gis_local=> select a.landuse,ST_Area(ST_Transform(ST_Union(a.way),4326)::geography) from planet_osm_polygon a,planet_osm_polygon b where a.way && b.way and st_within(a.way,b.way) and b.osm_id=-1738468 and a.landuse is not null group by a.landuse
;
  landuse   |     st_area
------------+------------------
 cemetery   | 9796.49467898815
 meadow     | 1017.31218878931
 farm       | 227498.036150773
 landfill   | 5751881.69882699
 farmland   | 23018403.2776626
 allotments | 551756.553468814
 reservoir  | 8910753.30623372
 forest     | 270299.308343124
 industrial | 9931401.54529006
(9 rows)