a.) SELECT Titel FROM Musikstueck m, Autor a, Person p WHERE a.Taetigkeit = "Komponist" 
AND p.Name = "F. Chopin" 
AND p.PID = a.PID
AND a.StueckID = m.StueckID

b.) SELECT DiskTitel, Preis FROM Disks d 
WHERE NOT EXISTS ( SELECT * FROM Disk d2 WHERE d2.Preis > d.Preis);

d.) SELECT DiskTitle FROM Disks a
WHERE NOT EXISTS 
( SELECT * FROM Autor a, Person p, Musikstueck m 
WHERE a.PID = p.PID 
AND a.Taetigkeit = "Komponist" 
AND p.Name != "F. Chopin" 
AND m.DiskID = d.DiskID 
AND m.StueckID = a.StueckID);

g.) SELECT d.DiskID, d.DiskTitel, SUM(m.Laenge), --> ???COUNT(*) ??? FÜR WAS <--
FROM Disk d, Musikstueck m
WHERE d.DiskID = m.DiskID
AND 3 > (SELECT COUNT(*)) FROM Disk d2, MusikStueck m2 
									WHERE (BAUCHT MAN DAS???d2.DiskID = d.DiskID BRAUCHT MAN DAS???)
									AND m2.DiskID = m.DIskID
									AND m2.Laenge > m.Laenge)
									
GROUPED BY d.DiskID, d.DiskTitel ;
