Concatenate row values T-SQL

Have a look at this

DECLARE @Reviews TABLE(
        ReviewID INT,
        ReviewDate DATETIME
)

DECLARE @Reviewers TABLE(
        ReviewerID   INT,
        ReviewID   INT,
        UserID INT
)

DECLARE @Users TABLE(
        UserID  INT,
        FName  VARCHAR(50),
        LName VARCHAR(50)
)

INSERT INTO @Reviews SELECT 1, '12 Jan 2009'
INSERT INTO @Reviews SELECT 2, '25 Jan 2009'

INSERT INTO @Users SELECT 1, 'Bob', ''
INSERT INTO @Users SELECT 2, 'Joe', ''
INSERT INTO @Users SELECT 3, 'Frank', ''
INSERT INTO @Users SELECT 4, 'Sue', ''
INSERT INTO @Users SELECT 5, 'Alice', ''

INSERT INTO @Reviewers SELECT 1, 1, 1
INSERT INTO @Reviewers SELECT 2, 1, 2
INSERT INTO @Reviewers SELECT 3, 1, 3
INSERT INTO @Reviewers SELECT 4, 2, 4
INSERT INTO @Reviewers SELECT 5, 2, 5

SELECT  *,
        ( 
            SELECT  u.FName + ','
            FROM    @Users u INNER JOIN 
                    @Reviewers rs ON u.UserID = rs.UserID
            WHERE   rs.ReviewID = r.ReviewID
            FOR XML PATH('')
        ) AS Products
FROM    @Reviews r

Turns out there is an even easier way to do this which doesn't require a UDF:

select replace(replace(replace((cast((
        select distinct columnName as X
        from tableName 
        for xml path('')) as varchar(max))), 
   '</X><X>', ', '),'<X>', ''),'</X>','')

Had similar problem and found a sweet solution after playing with code for 15 minutes

declare @result varchar(1000)
select @result = COALESCE(@result+','+A.col1, A.col1)
                FROM (  select  col1
                        from [table] 
                ) A
select @result

Returns result as value1,value2,value3,value4

Enjoy ;)

SqlServer 2017 now has STRING_AGG that aggregates multiple strings into one using a given separator.