[lab-sql-self-cross-join]Pedro

lab-sql-self-cross-join.sql

@@ -0,0 +1,42 @@
+#all pairs of actors that worked together
+select a1.actor_id, a2.actor_id from sakila.film_actor a1 
+inner join sakila.film_actor a2 on a1.film_id = a2.film_id
+and a1.actor_id < a2.actor_id
+group by a1.actor_id, a2.actor_id
+order by a1.actor_id, a2.actor_id asc;
+
+#number or rentals each customer rented the same film
+select a1.customer_id, a2.film_id, count(a1.rental_id) as nr_rentals 
+from sakila.rental a1
+inner join sakila.inventory a2 on a1.inventory_id = a2.inventory_id
+group by a1.customer_id, a2.film_id order by 3 desc, 2 desc;
+
+create table sakila.t2
+select a1.customer_id, a2.film_id 
+from sakila.rental a1
+inner join sakila.inventory a2 on a1.inventory_id = a2.inventory_id
+group by a1.customer_id, a2.film_id order by 2 desc;
+
+select * from sakila.t2 order by 1 asc;
+
+#checking which films customers 24 and 111 rented
+select * from sakila.t2 where customer_id in (24,111) order by 2 asc;
+
+#all pairs of customers which rented more than 3 films in common
+select b1.customer_id, b2.customer_id, count(distinct b1.film_id) as nr_films from sakila.t2 b1 
+inner join sakila.t2 b2 on b1.film_id = b2.film_id
+and b1.customer_id <> b2.customer_id
+where b1.customer_id < b2.customer_id
+group by b1.customer_id, b2.customer_id
+having nr_films > 3
+order by nr_films desc;
+
+
+create temporary table sakila.distinct_films
+select distinct title from sakila.film;
+
+create temporary table sakila.distinct_actors
+select concat(first_name, " ", last_name) as actor_name from sakila.actor;
+
+#all possible pairs of actors and films
+select * from sakila.distinct_films cross join sakila.distinct_actors;