I noticed that the above part of the OPs question was never answered. As Jack Corbett suggested, you just need a good splitter and the code becomes simple.

Here's the test data I used.

DROP TABLE dbo.TblTran

SELECT TranID, Month, MonthValue

INTO dbo.TblTran

FROM (

SELECT 1, 4, 50 UNION ALL

SELECT 1, 5, 30 UNION ALL

SELECT 1, 6, 11 UNION ALL

SELECT 1, 7, 30 UNION ALL

SELECT 2, 4, 51 UNION ALL

SELECT 2, 5, 39 UNION ALL

SELECT 2, 6, 100 UNION ALL

SELECT 2, 7, 30

) d (TranID, Month, MonthValue)

;

Stored procedures are a real PITA if you want to use their data for something else so I made this as an iTVF (Inline Table Valued Function).

CREATE FUNCTION dbo.SomeFunctionName

(@MonthsCSV VARCHAR(100))

RETURNS TABLE WITH SCHEMABINDING AS

RETURN

WITH cteGetData AS

(

SELECT t.TranID

, t.Month

, t.MonthValue

FROM dbo.TblTran t

JOIN dbo.DelimitedSplit8K(@MonthsCSV,',') split

ON t.Month = split.Item

)

SELECT c1.TranID

, MonthValues =

STUFF(

(

SELECT ',' + CAST(MonthValue AS VARCHAR(10))

FROM cteGetData c2

WHERE c2.TranID = c1.TranID

ORDER BY c2.[Month]

FOR XML PATH('')

)

,1,1,'')

FROM cteGetData c1

GROUP BY c1.TranID

;

Then you can call it like the following:

SELECT * FROM dbo.SomeFunctionName('4,5,6');

That returns the desired answer:

TranID MonthValues

----------- ------------

1 50,30,11

2 51,39,100

As a bit of a sidebar, please consider not abbreviating names nor using reserved words like "Month" for names of objects or columns. 😉