使用新条目更新列

Question

我创建了一个包含以下属性的表：

VendorAccount(
  Ven_AccountId, 
  Ven_RegNo,   
  Ven_TxDate,   
  Ven_Invoice_RefNo,    
  TotalAmount,
  Paid_ToVen ,    
  Balance
)

在上表中，当我从POP up LOV中选择Ven_Invoice_RefNo时，它会从另一个表中提供TotalAmount。每当我在Paid_ToVen列中输入该值时，我都希望这样应从Total_Amount中减去Balance，新的减去值应显示在下一个条目的TotalBalance列中。以下是该表的报告。

我想在新条目的TotalAmount列中更新值i-e 2300。是否有任何触发或查询。

Answer 1

您可以在更新后尝试trigger。您将需要如下逻辑。请根据您的表格使用正确的字段并进行试用。

CREATE TRIGGER trg_totalBalance AFTER UPDATE ON vendoraccount
FOR EACH ROW
BEGIN
  DECLARE new_balance INT;
  DECLARE new_total INT;
  DECLARE new_paid INT;

   SELECT balance INTO old_balance, 
   total INTO old_total,
   paidtoven INTO new_paid 
   FROM vendoraccount
   WHERE ven_regno = new.ven_regno
   AND ven_invoice_refno = new.ven_invoice_refno;

   -- depending on your current balance update logic,
   --  you could wrap this update with an IF/ELSE
   -- IF XYZ THEN
   UPDATE vendoraccount SET totalamount = old_total + old_balance - new_paid,
   balance = totalamount - new_paid
   WHERE ven_regno = new.ven_regno
   AND ven_invoice_refno = new.ven_invoice_refno;
   -- END IF;
END;