这句UPDATE的SQL该怎么写？
1、表 CompanyBgt 的数据结构是这样的：
fyearmonth branchid categoryid oborrb
其中，fyearmonth branchid categoryid为主健
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2、我需要把这张表中，fyearmonth从200704到200803的，channelid为“IT”的OBRORB数据全部替换成channelid是“DPIT”的数据 ？
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3、我试着写了一下，不知道是否正确，请各位看一下：
UPDATE CompanyBgt a
SET a.oborrb =(select oborrb from CompanyBgt b where
a.fyearmonth =b.fyearmonth
and a.branchid=b.branchid
and a.categoryid=b.categoryid
and b.channelid = 'DPIT ' and a.channelid= 'IT ')
where a.channelid= 'IT ' and a.Fyearmonth> = '200704 ' and a.Fyearmonth <= '200803
[解决办法]
可以用關聯寫
Update A Set OBRORB = B.OBRORB
From CompanyBgt A
Inner Join CompanyBgt B
On A.Fyearmonth = B.Fyearmonth And A.branchid = B.branchid And A.categoryid = B.categoryid
Where A.channelid = 'IT ' And B.channelid = 'DPIT ' And A.Fyearmonth Between '200704 ' And '200803 '
[解决办法]
update CompanyBgt set CompanyBgt.oborrb = c.oborrb from (select * from CompanyBgt b where b.channelid = 'DPIT ') c,CompanyBgt where
c.fyearmonth =CompanyBgt.fyearmonth
and c.branchid=CompanyBgt.branchid
and c.categoryid=CompanyBgt.categoryid
and CompanyBgt.channelid = 'IT ' and CompanyBgt.Fyearmonth between '200704 'and '200803 '
