Thanks for this question - I really enjoyed trying to work it out in my head. That I then got it right was an added bonus to create a good start to the day.

Being able to copy and paste the the query into management studio is a good way to follow up on this learning - so thanks for the change in policy on QoD's. I never had time to type in some of the queries that were submitted previously so quite possibly did not get the most from them.