使用SQL CTE表包括

Question

我有以下層次樹表

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 

映射到下面的樹

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

使用CTE遞歸表，我怎麼能得到的路徑和路徑，所有的孩子也是選定節點的所有子節點。例如，具有2作爲輸入，我怎麼能得到以下數據（有序如果可能的話）

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

我知道我可以在樹遍歷了（得到的路徑）與下面的語句

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 

並與下面的語句，在樹向下遍歷（讓所有的孩子）

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 

問題：如何結合這兩個命令變成一個？

Answer 1

只需使用這兩種選擇

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