Show all the directors.
select directed_by from film
List those directors in descending order by the total number of showtimes.
select t2.directed_by from schedule as t1 join film as t2 on t1.film_id = t2.film_id group by t2.directed_by order by sum(t1.show_times_per_day) desc
Who has the most?
select t2.directed_by from schedule as t1 join film as t2 on t1.film_id = t2.film_id group by t2.directed_by order by sum(t1.show_times_per_day) desc limit 1