SlNo	Id	TName
1	1	REC1
2	2	REC2
4.2	4	REC3
5.2	5	REC4
10.5.2	10	REC5

/*
Declare @tbl_Test as Table(Id INt,TName VARCHAR(10) , ParentId INT)

INSERT INTO @tbl_Test(Id ,TName,ParentId) VALUES(1,'REC1',NULL)
INSERT INTO @tbl_Test(Id ,TName,ParentId) VALUES(2,'REC2',NULL)
INSERT INTO @tbl_Test(Id ,TName,ParentId) VALUES(4,'REC3',2)
INSERT INTO @tbl_Test(Id ,TName,ParentId) VALUES(5,'REC4',2)
INSERT INTO @tbl_Test(Id ,TName,ParentId) VALUES(10,'REC5',5)

For this Records I want to get SLNo Like this wtr ParentId values (Gnerate one after another when ParentId isNull)

SlNo Id TName 
1 1 REC1
2 2 REC2
2.1 4 REC3
2.2 5 REC4
2.2.1 10 REC5

Is it posible with Sql server Programming(2,2.1,2.1.2 like that ..Then How

*/

DECLARE @test TABLE (
	[ID] INT PRIMARY KEY
	, [TName] VARCHAR(10)
	, [parentID] INT
	)

-- Populate test table
INSERT @test ([ID], [tName], [parentId])
      SELECT 1, 'REC1', NULL
UNION SELECT 2, 'REC2', NULL
UNION SELECT 4, 'REC3', 2
UNION SELECT 5, 'REC4', 2
UNION SELECT 10, 'REC5', 5

-- Raw Dump of Table
SELECT * FROM @test

-- Recursive Tree
;WITH cte (
	[SlNo]
	, [Id]
	, [TName]
	)
AS
	(
	-- Anchor Definition
	SELECT
		CAST([Id] AS VARCHAR(MAX))
		, [Id]
		, [tName]
	FROM
		@test
	WHERE
		parentId IS NULL

	-- Recursive Definition
	UNION ALL SELECT
		CAST(t.[Id] AS VARCHAR(MAX)) + '.' + p.[SlNo]
		, t.[Id]
		, t.[tName]
	FROM
		@test t
		JOIN cte p ON p.[Id] = t.[parentId]
	)
SELECT
	*
FROM
	cte

quote:

---

Can generate Sl No as 1,2 when ParentId IS NULL otherwise as No SlNo(Null)

---