solved lab

lab_subqueries.sql

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+-- 1. Number of copies of "Hunchback Impossible" in inventory
+SELECT 
+    COUNT(*) AS number_of_copies
+FROM inventory
+WHERE film_id = (
+    SELECT film_id
+    FROM film
+    WHERE title = 'HUNCHBACK IMPOSSIBLE'
+);
+
+-- 2. Films longer than the average length
+SELECT 
+    title,
+    length
+FROM film
+WHERE length > (
+    SELECT AVG(length)
+    FROM film
+);
+
+-- 3. Actors who appear in "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'
+    )
+);
+
+-- 4. 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'
+    )
+);
+
+-- 5. 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'
+        )
+    )
+);
+
+-- 5. 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';
+
+-- 6. Films starred by the most prolific actor
+SELECT 
+    title
+FROM film
+WHERE film_id IN (
+    SELECT film_id
+    FROM film_actor
+    WHERE actor_id = (
+        SELECT actor_id
+        FROM film_actor
+        GROUP BY actor_id
+        ORDER BY COUNT(film_id) DESC
+        LIMIT 1
+    )
+);
+
+-- 7. Films rented by the most profitable customer
+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
+);
+
+-- 8. Clients who spent more than the average total amount spent by each client
+SELECT 
+    customer_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
+);