STPointN (geometry Data Type)
Applies to:
SQL Server
Azure SQL Database
Azure SQL Managed Instance
SQL analytics endpoint in Microsoft Fabric
Warehouse in Microsoft Fabric
Returns a specified point in a geometry instance.
Syntax
.STPointN ( 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 points in the geometry instance.
Return Types
SQL Server return type: geometry
CLR return type: SqlGeometry
Open Geospatial Consortium (OGC) type: Point
Remarks
If a geometry instance is user created, STPointN()
returns the point specified by expression by ordering the points in the order in which they were originally input.
If a geometry instance was constructed by the system, STPointN()
returns the point specified by expression by ordering all the points in the same order they would be output: first by geometry, then by ring within the geometry (if appropriate), and then by point within the ring. This order is deterministic.
If this method is called with a value less than 1, it throws an ArgumentOutOfRangeException.
If this method is called with a value greater than the number of points in the instance, it returns null.
Examples
The following example creates a LineString
instance and uses STPointN()
to retrieve the second point in the description of the instance.
DECLARE @g geometry;
SET @g = geometry::STGeomFromText('LINESTRING(0 0, 2 2, 1 0)', 0);
SELECT @g.STPointN(2).ToString();
See Also
Phản hồi
https://aka.ms/ContentUserFeedback.
Sắp ra mắt: Trong năm 2024, chúng tôi sẽ dần gỡ bỏ Sự cố với GitHub dưới dạng cơ chế phản hồi cho nội dung và thay thế bằng hệ thống phản hồi mới. Để biết thêm thông tin, hãy xem:Gửi và xem ý kiến phản hồi dành cho