Further on the previous solution, here is an executable sample

😎

USE tempdb;

GO

;WITH BASE_DATA(NNAME,NGROUP) AS

(SELECT NNAME,NGROUP FROM (VALUES

('Bill','Finance')

,('Nancy','Ops')

,('Bill','IT')

,('Stacy','Mktg')

) AS X(NNAME,NGROUP)

)

SELECT DISTINCT

BD.NNAME

,(STUFF((SELECT N',',X.NGROUP

FROM BASE_DATA X

WHERE X.NNAME = BD.NNAME

FOR XML PATH(''),TYPE).value('.[1]','NVARCHAR(1024)'),1,1,'')) AS GGROUP

FROM BASE_DATA BD;

Results

NNAME GGROUP

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

Bill Finance,IT

Nancy Ops

Stacy Mktg