This might be helpful for some who accidentally tumbles upon this thread 😀

IF OBJECT_ID('TEMPDB..#CONCAT_COLUMN_VALUES') IS NOT NULL

DROP TABLE #CONCAT_COLUMN_VALUES

CREATE TABLE #CONCAT_COLUMN_VALUES

(

GROUP_ID INT,

COL_VAL VARCHAR(5)

)

INSERT INTO #CONCAT_COLUMN_VALUES

SELECT 1, 'A' UNION ALL

SELECT 1, 'B' UNION ALL

SELECT 1, 'C' UNION ALL

SELECT 2, 'D' UNION ALL

SELECT 2, 'E' UNION ALL

SELECT 3, 'F' UNION ALL

SELECT 4, 'G'

SELECT * FROM #CONCAT_COLUMN_VALUES

SELECT p1.GROUP_ID,

( SELECT COL_VAL + ','

FROM #CONCAT_COLUMN_VALUES p2

WHERE p2.GROUP_ID = p1.GROUP_ID

ORDER BY COL_VAL

FOR XML PATH('')

) AS Concat_Values

FROM #CONCAT_COLUMN_VALUES p1

GROUP BY p1.GROUP_ID ;

Cheers!!