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ST_Contains

Tests whether geometry A completely contains geometry B.

Syntax​

ST_Contains(geometry_a, geometry_b)

Parameters​

ParameterTypeDescription
geometry_aGeometryContainer geometry
geometry_bGeometryContained geometry

Returns​

TypeDescription
BooleanTrue if A contains B, false otherwise

Examples​

Test Point in Polygon​

SELECT ST_Contains(
    ST_GeomFromText('POLYGON((0 0, 4 0, 4 4, 0 4, 0 0))'),
    ST_Point(2, 2)
);
-- Returns: true

Find Points in Region​

SELECT p.id, p.name
FROM points p, regions r
WHERE r.name = 'District A'
  AND ST_Contains(r.geom, p.geom);

Filter Features Within Boundary​

SELECT * FROM buildings
WHERE ST_Contains(
    (SELECT geom FROM boundaries WHERE name = 'City Limits'),
    geom
);

Notes​

  • A contains B means B is completely inside A (including on boundary)
  • ST_Contains(A, B) is equivalent to ST_Within(B, A)
  • Returns false if B extends outside A or if A equals B with matching boundaries
  • Point on polygon boundary returns false (use ST_Covers for inclusive boundary)

See Also​