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

lab-sql-self-cross- join.sql

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+-- lab-sql-join-multiple-tables
+-- Get all pairs of actors that worked together.
+
+select * from sakila.actor;
+select * from sakila.film;
+select * from sakila.film_actor;
+
+-- Performing self join on tables film_actor to get the pair of actor 
+select *
+from sakila.film_actor f1
+inner join sakila.film_actor f2
+on f1.film_id = f2.film_id
+and f1.actor_id <> f2.actor_id
+;
+
+-- Get all pairs of customers that have rented the same film more than 3 times.
+
+select * from sakila.customer;
+select * from sakila.rental;
+select * from sakila.inventory;
+select * from sakila.film;
+
+-- step 1
+select *
+from sakila.rental r
+inner join sakila.inventory i
+on r.inventory_id = i.inventory_id
+;
+
+-- step 2
+
+-- get all different pair of customer who have rented the same movie more than 3 times 
+SELECT
+    i.film_id,
+    r.customer_id AS customer1,
+    r1.customer_id AS customer2,
+    COUNT(r.rental_id) AS rental_count
+FROM
+    sakila.rental r
+INNER JOIN
+    sakila.inventory i ON r.inventory_id = i.inventory_id
+INNER JOIN
+    sakila.rental r1 ON i.inventory_id = r1.inventory_id
+                      AND r.customer_id < r1.customer_id 
+INNER JOIN
+    sakila.inventory i1 ON i.film_id = i1.film_id
+                      AND r.customer_id < r1.customer_id                
+
+GROUP BY
+    i.film_id, r.customer_id, r1.customer_id
+HAVING
+    rental_count > 3
+    order by i.film_id, r.customer_id
+    ;
+
+
+    -- Get all possible pairs of actors and films.
+-- checking the table
+
+select * from sakila.film_actor;
+select * from sakila.actor;
+select * from sakila.film;
+
+-- step to join the table 
+select *
+from sakila.film_actor fa
+INNER JOIN
+    sakila.actor a ON fa.actor_id = a.actor_id 
+INNER JOIN
+    sakila.film f ON f.film_id = fa.film_id ;
+
+
+-- step to self join to get two different actor Id per movie row
+select f.title ,f.film_id, fa.actor_id as Actor1,  a.first_name as Name_Actor1 , a.last_name as Name_Actor1 ,
+ fa1.actor_id as Second_Actor ,a1.first_name as Name_Actor2 , a1.last_name as Name_Actor2
+
+from sakila.film_actor fa
+left JOIN
+    sakila.actor a ON fa.actor_id = a.actor_id 
+left JOIN
+    sakila.film f ON f.film_id = fa.film_id 
+inner JOIN
+    sakila.film_actor fa1 ON fa1.film_id = f.film_id
+                      AND fa.actor_id > fa1.actor_id 
+inner join sakila.actor a1 on fa1.actor_id = a1.actor_id 
+;
+
+
+-- using function coutn to count the number of time a pair of actor is playing in a movie together
+SELECT
+    COUNT(f.film_id) AS film_count,
+    fa.actor_id AS Actor1,
+    a.first_name AS Name_Actor1,
+    a.last_name AS Last_Name_Actor1,
+    fa1.actor_id AS Second_Actor,
+    a1.first_name AS Name_Actor2,
+    a1.last_name AS Last_Name_Actor2
+FROM
+    sakila.film_actor fa
+LEFT JOIN
+    sakila.actor a ON fa.actor_id = a.actor_id
+LEFT JOIN
+    sakila.film f ON f.film_id = fa.film_id
+INNER JOIN
+    sakila.film_actor fa1 ON fa1.film_id = f.film_id
+                      AND fa.actor_id > fa1.actor_id
+INNER JOIN
+    sakila.actor a1 ON fa1.actor_id = a1.actor_id
+GROUP BY
+
+    fa.actor_id,
+    a.first_name,
+    a.last_name,
+    fa1.actor_id,
+    a1.first_name,
+    a1.last_name;
+
+
+
+