two.sql

SELECT s.sid, s.sname, m.dname, s.gpa, e.dname, e.cno, e.grade
FROM student s, enroll e, major m
WHERE s.sid = e.sid AND s.sid = m.sid AND
	(SELECT AVG(e1.grade)
	FROM enroll e1
	WHERE s.sid = e1.sid AND e1.dname in (
		SELECT m1.dname
		FROM major m1
		WHERE s.sid = m1.sid)) <
	(SELECT AVG(e2.grade)
	FROM enroll e2
	WHERE s.sid = e2.sid AND e2.dname NOT IN (
		SELECT m2.dname
		FROM major m2
		WHERE s.sid = m2.sid))