I hope you enjoy solving these puzzles as much as I have enjoyed creating them.
Please visit my website at:
All solutions are written in Microsoft SQL Server's T-SQL, but can be easily modified to fit your flavor of SQL.
I also have quite a few tips, tricks and learning materials available if you scroll through. I try to keep things to the advanced level and not recreate the already abundant amount of SQL resource materials available.
Feel free to contact me with any new puzzles that would be a great for my website.