Sakila is a sample database provided by MySQL, meant to be used in tests and documentation examples. This page lists some example queries against that database.
Get a non-normalized selection of actors and films in which they played:
SELECT actor.first_name, actor.last_name, film.title FROM actor, film, film_actor WHERE film_actor.actor_id = actor.actor_id AND film_actor.film_id = film.film_id;
Get the same result with double
SELECT actor.first_name, actor.last_name, film.title FROM film_actor INNER JOIN actor ON film_actor.actor_id = actor.actor_id INNER JOIN film ON film_actor.film_id = film.film_id;