SELECT  dbo.cj.cjid, dbo.xs.xsid AS xsxsid, dbo.xs.xuehao, dbo.cj.xsid
FROM  dbo.xs INNER JOIN
dbo.cj ON dbo.xs.xuehao = dbo.cj.xuehao

update dbo.cj set dbo.cj.xsid=xs.xsid
from dbo.xs
where dbo.xs.xuehao = dbo.cj.xuehao

------解决方案--------------------
update cj set cj.xsid=xs.xsid
FROM  dbo.xs INNER JOIN
dbo.cj ON dbo.xs.xuehao = dbo.cj.xuehao



------解决方案--------------------
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