Solved lab

lab-sql-subqueries.sql

@@ -0,0 +1,140 @@
+USE sakila;
+
+-- 1. Determine the number of copies of the film "Hunchback Impossible" that exist in the inventory system.
+
+SELECT COUNT(*) AS number_of_copies
+FROM inventory
+WHERE film_id = (
+    SELECT film_id
+    FROM film
+    WHERE title = 'Hunchback Impossible'
+);
+
+
+-- 2. List all films whose length is longer than the average length of all the films in the Sakila database.
+
+SELECT title, length
+FROM film
+WHERE length > (
+    SELECT AVG(length)
+    FROM film
+)
+ORDER BY length DESC;
+
+
+-- 3. Use a subquery to display all actors who appear in the film "Alone Trip".
+
+SELECT first_name, last_name
+FROM actor
+WHERE actor_id IN (
+    SELECT actor_id
+    FROM film_actor
+    WHERE film_id = (
+        SELECT film_id
+        FROM film
+        WHERE title = 'Alone Trip'
+    )
+);
+
+
+-- BONUS 1. Identify all movies categorized as family films.
+
+SELECT title
+FROM film
+WHERE film_id IN (
+    SELECT film_id
+    FROM film_category
+    WHERE category_id = (
+        SELECT category_id
+        FROM category
+        WHERE name = 'Family'
+    )
+)
+ORDER BY title;
+
+
+-- BONUS 2A. Retrieve the name and email of customers from Canada using subqueries.
+
+SELECT first_name, last_name, email
+FROM customer
+WHERE address_id IN (
+    SELECT address_id
+    FROM address
+    WHERE city_id IN (
+        SELECT city_id
+        FROM city
+        WHERE country_id = (
+            SELECT country_id
+            FROM country
+            WHERE country = 'Canada'
+        )
+    )
+)
+ORDER BY last_name, first_name;
+
+
+-- BONUS 2B. Retrieve the name and email of customers from Canada using joins.
+
+SELECT c.first_name, c.last_name, c.email
+FROM customer c
+JOIN address a 
+    ON c.address_id = a.address_id
+JOIN city ci 
+    ON a.city_id = ci.city_id
+JOIN country co 
+    ON ci.country_id = co.country_id
+WHERE co.country = 'Canada'
+ORDER BY c.last_name, c.first_name;
+
+
+-- BONUS 3. Determine which films were starred by the most prolific actor in the Sakila database.
+
+SELECT f.title
+FROM film f
+JOIN film_actor fa 
+    ON f.film_id = fa.film_id
+WHERE fa.actor_id = (
+    SELECT actor_id
+    FROM film_actor
+    GROUP BY actor_id
+    ORDER BY COUNT(film_id) DESC
+    LIMIT 1
+)
+ORDER BY f.title;
+
+
+-- BONUS 4. Find the films rented by the most profitable customer in the Sakila database.
+
+SELECT DISTINCT f.title
+FROM film f
+JOIN inventory i 
+    ON f.film_id = i.film_id
+JOIN rental r 
+    ON i.inventory_id = r.inventory_id
+WHERE r.customer_id = (
+    SELECT customer_id
+    FROM payment
+    GROUP BY customer_id
+    ORDER BY SUM(amount) DESC
+    LIMIT 1
+)
+ORDER BY f.title;
+
+
+-- BONUS 5. Retrieve the client_id and total_amount_spent of those clients 
+-- who spent more than the average of the total amount spent by each client.
+
+SELECT customer_id AS client_id, 
+       SUM(amount) AS total_amount_spent
+FROM payment
+GROUP BY customer_id
+HAVING SUM(amount) > (
+    SELECT AVG(total_spent)
+    FROM (
+        SELECT customer_id, SUM(amount) AS total_spent
+        FROM payment
+        GROUP BY customer_id
+    ) AS customer_totals
+)
+ORDER BY total_amount_spent DESC; 
+