Set Operations
--------------------------------------------------

1.
a) n + m
b) min(n, m)
c) max(n - m, 0)

2.
(SELECT term FROM offering WHERE instructor = 'Suzuki')
INTERSECT ALL
(SELECT term FROM offering WHERE instructor = 'Jepson');

3.
(SELECT sid FROM took WHERE grade >= 85)
UNION
(SELECT sid
FROM took, offering
WHERE took.oid = offering.oid AND instructor = 'Atwood' AND grade >= 50);

4.
(SELECT term FROM offering)
EXCEPT
(SELECT term FROM offering WHERE dept = 'CSC' AND cnum = 369);

5.
(SELECT oid, 'high' AS results
FROM took
GROUP BY oid
HAVING AVG(grade) >= 80)
UNION
(SELECT oid, 'low' AS results
FROM took
GROUP BY oid
HAVING AVG(grade) < 60);