Stuff

SELECT a.district, cat.name, COUNT( r.rental_id ) AS popularityFROM rental r, customer cus, address a, inventory i, film_category f_c, category catWHERE r.customer_id = cus.customer_id AND cus.address_id = a.address_idAND r.inventory_id = i.inventory_id AND i.film_id = f_c.film_id AND f_c.category_id = cat.category_idAND a.district != ''GROUP BY a.district, f_c.category_idHAVING popularity = (  SELECT COUNT( r2.rental_id ) AS max_popularity  FROM rental r2, customer cus2, address a2, inventory i2, film_category f_c2  WHERE r2.customer_id = cus2.customer_id AND cus2.address_id = a2.address_id  AND r2.inventory_id = i2.inventory_id AND i2.film_id = f_c2.film_id  AND a2.district = a.district  GROUP BY f_c2.category_id  ORDER BY max_popularity DESC  LIMIT 1)