将CTE SELECT更改为表值用户定义函数

Question

在earlier post中，我构建了一个SQL，它在SO贡献者的帮助下使用CTE。我想现在将这个SQL封装在一个用户定义的函数中，该函数返回一个表，但是我得到下面的错误。

下面的代码：

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; 

我得到的错误：

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

注意，8号线是：

;WITH cteRecursion 

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

而且，这个简单的例子工程：

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条款。

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