怎么查看一個表(严格来说是对象）所占用的空間大小？

select owner,segment_name,SEGMENT_TYPE,tablespace_name,sum(bytes/1024/1024) from dba_segments
group by owner,segment_name,tablespace_name
order by 5 desc

ref:http://www.itpub.net/thread-718327-1-1.html