create table film like sakila.film;
insert into film select * from sakila.film;;
UPDATE film f
JOIN film_category fc ON f.film_id = fc.film_id
JOIN category c ON fc.category_id = c.category_id
SET f.rental_rate =
CASE
WHEN c.name = 'G' THEN f.rental_rate * 0.95
WHEN c.name IN ('R', 'NC-17') THEN f.rental_rate * 1.20
ELSE f.rental_rate * 1.05
END;
;
select film_id, rental_rate from film;