使用其他兩個表的更新表

Question

我有三個表t1，t2和t3。

我要的是更新表t1與t1.Quantity= sum(t2.quantity) - sum(t3.quantity) where id= $_POST['id']

如何寫入查詢這一點。

我試過這個..但它不工作。

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

五月它有助於

UPDATE表1，表2 SET table1.column1 = （ SELECT SUM（ （SELECT FROM表3常數）+ （SELECT table2.sum_number *** WHERE表2。 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

試試這個

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