Syntax
------

Touches(g1,g2)

Description
-----------

Returns 1 or 0 to indicate whether g1 spatially touches 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.

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

URL: https://mariadb.com/kb/en/touches/