Returns the shortest distance between a point in a geometry instance and a point in another geometry instance.
.STDistance ( other_geometry )
Is another geometry instance from which to measure the distance between the instance on which STDistance() is invoked. If other_geometry is an empty set, STDistance() returns null.
STDistance()
SQL Server return type: float
CLR return type: SqlDouble
STDistance() always returns null if the spatial reference IDs (SRIDs) of the geometry instances do not match.
DECLARE @g geometry; DECLARE @h geometry; SET @g = geometry::STGeomFromText('POLYGON((0 0, 2 0, 2 2, 0 2, 0 0))', 0); SET @h = geometry::STGeomFromText('POINT(10 10)', 0); SELECT @g.STDistance(@h);