代码如下:selectb.tablespace_name,mbytes_alloc,mbytes_free

from(select round(sum(bytes)/1024/1024) mbytes_free,tablespace_name

from dba_free_space

group by tablespace_name) a,

(select round(sum(bytes)/1024/1024) mbytes_alloc,tablespace_name

from dba_data_files

group by tablespace_name) b

where a.tablespace_name(+)=b.tablespace_name

and b.tablespace_name=’USERS’

/