show director with the largest number of show times in total
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
largest number of show times in total refers to MAX(SUM(show_times_per_day)); director refers to directed_by;