sqlserver中将行拼接成为一个字符串

SELECT      m.maskid    , m.maskname    , m.schoolid    , s.schoolname    , maskdetail = STUFF((          SELECT ',' + md.maskdetail          FROM dbo.maskdetails md          WHERE m.maskid = md.maskid          FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'), 1, 1, '')FROM dbo.tblmask mJOIN dbo.school s ON s.ID = m.schoolidORDER BY m.maskname