ST_Difference
Signatures
GEOMETRY ST_Difference(GEOMETRY geomA, GEOMETRY geomB)Description
Computes the difference between geomA and geomB.
Implements the OpenGIS Simple Features Implementation Specification for SQL version 1.2.1.
Examples
| geomA Polygon | geomB Polygon |
|---|---|
| POLYGON((1 1, 7 1, 7 6, 1 6, 1 1)) | POLYGON((3 2, 8 2, 8 8, 3 8, 3 2)) |
SELECT ST_Difference(geomA, geomB) FROM input_table;
-- Answer: POLYGON((1 1, 7 1, 7 2, 3 2, 3 6, 1 6, 1 1))
SELECT ST_Difference(geomB, geomA) FROM input_table;
-- Answer: POLYGON((7 2, 8 2, 8 8, 3 8, 3 6, 7 6, 7 2))