Counting Attendance Per Student - sql

Question

Software: PowerSchool (Oracle database) Education software
When I run the sql for one student the attendance count in correct. When I add addition students the count becomes the total from all the students, and that total is listed for each student. How do I reset the count after each student or does the subquery go in a different location? Any suggestions appreciated. ~Liz
SELECT s.DCID,
s.lastfirst,
(SELECT COUNT(distinct att.ID)
FROM Students s JOIN Attendance att ON
s.id=att.studentid
JOIN Attendance_code attc ON
attc.id=att.attendance_codeID
WHERE s.id=att.studentid
AND s.id=5538
AND att.Att_Mode_Code='ATT_ModeDaily'
AND att.yearid=27
AND attc.Presence_Status_CD = ('Absent')) AS TAbs
FROM Students s
WHERE s.enroll_tatus=0
AND s.grade_level IN (6, 7, 8)
AND s.id=5538
ORDER BY s.grade_level ASC, s.lastfirst ASC;

Answer 1

Your query should be something like this:
SELECT s.DCID,
s.lastfirst,
(SELECT COUNT(distinct att.ID)
FROM Students s JOIN Attendance att ON
s.id=att.studentid
JOIN Attendance_code attc ON
attc.id=att.attendance_codeID
WHERE s.id=att.studentid
AND s.id=5538
AND att.Att_Mode_Code='ATT_ModeDaily'
AND att.yearid=27
AND attc.Presence_Status_CD = ('Absent')) AS TAbs
FROM Students s
WHERE s.enroll_tatus=0
AND s.grade_level IN (6, 7, 8)
AND s.id=5538
GROUP BY s.DCID, s.lastfirst #You should add this line
ORDER BY s.grade_level ASC, s.lastfirst ASC;

Answer 2

3 things you should change:
Remove both student's IDs filters. You want to see all students, not just the one with ID 5538.
Use different alias for the same table! You are referencing the Students table twice, and both times with the same alias (S).
Link the outmost Student table ID with the subquery's Student table ID, so each COUNT(DISTINCT att.ID) is calculated by student, and not overall.
Here is the edited query:
SELECT
s1.DCID,
s1.lastfirst,
(
SELECT
COUNT(distinct att.ID)
FROM
Students s2 -- Use different alias!
JOIN Attendance att ON s2.id=att.studentid
JOIN Attendance_code attc ON attc.id=att.attendance_codeID
WHERE
att.Att_Mode_Code='ATT_ModeDaily' AND
att.yearid=27 AND
attc.Presence_Status_CD = ('Absent') AND
s1.id = s2.id -- Relate both Student tables
) AS TAbs
FROM
Students s1
WHERE
s1.enroll_tatus=0 AND
s1.grade_level IN (6, 7, 8)
ORDER BY
s1.grade_level ASC,
s1.lastfirst ASC;