SELECT b.tablespace_name  "表空间名",      

round(b.all_byte)  "总空间(M)",

round(b.all_byte-a.free_byte)  "已使用(M)",

round(a.free_byte)             "剩余空间",

round((a.free_byte/b.all_byte)*100)||'%'  "剩余百分比"  

FROM

(SELECT tablespace_name,SUM(nvl(bytes,0))/1024/1024 free_byte FROM dba_free_space GROUP BY tablespace_name) a,

(SELECT tablespace_name,SUM(nvl(bytes,0))/1024/1024 all_byte FROM dba_data_files GROUP BY tablespace_name) b

WHERE b.tablespace_name = a.tablespace_name(+)

ORDER BY 1,5;