如何在SQL中生成导致给定节点的层次结构路径？

在我的MS sql 2008 R2数据库中,我有这个表：

TABLE [Hierarchy]
[ParentCategoryId] [uniqueidentifier] NULL,[ChildCategoryId] [uniqueidentifier] NOT NULL

我需要编写一个查询来生成通向给定节点的所有路径.

让我们说我有以下树：

A
-B
--C
-D
--C

哪个将存储为：

NULL | A
A    | B
A    | D
B    | C
D    | C

在询问C的路径时,我想回到两条路径(写得更多或更少这样)：

A > B > C,A > D > C

解决方法

这是我的解决方案,Sql Fiddle

DECLARE @child VARCHAR(10) = 'C'

    ;WITH children AS
    (

       SELECT 
         ParentCategoryId,CAST(ISNULL(ParentCategoryId + '->','')  + ChildCategoryId AS VARCHAR(4000)) AS Path
       FROM Hierarchy
       WHERE ChildCategoryId =  @child
     UNION ALL
       SELECT 
         t.ParentCategoryId,list= CAST(ISNULL(t.ParentCategoryId  + '->','')  + d.Path AS VARCHAR(4000))
       FROM Hierarchy t
       INNER JOIN children  AS d
            ON t.ChildCategoryId = d.ParentCategoryId
     )

    SELECT Path 
    from children c
    WHERE ParentCategoryId IS NULL

输出：

A->D->C 
A->B->C

更新：

@AlexeiMalashkevich,为了获得身份证,你可以试试这个

SQL Fiddle

DECLARE @child VARCHAR(10) = 'C'

;WITH children AS
(

   SELECT 
     ParentCategoryId,ChildCategoryId  AS Path
   FROM Hierarchy
   WHERE ChildCategoryId =  @child
 UNION ALL
   SELECT 
     t.ParentCategoryId,d.ParentCategoryId 
   FROM Hierarchy t
   INNER JOIN children  AS d
        ON t.ChildCategoryId = d.ParentCategoryId
 )

SELECT disTINCT PATH
from children c