cannot drop a user that is currently connected

问题提出：

SQL〉DROP USER USER1 CASCADE

ERROR：ORA-01940: cannot drop a user that is currently connected

由于当前用户正连接到数据库，所以无法删除

解决办法：

1、查询此用户的会话进程，

SQL〉SELECT SID,SERIAL# FROM V$SESSION WHERE USERNAME='USER1';

注意：这里的用户名是大写

       SID    SERIAL#
---------- ----------
24      25341
86      18117

2、结束此用户的所有会话

SQL>ALTER SYSTEM KILL SESSION '24,25341';

System altered.

SQL>ALTER SYSTEM KILL SESSION '86,18117';

System altered.

3、删除用户

SQL〉DROP USER USER1 CASCADE；