如何查看数据库里否有锁表？？？

Question

select t2.username,
         t2.sid,
         t2.serial#,
         t2.logon_time  
    from v$locked_object t1,
         v$session t2  
   where t1.session_id=t2.sid 
order by t2.logon_time

Answer 1

SELECT S.SID SESSION_ID,S.USERNAME,LMODE,REQUEST,O.OWNER||'.'||O.OBJECT_NAME||' ('||O.OBJECT_TYPE||')',S.TYPE LOCK_TYPE,L.ID1 LOCK_ID1,L.ID2 LOCK_ID2
 FROM V$LOCK L,SYS.DBA_OBJECTS O,V$SESSION S 
 WHERE L.SID = S.SID AND L.ID1 = O.OBJECT_ID;

Answer 2

select * from dba_dml_locks
select * from dba_ddl_locks