19. Select the guest number, guest first name, last name, and the arrival and departure dates for those guests that have bookings. Hint: When you have an ambiguous column (like guest number which is in both tables, you need to specify the table name or letter in front of that attribute) 20. Paste the results. 21. Select the guest number, guest first name, last name, and arrival and departure dates whether or not there is a booking. (All guests in the guest table should appear) Hint: Use Left or Right Join 22. Paste the results.