STDifference (geometry)#
Returns an object that represents the point set from one geometry instance that does not lie within another geometry instance.
Syntax#
.STDifference ( other_geometry )
Arguments#
other_geometry
Is another geometry instance indicating which points to remove from the instance on which STDifference() is being invoked.
Return type#
geometry
Remarks#
This method always returns null if the spatial reference IDs (SRIDs) of the geometry instances do not match. The result may contain circular arc segments only if the input instances contain circular arc segments.
Example#
Compute the difference between two Polygon instances.
DECLARE @g geometry;
DECLARE @h geometry;
SET @g = geometry::STGeomFromText('POLYGON((0 0, 0 2, 2 2, 2 0, 0 0))', 0);
SET @h = geometry::STGeomFromText('POLYGON((1 1, 3 1, 3 3, 1 3, 1 1))', 0);
SELECT @g.STDifference(@h).ToString();