update t3 set UnitPrice =taba.UnitPrice from (
select t2.ProductName ,t2.ProductModel,T2.UnitPrice-T1.UnitPrice as UnitPrice
from t2
left join t1 on t2.ProductName =t1.ProductName and t2.ProductModel=t1.ProductModel
) taba
where t3.ProductName =taba.ProductName and t3.ProductModel=taba.ProductModel
select t2.ProductName ,t2.ProductModel,T2.UnitPrice-T1.UnitPrice as UnitPrice
from t2
left join t1 on t2.ProductName =t1.ProductName and t2.ProductModel=t1.ProductModel
) taba
where t3.ProductName =taba.ProductName and t3.ProductModel=taba.ProductModel
解决方案 »
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