MBRDisjoint(g1,g2)

Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles of
the two geometries g1 and g2 are disjoint (do not intersect).

URL: http://dev.mysql.com/doc/refman/5.5/en/functions-for-testing-spatial-relations-between-geometric-objects.html#relations-on-geometry-mbr

