oracle查看錶空間使用方式

select
dbf.file_name 物理檔案名稱,
dbf.tablespace_name 資料表空間,
dbf.totalspace "總量(M)",
dbf.totalblocks as 總塊數,
dfs.freespace "剩餘總量(M)",
dfs.freeblocks "剩餘塊數",
(dfs.freespace / dbf.totalspace) * 100 "空閑比例" 
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)