ORA-01940: 无法删除当前连接的用户（解决办法）

SQL> drop user lisi;
drop user lisi
ORA-01940: 无法删除当前连接的用户

SQL> select username,sid,serial# from v$session where username is not null;
USERNAME                              SID    SERIAL#
------------------------------ ---------- ----------
AAA                                    12         28
AAA                                    13        186
AAA                                    21        204
AAA                                    24         45
AAA                                   143        206
LISI                                  145        487
6 rows selected

SQL> select username,sid,serial# from v$session where username='LISI';
USERNAME                              SID    SERIAL#
------------------------------ ---------- ----------
LISI                                  145        487

SQL> alter system kill session '145,487';
System altered

SQL> drop user lisi cascade;
SQL> 
User dropped

SQL> select username,sid,serial# from v$session where username='LISI';
USERNAME                              SID    SERIAL#
------------------------------ ---------- ----------
LISI                                  145        487

SQL> select username,sid,serial# from v$session where username is not null;
USERNAME                              SID    SERIAL#
------------------------------ ---------- ----------
AAA                                    12         28
AAA                                    21        204
AAA                                    24         45
AAA                                   143        206
LISI                                  145        487

SQL> alter system kill session'145,487';
System altered

SQL> drop user lisi cascade;
drop user lisi cascade
ORA-01918: 用户 'LISI' 不存在

SQL> select username,sid,serial# from v$session where username is not null;
USERNAME                              SID    SERIAL#
------------------------------ ---------- ----------
AAA                                    12         28
AAA                                    21        204
AAA                                    24         45
AAA                                   143        206
LISI                                  145        487

SQL> select username,sid,serial# from v$session where username is not null;
USERNAME                              SID    SERIAL#
------------------------------ ---------- ----------
AAA                                    12         28
AAA                                    21        204
AAA                                    24         45
AAA                                   143        206
LISI                                  145        487