NumRings (geography Data Type)

Applies to: yesSQL Server (all supported versions) YesAzure SQL Database

Returns the total number of rings in a Polygon instance. In the SQL Server geography type, external and internal rings are not distinguished, as any ring can be taken to be the external ring.


.NumRings ()  


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

Return Type

SQL Server return type: int

CLR return type: SqlInt32


This method will return NULL if this is not a Polygon instance and will return 0 if the instance is empty. This method is precise.


This example creates a Polygon instance with two rings and confirms that it has two rings.

DECLARE @g geography;  
SET @g = geography::STGeomFromText('POLYGON((-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653), (-122.357 47.654, -122.357 47.657, -122.349 47.657, -122.349 47.650, -122.357 47.654))', 4326);  
SELECT @g.NumRings();  

See Also

Extended Methods on Geography Instances