I got 4 out of 5 for mysql. Should have given it more thought :-) A suggestion: also mention that the correct results with an explanation are shown at the end.

I got 4 out of 5 for mysql. Should have given it more thought :-) A suggestion: also mention that the correct results with an explanation are shown at the end. It was not clear to me and therefore I decided to answer just quickly. But maybe that is intentional ;-)