ORACLE 查看表空間使用率

SELECT a.tablespace_name,
a.bytes/1073741824 total,
b.bytes/1073741824 used,
c.bytes/1073741824 free,
(b.bytes * 100) / a.bytes "% USED ",
(c.bytes * 100) / a.bytes "% FREE "
FROM sys.sm$ts_avail a, sys.sm$ts_used b, sys.sm$ts_free c
WHERE a.tablespace_name = b.tablespace_name
AND a.tablespace_name = c.tablespace_name;