ST_Touches( ST_Geometry ) method

Tests if a geometry value spatially touches another geometry value.

Syntax

geometry-expression.ST_Touches( ST_Geometry geo2)

geo2 – The other geometry value that is to be compared to the geometry-expression.

BIT Returns 1 if the geometry-expression touches geo2, otherwise 0. Returns NULL if both geometry-expression and geo2 have dimension 0.

Example 1 – The following example returns NULL because both inputs are points and have no boundary.
```
SELECT NEW ST_Point(1,1).ST_Touches( NEW ST_Point( 1,1 ) )
```
The following example lists the ShapeIDs of the geometries that touch the "Lighting Bolt" shape, which has ShapeID 6. This example returns the result 5,16,26. Each of the three touching geometries intersect the Lighting Bolt only at its boundary.
```
SELECT List( ShapeID ORDER BY ShapeID )
FROM SpatialShapes
WHERE Shape.ST_Touches( ( SELECT Shape FROM SpatialShapes WHERE ShapeID = 6 ) ) = 1
```

SQL/MM (ISO/IEC 13249-3: 2006) 5.1.28