Estadísticas de países:
select country pais,count(amount),sum(amount) total, avg(amount) media,max(amount) máximo, min(amount) minimo, variance(amount),std(amount) from country join city using(country_id) join address using(city_id) join customer using(address_id) join payment using(customer_id) group by pais order by media desc
Número de películas por actor:
SELECT first_name,last_name, count(film_id) total from actor left join film_actor using(actor_id) left join film using(film_id) group by first_name,last_name order by first_name desc
Ciudades por país:
select country,count(city_id) total from country join city using(country_id) group by country order by total asc
Categorías con más de 60 películas:
select name,count(film_id) total from category join film_category using(category_id) group by name having total>=60
Actor que ha participado en más películas:
select first_name,last_name,count(film_id) total from actor join film_actor using(actor_id) join film using(film_id) group by actor_id order by total desc limit 1
Total de categorías por actor (diferentes):
select distinct first_name,last_name,count(distinct name) from actor join film_actor using(actor_id) join film using(film_id) join film_category using(film_id) join category using(category_id) group by actor_id
Películas alquiladas por clientes:
select first_name,last_name, count(film_id) total from film join inventory using(film_id) join rental using(inventory_id) join customer using(customer_id) group by customer_id
Categoría más alquilada:
select name,count(customer_id) total from category join film_category using(category_id) join film using(film_id) join inventory using(film_id) join rental using(inventory_id) group by category_id order by total desc limit 1