联表更新问题
有以下两表（部分数据）：
表PURTH
TH001TH002 TH054
34012011060038 200.000000
34012011060039 5000.000000
34012011060044 3000.000000
34012011060045 50.000000
34012011070001 1.000000
34012011060026 10000.000000
34982011060004 56.100000
34982011060005 10150.000000
表ACPTB
TB005TB006
34982011100014
34982012010002
34982011120007
34982012020001
34982012020001
34982011100015
34982011110010
34982011120006
现要更新表PURTH中字段TH054为0，条件是TH001和TH002联合时，不在表ACPTB中的TB005和TB006的联合,因为TH001和TH002组合在一起才是唯一，分开了就都不是唯一值
[解决办法]
--我改了一条数据declare @PURTH table (TH001 int,TH002 int,TH054 numeric(11,6))insert into @PURTHselect 3401,2011060038,200.000000 union allselect 3401,2011060039,5000.000000 union allselect 3401,2011060044,3000.000000 union allselect 3401,2011060045,50.000000 union allselect 3401,2011070001,1.000000 union allselect 3401,2011060026,10000.000000 union allselect 3498,2011060004,56.100000 union allselect 3498,2011060005,10150.000000declare @ACPTB table (TB005 int,TB006 int)insert into @ACPTBselect 3401,2011060038 union allselect 3498,2012010002 union allselect 3498,2011120007 union allselect 3498,2012020001 union allselect 3498,2012020001 union allselect 3498,2011100015 union allselect 3498,2011110010 union allselect 3498,2011120006update @PURTH set TH054=0 from @PURTH a left join @ACPTB bon a.TH001=b.TB005 and a.TH002=b.TB006 where b.TB005 is nullselect * from @PURTH/*TH001 TH002 TH054----------- ----------- ---------------------------------------3401 2011060038 200.0000003401 2011060039 0.0000003401 2011060044 0.0000003401 2011060045 0.0000003401 2011070001 0.0000003401 2011060026 0.0000003498 2011060004 0.0000003498 2011060005 0.000000*/
