Can use XML PATH as shown below:SELECT
a.Date,
STUFF(b.Rs,1,1,'') AS RtHS
FROM
(SELECT DISTINCT Date FROM [dbo].[2012_RtHs]) a
CROSS APPLY
(
SELECT
',' AS [text()],
b.[RtHs] AS [text()]
FROM
[dbo].[2012_RtHs] b
WHERE
b.Date = a.Date
FOR XML PATH('')
) b(Rs);