LAYER
 NAME         res
 DATA         res
 STATUS       ON
 TYPE         POLYGON
 DUMP    TRUE
 CONNECTIONTYPE POSTGIS
 CONNECTION "user=blue password=applesnoranges dbname=dappl host=127.0.0.1"
 DATA "the_geom from (SELECT ST_ConvexHull(ST_Collect(the_geom))
    FROM resturants) as blankers using unique gid using SRID=5570"
 CLASS
   NAME       "Resturants"
   STYLE
     COLOR        232 232 232
     OUTLINECOLOR 32 32 32
   END
 END

the_geom from (SELECT ST_ConvexHull(ST_Collect(the_geom))
    FROM resturants) as blankers using unique gid using SRID=5570;

SELECT ST_ConvexHull(
    ST_Collect(r.the_geom::geometry)
) AS the_geom
FROM restaurants AS r;

CREATE TABLE ch AS
SELECT ST_ConvexHull(
    ST_Collect(r.the_geom::geometry)
) AS the_geom
FROM restaurants AS r;