使用SQL CTE表包括

Question

我有以下层次树表

GO 
DROP TABLE #tbl 
GO 
CREATE TABLE #tbl (Id int , ParentId int) 
INSERT INTO #tbl (Id, ParentId) VALUES (0, NULL) 
INSERT INTO #tbl (Id, ParentId) VALUES (1, 0) 
INSERT INTO #tbl (Id, ParentId) VALUES (2, 1) 
INSERT INTO #tbl (Id, ParentId) VALUES (3, 1) 
INSERT INTO #tbl (Id, ParentId) VALUES (4, 2) 
INSERT INTO #tbl (Id, ParentId) VALUES (5, 2) 
INSERT INTO #tbl (Id, ParentId) VALUES (6, 3) 
INSERT INTO #tbl (Id, ParentId) VALUES (7, 3) 
GO 

映射到下面的树

0 
+- 1 
    +- 2 
     +- 4 
     +- 5 
    +- 3 
     +- 6 
     +- 7 

使用CTE递归表，我怎么能得到的路径和路径，所有的孩子也是选定节点的所有子节点。例如，具有2作为输入，我怎么能得到以下数据（有序如果可能的话）

Id, ParentID 
------- 
0, NULL 
1, 0 
2, 1 
4, 2 
5, 2 

我知道我可以在树遍历了（得到的路径）与下面的语句

WITH RecursiveTree AS (
    -- Anchor 
    SELECT * 
     FROM #tbl 
     WHERE Id = 2 
    UNION ALL 
     -- Recursive Member 
     SELECT Parent.* 
     FROM 
      #tbl AS Parent 
      JOIN RecursiveTree AS Child ON Child.ParentId = Parent.Id 
) 
SELECT * FROM RecursiveTree 

并与下面的语句，在树向下遍历（让所有的孩子）

WITH RecursiveTree AS (
    -- Anchor 
    SELECT * 
     FROM #tbl 
     WHERE Id = 2 
    UNION ALL 
     -- Recursive Member 
     SELECT Child.* 
     FROM 
      #tbl AS Child 
      JOIN RecursiveTree AS Parent ON Child.ParentId = Parent.id 
) 
SELECT * FROM RecursiveTree 

问题：如何结合这两个命令变成一个？

Answer 1

只需使用这两种选择

SQLFiddle demo

WITH RecursiveTree AS (
    -- Anchor 
    SELECT * 
     FROM #tbl 
     WHERE Id = 2 
    UNION ALL 
     -- Recursive Member 
     SELECT Parent.* 
     FROM 
      #tbl AS Parent 
      JOIN RecursiveTree AS Child ON Child.ParentId = Parent.Id 
), 
RecursiveTree2 AS 
(
    -- Anchor 
    SELECT * 
     FROM #tbl 
     WHERE Id = 2 
    UNION ALL 
     -- Recursive Member 
     SELECT Child.* 
     FROM 
      #tbl AS Child 
      JOIN RecursiveTree2 AS Parent ON Child.ParentId = Parent.id 
) 
select * from 
(
SELECT * FROM RecursiveTree 
union 
SELECT * FROM RecursiveTree2 
) t 
order by id