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本版专家分：41结帖率 100% -
表如上，可以一条语句更新：把C列为2012的B列更新为 A列在C列为2014的B列不？
更新结果为2012的（A）12345对应成（B）ABCDE![]()
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本版专家分：5090
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select A='1',B='A',C='2014' INTO #LIST UNION ALL
select A='2',B='B',C='2014' UNION ALL
select A='3',B='C',C='2014' UNION ALL
select A='4',B='D',C='2014' UNION ALL
select A='5',B='E',C='2014' UNION ALL
select A='1',B='F',C='2013' UNION ALL
select A='2',B='G',C='2013' UNION ALL
select A='3',B='H',C='2013' UNION ALL
select A='4',B='I',C='2013' UNION ALL
select A='5',B='J',C='2013' UNION ALL
select A='1',B='K',C='2012' UNION ALL
select A='2',B='L',C='2012' UNION ALL
select A='3',B='M',C='2012' UNION ALL
select A='4',B='N',C='2012' UNION ALL
select A='5',B='P',C='2012'
update a set b=b.B
from #list a
inner join (select * from #list where c='2014') b on a.a=b.A
where a.C='2012'
select * from #list
/*
A B C
---- ---- ----
1 A 2014
2 B 2014
3 C 2014
4 D 2014
5 E 2014
1 F 2013
2 G 2013
3 H 2013
4 I 2013
5 J 2013
1 A 2012
2 B 2012
3 C 2012
4 D 2012
5 E 2012
(15 行受影响)
*/
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版主本版专家分：96989
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--测试数据
if not object_id(N'Tempdb..#T') is null
drop table #T
Go
Create table #T([A] int,[B] nvarchar(21),[C] NVARCHAR(20))
Insert #T
select 1,N'A','2014' union all
select 2,N'B','2014' union all
select 3,N'C','2014' union all
select 4,N'D','2014' union all
select 5,N'E','2014' union all
select 1,N'F','2013' union all
select 2,N'G','2013' union all
select 3,N'H','2013' union all
select 4,N'I','2013' union all
select 5,N'J','2013' union all
select 1,N'K','2012' union all
select 2,N'L','2012' union all
select 3,N'M','2012' union all
select 4,N'N','2012' union all
select 5,N'P','2012'
Go
--测试数据结束
--更新语句
UPDATE t1
SET T1.B = T2.B
FROM #T t1,
#T t2
WHERE t1.C = '2012'
AND t2.C = '2014'
AND t1.A = t2.A;
--测试结果
SELECT * FROM #T
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本版专家分：41
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都正确，感谢大大