Comma separated results in SQL

Use FOR XML PATH('') – which is converting the entries to a comma separated string and STUFF() -which is to trim the first comma- as follows Which gives you the same comma separated result

SELECT  STUFF((SELECT  ',' + INSTITUTIONNAME
            FROM EDUCATION EE
            WHERE  EE.STUDENTNUMBER=E.STUDENTNUMBER
            ORDER BY sortOrder
            FOR XML PATH(''), TYPE).value('text()[1]','nvarchar(max)')
           , 1, LEN(','), '') AS listStr

FROM EDUCATION E
GROUP BY E.STUDENTNUMBER

Here is the FIDDLE