using pivot wuery how to concate the the rows in sql

SELECT *
FROM (
SELECT [Date],[Course],[Session],
    SUBSTRING((SELECT ','+ [Faculty_Code]
        FROM [Tb_SCh_TIme_Table ] dp2 
        WHERE dp2.[Date] = dp1.[Date] and dp2.[Course]=dp1.[Course] and dp2.[Session]=dp1.[Session]
    FOR XML PATH('')), 2, 8000) AS [Faculty_Code]
FROM [Tb_SCh_TIme_Table ] dp1
GROUP BY [Date],[Session],[Course]
) P
PIVOT (
MAX([Faculty_Code])
FOR [Session] IN ([1],[2],[3] ,[4])
) AS PVT
WHERE [Course]='PH2'