Sql server 使用declare和set变量创建存储过程

我正在创建一个存储过程，其中只需传递值，并且必须从多个表中检索多个值。我试着这样做，但它显示错误如下

靠近开始的语法不正确

及

必须声明标量变量@OrderID

---

我想你想把订单ID传进来。因此：

CREATE PROCEDURE [dbo].[Procedure_Name]
(
    @OrderID INT
) AS
BEGIN
    Declare @OrderItemID AS INT
    DECLARE @AppointmentID AS INT
    DECLARE @PurchaseOrderID AS INT
    DECLARE @PurchaseOrderItemID AS INT
    DECLARE @SalesOrderID AS INT
    DECLARE @SalesOrderItemID AS INT

    SET @OrderItemID = (SELECT OrderItemID FROM [OrderItem] WHERE OrderID = @OrderID)
    SET @AppointmentID = (SELECT AppoinmentID FROM [Appointment] WHERE OrderID = @OrderID)
    SET @PurchaseOrderID = (SELECT PurchaseOrderID FROM [PurchaseOrder] WHERE OrderID = @OrderID)
END

---

您应该尝试此语法-假设希望将

@OrderID

作为存储过程的参数：

CREATE PROCEDURE dbo.YourStoredProcNameHere
   @OrderID INT
AS
BEGIN
 DECLARE @OrderItemID AS INT
 DECLARE @AppointmentID AS INT
 DECLARE @PurchaseOrderID AS INT
 DECLARE @PurchaseOrderItemID AS INT
 DECLARE @SalesOrderID AS INT
 DECLARE @SalesOrderItemID AS INT

 SELECT @OrderItemID = OrderItemID 
 FROM [OrderItem] 
 WHERE OrderID = @OrderID

 SELECT @AppointmentID = AppoinmentID 
 FROM [Appointment] 
 WHERE OrderID = @OrderID

 SELECT @PurchaseOrderID = PurchaseOrderID 
 FROM [PurchaseOrder] 
 WHERE OrderID = @OrderID

END

---

当然，只有当您只返回一个值（而不是多个值！）时，这才有效。

哪里声明了

@OrderID

？请发布整个过程，您发布的代码中没有

BEGIN

。还有，为什么你给变量赋值，却从不在任何地方使用结果？这些应该是输出参数吗？因为我假设一个订单可能有许多订单项、约会或采购订单，您能描述一下要分配给变量的参数吗？按照@Martin的建议发布所有代码，以及发布您的实际目标、一些示例数据和期望的结果，也可能会有所帮助。我不知道，我想这是个人偏好，但使用

SET

更清楚，尤其是对于单个值。否则，它将隐藏在整个

SELECT

语句中。另一方面，您的结果是未定义的，因为您使用了

TOP

，而没有

ORDER BY

——它将拾取任意行。我更愿意省略

顶部

——这样，如果您的意思是内部查询只选择一行，否则会出现错误。使用

SELECT@OrderItemID=

或

top1

方法，可以静默地获取任意行。对于

OrderID

是主键的情况，这是一回事，但在其他情况下，我认为我们需要更好地定义实际需要哪个AppointmentID/PurchaseOrderID。老大？最近的？价值最高的那个？

CREATE PROCEDURE dbo.YourStoredProcNameHere
   @OrderID INT
AS
BEGIN
 DECLARE @OrderItemID AS INT
 DECLARE @AppointmentID AS INT
 DECLARE @PurchaseOrderID AS INT
 DECLARE @PurchaseOrderItemID AS INT
 DECLARE @SalesOrderID AS INT
 DECLARE @SalesOrderItemID AS INT

 SELECT @OrderItemID = OrderItemID 
 FROM [OrderItem] 
 WHERE OrderID = @OrderID

 SELECT @AppointmentID = AppoinmentID 
 FROM [Appointment] 
 WHERE OrderID = @OrderID

 SELECT @PurchaseOrderID = PurchaseOrderID 
 FROM [PurchaseOrder] 
 WHERE OrderID = @OrderID

END