ST_Intersection - Amazon Redshift
SyntaxArgumentsReturn typeExamples
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ST_Intersection

ST_Intersection returns a geometry representing the point-set intersection of two geometries. That is, it returns the portion of the two input geometries that is shared between them.

Syntax

ST_Intersection(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.

Return type

GEOMETRY

If geom1 and geom2 don't share any space (they are disjoint), then an empty geometry is returned.

If geom1 or geom2 are empty, then an empty geometry 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.

If geom1 or geom2 is not a two-dimensional (2D) geometry, then an error is returned.

Examples

The following SQL returns the non-empty geometry representing the intersection of two input geometries. 

SELECT ST_AsEWKT(ST_Intersection(ST_GeomFromText('polygon((0 0,100 100,0 200,0 0))'), ST_GeomFromText('polygon((0 0,10 0,0 10,0 0))')));

        st_asewkt        
-------------------------
 POLYGON((0 0,0 10,5 5,0 0))

The following SQL returns an empty geometry when passed disjoint (non-intersecting) input geometries. 

SELECT ST_AsEWKT(ST_Intersection(ST_GeomFromText('linestring(0 100,0 0)'), ST_GeomFromText('polygon((1 0,10 0,1 10,1 0))')));

    st_asewkt     
------------------
 LINESTRING EMPTY