Database Schema:

Sailors (sid, sname, rating, age) Boats (bid, color) Reserve (sid, bid, date)

Find sids and snames of sailors whove reserved a red or a green boat

(SELECT S.sid, sname FROM Sailors S, Boats B, Reserves R WHERE S.sid=R.sid AND R.bid=B.bid AND B.color=red) UNION (SELECT S.sid, sname FROM Sailors S, Boats B, Reserves R WHERE S.sid=R.sid AND R.bid=B.bid AND B.color=green)

What do we get if we replace UNION by EXCEPT ALL?