Solving a Tricky Harry Potter Themed SQL Problem from HackerRank

Thank you.
it can not work in mysql

why i select from second table not from the first table and when i selectt all attribute in first query all of this in second table i cant understand can you explain for me pleaze?

I tried this exaclty but it's not working for me for some reason.

Just ran into this exact problem on hackerrank. Nice touch of the challenge creator that the language used to describe the problem is reflective of real-world ambiguity. Really makes you feel immersed in the business problem.

And by "nice", I mean...