Make query like treeview - sql-server

Question

Brothers can you help me? Thanks
Table A
Id Name IdParent
1 Operation Null
2 Developer 1
3 Android 2
4 IOS 2
Expectes result:
ID Name
1 +Operation
2 +------ Developer
3 +------------Android
4 +------------ IOS

Answer 1

By adding a sequence during the recursive build, you can easily create the proper presentation sequence and nesting
Declare #YourTable table (id int,IdParent int,Name varchar(50))
Insert into #YourTable values
( 1, NULL,'Operation')
,( 2, 1 ,'Developer')
,( 3, 2 ,'Android')
,( 4, 2 ,'IOS')
,( 5, 1 ,'Poet')
,( 6, 5 ,'Limerick')
,( 7, 5 ,'Haiku')
Declare #Top int = null --<< Sets top of Hier Try 2
Declare #Nest varchar(25) = '|-----' --<< Optional: Added for readability
;with cteP as (
Select Seq = cast(10000+Row_Number() over (Order by Name) as varchar(500))
,ID
,IdParent
,Lvl=1
,Name
From #YourTable
Where IsNull(#Top,-1) = case when #Top is null then isnull(IdParent ,-1) else ID end
Union All
Select Seq = cast(concat(p.Seq,'.',10000+Row_Number() over (Order by r.Name)) as varchar(500))
,r.ID
,r.IdParent
,p.Lvl+1
,r.Name
From #YourTable r
Join cteP p on r.IdParent = p.ID)
Select A.ID
,A.IdParent
,A.Lvl
,Name = Replicate(#Nest,A.Lvl-1) + A.Name
From ctep A
Order By A.Seq
Returns
ID IdParent Lvl Name
1 NULL 1 Operation
2 1 2 |-----Developer
3 2 3 |-----|-----Android
4 2 3 |-----|-----IOS
5 1 2 |-----Poet
7 5 3 |-----|-----Haiku
6 5 3 |-----|-----Limerick

Answer 2

Here's another version:
WITH RawData AS (
SELECT 1 AS Id, 'Operation' AS Name, CONVERT(INT, NULL) AS IdParent
UNION ALL
SELECT 2 AS Id, 'Developer' AS Name, 1 AS IdParent
UNION ALL
SELECT 3 AS Id, 'Android' AS Name, 2 AS IdParent
UNION ALL
SELECT 4 AS Id, 'IOS' AS Name, 2 AS IdParent),
Depth AS (
SELECT
Id,
1 AS depth,
IdParent
FROM
RawData
UNION ALL
SELECT
d.Id,
d.depth + 1,
r.IdParent
FROM
Depth d
INNER JOIN RawData r ON r.Id = d.IdParent),
MaxDepth AS (
SELECT
Id,
MAX(depth) AS depth
FROM
Depth
GROUP BY
Id)
SELECT
r.Id,
'+' + REPLICATE('----', m.depth - 1) + r.Name AS Name
FROM
RawData r
INNER JOIN MaxDepth m ON m.Id = r.Id;
Results:
Id Name
1 +Operation
2 +----Developer
3 +--------Android
4 +--------IOS

Answer 3

DECLARE #mockup TABLE(Id INT, Name VARCHAR(100), IdParent INT);
INSERT INTO #mockup VALUES
(1,'Operation',Null)
,(2,'Developer',1)
,(3,'Android',2)
,(4,'IOS',2);
--The query uses a recursive CTE and finally REPLICATE with the recursive level to add the number of hyphens...
WITH recCTE AS
(
SELECT Id, Name, 1 AS Lvl, CAST(REPLACE(STR(ROW_NUMBER() OVER (ORDER BY Id),5),' ','0') AS VARCHAR(MAX)) AS Seq
FROM #mockup
WHERE IdParent IS NULL
UNION ALL
SELECT m.Id,m.Name,r.Lvl +1,r.Seq + '.' + REPLACE(STR(ROW_NUMBER() OVER (ORDER BY m.Id),5),' ','0')
FROM #mockup AS m
INNER JOIN recCTE AS r ON m.IdParent=r.Id
)
SELECT *
,'+' + REPLICATE('-',Lvl*4) + Name
FROM recCTE
ORDER BY Seq
the result
+----+-----------+-----+----------------------+
| Id | Name | Lvl | (Kein Spaltenname) |
+----+-----------+-----+----------------------+
| 1 | Operation | 1 | +----Operation |
+----+-----------+-----+----------------------+
| 2 | Developer | 2 | +--------Developer |
+----+-----------+-----+----------------------+
| 3 | Android | 3 | +------------Android |
+----+-----------+-----+----------------------+
| 4 | IOS | 3 | +------------IOS |
+----+-----------+-----+----------------------+