Group a set of chain values - sql-server

Question

I have the following table in SQL Server 2008
DECLARE #UnitConvert table
(
ID int identity(1,1),
ConvertUnitOne nvarchar(50),
ConvertUnitTwo nvarchar(50)
)
INSERT INTO #UnitConvert
SELECT 100,500
UNION ALL SELECT 200,100
UNION ALL SELECT 500,300
UNION ALL SELECT 2000,1000
UNION ALL SELECT 3000,9000
UNION ALL SELECT 2000,700
UNION ALL SELECT 820,3000
SELECT * FROM #UnitConvert
Here value in UnitConvertOne is equivalent to UnitConvertTwo
So it has a chain of value linking
So i want to display the result like
Group unit
1 100
200
300
500
2 700
1000
2000
3 820
3000
9000
Group value will be autoincrement based on the number of groups can be created
Unit value can be sorted from small to large value

Answer 1

Thanks to Eugene Elutin from sqlservercentral.com
DECLARE #UnitConvert table
(
ID int identity(1,1),
ConvertUnitOne nvarchar(50),
ConvertUnitTwo nvarchar(50)
)
INSERT INTO #UnitConvert
SELECT 100,500
UNION ALL SELECT 200,100
UNION ALL SELECT 500,300
UNION ALL SELECT 2000,1000
UNION ALL SELECT 3000,9000
UNION ALL SELECT 2000,700
UNION ALL SELECT 820,3000
;WITH cteUP AS
(
SELECT ConvertUnitTwo AS childUP, ConvertUnitOne AS unitUP, 0 AS Lvl
FROM #UnitConvert
UNION ALL
SELECT cte.childUP, u.ConvertUnitOne AS unitUP, Lvl = Lvl + 1
FROM #UnitConvert u
INNER JOIN cteUP cte ON cte.unitUP = u.ConvertUnitTwo
)
--select * from cteUP
SELECT c.ConvertUnit
,DENSE_RANK() OVER (ORDER BY ISNULL(cm.unitUP, c.ConvertUnit)) AS GrpNO
FROM (SELECT ConvertUnitOne AS ConvertUnit FROM #UnitConvert
UNION
SELECT ConvertUnitTwo AS ConvertUnit FROM #UnitConvert) c
OUTER APPLY (SELECT TOP 1 unitUP FROM cteUP m WHERE
m.childUP = c.ConvertUnit ORDER BY Lvl DESC) cm