SQL Server 2017

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

CREATE TABLE dbo.YourTable (W_ID int NOT NULL,
							Title varchar(3) NOT NULL,
							Parent_id int NULL,
							View_Parent_id varchar(100) NULL);
INSERT INTO dbo.YourTable
VALUES (1,'AAA',NULL,NULL),
	   (2,'BV',1,'1'),
	   (3,'CX',2,'1+2'),
	   (4,'DSO',2,'1+2'),
	   (5,'ER',3,'1+2+3'),
	   (6,'ER',5,'1+2+3+5');
6 rows affected

SELECT *
FROM dbo.YourTable;


W_ID
Title
Parent_id
View_Parent_id


1
AAA
null
null

2
BV
1
1

3
CX
2
1+2

4
DSO
2
1+2

5
ER
3
1+2+3

6
ER
5
1+2+3+5


WITH rCTE AS(
	SELECT (YT.W_ID + 99) AS ID,
		   YT.W_ID		,
		   YT.Parent_id,
		   Title AS level_1,
		   CONVERT(varchar(3),NULL) AS Level_2,
		   CONVERT(varchar(3),NULL) AS Level_3,
		   CONVERT(varchar(3),NULL) AS Level_4,
		   CONVERT(varchar(3),NULL) AS Level_5,
		   CONVERT(varchar(3),NULL) AS Level_6,
		   CONVERT(varchar(3),NULL) AS Level_7,
		   CONVERT(varchar(3),NULL) AS Level_8,
		   CONVERT(varchar(3),NULL) AS Level_9,
		   CONVERT(varchar(3),NULL) AS Level_10,
		   CONVERT(varchar(3),NULL) AS Level_11,
		   CONVERT(varchar(3),NULL) AS Level_12,
		   CONVERT(varchar(3),NULL) AS Level_13,
		   CONVERT(varchar(3),NULL) AS Level_14,
		   CONVERT(varchar(3),NULL) AS Level_15,
		   1 AS [Level]
	FROM dbo.YourTable YT
	WHERE YT.Parent_id IS NULL
	UNION ALL
	SELECT (YT.W_ID + 99) AS ID,
		   YT.W_ID,
		   YT.Parent_id,
		   r.Level_1,
		   CASE r.[Level] WHEN 1 THEN YT.Title ELSE r.Level_2 END AS Level_2,
		   CASE r.[Level] WHEN 2 THEN YT.Title ELSE r.Level_3 END AS Level_3,
		   CASE r.[Level] WHEN 3 THEN YT.Title ELSE r.Level_4 END AS Level_4,
		   CASE r.[Level] WHEN 4 THEN YT.Title ELSE r.Level_5 END AS Level_5,
		   CASE r.[Level] WHEN 5 THEN YT.Title ELSE r.Level_6 END AS Level_6,
		   CASE r.[Level] WHEN 6 THEN YT.Title ELSE r.Level_7 END AS Level_7,
		   CASE r.[Level] WHEN 7 THEN YT.Title ELSE r.Level_8 END AS Level_8,
		   CASE r.[Level] WHEN 8 THEN YT.Title ELSE r.Level_9 END AS Level_9,
		   CASE r.[Level] WHEN 9 THEN YT.Title ELSE r.Level_10 END AS Level_10,
		   CASE r.[Level] WHEN 10 THEN YT.Title ELSE r.Level_11 END AS Level_11,
		   CASE r.[Level] WHEN 11 THEN YT.Title ELSE r.Level_12 END AS Level_12,
		   CASE r.[Level] WHEN 12 THEN YT.Title ELSE r.Level_13 END AS Level_13,
		   CASE r.[Level] WHEN 13 THEN YT.Title ELSE r.Level_14 END AS Level_14,
		   CASE r.[Level] WHEN 14 THEN YT.Title ELSE r.Level_15 END AS Level_15,
		   r.[Level] + 1 AS [Level]
	FROM dbo.YourTable YT
		 JOIN rCTe r ON YT.Parent_id = r.W_ID)
SELECT r.ID,
	   r.W_ID,
	   r.Parent_id,
	   r.Level_1,
	   r.Level_2,
	   r.Level_3,
	   r.Level_4,
	   r.Level_5,
	   r.Level_6,
	   r.Level_7,
	   r.Level_8,
	   r.Level_9,
	   r.Level_10,
	   r.Level_11,
	   r.Level_12,
	   r.Level_13,
	   r.Level_14,
	   r.Level_15
FROM rCTE r;


ID
W_ID
Parent_id
Level_1
Level_2
Level_3
Level_4
Level_5
Level_6
Level_7
Level_8
Level_9
Level_10
Level_11
Level_12
Level_13
Level_14
Level_15


100
1
null
AAA
null
null
null
null
null
null
null
null
null
null
null
null
null
null

101
2
1
AAA
BV
null
null
null
null
null
null
null
null
null
null
null
null
null

102
3
2
AAA
BV
CX
null
null
null
null
null
null
null
null
null
null
null
null

103
4
2
AAA
BV
DSO
null
null
null
null
null
null
null
null
null
null
null
null

104
5
3
AAA
BV
CX
ER
null
null
null
null
null
null
null
null
null
null
null

105
6
5
AAA
BV
CX
ER
ER
null
null
null
null
null
null
null
null
null
null

ID	W_ID	Parent_id	Level_1	Level_2	Level_3	Level_4	Level_5	Level_6	Level_7	Level_8	Level_9	Level_10	Level_11	Level_12	Level_13	Level_14	Level_15
100	1	null	AAA	null	null	null	null	null	null	null	null	null	null	null	null	null	null
101	2	1	AAA	BV	null	null	null	null	null	null	null	null	null	null	null	null	null
102	3	2	AAA	BV	CX	null	null	null	null	null	null	null	null	null	null	null	null
103	4	2	AAA	BV	DSO	null	null	null	null	null	null	null	null	null	null	null	null
104	5	3	AAA	BV	CX	ER	null	null	null	null	null	null	null	null	null	null	null
105	6	5	AAA	BV	CX	ER	ER	null	null	null	null	null	null	null	null	null	null