STIsRing (geometry Data Type)
Returns 1 if a geometry instance fulfills the following requirements:
It is a LineString instance.
It is closed.
It is simple.
Returns 0 if the LineString instance does not meet the requirements.
The following example creates a LineString instance and uses STIsRing() to test whether the instance is a ring.
DECLARE @g geometry; SET @g = geometry::STGeomFromText('LINESTRING(0 0, 2 2, 1 0, 0 0)', 0); SELECT @g.STIsRing();