查看表空间剩余：
select tablespace_name,sum(bytes)/1024/1024||'M'
from dba_free_space group by tablespace_name
查看表空间总大小、使用大小、剩余大小，使用率、剩余率
select a.tablespace_name,a.bytes/1024/1024||'M' total,b.bytes/1024/1024||'M' used,c.bytes/1024/1024||'M' free ,
trunc(b.bytes/a.bytes,2) useded, trunc(c.bytes/a.bytes,2) freeed
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