ORACLE 下如何 查看用户session 及 kill

SQL> drop user sysman cascade;
drop user sysman cascade
*
ERROR at line 1:
ORA-01940: cannot drop a user that is currently connected

 

SQL> select sid,serial# from v$session where username='SYSMAN';

       SID    SERIAL#
---------- ----------
      2558        522
      2564         29
      2576       1023

SQL> alter system kill session '2558,522';

System altered.