resolved, lab 01, day 13

lab_sql_joins.sql

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+-- ==========================================================
+-- Lab · SQL Joins (Sakila)
+-- Objetivo: rellenar cada apartado con tu query (sin resolver aquí)
+-- ==========================================================
+
+USE sakila;
+
+-- ==========================================================
+-- CHALLENGE · Joining on multiple tables
+-- ==========================================================
+
+-- 1) List the number of films per category.
+-- TODO:
+-- 
+SELECT
+	c.name,
+	COUNT(DISTINCT fc.film_id) as num_films
+FROM category as c
+LEFT JOIN film_category as fc 
+	ON c.category_id = fc.category_id
+GROUP BY c.name
+ORDER BY num_films DESC;
+
+-- ==========================================================
+-- 2) Retrieve the store ID, city, and country for each store.
+-- TODO:
+
+SELECT
+	store.store_id,
+	city.city,
+	country.country
+FROM store as store
+LEFT JOIN address as address
+	ON store.address_id = address.address_id
+LEFT JOIN city as city
+	ON city.city_id = address.city_id
+LEFT JOIN country as country
+	ON city.country_id = country.country_id;
+
+
+-- ==========================================================
+-- 3) Calculate the total revenue generated by each store in dollars.
+-- TODO:
+
+SELECT
+	store.store_id,
+	SUM(payment.amount) AS total_revenue
+FROM store AS store
+LEFT JOIN staff AS staff
+	ON store.store_id = staff.store_id
+LEFT JOIN payment AS payment
+	ON staff.staff_id = payment.staff_id
+GROUP BY
+	store.store_id;
+
+
+-- ==========================================================
+-- 4) Determine the average running time of films for each category.
+-- TODO:
+
+SELECT
+	c.name,
+	ROUND(AVG(f.length), 0) as avg_length
+FROM category AS c
+LEFT JOIN film_category AS fc
+	ON c.category_id = fc.category_id
+LEFT JOIN film AS f
+	ON fc.film_id = f.film_id
+GROUP BY
+	c.name
+ORDER BY
+	avg_length DESC;
+
+
+-- ==========================================================
+-- BONUS
+-- ==========================================================
+
+-- 5) Identify the film categories with the longest average running time.
+-- TODO:
+
+SELECT
+	c.name,
+	ROUND(AVG(f.length), 0) as avg_length
+FROM category AS c
+LEFT JOIN film_category AS fc
+	ON c.category_id = fc.category_id
+LEFT JOIN film AS f
+	ON fc.film_id = f.film_id
+GROUP BY
+	c.name
+ORDER BY
+	avg_length DESC LIMIT 5;
+
+
+
+-- ==========================================================
+-- 6) Display the top 10 most frequently rented movies in descending order.
+-- TODO:
+
+SELECT
+	f.title,
+    COUNT(r.rental_id) as freq_rented
+FROM film AS f
+JOIN inventory AS i
+	ON f.film_id = i.film_id
+JOIN rental AS r
+	ON i.inventory_id = r.inventory_id
+GROUP BY f.title
+ORDER BY freq_rented DESC 
+LIMIT 10;
+
+
+-- ==========================================================
+-- 7) Determine if "Academy Dinosaur" can be rented from Store 1.
+-- TODO:
+
+SELECT
+	DISTINCT f.title
+FROM film AS f
+JOIN inventory AS i
+	ON f.film_id = i.film_id
+JOIN store AS s
+	ON i.store_id = s.store_id
+WHERE
+	f.title = 'Academy Dinosaur' AND s.store_id = 1;
+
+
+-- ==========================================================
+-- 8) Distinct film titles + availability status ('Available' / 'NOT available')
+-- Hint: `CASE` + `IFNULL`
+-- TODO:
+SELECT
+	f.title,
+	CASE
+		WHEN COUNT(i.inventory_id) > 0 THEN 'Available'
+		ELSE 'NOT available'
+	END AS availability_status
+FROM film AS f
+LEFT JOIN inventory AS i
+	ON f.film_id = i.film_id
+GROUP BY
+	f.film_id,
+	f.title;
+
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