That's pretty flawed methodology since you'd want to know what problems people encounter in the real world and how quickly they solve them.

I mean, who writes queries on paper? And by pressing Execute, SQL will gladly provide error message that the student will, I think, quickly resolve. Is this a contest that measures how well students can write compile-able code without executing it or what?

Moreover, IDE would have helped those students for sure: SQL keywords are highlighted in different color + autocomplete.