Question

INSERT INTO SaleItem (ProdId, SaleQuantity)
SELECT ProdId, BasketProdQuantity FROM Basket;

CREATE TRIGGER TRG_Stock_Decrease
    ON SaleItem
AFTER INSERT
AS
DECLARE @ProdId INT
DECLARE @SaleQuantity INT
SELECT @ProdId=ProdId,@SaleQuantity=SaleQuantity FROM inserted
UPDATE Product SET ProdStockQuantity=ProdStockQuantity-@SaleQuantity WHERE ProdId=@ProdId
UPDATE Product SET ProdNoOfSold =ProdNoOfSold+@SaleQuantity WHERE ProdId=@ProdId
DELETE FROM Basket Where ProdId = @ProdId

当我将数据从Basket插入SaleItem时，它运行良好，但触发仅适用于插入的第一个id。如何让它适用于所有ID？

EDIT！我像这样改变了我的触发器，我猜它有点工作。

CREATE TRIGGER TRG_Stock_Decrease
    ON SaleItem
AFTER INSERT
AS
BEGIN
UPDATE Product SET ProdStockQuantity = ProdStockQuantity - (Select SaleQuantity From inserted Where Product.ProdId = inserted.ProdId ) Where Product.ProdId IN (Select ProdId From inserted)
UPDATE Product SET ProdNoOfSold =ProdNoOfSold + (Select SaleQuantity From inserted Where Product.ProdId = inserted.ProdId ) Where Product.ProdId IN (Select ProdId From inserted)
DELETE FROM Basket WHERE Basket.ProdId IN (Select ProdId From inserted)
END

这是对的吗？

Answer 1

不需要每行或嵌套选择，只需要插入内部连接：）

CREATE TRIGGER TRG_Stock_Decrease
    ON SaleItem
AFTER INSERT
AS
    UPDATE P 
    SET ProdStockQuantity=ProdStockQuantity-i.SaleQuantity,
        ProdNoOfSold =ProdNoOfSold+i.SaleQuantity 
    FROM Product P
    INNER JOIN inserted i
        ON P.ProdId=i.ProdId


    DELETE B
    FROM Basket B
    INNER JOIN inserted i
        ON i.ProdId = B.ProdId

Answer 2

添加 FOR EACH ROW

DROP TRIGGER `TRG_Stock_Decrease`;
DELIMITER //

CREATE TRIGGER TRG_Stock_Decrease
AFTER INSERT ON `TABLE` FOR EACH ROW
BEGIN
  DECLARE @ProdId INT;
  DECLARE @SaleQuantity INT;
  SELECT @ProdId=ProdId,@SaleQuantity=SaleQuantity FROM inserted;
  UPDATE Product SET ProdStockQuantity=ProdStockQuantity-@SaleQuantity WHERE ProdId=@ProdId;
  UPDATE Product SET ProdNoOfSold =ProdNoOfSold+@SaleQuantity WHERE ProdId=@ProdId;
  DELETE FROM Basket Where ProdId = @ProdId;
END; //

DELIMITER ;

从表插入到另一个表并激活触发器

2 个答案: