ST_Contains

ST_Contains returns true if the 2D projection of the first input geometry contains the 2D projection of the second input geometry. Geometry A contains geometry B if every point in B is a point in A, and their interiors have nonempty intersection.

ST_Contains(A, B) is equivalent to ST_Within(B, A).

Syntax

ST_Contains(geom1, geom2)

Arguments

geom1

A value of data type GEOMETRY or an expression that evaluates to a GEOMETRY type.

geom2

A value of data type GEOMETRY or an expression that evaluates to a GEOMETRY type. This value is compared with geom1 to determine if it is contained within geom1.

Return type

BOOLEAN

If geom1 or geom2 is null, then null is returned.

If geom1 and geom2 don't have the same value for the spatial reference system identifier (SRID), then an error is returned.

If geom1 or geom2 is a geometry collection, then an error is returned.

Examples

The following SQL checks if the first polygon contains the second polygon.

SELECT ST_Contains(ST_GeomFromText('POLYGON((0 2,1 1,0 -1,0 2))'), ST_GeomFromText('POLYGON((-1 3,2 1,0 -3,-1 3))'));

st_contains
-----------
 false