always provide sample data in order for you to get quick response
declare @table table(names varchar(255))
insert into @table
values('Joe 123')
insert into @table
values('Joe 456')
insert into @table
values('Joe 789')
SELECT
STUFF(
(
SELECT
', ' + names
FROM @table
FOR XML PATH('')
), 1, 1, ''
) As concatenated_string
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