1、查看用户使用的缺省表空间名称

你一定知道你登陆的用户名是吧，

以sysdba登陆。

sqlplus / as sysdba

select username,default_tablespace from dba_users;

2、查看表空间总大小，及其已使用大小

select a.tablespace_name,a.bytes/1024/1024 "Sum MB",(a.bytes-b.bytes)/1024/1024 "used MB",b.bytes/1024/1024 "free MB",

round(((a.bytes-b.bytes)/a.bytes)*100,2) "percent_used"

from

(select tablespace_name,sum(bytes) bytes from dba_data_files group by tablespace_name) a,

(select tablespace_name,sum(bytes) bytes,max(bytes) largest from dba_free_space group by tablespace_name) b

where a.tablespace_name=b.tablespace_name

order by ((a.bytes-b.bytes)/a.bytes) desc;