Question

在earlier post中，我构建了一个在SO贡献者的帮助下使用CTE的SQL。我现在想将SQL封装在一个用户定义的函数中，该函数返回一个表，但我收到的错误如下。

以下是代码：

Alter FUNCTION GetDescendentSteps 
(   
@StepId INT 
)
RETURNS TABLE 
AS
RETURN
    ;WITH cteRecursion
         AS (SELECT
                 StepId
                 ,1 AS Level
             FROM
                 Step
             WHERE
                 StepId = @StepId
             UNION ALL
             SELECT
                 t.StepId
                 ,c.Level + 1
             FROM
                 Step t
                 INNER JOIN cteRecursion c
                     ON t.ParentStepId = c.StepId
            )
    SELECT
        StepId,Level
    FROM
        cteRecursion
    ORDER BY
        Level,
        StepId;

我收到错误：

Msg 102, Level 15, State 1, Procedure GetDescendentSteps, Line 8
Incorrect syntax near ';'.

注意第8行是：

;WITH cteRecursion

..如果我只执行从第8行开始的SQL（在我用文字替换变量@StepId之后）。

此外，这个简单的例子有效：

ALTER FUNCTION GetDescendentSteps 
(   
@StepId INT 
)

RETURNS TABLE 

AS
RETURN
select 7 As Stepid,1 As Level

Answer 1

删除第一个;和order by子句。

Alter FUNCTION GetDescendentSteps 
(   
@StepId INT 
)
RETURNS TABLE 
AS
RETURN
    WITH cteRecursion
         AS (SELECT
                 StepId
                 ,1 AS Level
             FROM
                 Step
             WHERE
                 StepId = @StepId
             UNION ALL
             SELECT
                 t.StepId
                 ,c.Level + 1
             FROM
                 Step t
                 INNER JOIN cteRecursion c
                     ON t.ParentStepId = c.StepId
            )
    SELECT
        StepId,Level
    FROM
        cteRecursion

将CTE SELECT更改为用户定义的表值函数

1 个答案: