**THIS TOPIC APPLIES TO:**SQL Server (starting with 2008)Azure SQL DatabaseAzure SQL Data Warehouse Parallel Data Warehouse

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**.

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|**Applies to**: SQL Server ( SQL Server 2008 through current version), Azure SQL Database.|

## Syntax

```
.STNumCurves()
```

## Return Types

SQL Server 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