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

[lab-sql-self-cross-join]leonardo.sql

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+-- 1. Get all pairs of actors that worked together.
+select * 
+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
+order by a1.actor_id;
+
+-- 2. Get all pairs of customers that have rented the same film more than 3 times.
+select * from sakila.customer; -- customer names / customer_id pk
+select * from sakila.rental; -- customer_id fk / rental_id pk
+select * from sakila.inventory; -- invetory_id fk / film_id fk
+
+create table temp_rental as
+select 
+	concat(c.first_name, '_', c.last_name) as customer_name,
+    c.customer_id as customer_id,
+    r.rental_id as rental_id,
+    inv.film_id as film_id
+from sakila.customer c
+left join sakila.rental r on c.customer_id = r.customer_id
+left join sakila.inventory inv on r.inventory_id = inv.inventory_id;
+
+select * from temp_rental;
+
+select 
+	t1.customer_name,
+	t2.customer_name,
+	count(t1.film_id) as count_film
+from sakila.temp_rental t1
+inner join sakila.temp_rental t2
+on t1.customer_id <> t2.customer_id and t1.film_id = t2.film_id
+group by 1,2
+having count_film > 3
+order by 3 desc;
+
+
+
+-- 3. Get all possible pairs of actors and films.
+select 
+	concat(a.first_name, ' ', a.last_name) as actor_name,
+    f.title as title
+from sakila.actor a
+cross join sakila.film f;