ST_TOUCHES

Checks if two geometries touch. Returns 1 if they intersect only at their boundaries and not their interiors.

Syntax

ST_TOUCHES(g1,g2)

Description

Returns 1 or 0 to indicate whether geometry g1 spatially touches geometry g2. Two geometries spatially touch if the interiors of the geometries do not intersect, but the boundary of one of the geometries intersects either the boundary or the interior of the other.

ST_TOUCHES() uses object shapes, while TOUCHES(), based on the original MySQL implementation, uses object bounding rectangles.

Examples

SET @g1 = ST_GEOMFROMTEXT('POINT(2 0)');

SET @g2 = ST_GEOMFROMTEXT('LINESTRING(2 0, 0 2)');

SELECT ST_TOUCHES(@g1,@g2);
+---------------------+
| ST_TOUCHES(@g1,@g2) |
+---------------------+
|                   1 |
+---------------------+

SET @g1 = ST_GEOMFROMTEXT('POINT(2 1)');

SELECT ST_TOUCHES(@g1,@g2);
+---------------------+
| ST_TOUCHES(@g1,@g2) |
+---------------------+
|                   0 |
+---------------------+

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