带有 CTE 的存储过程语法

Question

这可能是微不足道的，但我只是在学习 CTE（感谢这里的帮助）。

我有一个用于确定总数的程序。

第一部分是总计是其级别以下位置的总和。因此，我需要一种方法来检索记录，该方法 (1) 确定记录的级别（层次结构）并且 (2) 返回所有记录及其以下的记录。有人问并回答了here。

现在想从上面的答案中获取 CTE 表，并在我的程序的第二部分使用它（获取总数）

CREATE PROCEDURE [dbo].[GetProgramTotals]
    @programId nvarchar(10) = null,
    @owner int = null,
    @totalAmount money OUT,
    @usedAmount money OUT,
    @remainingAmount money OUT
AS
BEGIN
    WITH rCTE AS
    (
        SELECT 
            *, 0 AS Level 
        FROM Forecasting.dbo.Addressbook 
        WHERE Addressbook = @owner

        UNION ALL

        SELECT
            t.*, r.Level + 1 AS Level
        FROM Addressbook t
        INNER JOIN rCTE r ON t.ParentAddressbook = r.Addressbook
    )

    Select @totalAmount = (Select Sum(Amount) from dbo.Budget where 
                                (@programId IS NULL or (ProgramId = @programId)) and (@owner IS NULL or (BudgetOwner in (SELECT Addressbook from rCTE))))


    Select @usedAmount = (Select Sum(SubTotal) from dbo.OrderLine where 
                                (@programId IS NULL or (ProgramId = @programId) and (@owner IS NULL) or (Budget in (SELECT Addressbook from rCTE))))

    if (@totalAmount is null)
        set @totalAmount = 0

    if (@usedAmount is null)
        set @usedAmount = 0

    Set @remainingAmount = (@totalAmount - @usedAmount)
END

此过程的想法是根据用户在层次结构中的位置动态计算单个（或所有）程序。

因此，区域经理总数将是所有地区和地区代表的总和。

更新：我根据下面的 squillman（谢谢）评论更新了这个。

现在我有一个不同的问题。当我执行 proc - 我得到“无效的对象名称 rCTE”。

Answer 1

您不能在这样的查询中间使用SET。将其更改为SELECT，它应该可以纠正您的语法错误。

CREATE PROCEDURE [dbo].[GetProgramTotals]
    @programId nvarchar(10) = null,
    @owner int = null,
    @totalAmount money OUT,
    @usedAmount money OUT,
    @remainingAmount money OUT
AS
BEGIN
    WITH rCTE AS(
    SELECT *, 0 AS Level FROM Forecasting.dbo.Addressbook WHERE Addressbook = @owner
    UNION ALL
    SELECT t.*, r.Level + 1 AS Level
    FROM Addressbook t
    INNER JOIN rCTE r ON t.ParentAddressbook = r.Addressbook)

    SELECT @totalAmount = (Select Sum(Amount) from dbo.Budget where 
                                (@programId IS NULL or (ProgramId = @programId)) and (@owner IS NULL or (BudgetOwner in (SELECT Addressbook from rCTE))))



    , @usedAmount = (Select Sum(SubTotal) from dbo.OrderLine where 
                                (@programId IS NULL or (ProgramId = @programId) and (@owner IS NULL) or (Budget in (SELECT Addressbook from rCTE))))

    if (@totalAmount is null)
        set @totalAmount = 0

    if (@usedAmount is null)
        set @usedAmount = 0

    Set @remainingAmount = (@totalAmount - @usedAmount)

END

一开始 CTE 可能会有点令人困惑，但一旦它们变得有意义，它们就会变得非常简单。对我来说，当我开始将它们视为另一种临时表语法时，它点击了（专业提示：它们不在现实中，只是在概念上）。所以基本上：

1. 创建一个或多个“临时表”。这些是您的 CTE 表达式，可能不止一个。
2. 使用紧跟 CTE 的语句中的一个或多个 CTE 表达式执行标准操作。

正如 Martin 在下面的 cmets 中提到的，CTE(s) 仅适用于下一个直接语句，并且在此之后超出范围。

所以，

;WITH cte1 AS
       (
        SELECT Col1 FROM Table1
       ),
      cte2 AS
       (
        SELECT Col1 FROM Table2
       )
SELECT Col1 FROM cte1 //In scope here
UNION
SELECT Col1 FROM cte1; //Still in scope since we're still in the first statement

SELECT Col1 FROM cte1; //Fails.  cte1 is now out of scope (as is cte2) 

在您的情况下，您使用递归 CTE 来形成父/子层次结构，然后根据结果设置变量。编辑后您的 CTE 语法非常接近，您只需要用逗号将内容重新组合到一个语句中。

//Variable assignment example
;WITH cte1 AS
       (
        SELECT Col1 FROM Table1
       ),
      cte2 AS
       (
        SELECT Col1 FROM Table2
       )
SELECT @var1 = (SELECT TOP 1 Col1 FROM cte1)
      ,@var2 = (SELECT TOP 1 Col1 FROM cte2) //You're missing the comma at the start of this line

将Select @usedAmount=... 更改为, @usedAmount=...