I have made a working SQL script for your problem.
I noticed Blindman has replied before I submitted my solution. I too made a comment about homework, but the solution is not mainstream (simple INNER JOINs or an occasional LEFT OUTER JOIN) so I made an exception at first, but I'll second Blindman.
I'll give you a hint, my solution uses a FULL OUTER JOIN.
Try to come up with something, and we'll help you further.
With kind regards . . . . . SQL Server 2000/2005/2012
Grabel's Law: 2 is not equal to 3 -- not even for very large values of 2. Pat Phelan's Law: 2 very definitely CAN equal 3 -- in at least two programming languages