Come concatenare il testo quando si raggruppa per una determinata colonna in SQL Server

prova questo

SELECT T1.STUDENTID,
       STUFF((SELECT ',' + CONVERT(VARCHAR(50), NOTE) + ','
                     + CONVERT(VARCHAR(50), DATE)
              FROM   STUDENTNOTE B
              WHERE  B.STUDENTID = T1.STUDENTID
              FOR XML PATH('')), 1, 1, '') [NOTE]
FROM   STUDENTNOTE T1
GROUP  BY T1.STUDENTID