Oracle查看表空间的sql语句

select f.tablespace_name,a.total,u.used,f.free,round((u.used/a.total)*100) "% used",
round((f.free/a.total)*100) "% Free" 
from
(select tablespace_name, sum(bytes/(1024*1024)) total 
       from dba_data_files group by tablespace_name) a,
(select tablespace_name, round(sum(bytes/(1024*1024))) used 
       from dba_extents group by tablespace_name) u,
(select tablespace_name, round(sum(bytes/(1024*1024))) free 
       from dba_free_space group by tablespace_name) f
WHERE a.tablespace_name = f.tablespace_name
and a.tablespace_name = u.tablespace_name;