STInteriorRingN (geometry Data Type)

Article
05/23/2023

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance SQL analytics endpoint in Microsoft Fabric Warehouse in Microsoft Fabric

Returns the specified interior ring of a Polygongeometry instance.

Syntax

  
.STInteriorRingN ( expression )

Note

To view Transact-SQL syntax for SQL Server 2014 (12.x) and earlier versions, see Previous versions documentation.

Arguments

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

Remarks

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``().

Examples

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();