如何从SQL数据库中的多个父类别中检索多个子类别

Question

我目前正在检索具有多个父类别及其子类别的费用类别，依此类推。为此，我使用通用表表达式来应用递归，但无法检索所需的结果。

这是我得到的结果

   CId                Tit                    Par
 ----------------------------------------------------------------
 D61D6C22             Electricity Bill       NULL
 52113021             Wire Bill              D61D6C22
 E34B6F68             Wireless Bill          D61D6C22
 41A35796             B category Bill        52113021
 D063745A             A category Bill        52113021

这是我使用的查询：

WITH cte1 AS 
(
    SELECT 
        Id AS [CId], Title as [Tit], ParentId as [Par],
        RN = ROW_NUMBER() OVER (ORDER BY Title)
    FROM 
        dbo.[ExpenseCategory] 
    WHERE
        ParentId IS NULL
    GROUP BY 
        Id, Title, ParentId

    UNION ALL

    SELECT 
        Id AS [CId], Title, ParentId, RN
    FROM 
        cte1
    INNER JOIN 
        dbo.[ExpenseCategory] ec ON cte1.[CId] = ec.ParentId
)
SELECT
    cte1.[CId], [Tit],[Par] 
FROM
    cte1   
ORDER BY
    RN ASC

   CId                Tit                    Par
 ----------------------------------------------------------------
 D61D6C22             Electricity Bill       NULL
 52113021             Wire Bill              D61D6C22
 41A35796             B category Bill        52113021
 D063745A             A category Bill        52113021
 E34B6F68             Wireless Bill          D61D6C22