Return the title and inventory id of the film that is rented most often.
SELECT T1.title ,  T2.inventory_id FROM film AS T1 JOIN inventory AS T2 ON T1.film_id  =  T2.film_id JOIN rental AS T3 ON T2.inventory_id  =  T3.inventory_id GROUP BY T2.inventory_id ORDER BY count(*) DESC LIMIT 1
film that is rented most often refers to MAX(COUNT(rental_id)); title refers to film title; inventory id refers to inventory.inventory_id; need to join film, inventory, and rental tables on film_id and inventory_id to count rentals per film.