查看表空间(oracle)占用情况

select total.tablespace_name,round(total.MB,2) as Total_MB,
round(total.MB-free.MB, 2) as Used_MB
from (select tablespace_name, sum(bytes)/1024/1024 as MB from dba_free_space group by tablespace_name) free,
(select tablespace_name, sum(bytes)/1024/1024 as MB from dba_data_files group by tablespace_name) total 
where free.tablespace_name=total.tablespace_name