SQL UpdateÓï¾äµÄÖ´ÐÐ˳Ðò

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 Õª×ÔCSDNµÄÀý×Ó(http://topic.csdn.net/u/20091030/16/7fd75fa6-bdb9-4516-9b27-48aef69703ba.html
http://topic.csdn.net/u/20090904/16/e5dad9c7-fb59-41b9-b28d-e3b71c3e8420.html)
1.±äÁ¿ÓÅÏÈ
create table #t (field1 varchar(10),field2 varchar(10))
insert #t select 'a','b'
declare @str varchar(10)
set @str='Test'
update #t set Field1=@str,@str=Field2,Field2=Field1
select * from #t
drop table #t
/*field1     field2
---------- ----------
b          a*/
2.Ö𲽸üÐÂ
if OBJECT_ID('ta') is not null drop table ta
create table ta(empNo varchar(8) ,empName varchar(20),nIndex int)  --drop table ta
insert into ta
select 'A0001','張Èý',null
union
select 'A0002','ÀîËÄ',null
union
select 'A0003','Íõ¶þ',null
union
select 'A0004','ôôÁù',null
declare @tmpIndex int
set @tmpIndex=0
update ta set nIndex=@tmpIndex,@tmpIndex=@tmpIndex+1
select * from ta
/*
empNo    empName    nIndex
A0001    張Èý    1
A0002    ÀîËÄ    2
A0003    Íõ¶þ    3
A0004    ôôÁù    4
*/
(1 ÐÐÊÜÓ°Ïì)*/
3.×Ö¶ÎÖ®¼ä, ²¢ÐÐÖ´ÐÐ
create table #t (field1 varchar(10),field2 varchar(10))
insert #t select 'a','b'
declare @str varchar(10)
update #t set Field1=Field2,Field2=Field1
select * from #t
/*
field1     field2
---------- ----------
b          a
*/
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