This topic describes the ST_SymDifference function. This function returns a geometry object representing the part that Geometry Object A does not intersect with Geometry Object B.
Syntax
geometry ST_SymDifference(geometry geomA , geometry geomB);Parameters
| Parameter | Description |
|---|---|
| geomA | Geometry Object A that you want to specify. |
| geomB | Geometry Object B that you want to specify. |
Description
- This function does not support GeometryCollection objects.
- This function supports 3D objects and does not delete z coordinates. This function processes only the x and y coordinates of the input geometry objects. This function returns the output geometry object with the original z coordinates.
Examples
Results returned by using the default parameter settings:
SELECT ST_AsText(ST_SymDifference('LINESTRING(0 0,2 0)'::geometry,'LINESTRING(1 0,3 0)'::geometry));
st_astext
--------------------------------------
MULTILINESTRING((0 0,1 0),(2 0,3 0))
(1 row)