CREATE TABLE rooms (roomid CLOB, roomname CLOB, beds NUMBER, bedtype CLOB, maxoccupancy NUMBER, baseprice NUMBER, decor CLOB)
CREATE TABLE reservations (code NUMBER, room CLOB, checkin CLOB, checkout CLOB, rate NUMBER, lastname CLOB, firstname CLOB, adults NUMBER, kids NUMBER)

Find the first and last names of people who payed more than the rooms' base prices.
SELECT T1.firstname, T1.lastname FROM reservations AS T1 JOIN rooms AS T2 ON T1.room = T2.roomid WHERE T1.rate - T2.baseprice > 0
SELECT "T1"."firstname", "T1"."lastname" FROM "reservations" "T1" JOIN "rooms" "T2" ON "T1"."rate" - "T2"."baseprice" > 0 AND "T1"."room" = "T2"."roomid"