执行时，SQL触发器不会运行

Question

我编写了一个SQL触发器，首先验证项目是否具有折扣价格，如果不是则必须引发错误。触发器的第二部分需要检查文档的日期并确保该项目未过期。我的触发器会同时执行一个但不能同时执行两个操作。任何人都可以提供协助，我的代码如下。

SELECT @DocType = DocType, @OrderDate = OrderDate, @InvDate = InvDate 
FROM InvNum 
WHERE AutoIndex = @Invoice

SELECT @DocState = DocState 
FROM InvNum 
WHERE AutoIndex = @Invoice

SELECT @Account = AccountID 
FROM InvNum 
WHERE AutoIndex = @Invoice

SELECT  @Valid = iStockCodeID 
FROM _btblInvoiceLines 
LEFT JOIN InvNum ON iInvoiceID = AutoIndex 
LEFT JOIN _etblVDAR ON iARAPID = AccountID 
LEFT JOIN _etblVDLnAR ON iVDID = IDVD
WHERE iStockID = @StockCode AND iARAPID = @Account

SELECT  @ValidPO = iStockCodeID 
FROM _btblInvoiceLines 
LEFT JOIN InvNum ON iInvoiceID = AutoIndex 
LEFT JOIN _etblVDAP ON iARAPID = AccountID 
LEFT JOIN _etblVDLnAP ON iVDID = IDVD
WHERE iStockID = @StockCode AND iARAPID = @Account

select @dExpDate=dexpdate 
from _btblInvoiceLines 
inner join _etblVDLnAR on _btblInvoiceLines.iStockCodeID = _etblVDLnAR.iStockID 
where _btblInvoiceLines.iStockCodeID = iStockCodeID
-- BEGIN
--  IF (@DocType = 4 OR @DocType = 1) AND @DocState <> 7
--  BEGIN
--   IF @Module = 0 AND @Valid IS NULL 
--   BEGIN
--    RAISERROR ('Message from Management: 
--You are not allowed to select an item for which no Volume Discount Price has been entered for this customer.
--The transaction will be rolled back. ', 16, 1)
--    ROLLBACK TRANSACTION
--    End
IF (@DocType = 4  AND @DocState IN (0,1,2,3)) AND @OrderDate>=@dExpDate
BEGIN
    RAISERROR ('Message from Management: 
Please check expiry date! . ', 16, 1)
ROLLBACK TRANSACTION
END    
END
END
END