oracle查看表空间使用情况

select
dbf.file_name 物理文件名,
dbf.tablespace_name 表空间,
dbf.totalspace "总量(M)",
dbf.totalblocks as 总块数,
dfs.freespace "剩余总量(M)",
dfs.freeblocks "剩余块数",
(dfs.freespace / dbf.totalspace) * 100 "空闲比例" 
from (select t.file_name,t.tablespace_name,sum(t.bytes) / 1024 / 1024 totalspace,sum(t.blocks) totalblocks from dba_data_files t  group by t.tablespace_name,t.file_name) dbf,
       (select tt.tablespace_name,sum(tt.bytes) / 1024 / 1024 freespace,sum(tt.blocks) freeblocks from dba_free_space tt,dba_data_files b group by tt.tablespace_name) dfs
where trim(dbf.tablespace_name) = trim(dfs.tablespace_name)