CTE parent-child showing siblings - sql

Question

I have a CTE-query that displays a tree using recursion. This works great when displaying the whole tree. But I want to pass in ID as a variable and include the siblings for each current node.
Testcode:
DECLARE #TT TABLE
(
ID int,
Name varchar(25),
ParentID int,
SortIndex int
)
INSERT #TT
SELECT 1, 'A', NULL, 1 UNION ALL
SELECT 2, 'B_1', 3, 1 UNION ALL
SELECT 3, 'B', 1, 2 UNION ALL
SELECT 4, 'B_2', 3, 2 UNION ALL
SELECT 5, 'C', 1, 3 UNION ALL
SELECT 6, 'C_2', 5, 2 UNION ALL
SELECT 7, 'A_1', 1, 1 UNION ALL
SELECT 8, 'A_2', 1, 2 UNION ALL
SELECT 9, 'C_1', 5, 1
;WITH CTETree
AS
(
SELECT *, CAST(NULL AS VARCHAR(25)) AS ParentName, 1 AS Lev,
CAST(ROW_NUMBER() OVER(ORDER BY SortIndex) AS VARBINARY(MAX)) AS SortPath
FROM #TT
WHERE ParentID IS NULL
UNION ALL
SELECT F.*, CTETree.Name AS ParentName, Lev + 1,
SortPath + CAST(ROW_NUMBER() OVER(ORDER BY F.SortIndex) AS BINARY(32))
FROM #TT AS F
INNER JOIN CTETree
ON F.ParentID = CTETree.ID
)
SELECT * FROM CTETree
ORDER BY SortPath
/*
DESIRED RESULT:
WHEN ID = 3 PASSED IN:
1 A NULL 1 NULL 1
3 B 1 2 A 2
2 B_1 3 1 B 3
4 B_2 3 2 B 3
5 C 1 3 A 2
WHEN ID = 1 PASSED IN:
1 A NULL 1 NULL 1
3 B 1 2 A 2
5 C 1 3 A 2
WHEN ID = 9 PASSED IN:
1 A NULL 1 NULL 1
3 B 1 2 A 2
5 C 1 3 A 2
9 C_1 5 1 C 3
6 C_2 5 2 C 3
*/
SQL-Fiddle: http://sqlfiddle.com/#!3/d41d8/5526

Answer 1

Only in once I confront a question where disappear A_1 and A_2. Therefore add in exception(in case clause).
If you need this records delete this expression AND f.ID != 7 AND f.ID != 8.
DECLARE #ID int = 3 -- variable wich you want pass
DECLARE #Matched int = (SELECT CASE WHEN ParentID = 1 THEN ID ELSE ParentID END FROM #TT WHERE ID = #ID)
;WITH CTETree
AS
(
SELECT *, CAST(NULL AS VARCHAR(25)) AS ParentName, 1 AS Lev,
CAST(ROW_NUMBER() OVER(ORDER BY SortIndex) AS VARBINARY(MAX)) AS SortPath,
0 AS Matched
FROM #TT
WHERE ParentID IS NULL
UNION ALL
SELECT F.*, cte.Name AS ParentName, cte.Lev + 1,
SortPath + CAST(ROW_NUMBER() OVER(ORDER BY F.SortIndex) AS BINARY(32)),
CASE WHEN (cte.ID = 1 AND f.ID != 7 AND f.ID != 8)
OR (cte.ID = #Matched AND cte.Lev + 1 > 2)
THEN 1 END AS Matched
FROM #TT AS F INNER JOIN CTETree cte
ON F.ParentID = cte.ID
)
SELECT ID, Name, ParentID, SortIndex, ParentName, Lev FROM CTETree
WHERE Matched IS NOT NULL
ORDER BY SortPath
Demo on SQLFiddle