SQL to find out tables consuming more space in a disk – Netezza

select
 database as db_name,
       hwid as spu_id, dsid,
       (allocated_bytes/1048576) as allocated_mbytes
  from _v_sys_relation_xdb sys,
       _v_sys_object_dslice_info ds
 where ds.tblid = sys.objid
   and dsid in (1,2,3,4)
and allocated_mbytes > 1000
 order by  allocated_mbytes desc, table_name,db_name, dsid;