-- select * from film;
-- select title, rating, length from film
-- where rating ='G' or rating = 'PG';
-- select title, rating, length from film
-- where rating in ('G', 'PG','PG-13');
-- select title, rating, length from film
-- where rating in ('G', 'PG') and length > 150;
-- select length from film;
-- select title, rating, length from film
-- where title like '%EA%';
-- select title from film ;
select rating, count(title) as number of movies from film
group by rating;