How many movies are in both the top ten highest rated movies according to the imdb.rating and the metacritic fields? We should get these results with exactly one access to the database.
Detailed answer from the course assumes that metacritic field should be mandatory in top 10 imdb.rating. But there is no word about that in the question. If we take top 10 with imdb.rating field, there will be extra movies without defined metacritic field.