select b.tablespace_name "表空间",

       b.bytes /  /  "大小M",

       (b.bytes - sum(nvl(a.bytes, ))) /  /  "已使用M",

       substr((b.bytes - sum(nvl(a.bytes, ))) / (b.bytes) * , , ) "利用率"

  from dba_free_space a, dba_data_files b

 where a.file_id = b.file_id

   and b.tablespace_name = 'SYSTEM'

 group by b.tablespace_name, b.file_name, b.bytes

 order by b.tablespace_name;

SELECT *

  FROM (SELECT SEGMENT_NAME, SUM(BYTES) /  /  MB

          FROM DBA_SEGMENTS

         WHERE TABLESPACE_NAME = 'SYSTEM'

         GROUP BY SEGMENT_NAME

         ORDER BY  DESC)

 WHERE ROWNUM < ;

truncate table  SYS.AUD$;