MySQL provides a set of useful nonstandard functions for creating geometry values. The functions described in this section are MySQL extensions to the OpenGIS specification.
These functions produce geometry objects from either WKB values or
geometry objects as arguments. If any argument is not a proper WKB
or geometry representation of the proper object type, the return
value is NULL
.
For example, you can insert the geometry return value from
Point()
directly into a
POINT
column:
INSERT INTO t1 (pt_col) VALUES(Point(1,2));
Constructs a
GeomCollection
value from the geometry arguments.GeomCollection()
returns all the proper geometries contained in the arguments even if a nonsupported geometry is present.GeomCollection()
with no arguments is permitted as a way to create an empty geometry. Also, functions such asST_GeomFromText()
that accept WKT geometry collection arguments understand both OpenGIS'GEOMETRYCOLLECTION EMPTY'
standard syntax and MySQL'GEOMETRYCOLLECTION()'
nonstandard syntax.GeomCollection()
andGeometryCollection()
are synonymous, withGeomCollection()
the preferred function.GeometryCollection(
g
[,g
] ...)Constructs a
GeomCollection
value from the geometry arguments.GeometryCollection()
returns all the proper geometries contained in the arguments even if a nonsupported geometry is present.GeometryCollection()
with no arguments is permitted as a way to create an empty geometry. Also, functions such asST_GeomFromText()
that accept WKT geometry collection arguments understand both OpenGIS'GEOMETRYCOLLECTION EMPTY'
standard syntax and MySQL'GEOMETRYCOLLECTION()'
nonstandard syntax.GeomCollection()
andGeometryCollection()
are synonymous, withGeomCollection()
the preferred function.Constructs a
LineString
value from a number ofPoint
or WKBPoint
arguments. If the number of arguments is less than two, the return value isNULL
.MultiLineString(
ls
[,ls
] ...)Constructs a
MultiLineString
value usingLineString
or WKBLineString
arguments.Constructs a
MultiPoint
value usingPoint
or WKBPoint
arguments.MultiPolygon(
poly
[,poly
] ...)Constructs a
MultiPolygon
value from a set ofPolygon
or WKBPolygon
arguments.Constructs a
Point
using its coordinates.Constructs a
Polygon
value from a number ofLineString
or WKBLineString
arguments. If any argument does not represent aLinearRing
(that is, not a closed and simpleLineString
), the return value isNULL
.