CREATE TABLE film (
film_id serial,
title varchar
);
INSERT INTO film VALUES (1, 'Matrix 4');
CREATE TABLE inventory (
inventory_id serial,
film_id int
);
INSERT INTO inventory VALUES (1, 1);
CREATE TABLE rental (
inventory_id int
);
INSERT INTO rental VALUES (1), (1);
SELECT inventory.film_id, film.title, COUNT(*) AS rentals
FROM inventory
JOIN rental ON rental.inventory_id = inventory.inventory_id
JOIN film ON film.film_id = inventory.film_id
GROUP BY inventory.film_id, film.title
ORDER BY inventory.film_id