Please check below query result.
SELECT
[login to view URL] as classroom,
[login to view URL] as student,
[login to view URL] as firstname,
[login to view URL] as lastname,
[login to view URL] as student_id,
[login to view URL],
STUFF((SELECT
',' + Alert
FROM Alert n
WHERE [login to view URL] = [login to view URL]
AND [login to view URL] IS NULL
FOR XML PATH('')),1,1,'') AS Alert,
[login to view URL] as attendanceId,
[login to view URL],
case [login to view URL]
when '$week_start_day_1' then [login to view URL]
else ''
end as 'day_1',
case [login to view URL]
when '$week_start_day_2' then [login to view URL]
else ''
end as 'day_2',
case [login to view URL]
when '$week_start_day_3' then [login to view URL]
else ''
end as 'day_3',
case [login to view URL]
when '$week_start_day_4' then [login to view URL]
else ''
end as 'day_4',
case [login to view URL]
when '$week_start_day_5' then [login to view URL]
else ''
end as 'day_5',
STUFF(
(SELECT ',' + [login to view URL]
FROM Attendance AC
WHERE [login to view URL] = [login to view URL]
FOR XML PATH('')),1,1,'') AS notes
FROM Attendance a
INNER JOIN Student s on [login to view URL] = [login to view URL]
INNER JOIN Classroom c on [login to view URL] = [login to view URL]
INNER JOIN
(
SELECT
[login to view URL],
[login to view URL],
MAX(CONCAT([login to view URL],' - ', [login to view URL],'[', [login to view URL],']', [login to view URL], [login to view URL]
, [login to view URL], '|', ISNULL([login to view URL],''),':', ISNULL([login to view URL],''),'|')) AS DAYN
FROM Attendance AT
GROUP BY [login to view URL], [login to view URL]
) AS T1 ON [login to view URL] = [login to view URL]
AND [login to view URL] = [login to view URL]
WHERE [login to view URL] IN ('$week_start_day_1','$week_start_day_2','$week_start_day_3','$week_start_day_4','$week_start_day_5')
AND [login to view URL] = '$period_class_room'