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/