| title | STDifference (geometry Data Type) | ||
|---|---|---|---|
| description | STDifference (geometry Data Type) | ||
| author | MladjoA | ||
| ms.author | mlandzic | ||
| ms.date | 08/03/2017 | ||
| ms.service | sql | ||
| ms.subservice | t-sql | ||
| ms.topic | reference | ||
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| monikerRange | =azuresqldb-current || >=sql-server-2016 || >=sql-server-linux-2017 || =azuresqldb-mi-current || =fabric-sqldb |
[!INCLUDE SQL Server Azure SQL Database Azure SQL Managed Instance FabricSQLDB]
Returns an object that represents the point set from one geometry instance that does not lie within another geometry instance.
.STDifference ( other_geometry )
other_geometry
Is another geometry instance indicating which points to remove from the instance on which STDifference() is being invoked.
[!INCLUDEssNoVersion] return type: geometry
CLR return type: SqlGeometry
This method always returns null if the spatial reference IDs (SRIDs) of the geometry instances do not match. The result may contain circular arc segments only if the input instances contain circular arc segments.
The following example uses STDifference() to compute the difference between two polygons.
DECLARE @g geometry;
DECLARE @h geometry;
SET @g = geometry::STGeomFromText('POLYGON((0 0, 0 2, 2 2, 2 0, 0 0))', 0);
SET @h = geometry::STGeomFromText('POLYGON((1 1, 3 1, 3 3, 1 3, 1 1))', 0);
SELECT @g.STDifference(@h).ToString(); The following example uses STDifference() on a CurvePolygon instance.
DECLARE @g geometry = 'CURVEPOLYGON (CIRCULARSTRING (0 -4, 4 0, 0 4, -4 0, 0 -4))';
DECLARE @h geometry = 'POLYGON ((1 -1, 5 -1, 5 3, 1 3, 1 -1))';
-- Note the different results returned by the two SELECT statements
SELECT @h.STDifference(@g).ToString(), @g.STDifference(@h).ToString();