stnumcurves-geometry-data-type.md

title	STNumCurves (geometry Data Type)
description	STNumCurves (geometry Data Type)
author	MladjoA
ms.author	mlandzic
ms.date	08/03/2017
ms.service	sql
ms.subservice	t-sql
ms.topic	reference
ms.custom	ignite-2025
helpviewer_keywords	STNumCurves method (geometry)
dev_langs	TSQL
monikerRange	=azuresqldb-current || >=sql-server-2016 || >=sql-server-linux-2017 || =azuresqldb-mi-current || =fabric-sqldb

STNumCurves (geometry Data Type)

[!INCLUDE SQL Server Azure SQL Database Azure SQL Managed Instance FabricSQLDB]

This method returns the number of curves in a geometry instance when the instance is a one-dimensional spatial data type. One-dimensional spatial data types include LineString, CircularString, and CompoundCurve. STNumCurves() works only on simple types; it does not work with geometry collections like MultiLineString.

Syntax

  
.STNumCurves()  

Return Types

[!INCLUDEssNoVersion] return type: geometry

CLR return type: SqlGeometry

Remarks

An empty one-dimensional geometry instance returns 0. NULL is returned when the geometry instance is not a one-dimensional instance or is an uninitialized instance.

Examples

A. Using STNumCurves() on a CircularString instance

The following example shows how to get the number of curves in a CircularString instance:

 DECLARE @g geometry;  
 SET @g = geometry::Parse('CIRCULARSTRING(10 0, 0 10, -10 0, 0 -10, 10 0)');  
 SELECT @g.STNumCurves();

B. Using STNumCurves() on a CompoundCurve instance

The following example uses STNumCurves() to return the number of curves in a CompoundCurve instance.

 DECLARE @g geometry;  
 SET @g = geometry::Parse('COMPOUNDCURVE(CIRCULARSTRING(10 0, 0 10, -10 0, 0 -10, 10 0))');  
 SELECT @g.STNumCurves();

See Also

Spatial Data Types Overview
OGC Methods on Geometry Instances