使用其他兩個表更新表

Question

我有三個表t1 ， t2和t3 。

我想要的是用t1.Quantity= sum(t2.quantity) - sum(t3.quantity) where id= $_POST['id']更新表t1 ， t1.Quantity= sum(t2.quantity) - sum(t3.quantity) where id= $_POST['id']

如何為此寫查詢。

我嘗試了這個..但是沒有用。

 INSERT INTO Products
   ( `ProductID`, `ProductName`, `TotalQuantity`,
     `TotalPrice`, `DateOfLastupdate` )
 values
  ( '$ProductID', '$ProductName', '$Quantity',
    '$TotalPrice', '$PurchaseDate' )
 ON DUPLICATE KEY
   UPDATE Products.TotalQuantity =
     ( select sum(Products_Purchased.Quantity) from Products_Purchased
       where ProductID = '$ProductID' )
     - ( select sum(Products_Sold.Quantity) from Products_Sold 
           where ProductID = '$ProductID' )

Answer 1

可能有幫助

更新table1，table2 SET table1.column1 =（SELECT SUM（（來自table3的SELECT常量）+（SELECT table2.sum_number *** WHERE table2.table2_id1 = table1.id）））WHERE table1.id = table2.table2_id1;

UPDATE table1 SET column1 =（SUM（table2 {＆table3} WHERE table2_id1 = id1）WHERE id1 = table2_id1

Answer 2

嘗試這個

update products t1,
(select productid,sum(Products_Purchased.Quantity) as x from Products_Purchased
   group by productid having ProductID = '$ProductID' ) t2,
(select productid,sum(Products_Sold.Quantity) as y from Products_Sold 
   group by productid having ProductID = '$ProductID' ) t3
 set TotalQuantity=t2.x-t3.y where t1.ProductID = '$ProductID' 
      and t1.productid=t2.productid and t1.productid=t3.productid