text: CREATE OR REPLACE FUNCTION "public"."geoc_cgcs2000togcj02"("geom" "public"."geometry")
    RETURNS "public"."geometry" AS $BODY$
  DECLARE
  BEGIN
  IF st_srid(geom) != '4490' THEN
          RETURN null;
  end if;
  return geoc_wgs84togcj02(st_transform(st_setsrid(geom,4490),4326));
  END;
  $BODY$
    LANGUAGE plpgsql VOLATILE
    COST 100;