sql更新不起作用

Question

This works

SELECT * FROM productinfo a 
WHERE NOT EXISTS(SELECT NULL 
                FROM productinfo_temp b 
                            WHERE a.ProductID = b.ProductID)

However, it would like to update productinfo table from that result

UPDATE a SET Deleted = '1' FROM productinfo a 
    WHERE NOT EXISTS(SELECT NULL 
                    FROM productinfo_temp b 
                                WHERE a.ProductID = b.ProductID)

But it does not works. What is wrong with UPDATE? Here is error

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FROM productinfo a WHERE NOT EXISTS(SELECT NULL FROM productinfo' at line 1

Answer 1

Try:

UPDATE productinfo a SET Deleted = '1'
    WHERE NOT EXISTS(SELECT NULL 
                    FROM productinfo_temp b 
                                WHERE a.ProductID = b.ProductID)

Answer 2

remove FROM clause.

 
 
 
 
  
  
  UPDATE productinfo a SET Deleted = '1' WHERE NOT EXISTS(SELECT NULL FROM productinfo_temp b WHERE a.ProductID = b.ProductID)
 
 
  

or simply use this one using LEFT JOIN

 UPDATE productinfo a LEFT JOIN productinfo_temp b ON a.ProductID = b.ProductID SET a.Deleted = 1 WHERE b.ProductID IS NULL 

Answer 3

I'm getting in too!

UPDATE a SET Deleted = '1'
WHERE NOT EXISTS(SELECT NULL 
FROM productinfo_temp  b
WHERE a.ProductID = b.ProductID)