原来update可以这样写！

1.今天在csdn上看到网友的提问：http://community.csdn.net/Expert/topic/4595/4595522.xml?temp=.366543

其中有一个update写法如下：update (select d.id as did, d.next as dnext, d.message as dmessage, s.id as sid, s.next as snext, s.message as smessage from destination d, dbmsglin s where d.next= s.id) set did=sid,dnext=snext, dmessage=dmessage||smessage

没有见过这样的update写法，故测试了一下：

Connected to Oracle9i Enterprise Edition Release 9.2.0.1.0

SQL> SELECT * FROM test0302;

TESTCOL
--------------------------------------------------
xxx
xxx
xxx
xxx
xxx
xxx

6 rows selected

SQL> UPDATE (SELECT * FROM test0302) SET testcol='111';

6 rows updated

SQL> commit;

Commit complete

SQL> SELECT * FROM test0302;

TESTCOL
--------------------------------------------------
111
111
111
111
111
111

6 rows selected

SQL>