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with total_films as ( select count(distinct f.film_id) from film f ), total_payment as ( select sum(p.amount) from payment p ) select c.name as category, count(distinct t1.film_id) as cnt from category c join ( select fc.category_id, f.film_id from film_category fc left join film f on fc.film_id = f.film_id ) t1 on c.category_id = t1.category_id group by category -- select -- t2.category, -- t2.cnt * 100 / (select * from total_films) as relative_rentals_count -- from ( -- select -- c.name as category, -- count(distinct t1.film_id) as cnt -- from category c -- join ( -- select -- fc.category_id, -- f.film_id -- from film_category fc -- left join film f -- on fc.film_id = f.film_id -- ) t1 on c.category_id = t1.category_id -- group by category -- ) as t2