Oracle查询表占用空间的大小

select * from (select OWNER, segment_name, segment_type, sum(bytes) mmm from dba_segments where /*tablespace_name=\'SCMPT_TBS\'/* and segment_type=\'TABLE\'*/
owner=\'\' and segment_type=\'TABLE\' and segment_name=\'\'
group by OWNER, segment_name,segment_type
order by mmm desc)