLAVE;\nCHANGE MASTER TO\n
MASTER_SSL_CERT=\'/etc/my.cnf.d/certificates/server-cert.pem\',\n
MASTER_SSL_KEY=\'/etc/my.cnf.d/certificates/server-key.pem\',\n
MASTER_SSL_CA=\'/etc/my.cnf.d/certificates/ca.pem\',\n
MASTER_SSL_VERIFY_SERVER_CERT=1;\nSTART SLAVE;\n\nThe maximum length of
MASTER_SSL_CERT string is 511
characters.\n\nMASTER_SSL_CRL\n--------------\n\nThe MASTER_SSL_CRL option
for CHANGE MASTER defines a path to a PEM file that\nshould contain one or
more revoked X509 certificates to use for TLS. This\noption requires that
you use the absolute path, not a relative path.\n\nThis option is only
supported if the server was built with OpenSSL. If the\nserver was built
with yaSSL, then this option is not supported. See TLS and\nCryptography
Libraries Used by MariaDB for more information about which\nlibraries are
used on which platforms.\n\nFor example:\n\nSTOP SLAVE;\nCHANGE MASTER TO\n
MASTER_SSL_CERT=\'/etc/my.cnf.d/certificates/server-cert.pem\',\n
MASTER_SSL_KEY=\'/etc/my.cnf.d/certificates/server-key.pem\',\n
MASTER_SSL_CA=\'/etc/my.cnf.d/certificates/ca.pem\',\n
MASTER_SSL_VERIFY_SERVER_CERT=1,\n
MASTER_SSL_CRL=\'/etc/my.cnf.d/certificates/crl.pem\';\nSTART
SLAVE;\n\nSee Secure Connections Overview: Certificate Revocation Lists
(CRLs) for more\ninformation.\n\nThe maximum length of MASTER_SSL_CRL
string is 511 characters.\n\nMASTER_SSL_CRLPATH\n------------------\n\nThe
MASTER_SSL_CRLPATH option for CHANGE MASTER defines a path to a
directory\nthat contains one or more PEM files that should each contain one
revoked X509\ncertificate to use for TLS. This option requires that you use
the absolute\npath, not a relative path. The directory specified by this
variable needs to\nbe run through the openssl rehash command.\n\nThis
option is only supported if the server was built with OpenSSL. If
the\nserver was built with yaSSL, then this option is not supported. See
TLS and\nCryptography Libraries Used by MariaDB for more information about
which\nlibraries are used on which platforms.\n\nFor example:\n\nSTOP
SLAVE;\nCHANGE MASTER TO\n
MASTER_SSL_CERT=\'/etc/my.cnf.d/certificates/server-cert.pem\',\n
MASTER_SSL_KEY=\'/etc/my.cnf.d/certificates/server-key.pem\',\n
MASTER_SSL_CA=\'/etc/my.cnf.d/certificates/ca.pem\',\n
MASTER_SSL_VERIFY_SERVER_CERT=1,\n
MASTER_SSL_CRLPATH=\'/etc/my.cnf.d/certificates/crl/\';\nSTART
SLAVE;\n\nSee Secure Connections Overview: Certificate Revocation Lists
(CRLs) for more\ninformation.\n\nThe maximum length of MASTER_SSL_CRL_PATH
string is 511 characters.\n\nMASTER_SSL_KEY\n--------------\n\nThe
MASTER_SSL_KEY option for CHANGE MASTER defines a path to a private
key\nfile to use for TLS. This option requires that you use the absolute
path, not\na relative path. This option implies the MASTER_SSL
option.\n\nFor example:\n\nSTOP SLAVE;\nCHANGE MASTER TO\n
MASTER_SSL_CERT=\'/etc/my.cnf.d/certificates/server-cert.pem\',\n
MASTER_SSL_KEY=\'/etc/my.cnf.d/certificates/server-key.pem\',\n
MASTER_SSL_CA=\'/etc/my.cnf.d/certificates/ca.pem\',\n
MASTER_SSL_VERIFY_SERVER_CERT=1;','','https://mariadb.com/kb/en/change-master-to/');
update help_topic set description = CONCAT(description, '\nSTART
SLAVE;\n\nThe maximum length of MASTER_SSL_KEY string is 511
characters.\n\nMASTER_SSL_CIPHER\n-----------------\n\nThe
MASTER_SSL_CIPHER option for CHANGE MASTER defines the list of
permitted\nciphers or cipher suites to use for TLS. Besides cipher names,
if MariaDB was\ncompiled with OpenSSL, this option could be set to
\"SSLv3\" or \"TLSv1.2\" to\nallow all SSLv3 or all
TLSv1.2 ciphers. Note that the TLSv1.3 ciphers cannot\nbe excluded when
using OpenSSL, even by using this option. See Using TLSv1.3\nfor details.
This option implies the MASTER_SSL option.\n\nFor example:\n\nSTOP
SLAVE;\nCHANGE MASTER TO\n
MASTER_SSL_CERT=\'/etc/my.cnf.d/certificates/server-cert.pem\',\n
MASTER_SSL_KEY=\'/etc/my.cnf.d/certificates/server-key.pem\',\n
MASTER_SSL_CA=\'/etc/my.cnf.d/certificates/ca.pem\',\n
MASTER_SSL_VERIFY_SERVER_CERT=1,\n
MASTER_SSL_CIPHER=\'TLSv1.2\';\nSTART SLAVE;\n\nThe maximum
length of MASTER_SSL_CIPHER string is 511
characters.\n\nMASTER_SSL_VERIFY_SERVER_CERT\n-----------------------------\n\nThe
MASTER_SSL_VERIFY_SERVER_CERT option for CHANGE MASTER enables
server\ncertificate verification. This option is disabled by
default.\n\nFor example:\n\nSTOP SLAVE;\nCHANGE MASTER TO\n
MASTER_SSL_CERT=\'/etc/my.cnf.d/certificates/server-cert.pem\',\n
MASTER_SSL_KEY=\'/etc/my.cnf.d/certificates/server-key.pem\',\n
MASTER_SSL_CA=\'/etc/my.cnf.d/certificates/ca.pem\',\n
MASTER_SSL_VERIFY_SERVER_CERT=1;\nSTART SLAVE;\n\nSee Secure Connections
Overview: Server Certificate Verification for more\ninformation.\n\nBinary
Log Options\n------------------\n\nThese options are related to the binary
log position on the primary.\n\nMASTER_LOG_FILE\n---------------\n\nThe
MASTER_LOG_FILE option for CHANGE MASTER can be used along
with\nMASTER_LOG_POS to specify the coordinates at which the
replica\'s I/O thread\nshould begin reading from the primary\'s
binary logs the next time the thread\nstarts.\n\nFor example:\n\nSTOP
SLAVE;\nCHANGE MASTER TO\n MASTER_LOG_FILE=\'master2-bin.001\',\n
MASTER_LOG_POS=4;\nSTART SLAVE;\n\nThe MASTER_LOG_FILE and MASTER_LOG_POS
options cannot be specified if the\nRELAY_LOG_FILE and RELAY_LOG_POS
options were also specified.\n\nThe MASTER_LOG_FILE and MASTER_LOG_POS
options are effectively ignored if you\nenable GTID mode for replication by
setting the MASTER_USE_GTID option to some\nvalue other than no in the
statement.\n\nMASTER_LOG_POS\n--------------\n\nThe MASTER_LOG_POS option
for CHANGE MASTER can be used along with\nMASTER_LOG_FILE to specify the
coordinates at which the replica\'s I/O thread\nshould begin reading
from the primary\'s binary logs the next time the
thread\nstarts.\n\nFor example:\n\nSTOP SLAVE;\nCHANGE MASTER TO\n
MASTER_LOG_FILE=\'master2-bin.001\',\n MASTER_LOG_POS=4;\nSTART
SLAVE;\n\nThe MASTER_LOG_FILE and MASTER_LOG_POS options cannot be
specified if the\nRELAY_LOG_FILE and RELAY_LOG_POS options were also
specified.\n\nThe MASTER_LOG_FILE and MASTER_LOG_POS options are
effectively ignored if you\nenable GTID mode for replication by setting the
MASTER_USE_GTID option to some\nvalue other than no in the
statement.\n\nRelay Log Options\n-----------------\n\nThese options are
related to the relay log position on the
replica.\n\nRELAY_LOG_FILE\n--------------\n\nThe RELAY_LOG_FILE option for
CHANGE MASTER can be used along with the\nRELAY_LOG_POS option to specify
the coordinates at which the replica\'s SQL\nthread should begin
reading from the relay log the next time the thread starts.\n\nThe CHANGE
MASTER statement usually deletes all relay log files. However, if\nthe
RELAY_LOG_FILE and/or RELAY_LOG_POS options are specified, then
existing\nrelay log files are kept.\n\nWhen you want to change the relay
log position, you only need to stop the\nreplica\'s SQL thread. The
replica\'s I/O thread can continue running. The STOP\nSLAVE and START
SLAVE statements support the SQL_THREAD option for this\nscenario. For
example:\n\nSTOP SLAVE SQL_THREAD;\nCHANGE MASTER TO\n
RELAY_LOG_FILE=\'slave-relay-bin.006\',\n
RELAY_LOG_POS=4025;\nSTART SLAVE SQL_THREAD;\n\nWhen the value of this
option is changed, the metadata about the replica\'s
SQL\nthread\'s position in the relay logs will also be changed in the
relay-log.info\nfile or the file that is configured by the
relay_log_info_file system variable.\n\nThe RELAY_LOG_FILE and
RELAY_LOG_POS options cannot be specified if the\nMASTER_LOG_FILE and
MASTER_LOG_POS options were also
specified.\n\nRELAY_LOG_POS\n-------------\n\nThe RELAY_LOG_POS option for
CHANGE MASTER can be used along with the\nRELAY_LOG_FILE option to specify
the coordinates at which the replica\'s SQL\nthread should begin
reading from the relay log the next time the thread starts.\n\nThe CHANGE
MASTER statement usually deletes all relay log files. However, if\nthe
RELAY_LOG_FILE and/or RELAY_LOG_POS options are specified, then
existing\nrelay log files are kept.\n\nWhen you want to change the relay
log position, you only need to stop the\nreplica\'s SQL thread. The
replica\'s I/O thread can continue running. The STOP\nSLAVE and START
SLAVE statements support the SQL_THREAD option for this\nscenario. For
example:\n\nSTOP SLAVE SQL_THREAD;\nCHANGE MASTER TO\n
RELAY_LOG_FILE=\'slave-relay-bin.006\',\n
RELAY_LOG_POS=4025;\nSTART SLAVE SQL_THREAD;\n\nWhen the value of this
option is changed, the metadata about the replica\'s
SQL\nthread\'s position in the relay logs will also be changed in the
relay-log.info\nfile or the file that is configured by the
relay_log_info_file system variable.\n\nThe RELAY_LOG_FILE and
RELAY_LOG_POS options cannot be specified if the\nMASTER_LOG_FILE and
MASTER_LOG_POS options were also specified.\n\nGTID
Options\n------------\n\nMASTER_USE_GTID\n---------------\n\nThe
MASTER_USE_GTID option for CHANGE MASTER can be used to configure
the\nreplica to use the global transaction ID (GTID) when connecting to a
primary.\nThe possible values are:\n\n* current_pos - Replicate in GTID
mode and use gtid_current_pos as the\nposition to start downloading
transactions from the primary. Deprecated from\nMariaDB 10.10. Using to
transition to primary can break the replication state\nif the replica
executes local transactions due to actively updating\ngtid_current_pos with
gtid_binlog_pos and gtid_slave_pos. Use the new,
safe,\nMASTER_DEMOTE_TO_SLAVE=<bool> option instead.\n* slave_pos -
Replicate in GTID mode and use gtid_slave_pos as the position to\nstart
downloading transactions from the primary. From MariaDB
10.5.1,\nreplica_pos is an alias for slave_pos.\n* no - Don\'t
replicate in GTID
mode.\n\nMASTER_DEMOTE_TO_SLAVE\n----------------------\n\nMariaDB starting
with 10.10\n---------------------------\nUsed to transition a primary to
become a replica. Replaces the old\nMASTER_USE_GTID=current_pos with a safe
alternative by forcing users to set\nUsing_Gtid=Slave_Pos and merging
gtid_binlog_pos into gtid_slave_pos once at\nCHANGE MASTER TO time. If
gtid_slave_pos is more recent than gtid_binlog_pos\n(as in the case of
chain replication), the replication state should be\npreserved.\n\nFor
example:\n\nSTOP SLAVE;\nCHANGE MASTER TO\n MASTER_USE_GTID =
current_pos;\nSTART SLAVE;\n\nOr:\n\nSTOP SLAVE;\nSET GLOBAL
gtid_slave_pos=\'0-1-153\';\nCHANGE MASTER TO\n MASTER_USE_GTID =
slave_pos;\nSTART SLAVE;\n\nReplication Filter
Options\n--------------------------\n\nAlso see Replication
filters.\n\nIGNORE_SERVER_IDS\n-----------------\n\nThe IGNORE_SERVER_IDS
option for CHANGE MASTER can be used to configure a\nreplica to ignore
binary log events that originated from certain servers.\nFiltered binary
log events will not get logged to the replica’s relay log, and\nthey will
not be applied by the replica.\n\nThe option\'s value can be specified
by providing a comma-separated list of\nserver_id values. For
example:\n\nSTOP SLAVE;\nCHANGE MASTER TO \n IGNORE_SERVER_IDS =
(3,5);\nSTART SLAVE;\n\nIf you would like to clear a previously set list,
then you can set the value\nto an empty list. For example:\n\nSTOP
SLAVE;\nCHANGE MASTER TO \n IGNORE_SERVER_IDS = ();\nSTART
SLAVE;\n\nDO_DOMAIN_IDS\n-------------\n\nThe DO_DOMAIN_IDS option for
CHANGE MASTER can be used to configure a replica\nto only apply binary log
events if the transaction\'s GTID is in a specific\ngtid_domain_id
value. Filtered binary log events will not get logged to the\nreplica’s
relay log, and they will not be applied by the replica.\n\nThe
option\'s value can be specified by providing a comma-separated list
of\ngtid_domain_id values. Duplicate values are automatically ignored. For
example:\n\nSTOP SLAVE;\nCHANGE MASTER TO \n DO_DOMAIN_IDS = (1,2);\nSTART
SLAVE;\n\nIf you would like to clear a previously set list, then you can
set the value\nto an empty list. For example:\n\nSTOP SLAVE;\nCHANGE MASTER
TO \n DO_DOMAIN_IDS = ();\nSTART SLAVE;\n\nThe DO_DOMAIN_IDS option and the
IGNORE_DOMAIN_IDS option cannot both be set\nto non-empty values at the
same time. If you want to set the DO_DOMAIN_IDS\noption, and the
IGNORE_DOMAIN_IDS option was previously set, then you need to\nclear the
value of the IGNORE_DOMAIN_IDS option. For example:\n\nSTOP SLAVE;\nCHANGE
MASTER TO \n IGNORE_DOMAIN_IDS = (),\n DO_DOMAIN_IDS = (1,2);\nSTART
SLAVE;\n\nThe DO_DOMAIN_IDS option can only be specified if the replica is
replicating\nin GTID mode. Therefore, the MASTER_USE_GTID option must also
be set to some\nvalue other than no in order to use this
option.\n\nIGNORE_DOMAIN_IDS\n-----------------\n\nThe IGNORE_DOMAIN_IDS
option for CHANGE MASTER can be used to configure a\nreplica to ignore
binary log events if the transaction\'s GTID is in a
specific\ngtid_domain_id value. Filtered binary log events will not get
logged to the\nreplica’s relay log, and they will not be applied by the
replica.\n\nThe option\'s value can be specified by providing a
comma-separated list of\ngtid_domain_id values. Duplicate values are
automatically ignored. For example:\n\nSTOP SLAVE;\nCHANGE MASTER TO \n
IGNORE_DOMAIN_IDS = (1,2);\nSTART SLAVE;\n\nIf you would like to clear a
previously set list, then you can set the value\nto an empty list. For
example:\n\nSTOP SLAVE;\nCHANGE MASTER TO \n IGNORE_DOMAIN_IDS = ();\nSTART
SLAVE;\n\nThe DO_DOMAIN_IDS option and the IGNORE_DOMAIN_IDS option cannot
both be set\nto non-empty values at the same time. If you want to set the
IGNORE_DOMAIN_IDS\noption, and the DO_DOMAIN_IDS option was previously set,
then you need to\nclear the value of the DO_DOMAIN_IDS option. For
example:\n\nSTOP SLAVE;\nCHANGE MASTER TO \n DO_DOMAIN_IDS = (),\n
IGNORE_DOMAIN_IDS = (1,2);\nSTART SLAVE;\n\nThe IGNORE_DOMAIN_IDS option
can only be specified if the replica is\nreplicating in GTID mode.
Therefore, the MASTER_USE_GTID option must also be\nset to some value other
than no in order to use this option.\n\nDelayed Replication
Options\n---------------------------\n\nMASTER_DELAY\n------------\n\nThe
MASTER_DELAY option for CHANGE MASTER can be used to enable
delayed\nreplication. This option specifies the time in seconds (at least)
that a\nreplica should lag behind the primary up to a maximum value of
2147483647, or\nabout 68 years. Before executing an event, the replica will
first wait, if\nnecessary, until the given time has passed since the event
was created on the\nprimary. The result is that the replica will reflect
the state of the primary\nsome time back in the past. The default is zero,
no delay.\n\nSTOP SLAVE;\nCHANGE MASTER TO \n MASTER_DELAY=3600;\nSTART
SLAVE;\n\nChanging Option Values\n----------------------\n\nIf you
don\'t specify a given option when executing the CHANGE
MASTER\nstatement, then the option keeps its old value in most cases. Most
of the\ntime, there is no need to specify the options that do not need to
change. For\nexample, if the password for the user account that the replica
uses to connect\nto its primary has changed, but no other options need to
change, then you can\njust change the MASTER_PASSWORD option by executing
the following commands:\n\nSTOP SLAVE;\nCHANGE MASTER TO \n
MASTER_PASSWORD=\'new3cret\';\nSTART SLAVE;\n\nThere are some
cases where options are implicitly reset, such as when the\nMASTER_HOST and
MASTER_PORT options are changed.\n\nOption
Persistence\n------------------\n\nThe values of the MASTER_LOG_FILE and
MASTER_LOG_POS options (i.e. the binary\nlog position on the primary) and
most other options are written to either the\ndefault master.info file or
the file that is configured by the\nmaster_info_file option. The
replica\'s I/O thread keeps this binary log\nposition updated as it
downloads events only when MASTER_USE_GTID option is\nset to NO. Otherwise
the file is not updated on a per event basis.\n\nThe master_info_file
option can be set either on the command-line or in a\nserver option group
in an option file prior to starting up the server.
For\nexample:\n\n[mariadb]\n...\nmaster_info_file=/mariadb/myserver1-master.info\n\nThe
values of the RELAY_LOG_FILE and RELAY_LOG_POS options (i.e. the relay
log\nposition) are written to either the default relay-log.info file or the
file\nthat is configured by the relay_log_info_file system variable. The
replica\'s\nSQL thread keeps this relay log position updated as it
applies events.\n\nThe relay_log_info_file system variable can be set
either on the command-line\nor in a server option group in an option file
prior to starting up the server.\nFor
example:\n\n[mariadb]\n...\nrelay_log_info_file=/mariadb/myserver1-relay-log.info\n\nGTID
Persistence\n----------------\n\nIf the replica is replicating binary log
events that contain GTIDs, then the\nreplica\'s SQL thread will write
every GTID that it applies to the\nmysql.gtid_slave_pos table. This GTID
can be inspected and modified through\nthe gtid_slave_pos system
variable.\n\nIf the replica has the log_slave_updates system variable
enabled and if the\nreplica has the binary log enabled, then every write by
the replica\'s SQL\nthread will also go into the replica\'s
binary log. This means that GTIDs of\nreplicated transactions would be
reflected in the value of the gtid_binlog_pos\nsystem variable.\n\nCreating
a Replica from a Backup\n--------------------------------\n\nThe CHANGE
MASTER statement is useful for setting up a replica when you have a\nbackup
of the primary and you also have the binary log position or GTID\nposition
corresponding to the backup.\n\nAfter restoring the backup on the replica,
you could execute something like\nthis to use the binary log
position:\n\nCHANGE MASTER TO\n
MASTER_LOG_FILE=\'master2-bin.001\',\n MASTER_LOG_POS=4;\nSTART
SLAVE;\n') WHERE help_topic_id = 814;
update help_topic set description = CONCAT(description, '\nOr you
could execute something like this to use the GTID position:\n\nSET GLOBAL
gtid_slave_pos=\'0-1-153\';\nCHANGE MASTER TO\n
MASTER_USE_GTID=slave_pos;\nSTART SLAVE;\n\nSee Setting up a Replication
Slave with Mariabackup for more information on\nhow to do this with
Mariabackup.\n\nExample\n-------\n\nThe following example changes the
primary and primary\'s binary log\ncoordinates. This is used when you
want to set up the replica to replicate the\nprimary:\n\nCHANGE MASTER TO\n
MASTER_HOST=\'master2.mycompany.com\',\n
MASTER_USER=\'replication\',\n
MASTER_PASSWORD=\'bigs3cret\',\n MASTER_PORT=3306,\n
MASTER_LOG_FILE=\'master2-bin.001\',\n MASTER_LOG_POS=4,\n
MASTER_CONNECT_RETRY=10;\nSTART SLAVE;\n\nURL:
https://mariadb.com/kb/en/change-master-to/') WHERE help_topic_id =
814;
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(815,49,'START SLAVE','The terms master and slave have
historically been used in replication, but the\nterms terms primary and
replica are now preferred. The old terms are used\nstill used in parts of
the documentation, and in MariaDB commands, although\nMariaDB 10.5 has
begun the process of renaming. The documentation process is\nongoing. See
MDEV-18777 to follow progress on this effort.\n\nSyntax\n------\n\nSTART
SLAVE [\"connection_name\"] [thread_type [, thread_type] ... ]
[FOR\nCHANNEL \"connection_name\"]\nSTART SLAVE
[\"connection_name\"] [SQL_THREAD] UNTIL \n
MASTER_LOG_FILE = \'log_name\', MASTER_LOG_POS = log_pos [FOR
CHANNEL\n\"connection_name\"]\nSTART SLAVE
[\"connection_name\"] [SQL_THREAD] UNTIL\n RELAY_LOG_FILE =
\'log_name\', RELAY_LOG_POS = log_pos [FOR
CHANNEL\n\"connection_name\"]\nSTART SLAVE
[\"connection_name\"] [SQL_THREAD] UNTIL\n MASTER_GTID_POS =
<GTID position> [FOR CHANNEL \"connection_name\"]\nSTART
ALL SLAVES [thread_type [, thread_type]]\n\nSTART REPLICA
[\"connection_name\"] [thread_type [, thread_type] ... ] --
from\n10.5.1\nSTART REPLICA [\"connection_name\"] [SQL_THREAD]
UNTIL \n MASTER_LOG_FILE = \'log_name\',
MASTER_LOG_POS = log_pos -- from 10.5.1\nSTART REPLICA
[\"connection_name\"] [SQL_THREAD] UNTIL\n RELAY_LOG_FILE =
\'log_name\', RELAY_LOG_POS = log_pos -- from 10.5.1\nSTART
REPLICA [\"connection_name\"] [SQL_THREAD] UNTIL\n
MASTER_GTID_POS = <GTID position> -- from 10.5.1\nSTART ALL REPLICAS
[thread_type [, thread_type]] -- from 10.5.1\n\nthread_type: IO_THREAD |
SQL_THREAD\n\nDescription\n-----------\n\nSTART SLAVE (START REPLICA from
MariaDB 10.5.1) with no thread_type options\nstarts both of the replica
threads (see replication). The I/O thread reads\nevents from the primary
server and stores them in the relay log. The SQL\nthread reads events from
the relay log and executes them. START SLAVE requires\nthe SUPER privilege,
or, from MariaDB 10.5.2, the REPLICATION SLAVE ADMIN\nprivilege.\n\nIf
START SLAVE succeeds in starting the replica threads, it returns
without\nany error. However, even in that case, it might be that the
replica threads\nstart and then later stop (for example, because they do
not manage to connect\nto the primary or read its binary log, or some other
problem). START SLAVE\ndoes not warn you about this. You must check the
replica\'s error log for error\nmessages generated by the replica
threads, or check that they are running\nsatisfactorily with SHOW SLAVE
STATUS (SHOW REPLICA STATUS from MariaDB\n10.5.1).\n\nSTART SLAVE
UNTIL\n-----------------\n\nSTART SLAVE UNTIL refers to the SQL_THREAD
replica position at which the\nSQL_THREAD replication will halt. If
SQL_THREAD isn\'t specified both threads\nare started.\n\nSTART SLAVE
UNTIL master_gtid_pos=xxx is also supported. See Global\nTransaction
ID/START SLAVE UNTIL master_gtid_pos=xxx for more
details.\n\nconnection_name\n---------------\n\nIf there is only one
nameless primary, or the default primary (as specified by\nthe
default_master_connection system variable) is intended,
connection_name\ncan be omitted. If provided, the START SLAVE statement
will apply to the\nspecified primary. connection_name is
case-insensitive.\n\nMariaDB starting with
10.7.0\n----------------------------\nThe FOR CHANNEL keyword was added for
MySQL compatibility. This is identical\nas using the channel_name directly
after START SLAVE.\n\nSTART ALL SLAVES\n----------------\n\nSTART ALL
SLAVES starts all configured replicas (replicas with master_host
not\nempty) that were not started before. It will give a note for all
started\nconnections. You can check the notes with SHOW WARNINGS.\n\nSTART
REPLICA\n-------------\n\nMariaDB starting with
10.5.1\n----------------------------\nSTART REPLICA is an alias for START
SLAVE from MariaDB 10.5.1.\n\nURL:
https://mariadb.com/kb/en/start-replica/','','https://mariadb.com/kb/en/start-replica/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(816,49,'STOP SLAVE','The terms master and slave have
historically been used in replication, but the\nterms terms primary and
replica are now preferred. The old terms are used\nstill used in parts of
the documentation, and in MariaDB commands, although\nMariaDB 10.5 has
begun the process of renaming. The documentation process is\nongoing. See
MDEV-18777 to follow progress on this effort.\n\nSyntax\n------\n\nSTOP
SLAVE [\"connection_name\"] [thread_type [, thread_type] ... ]
[FOR CHANNEL\n\"connection_name\"]\n\nSTOP ALL SLAVES
[thread_type [, thread_type]]\n\nSTOP REPLICA
[\"connection_name\"] [thread_type [, thread_type] ... ] --
from\n10.5.1\n\nSTOP ALL REPLICAS [thread_type [, thread_type]] -- from
10.5.1\n\nthread_type: IO_THREAD |
SQL_THREAD\n\nDescription\n-----------\n\nStops the replica threads. STOP
SLAVE requires the SUPER privilege, or, from\nMariaDB 10.5.2, the
REPLICATION SLAVE ADMIN privilege.\n\nLike START SLAVE, this statement may
be used with the IO_THREAD and SQL_THREAD\noptions to name the thread or
threads to be stopped. In almost all cases, one\nnever need to use the
thread_type options.\n\nSTOP SLAVE waits until any current replication
event group affecting one or\nmore non-transactional tables has finished
executing (if there is any such\nreplication group), or until the user
issues a KILL QUERY or KILL CONNECTION\nstatement.\n\nNote that STOP SLAVE
doesn\'t delete the connection permanently. Next time you\nexecute
START SLAVE or the MariaDB server restarts, the replica connection
is\nrestored with it\'s original arguments. If you want to delete a
connection, you\nshould execute RESET SLAVE.\n\nSTOP ALL
SLAVES\n---------------\n\nSTOP ALL SLAVES stops all your running replicas.
It will give you a note for\nevery stopped connection. You can check the
notes with SHOW WARNINGS.\n\nconnection_name\n---------------\n\nThe
connection_name option is used for multi-source replication.\n\nIf there is
only one nameless master, or the default master (as specified by\nthe
default_master_connection system variable) is intended,
connection_name\ncan be omitted. If provided, the STOP SLAVE statement will
apply to the\nspecified master. connection_name is
case-insensitive.\n\nMariaDB starting with
10.7.0\n----------------------------\nThe FOR CHANNEL keyword was added for
MySQL compatibility. This is identical\nas using the channel_name directly
after STOP SLAVE.\n\nSTOP REPLICA\n------------\n\nMariaDB starting with
10.5.1\n----------------------------\nSTOP REPLICA is an alias for STOP
SLAVE from MariaDB 10.5.1.\n\nURL:
https://mariadb.com/kb/en/stop-replica/','','https://mariadb.com/kb/en/stop-replica/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(817,49,'RESET REPLICA/SLAVE','The terms master and slave
have historically been used in replication, but the\nterms terms primary
and replica are now preferred. The old terms are used\nstill used in parts
of the documentation, and in MariaDB commands, although\nMariaDB 10.5 has
begun the process of renaming. The documentation process is\nongoing. See
MDEV-18777 to follow progress on this effort.\n\nSyntax\n------\n\nRESET
REPLICA [\"connection_name\"] [ALL] [FOR CHANNEL
\"connection_name\"] --\nfrom MariaDB 10.5.1 \nRESET
SLAVE [\"connection_name\"] [ALL] [FOR CHANNEL
\"connection_name\"]\n\nDescription\n-----------\n\nRESET
REPLICA/SLAVE makes the replica forget its replication position in
the\nmaster\'s binary log. This statement is meant to be used for a
clean start. It\ndeletes the master.info and relay-log.info files, all the
relay log files, and\nstarts a new relay log file. To use RESET
REPLICA/SLAVE, the replica threads\nmust be stopped (use STOP REPLICA/SLAVE
if necessary).\n\nNote: All relay log files are deleted, even if they have
not been completely\nexecuted by the slave SQL thread. (This is a condition
likely to exist on a\nreplication slave if you have issued a STOP
REPLICA/SLAVE statement or if the\nslave is highly loaded.)\n\nNote: RESET
REPLICA does not reset the global gtid_slave_pos variable. This\nmeans that
a replica server configured with CHANGE MASTER
TO\nMASTER_USE_GTID=slave_pos will not receive events with GTIDs occurring
before\nthe state saved in gtid_slave_pos. If the intent is to reprocess
these events,\ngtid_slave_pos must be manually reset, e.g. by executing set
global\ngtid_slave_pos=\"\".\n\nConnection information stored in
the master.info file is immediately reset\nusing any values specified in
the corresponding startup options. This\ninformation includes values such
as master host, master port, master user, and\nmaster password. If the
replica SQL thread was in the middle of replicating\ntemporary tables when
it was stopped, and RESET REPLICA/SLAVE is issued, these\nreplicated
temporary tables are deleted on the slave.\n\nThe ALL also resets the PORT,
HOST, USER and PASSWORD parameters for the\nslave. If you are using a
connection name, it will permanently delete it and\nit will not show up
anymore in SHOW ALL REPLICAS/SLAVE
STATUS.\n\nconnection_name\n---------------\n\nThe connection_name option
is used for multi-source replication.\n\nIf there is only one nameless
primary, or the default primary (as specified by\nthe
default_master_connection system variable) is intended,
connection_name\ncan be omitted. If provided, the RESET REPLICA/SLAVE
statement will apply to\nthe specified primary. connection_name is
case-insensitive.\n\nMariaDB starting with
10.7.0\n----------------------------\nThe FOR CHANNEL keyword was added for
MySQL compatibility. This is identical\nas using the channel_name directly
after RESET REPLICA.\n\nRESET REPLICA\n-------------\n\nMariaDB starting
with 10.5.1\n----------------------------\nRESET REPLICA is an alias for
RESET SLAVE from MariaDB 10.5.1.\n\nURL:
https://mariadb.com/kb/en/reset-replica/','','https://mariadb.com/kb/en/reset-replica/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(818,49,'RESET MASTER','RESET MASTER [TO #]\n\nDeletes all
binary log files listed in the index file, resets the binary log\nindex
file to be empty, and creates a new binary log file with a suffix
of\n.000001.\n\nIf TO # is given, then the first new binary log file will
start from number #.\n\nThis statement is for use only when the master is
started for the first time,\nand should never be used if any slaves are
actively replicating from the\nbinary log.\n\nURL:
https://mariadb.com/kb/en/reset-master/','','https://mariadb.com/kb/en/reset-master/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(819,50,'EXECUTE Statement','Syntax\n------\n\nEXECUTE
stmt_name\n [USING expression[, expression] ...]\n\nMariaDB starting with
10.2.3\n----------------------------\nEXECUTE with expression as parameters
was introduced in MariaDB 10.2.3. Before\nthat one could only use variables
(@var_name) as parameters.\n\nDescription\n-----------\n\nAfter preparing a
statement with PREPARE, you execute it with an EXECUTE\nstatement that
refers to the prepared statement name. If the prepared\nstatement contains
any parameter markers, you must supply a USING clause that\nlists user
variables containing the values to be bound to the parameters.\nParameter
values can be supplied only by user variables, and the USING clause\nmust
name exactly as many variables as the number of parameter markers in
the\nstatement.\n\nYou can execute a given prepared statement multiple
times, passing different\nvariables to it or setting the variables to
different values before each\nexecution.\n\nIf the specified statement has
not been PREPAREd, an error similar to the\nfollowing is produced:\n\nERROR
1243 (HY000): Unknown prepared statement handler (stmt_name) given
to\nEXECUTE\n\nExample\n-------\n\nSee example in PREPARE.\n\nURL:
https://mariadb.com/kb/en/execute-statement/','','https://mariadb.com/kb/en/execute-statement/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(820,50,'PREPARE Statement','Syntax\n------\n\nPREPARE
stmt_name FROM preparable_stmt\n\nDescription\n-----------\n\nThe PREPARE
statement prepares a statement and assigns it a name, stmt_name,\nby which
to refer to the statement later. Statement names are not case\nsensitive.
preparable_stmt is either a string literal or a user variable (not\na local
variable, an SQL expression or a subquery) that contains the text of\nthe
statement. The text must represent a single SQL statement, not
multiple\nstatements. Within the statement, \"?\" characters can
be used as parameter\nmarkers to indicate where data values are to be bound
to the query later when\nyou execute it. The \"?\" characters
should not be enclosed within quotes, even\nif you intend to bind them to
string values. Parameter markers can be used\nonly where expressions should
appear, not for SQL keywords, identifiers, and\nso forth.\n\nThe scope of a
prepared statement is the session within which it is created.\nOther
sessions cannot see it.\n\nIf a prepared statement with the given name
already exists, it is deallocated\nimplicitly before the new statement is
prepared. This means that if the new\nstatement contains an error and
cannot be prepared, an error is returned and\nno statement with the given
name exists.\n\nPrepared statements can be PREPAREd and EXECUTEd in a
stored procedure, but\nnot in a stored function or trigger. Also, even if
the statement is PREPAREd\nin a procedure, it will not be deallocated when
the procedure execution ends.\n\nA prepared statement can access
user-defined variables, but not local\nvariables or procedure\'s
parameters.\n\nIf the prepared statement contains a syntax error, PREPARE
will fail. As a\nside effect, stored procedures can use it to check if a
statement is valid.\nFor example:\n\nCREATE PROCEDURE `test_stmt`(IN
sql_text TEXT)\nBEGIN\n DECLARE EXIT HANDLER FOR SQLEXCEPTION\n
BEGIN\n SELECT CONCAT(sql_text, \' is not valid\');\n
END;\n SET @SQL := sql_text;\n PREPARE stmt FROM @SQL;\n
DEALLOCATE PREPARE stmt;\nEND;\n\nThe FOUND_ROWS() and ROW_COUNT()
functions, if called immediatly after\nEXECUTE, return the number of rows
read or affected by the prepared\nstatements; however, if they are called
after DEALLOCATE PREPARE, they provide\ninformation about this statement.
If the prepared statement produces errors or\nwarnings, GET DIAGNOSTICS
return information about them. DEALLOCATE PREPARE\nshouldn\'t clear
the diagnostics area, unless it produces an error.\n\nA prepared statement
is executed with EXECUTE and released with DEALLOCATE\nPREPARE.\n\nThe
max_prepared_stmt_count server system variable determines the number
of\nallowed prepared statements that can be prepared on the server. If it
is set\nto 0, prepared statements are not allowed. If the limit is reached,
an error\nsimilar to the following will be produced:\n\nERROR 1461 (42000):
Can\'t create more than max_prepared_stmt_count statements \n (current
value: 0)\n\nOracle Mode\n-----------\n\nMariaDB starting with
10.3\n--------------------------\nIn Oracle mode from MariaDB 10.3, PREPARE
stmt FROM \'SELECT :1, :2\' is used,\ninstead of ?.\n\nPermitted
Statements\n--------------------\n\nMariaDB starting with
10.6.2\n----------------------------\nAll statements can be prepared,
except PREPARE, EXECUTE, and DEALLOCATE / DROP\nPREPARE.\n\nPrior to this,
not all statements can be prepared. Only the following SQL\ncommands are
permitted:\n\n* ALTER TABLE\n* ANALYZE TABLE\n* BINLOG\n* CACHE INDEX\n*
CALL\n* CHANGE MASTER\n* CHECKSUM {TABLE | TABLES}\n* COMMIT\n* {CREATE |
DROP} DATABASE\n* {CREATE | DROP} INDEX\n* {CREATE | RENAME | DROP}
TABLE\n* {CREATE | RENAME | DROP} USER\n* {CREATE | DROP} VIEW\n* DELETE\n*
DESCRIBE\n* DO\n* EXPLAIN\n* FLUSH {TABLE | TABLES | TABLES WITH READ LOCK
| HOSTS | PRIVILEGES | LOGS |\nSTATUS | \n MASTER | SLAVE | DES_KEY_FILE |
USER_RESOURCES | QUERY CACHE |\nTABLE_STATISTICS | \n INDEX_STATISTICS |
USER_STATISTICS | CLIENT_STATISTICS}\n* GRANT\n* INSERT\n* INSTALL {PLUGIN
| SONAME}\n* HANDLER READ\n* KILL\n* LOAD INDEX INTO CACHE\n* OPTIMIZE
TABLE\n* REPAIR TABLE\n* REPLACE\n* RESET {MASTER | SLAVE | QUERY CACHE}\n*
REVOKE\n* ROLLBACK\n* SELECT\n* SET\n* SET GLOBAL SQL_SLAVE_SKIP_COUNTER\n*
SET ROLE\n* SET SQL_LOG_BIN\n* SET TRANSACTION ISOLATION LEVEL\n* SHOW
EXPLAIN\n* SHOW {DATABASES | TABLES | OPEN TABLES | TABLE STATUS | COLUMNS
| INDEX |\nTRIGGERS | \n EVENTS | GRANTS | CHARACTER SET | COLLATION |
ENGINES | PLUGINS [SONAME] |\nPRIVILEGES | \n PROCESSLIST | PROFILE |
PROFILES | VARIABLES | STATUS | WARNINGS | ERRORS |\n TABLE_STATISTICS |
INDEX_STATISTICS | USER_STATISTICS | CLIENT_STATISTICS |\nAUTHORS | \n
CONTRIBUTORS}\n* SHOW CREATE {DATABASE | TABLE | VIEW | PROCEDURE |
FUNCTION | TRIGGER |\nEVENT}\n* SHOW {FUNCTION | PROCEDURE} CODE\n* SHOW
BINLOG EVENTS\n* SHOW SLAVE HOSTS\n* SHOW {MASTER | BINARY} LOGS\n* SHOW
{MASTER | SLAVE | TABLES | INNODB | FUNCTION | PROCEDURE} STATUS\n* SLAVE
{START | STOP}\n* TRUNCATE TABLE\n* SHUTDOWN\n* UNINSTALL {PLUGIN |
SONAME}\n* UPDATE\n\nSynonyms are not listed here, but can be used. For
example, DESC can be used\ninstead of DESCRIBE.\n\nCompound statements can
be prepared too.\n\nNote that if a statement can be run in a stored
routine, it will work even if\nit is called by a prepared statement. For
example, SIGNAL can\'t be directly\nprepared. However, it is allowed
in stored routines. If the x() procedure\ncontains SIGNAL, you can still
prepare and execute the \'CALL x();\'
prepared\nstatement.\n\nPREPARE supports most kinds of expressions as well,
for example:\n\nPREPARE stmt FROM CONCAT(\'SELECT * FROM \',
table_name);\n\nWhen PREPARE is used with a statement which is not
supported, the following\nerror is produced:\n\nERROR 1295 (HY000): This
command is not supported in the prepared statement\nprotocol
yet\n\nExample\n-------\n\ncreate table t1 (a int,b char(10));\ninsert into
t1 values (1,\"one\"),(2,
\"two\"),(3,\"three\");\nprepare test from
\"select * from t1 where a=?\";\nset @param=2;\nexecute test
using @param;\n+------+------+\n| a | b |\n+------+------+\n| 2 |
two |\n+------+------+\nset @param=3;\nexecute test using
@param;\n+------+-------+\n| a | b |\n+------+-------+\n| 3 |
three |\n+------+-------+\ndeallocate prepare test;\n\nSince identifiers
are not permitted as prepared statements parameters,\nsometimes it is
necessary to dynamically compose an SQL statement. This\ntechnique is
called dynamic SQL). The following example shows how to use\ndynamic
SQL:\n\nCREATE PROCEDURE test.stmt_test(IN tab_name
VARCHAR(64))\nBEGIN\n SET @sql = CONCAT(\'SELECT COUNT(*) FROM
\', tab_name);\n PREPARE stmt FROM @sql;\n EXECUTE stmt;\n DEALLOCATE
PREPARE stmt;\nEND;\n\nCALL
test.stmt_test(\'mysql.user\');\n+----------+\n| COUNT(*)
|\n+----------+\n| 4 |\n+----------+\n\nUse of variables in prepared
statements:\n\nPREPARE stmt FROM \'SELECT @x;\';\n\nSET @x =
1;\n\nEXECUTE stmt;\n+------+\n| @x |\n+------+\n| 1
|\n+------+\n\nSET @x = 0;\n\nEXECUTE stmt;\n+------+\n| @x
|\n+------+\n| 0 |\n+------+\n\nDEALLOCATE PREPARE stmt;\n\nURL:
https://mariadb.com/kb/en/prepare-statement/','','https://mariadb.com/kb/en/prepare-statement/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(821,50,'DEALLOCATE / DROP
PREPARE','Syntax\n------\n\n{DEALLOCATE | DROP} PREPARE
stmt_name\n\nDescription\n-----------\n\nTo deallocate a prepared statement
produced with PREPARE, use a DEALLOCATE\nPREPARE statement that refers to
the prepared statement name.\n\nA prepared statement is implicitly
deallocated when a new PREPARE command is\nissued. In that case, there is
no need to use DEALLOCATE.\n\nAttempting to execute a prepared statement
after deallocating it results in an\nerror, as if it was not prepared at
all:\n\nERROR 1243 (HY000): Unknown prepared statement handler (stmt_name)
given to\nEXECUTE\n\nIf the specified statement has not been PREPAREd, an
error similar to the\nfollowing will be produced:\n\nERROR 1243 (HY000):
Unknown prepared statement handler (stmt_name) given to\nDEALLOCATE
PREPARE\n\nExample\n-------\n\nSee example in PREPARE.\n\nURL:
https://mariadb.com/kb/en/deallocate-drop-prepare/','','https://mariadb.com/kb/en/deallocate-drop-prepare/');
insert into help_topic
(help_topic_id,help_category_id,name,description,example,url) values
(822,50,'EXECUTE IMMEDIATE','MariaDB starting with
10.2.3\n----------------------------\nEXECUTE IMMEDIATE was introduced in
MariaDB 10.2.3.\n\nSyntax\n------\n\nEXECUTE IMMEDIATE
statement\n\nDescription\n-----------\n\nEXECUTE IMMEDIATE executes a
dynamic SQL statement created on the fly, which\ncan reduce performance
overhead.\n\nFor example:\n\nEXECUTE IMMEDIATE \'SELECT
1\'\n\nwhich is shorthand for:\n\nprepare stmt from \"select
1\";\nexecute stmt;\ndeallocate prepare stmt;\n\nEXECUTE IMMEDIATE
supports complex expressions as prepare source and\nparameters:\n\nEXECUTE
IMMEDIATE CONCAT(\'SELECT COUNT(*) FROM \', \'t1\',
\' WHERE a=?\') USING\n5+5;\n\nLimitations: subselects and stored
function calls are not supported as a\nprepare source.\n\nThe following
examples return an error:\n\nCREATE OR REPLACE FUNCTION f1() RETURNS
VARCHAR(64) RETURN \'SELECT * FROM t1\';\nEXECUTE IMMEDIATE
f1();\nERROR 1970 (42000): EXECUTE IMMEDIATE does not support subqueries or
stored\nfunctions\n\nEXECUTE IMMEDIATE (SELECT \'SELECT * FROM
t1\');\nERROR 1064 (42000): You have an error in your SQL syntax;
check the manual\nthat \n corresponds to your MariaDB server version for
the right syntax to use near\n \'SELECT \'SELECT * FROM
t1\')\' at line 1\n\nCREATE OR REPLACE FUNCTION f1() RETURNS INT
RETURN 10;\nEXECUTE IMMEDIATE \'SELECT * FROM t1 WHERE a=?\'
USING f1();\nERROR 1970 (42000): EXECUTE..USING does not support subqueries
or stored\nfunctions\n\nEXECUTE IMMEDIATE \'SELECT * FROM t1 WHERE
a=?\' USING (SELECT 10);\nERROR 1064 (42000): You have an error in
your SQL syntax; check the manual\nthat \n corresponds to your MariaDB
server version for the right syntax to use near\n \'SELECT 10)\'
at line 1\n\nOne can use a user or an SP variable as a
workaround:\n\nCREATE OR REPLACE FUNCTION f1() RETURNS VARCHAR(64) RETURN
\'SELECT * FROM t1\';\nSET @stmt=f1();\nEXECUTE IMMEDIATE
@stmt;\n\nSET @stmt=(SELECT \'SELECT 1\');\nEXECUTE IMMEDIATE
@stmt;\n\nCREATE OR REPLACE FUNCTION f1() RETURNS INT RETURN 10;\nSET
@param=f1();\nEXECUTE IMMEDIATE \'SELECT * FROM t1 WHERE a=?\'
USING @param;\n\nSET @param=(SELECT 10);\nEXECUTE IMMEDIATE \'SELECT *
FROM t1 WHERE a=?\' USING @param;\n\nEXECUTE IMMEDIATE supports user
variables and SP variables as OUT parameters\n\nDELIMITER $$\nCREATE OR
REPLACE PROCEDURE p1(OUT a INT)\nBEGIN\n SET a:= 10;\nEND;\n$$\nDELIMITER
;\nSET @a=2;\nEXECUTE IMMEDIATE \'CALL p1(?)\' USING @a;\nSELECT
@a;\n+------+\n| @a |\n+------+\n| 10 |\n+------+\n\nSimilar to
PREPARE, EXECUTE IMMEDIATE is allowed in stored procedures but is\nnot
allowed in stored functions.\n\nThis example uses EXECUTE IMMEDIATE inside
a stored procedure:\n\nDELIMITER $$\nCREATE OR REPLACE PROCEDURE
p1()\nBEGIN\n EXECUTE IMMEDIATE \'SELECT
1\';\nEND;\n$$\nDELIMITER ;\nCALL p1;\n+---+\n| 1 |\n+---+\n| 1
|\n+---+\n\nThis script returns an error:\n\nDELIMITER $$\nCREATE FUNCTION
f1() RETURNS INT\nBEGIN\n EXECUTE IMMEDIATE \'DO 1\';\n RETURN
1;\nEND;\n$$\nERROR 1336 (0A000): Dynamic SQL is not allowed in stored
function or trigger\n\nEXECUTE IMMEDIATE can use DEFAULT and IGNORE
indicators as bind parameters:\n\nCREATE OR REPLACE TABLE t1 (a INT DEFAULT
10);\nEXECUTE IMMEDIATE \'INSERT INTO t1 VALUES (?)\' USING
DEFAULT;\nSELECT * FROM t1;\n+------+\n| a |\n+------+\n| 10
|\n+------+\n\nEXECUTE IMMEDIATE increments the Com_execute_immediate
status variable, as\nwell as the Com_stmt_prepare, Com_stmt_execute and
Com_stmt_close status\nvariables.\n\nNote, EXECUTE IMMEDIATE does not
increment the Com_execute_sql status\nvariable. Com_execute_sql is used
only for PREPARE..EXECUTE.\n\nThis session screenshot demonstrates how
EXECUTE IMMEDIATE affects status\nvariables:\n\nSELECT * FROM
INFORMATION_SCHEMA.SESSION_STATUS WHERE VARIABLE_NAME RLIKE \n
(\'COM_(EXECUTE|STMT_PREPARE|STMT_EXECUTE|STMT_CLOSE)\');\n\n+-----------------------+----------------+\n|
VARIABLE_NAME | VARIABLE_VALUE
|\n+-----------------------+----------------+\n| COM_EXECUTE_IMMEDIATE | 0
|\n| COM_EXECUTE_SQL | 0 |\n| COM_STMT_CLOSE
| 0 |\n| COM_STMT_EXECUTE | 0 |\n|
COM_STMT_PREPARE | 0
|\n+-----------------------+----------------+\n\nEXECUTE IMMEDIATE
\'SELECT 1\';\n+---+\n| 1 |\n+---+\n| 1 |\n+---+\n\nSELECT * FROM
INFORMATION_SCHEMA.SESSION_STATUS WHERE VARIABLE_NAME RLIKE \n
(\'COM_(EXECUTE|STMT_PREPARE|STMT_EXECUTE|STMT_CLOSE)\');\n+-----------------------+----------------+\n|
VARIABLE_NAME | VARIABLE_VALUE
|\n+-----------------------+----------------+\n| COM_EXECUTE_IMMEDIATE | 1
|\n| COM_EXECUTE_SQL | 0 |\n| COM_STMT_CLOSE
| 1 |\n| COM_STMT_EXECUTE | 1 |\n|
COM_STMT_PREPARE | 1
|\n+-----------------------+----------------+\n\nURL:
https://mariadb.com/kb/en/execute-immediate/','','https://mariadb.com/kb/en/execute-immediate/');
insert into help_keyword values (1, 'work');
insert into help_keyword values (2, 'locks');
insert into help_keyword values (3, 'locking');
insert into help_keyword values (4, 'drop');
insert into help_keyword values (5, 'super');
insert into help_keyword values (6, 'usage');
insert into help_keyword values (7, 'binlog admin');
insert into help_keyword values (8, 'binlog monitor');
insert into help_keyword values (9, 'binlog replay');
insert into help_keyword values (10, 'connection admin');
insert into help_keyword values (11, 'federated admin');
insert into help_keyword values (12, 'grant option');
insert into help_keyword values (13, 'read_only admin');
insert into help_keyword values (14, 'replica monitor');
insert into help_keyword values (15, 'replication replica');
insert into help_keyword values (16, 'roles');
insert into help_keyword values (17, 'values');
insert into help_keyword values (18, 'value');
insert into help_keyword values (19, 'not');
insert into help_keyword values (20, 'and');
insert into help_keyword values (21, 'or');
insert into help_keyword values (22, ':=');
insert into help_keyword values (23, 'assignment operator');
insert into help_keyword values (24, '=');
insert into help_keyword values (25, '!=');
insert into help_keyword values (26, '<>');
insert into help_keyword values (27, 'not equal');
insert into help_keyword values (28, 'less than');
insert into help_keyword values (29, 'less than or equal');
insert into help_keyword values (30, 'NULL-safe equal');
insert into help_keyword values (31, 'equal');
insert into help_keyword values (32, 'greater than');
insert into help_keyword values (33, 'greater than or equal');
insert into help_keyword values (34, 'bitwise and');
insert into help_keyword values (35, 'shift left');
insert into help_keyword values (36, 'shift right');
insert into help_keyword values (37, 'bitwise xor');
insert into help_keyword values (38, 'bitwise or');
insert into help_keyword values (39, 'bitwise not');
insert into help_keyword values (40, 'returns');
insert into help_keyword values (41, 'udfs');
insert into help_keyword values (42, 'udf calling sequences');
insert into help_keyword values (43, 'udf security');
insert into help_keyword values (44, 'int1');
insert into help_keyword values (45, 'int2');
insert into help_keyword values (46, 'int3');
insert into help_keyword values (47, 'integer');
insert into help_keyword values (48, 'int4');
insert into help_keyword values (49, 'int8');
insert into help_keyword values (50, 'dec');
insert into help_keyword values (51, 'numeric');
insert into help_keyword values (52, 'fixed');
insert into help_keyword values (53, 'number');
insert into help_keyword values (54, 'real');
insert into help_keyword values (55, 'double precision');
insert into help_keyword values (56, 'nchar');
insert into help_keyword values (57, 'long');
insert into help_keyword values (58, 'long varchar');
insert into help_keyword values (59, 'repeat');
insert into help_keyword values (60, 'declare');
insert into help_keyword values (61, 'cursor');
insert into help_keyword values (62, 'show');
insert into help_keyword values (63, 'columns');
insert into help_keyword values (64, 'kill connection');
insert into help_keyword values (65, 'kill query');
insert into help_keyword values (66, 'delete returning');
insert into help_keyword values (67, 'sql_big_result');
insert into help_keyword values (68, 'minus');
insert into help_keyword values (69, 'cte');
insert into help_keyword values (70, 'insert returning');
insert into help_keyword values (71, 'queries');
insert into help_keyword values (72, 'query');
insert into help_keyword values (73, 'explain format');
insert into help_keyword values (74, 'explain format json');
insert into help_keyword values (75, 'rlike');
insert into help_keyword values (76, 'character_length');
insert into help_keyword values (77, 'escape');
insert into help_keyword values (78, 'mode');
insert into help_keyword values (79, 'trim_oracle');
insert into help_keyword values (80, 'schedule');
insert into help_keyword values (81, 'row_format');
insert into help_keyword values (82, 'starts');
insert into help_keyword values (83, 'host');
insert into help_keyword values (84, 'generated columns');
insert into help_keyword values (85, 'virtual columns');
insert into help_keyword values (86, 'computed columns');
insert into help_keyword values (87, 'hidden columns');
insert into help_keyword values (88, 'nextval');
insert into help_keyword values (89, 'lastval');
insert into help_keyword values (90, '+');
insert into help_keyword values (91, 'addition operator');
insert into help_keyword values (92, '/');
insert into help_keyword values (93, 'division operator');
insert into help_keyword values (94, '%');
insert into help_keyword values (95, 'modulo operator');
insert into help_keyword values (96, '*');
insert into help_keyword values (97, 'multiplication operator');
insert into help_keyword values (98, '-');
insert into help_keyword values (99, 'subtraction operator');
insert into help_keyword values (100, 'master_ssl_verify_cert');
insert into help_keyword values (101, 'start replica');
insert into help_keyword values (102, 'stop replica');
insert into help_keyword values (103, 'reset slave');
insert into help_keyword values (104, 'reset replica');
insert into help_keyword values (105, 'drop prepare');
insert into help_keyword values (106, 'deallocate prepare');
insert into help_relation values (94, 1);
insert into help_relation values (97, 2);
insert into help_relation values (97, 3);
insert into help_relation values (99, 2);
insert into help_relation values (99, 3);
insert into help_relation values (101, 2);
insert into help_relation values (101, 3);
insert into help_relation values (106, 4);
insert into help_relation values (107, 5);
insert into help_relation values (107, 6);
insert into help_relation values (107, 7);
insert into help_relation values (107, 8);
insert into help_relation values (107, 9);
insert into help_relation values (107, 10);
insert into help_relation values (107, 11);
insert into help_relation values (107, 12);
insert into help_relation values (107, 13);
insert into help_relation values (107, 14);
insert into help_relation values (107, 15);
insert into help_relation values (112, 4);
insert into help_relation values (115, 16);
insert into help_relation values (116, 2);
insert into help_relation values (116, 3);
insert into help_relation values (147, 2);
insert into help_relation values (147, 3);
insert into help_relation values (152, 2);
insert into help_relation values (152, 3);
insert into help_relation values (157, 2);
insert into help_relation values (157, 3);
insert into help_relation values (161, 2);
insert into help_relation values (161, 3);
insert into help_relation values (162, 2);
insert into help_relation values (162, 3);
insert into help_relation values (167, 17);
insert into help_relation values (167, 18);
insert into help_relation values (168, 19);
insert into help_relation values (169, 20);
insert into help_relation values (171, 21);
insert into help_relation values (212, 22);
insert into help_relation values (212, 23);
insert into help_relation values (213, 23);
insert into help_relation values (213, 24);
insert into help_relation values (214, 25);
insert into help_relation values (214, 26);
insert into help_relation values (214, 27);
insert into help_relation values (215, 28);
insert into help_relation values (216, 29);
insert into help_relation values (217, 30);
insert into help_relation values (218, 31);
insert into help_relation values (219, 32);
insert into help_relation values (220, 33);
insert into help_relation values (234, 34);
insert into help_relation values (235, 35);
insert into help_relation values (236, 36);
insert into help_relation values (238, 37);
insert into help_relation values (239, 38);
insert into help_relation values (240, 39);
insert into help_relation values (251, 40);
insert into help_relation values (252, 4);
insert into help_relation values (253, 41);
insert into help_relation values (254, 42);
insert into help_relation values (255, 43);
insert into help_relation values (257, 44);
insert into help_relation values (259, 45);
insert into help_relation values (260, 46);
insert into help_relation values (261, 47);
insert into help_relation values (261, 48);
insert into help_relation values (262, 49);
insert into help_relation values (263, 50);
insert into help_relation values (263, 51);
insert into help_relation values (263, 52);
insert into help_relation values (263, 53);
insert into help_relation values (265, 54);
insert into help_relation values (265, 55);
insert into help_relation values (271, 56);
insert into help_relation values (277, 57);
insert into help_relation values (277, 58);
insert into help_relation values (306, 59);
insert into help_relation values (313, 60);
insert into help_relation values (313, 61);
insert into help_relation values (333, 62);
insert into help_relation values (334, 62);
insert into help_relation values (335, 63);
insert into help_relation values (335, 62);
insert into help_relation values (336, 62);
insert into help_relation values (337, 62);
insert into help_relation values (340, 2);
insert into help_relation values (340, 3);
insert into help_relation values (344, 62);
insert into help_relation values (345, 62);
insert into help_relation values (346, 62);
insert into help_relation values (347, 62);
insert into help_relation values (348, 62);
insert into help_relation values (349, 62);
insert into help_relation values (356, 62);
insert into help_relation values (358, 62);
insert into help_relation values (359, 62);
insert into help_relation values (360, 62);
insert into help_relation values (361, 62);
insert into help_relation values (362, 62);
insert into help_relation values (363, 62);
insert into help_relation values (364, 62);
insert into help_relation values (365, 62);
insert into help_relation values (366, 62);
insert into help_relation values (367, 62);
insert into help_relation values (368, 62);
insert into help_relation values (369, 62);
insert into help_relation values (370, 62);
insert into help_relation values (371, 62);
insert into help_relation values (372, 62);
insert into help_relation values (373, 62);
insert into help_relation values (374, 62);
insert into help_relation values (375, 62);
insert into help_relation values (376, 62);
insert into help_relation values (377, 62);
insert into help_relation values (378, 62);
insert into help_relation values (379, 62);
insert into help_relation values (380, 62);
insert into help_relation values (381, 62);
insert into help_relation values (382, 62);
insert into help_relation values (383, 62);
insert into help_relation values (384, 62);
insert into help_relation values (385, 62);
insert into help_relation values (386, 62);
insert into help_relation values (387, 62);
insert into help_relation values (388, 62);
insert into help_relation values (389, 62);
insert into help_relation values (390, 62);
insert into help_relation values (391, 62);
insert into help_relation values (392, 62);
insert into help_relation values (393, 62);
insert into help_relation values (394, 62);
insert into help_relation values (395, 62);
insert into help_relation values (396, 62);
insert into help_relation values (397, 62);
insert into help_relation values (398, 62);
insert into help_relation values (399, 62);
insert into help_relation values (400, 62);
insert into help_relation values (405, 64);
insert into help_relation values (405, 65);
insert into help_relation values (410, 62);
insert into help_relation values (411, 62);
insert into help_relation values (412, 66);
insert into help_relation values (416, 67);
insert into help_relation values (427, 68);
insert into help_relation values (433, 69);
insert into help_relation values (434, 69);
insert into help_relation values (435, 69);
insert into help_relation values (440, 2);
insert into help_relation values (440, 3);
insert into help_relation values (455, 70);
insert into help_relation values (462, 71);
insert into help_relation values (462, 72);
insert into help_relation values (468, 73);
insert into help_relation values (468, 74);
insert into help_relation values (625, 75);
insert into help_relation values (635, 76);
insert into help_relation values (654, 77);
insert into help_relation values (660, 78);
insert into help_relation values (667, 59);
insert into help_relation values (682, 79);
insert into help_relation values (691, 4);
insert into help_relation values (693, 80);
insert into help_relation values (700, 81);
insert into help_relation values (701, 4);
insert into help_relation values (705, 82);
insert into help_relation values (711, 83);
insert into help_relation values (715, 84);
insert into help_relation values (715, 85);
insert into help_relation values (715, 86);
insert into help_relation values (716, 87);
insert into help_relation values (717, 4);
insert into help_relation values (718, 4);
insert into help_relation values (719, 4);
insert into help_relation values (720, 4);
insert into help_relation values (721, 4);
insert into help_relation values (722, 4);
insert into help_relation values (723, 4);
insert into help_relation values (724, 4);
insert into help_relation values (726, 4);
insert into help_relation values (727, 4);
insert into help_relation values (735, 4);
insert into help_relation values (736, 88);
insert into help_relation values (737, 89);
insert into help_relation values (809, 90);
insert into help_relation values (809, 91);
insert into help_relation values (810, 92);
insert into help_relation values (810, 93);
insert into help_relation values (811, 94);
insert into help_relation values (811, 95);
insert into help_relation values (812, 96);
insert into help_relation values (812, 97);
insert into help_relation values (813, 98);
insert into help_relation values (813, 99);
insert into help_relation values (814, 100);
insert into help_relation values (815, 101);
insert into help_relation values (816, 102);
insert into help_relation values (817, 103);
insert into help_relation values (817, 104);
insert into help_relation values (821, 105);
insert into help_relation values (821, 106);
unlock tables;