oracle如何获取当前登录的用户名

Microsoft Windows [版本 5.2.3790]
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C:/>sqlplus

SQL*Plus: Release 9.2.0.1.0 - Production on 星期三 5月 30 00:04:26 2007

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

请输入用户名: scott
请输入口令:

连接到:
Oracle9i Enterprise Edition Release 9.2.0.1.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.1.0 - Production

SQL> select a.spid,b.username from v$process a,v$session b,v$instance d
2 where a.addr=b.paddr and b.audsid=sys_context('userenv','sessionid')
3 /
select a.spid,b.username from v$process a,v$session b,v$instance d
*
ERROR 位于第 1 行:
ORA-00942: 表或视图不存在

SQL> conn system/aa as sysdba;
已连接。
SQL> select a.spid,b.username from v$process a,v$session b,v$instance d
2 where a.addr=b.paddr and b.audsid=sys_context('userenv','sessionid')
3 /

SPID USERNAME
------------ ------------------------------
988
2948
3124
4064
2292
3060
1588
2552
3532 SYS

已选择9行。

SQL>