Spatial Operator Functions Returns a geometry that represents all points whose distance from the geometry value  g  is less than or equal to a distance of  d . The result is in the same SRS as the geometry argument. If the geometry argument is empty,  ST_Buffer()  returns an empty geometry. If the distance is 0,  ST_Buffer()  returns the geometry argument unchanged: mysql>  SET @pt = ST_GeomFromText(’POINT(0 0)’); mysql>  SELECT ST_AsText(ST_Buffer(@pt, 0)); +------------------------------+ | ST_AsText(ST_Buffer(@pt, 0)) | +------------------------------+ | POINT(0 0) | 2318