STInteriorRingN (geometry Data Type)

APPLIES TO: yesSQL Server yesAzure SQL Database noAzure Synapse Analytics (SQL DW) noParallel Data Warehouse

Returns the specified interior ring of a Polygongeometry instance.


.STInteriorRingN ( expression )  


Is an int expression between 1 and the number of interior rings in the geometry instance.

Return Types

SQL Server return type: geometry

CLR return type: SqlGeometry

Open Geospatial Consortium (OGC) type: LineString


This method returns null if the geometry instance is not a polygon. This method will also throw an ArgumentOutOfRangeException if the expression is larger than the number of rings. The number of rings can be returned using STNumInteriorRing``().


The following example creates a Polygon instance and uses STInteriorRingN() to return the interior ring of the polygon as a LineString.

DECLARE @g geometry;  
SET @g = geometry::STGeomFromText('POLYGON((0 0, 3 0, 3 3, 0 3, 0 0),(2 2, 2 1, 1 1, 1 2, 2 2))', 0);  
SELECT @g.STInteriorRingN(1).ToString();  

See Also

OGC Methods on Geometry Instances