mysql - 更新表列 Where

Question

我有productinfo桌子和product_temp桌子。我想更新UpdateDate表productinfo的字段productinfo.ProductID = productinfo_temp.ProductID

但是下面的代码不起作用。

UPDATE productinfo a 
SET UpdateDate = productinfo_temp.UpdateDate 
    WHERE EXISTS(SELECT NULL FROM productinfo_temp b WHERE a.ProductID = b.ProductID)

Answer 1

采用UPDATE with JOIN

UPDATE  productinfo a  
        INNER JOIN productinfo_temp b
            ON a.ProductID = b.ProductID
SET     a.UpdateDate = b.UpdateDate 

Answer 2

试试这个

UPDATE productinfo a JOIN productinfo_temp b ON a.ProductID = b.ProductID
SET a.UpdateDate = b.UpdateDate