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ST_WITHIN ​

Returns TRUE if one GEOGRAPHY object is within another.

A GEOGRAPHY A is within B if and only if:

  • All points of A lie inside B (either within the interior or on the boundary)
  • The interiors of A and B share at least one common point

This function has the following properties:

  • Reflexive: Every GEOGRAPHY object is within itself
  • Antisymmetric: If ST_WITHIN(A, B) = TRUE and ST_WITHIN(B, A) = TRUE, then A and B are topologically equal
  • Converse of ST_CONTAINS: ST_WITHIN(A, B) is equivalent to ST_CONTAINS(B, A)

See also:

Syntax ​

sql
ST_WITHIN(<a>, <b>)

Arguments ​

  • <a> and <b>: The GEOGRAPHY objects to check for the "within" relationship

Returns ​

Returns TRUE if <a> is within <b>, otherwise returns FALSE.

Example ​

sql
SELECT ST_WITHIN('POINT(1 1)'::GEOGRAPHY, 'POLYGON((0 0, 0 2, 2 2, 2 0, 0 0))'::GEOGRAPHY);
-- TRUE

SELECT ST_WITHIN('POINT(3 3)'::GEOGRAPHY, 'POLYGON((0 0, 0 2, 2 2, 2 0, 0 0))'::GEOGRAPHY);
-- FALSE