SQL Combining Two Totally seperate tables to one - sql

Question

I am VERY new to SQL and self taught. I have two SQL that I stuggled through but got working. Now I need to combine them into one and I'm lost.
SELECT
s.lastfirst,
s.student_number,
SUM(tr.howmany)
FROM
students s
JOIN
truancies tr ON s.id = tr.studentid
WHERE
s.enroll_status = 0 AND
s.schoolid = ~(curschoolid)
GROUP BY
s.lastfirst, s.student_number
HAVING
SUM(tr.howmany) > 0
ORDER BY
s.lastfirst
And this table:
SELECT
S.DCID as DCID,
S.LASTFIRST as LASTFIRST,
S.STUDENT_NUMBER as STUDENT_NUMBER,
S2.FC_SRVC_HRS_DUE as FC_SRVC_HRS_DUE,
CASE
WHEN S2.FC_SRVC_HRS_COMPLETED IS NULL
THEN '0'
ELSE S2.FC_SRVC_HRS_COMPLETED
END AS FC_SRVC_HRS_COMPLETED,
S2.FC_SRVC_HRS_BUYOUT as FC_SRVC_HRS_BUYOUT,
CASE
WHEN S2.FC_SRVC_HRS_COMPLETED IS NULL
THEN S2.FC_SRVC_HRS_DUE * S2.FC_SRVC_HRS_BUYOUT
ELSE ((S2.FC_SRVC_HRS_DUE - S2.FC_SRVC_HRS_COMPLETED) * S2.FC_SRVC_HRS_BUYOUT)
END as Balance_Due
FROM
STUDENTS S, U_STUDENTSUSERFIELDS S2
WHERE
S.DCID = S2.STUDENTSDCID AND
s.enroll_status = 0 AND
s.schoolid = ~(curschoolid) AND
(((S2.FC_SRVC_HRS_DUE - S2.FC_SRVC_HRS_COMPLETED) * S2.FC_SRVC_HRS_BUYOUT) > 0 OR
((S2.FC_SRVC_HRS_DUE - S2.FC_SRVC_HRS_COMPLETED) * S2.FC_SRVC_HRS_BUYOUT) IS NULL) AND
S2.FC_SRVC_HRS_DUE >.1
ORDER BY
s.lastfirst
What I am really looking for are the totals of both of these. I want the SUM(tr.howmany) from the first table and the balance due of the second BUT I need the filters that are in there. This would be sorted by student. I hope I am making sense. Any assistance would be appreciated.

Answer 1

You can join together 2 separate SQL select statements:
Eg:
Select A.id, A.value, B.value
From (select id, count(*) as value from TableA ...) AS A
join (select id, sum(field) as value from TableB ...) AS B
on A.id = B.id
order by A.id
As long as you have a common field to join on this would work. In your case the student_number looks like a good candidate. You will have to do the ordering outside of your subqueries.