From 000ce7531579aaaf7d7d898571fdc7c394b0ffb7 Mon Sep 17 00:00:00 2001
From: Adriana Alves <psiadrianaandradealves@gmail.com>
Date: Mon, 27 Apr 2026 18:15:58 +0100
Subject: [PATCH] Solved lab_AA

---
 lab-subqueries.sql | 109 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 lab-subqueries.sql

diff --git a/lab-subqueries.sql b/lab-subqueries.sql
new file mode 100644
index 0000000..701e5ed
--- /dev/null
+++ b/lab-subqueries.sql
@@ -0,0 +1,109 @@
+USE sakila;
+
+-- Determine the number of copies of the film "Hunchback Impossible" that exist in the inventory system.
+SELECT COUNT(inventory.inventory_id) AS number_copies
+FROM inventory
+WHERE film_id = (
+    SELECT film_id
+    FROM film
+    WHERE title = 'Hunchback Impossible'
+);
+
+
+-- 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;
+
+
+-- Use a subquery to display all actors who appear in the film "Alone Trip".
+SELECT actor.first_name, actor.last_name
+FROM actor
+WHERE actor.actor_id IN (
+    SELECT film_actor.actor_id
+    FROM film_actor
+    WHERE film_actor.film_id = (
+        SELECT film_id
+        FROM film
+        WHERE title = 'Alone Trip'
+	)
+);
+
+-- Sales have been lagging among young families, and you want to target family movies for a promotion. Identify all movies categorized as family films.
+SELECT title
+FROM film
+WHERE film.film_id IN (
+    SELECT film_id
+    FROM film_category
+    WHERE category_id = (
+        SELECT category.category_id
+        FROM category
+        WHERE category.name = 'Family'
+	)
+);
+
+
+-- Retrieve the name and email of customers from Canada using both subqueries and joins. To use joins, you will need to identify the relevant tables and their primary and foreign keys.
+SELECT customer.first_name, customer.last_name, customer.email
+FROM customer
+JOIN address ON customer.address_id = address.address_id
+JOIN city ON address.city_id = city.city_id
+WHERE city.country_id = (
+    SELECT country_id
+    FROM country
+    WHERE country = 'Canada'
+);
+
+
+-- Determine which films were starred by the most prolific actor in the Sakila database. A prolific actor is defined as the actor who has acted in the most number of films. First, you will need to find the most prolific actor and then use that actor_id to find the different films that he or she starred in.
+SELECT actor.first_name, actor.last_name, film.title
+FROM film
+JOIN film_actor ON film.film_id = film_actor.film_id
+JOIN actor     ON film_actor.actor_id = actor.actor_id
+WHERE film_actor.actor_id = (
+    SELECT actor_id
+    FROM film_actor
+    GROUP BY actor_id
+    ORDER BY COUNT(*) DESC
+    LIMIT 1
+);
+    
+
+
+-- Find the films rented by the most profitable customer in the Sakila database. You can use the customer and payment tables to find the most profitable customer, i.e., the customer who has made the largest sum of payments.
+SELECT customer.first_name,
+       customer.last_name,
+	   film.title,
+       COUNT(rental.rental_id) AS times_rented
+FROM film
+JOIN inventory ON film.film_id = inventory.film_id
+JOIN rental ON inventory.inventory_id = rental.inventory_id
+JOIN customer ON rental.customer_id = customer.customer_id
+WHERE rental.customer_id = (
+    SELECT customer_id
+    FROM payment
+    GROUP BY customer_id
+    ORDER BY SUM(amount) DESC 
+    LIMIT 1
+)
+GROUP BY customer.first_name, customer.last_name, film.title
+ORDER BY times_rented DESC;
+
+
+-- Retrieve the client_id and the total_amount_spent of those clients who spent more than the average of the total_amount spent by each client. You can use subqueries to accomplish this.
+SELECT payment.customer_id,
+       SUM(payment.amount) AS total_amount_spent
+FROM payment
+GROUP BY payment.customer_id
+HAVING SUM(payment.amount) > (
+     SELECT AVG(customer_total)
+     FROM (
+		SELECT SUM(amount) AS customer_total
+        FROM payment
+        GROUP BY customer_id
+     ) AS per_customer_totals
+);