1、查看所有表空间大小、剩余量：
select dbf.tablespace_name,
dbf.totalspace "总量(M)",
dbf.totalblocks as 总块数,
dfs.freespace "剩余总量(M)",
dfs.freeblocks "剩余块数",
(dfs.freespace / dbf.totalspace) * 100 "空闲比例"
from (select t.tablespace_name,
sum(t.bytes) / 1024 / 1024 totalspace,
sum(t.blocks) totalblocks
from dba_data_files t
group by t.tablespace_name) dbf,
(select tt.tablespace_name,
sum(tt.bytes) / 1024 / 1024 freespace,
sum(tt.blocks) freeblocks
from dba_free_space tt
group by tt.tablespace_name) dfs
where trim(dbf.tablespace_name) = trim(dfs.tablespace_name)
2、查看当前用户各表所占表空间
Select Segment_Name,Sum(bytes)/1024/1024 From User_Extents Group By Segment_Name
3. 使用如下语句查看一下谁在用临时段
SELECT se.username, se.SID, se.serial#, se.sql_address, se.machine, se.program, su.TABLESPACE, su.segtype, su.CONTENTS
FROM v$session se, v$sort_usage su
WHERE se.saddr = su.session_addr;