Solved lab

lab_sql_joins.sql

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+-- Write SQL queries to perform the following tasks using the Sakila database:
+
+-- 1. List the number of films per category.
+SELECT film_category.category_id AS category_films,
+COUNT(film.film_id) AS number_of_films
+FROM sakila.film
+JOIN sakila.film_category
+ON film_category.film_id = film.film_id
+GROUP BY film_category.category_id;
+
+
+-- 2. Retrieve the store ID, city, and country for each store.
+SELECT store.store_id, city.city AS city_name, country.country AS country_name
+FROM sakila.store
+JOIN sakila.address ON store.address_id = address.address_id
+JOIN sakila.city ON city.city_id = address.city_id
+JOIN sakila.country ON city.country_id = country.country_id;
+
+
+-- 3. Calculate the total revenue generated by each store in dollars.
+-- a minha lofica é: a coluna staff reune a store + payment, 
+-- ou seja staff está ligado a store com store_id e ligado a payment com staff_id
+-- store ↔ staff (via store_id) ↔ payment (via staff_id)
+SELECT store.store_id,
+SUM(payment.amount) AS total_revenue
+FROM sakila.store
+JOIN sakila.staff ON store.store_id = staff.store_id
+JOIN sakila.payment ON staff.staff_id = payment.staff_id
+GROUP BY store.store_ID;
+
+
+-- 4. Determine the average running time of films for each category.
+SELECT film_category.category_id AS category_films, 
+AVG(film.length) AS average_time
+FROM sakila.film 
+JOIN sakila.film_category ON film.film_id = film_category.film_id
+GROUP BY film_category.category_id;
+
+
+-- Bonus:
+
+-- 5. Identify the film categories with the longest average running time.
+SELECT film_category.category_id AS category_films, 
+AVG(film.length) AS average_time
+FROM sakila.film 
+JOIN sakila.film_category ON film.film_id = film_category.film_id
+GROUP BY film_category.category_id
+LIMIT 1;
+
+
+-- 6. Display the top 10 most frequently rented movies in descending order.
+SELECT film.title, 
+COUNT(rental.rental_id) AS frequency_rental_movie
+FROM sakila.film
+JOIN sakila.inventory ON film.film_id = inventory.film_id
+JOIN sakila.rental ON rental.inventory_id = inventory.inventory_id
+GROUP BY film.title
+ORDER BY frequency_rental_movie DESC
+LIMIT 10;
+
+-- 7. Determine if "Academy Dinosaur" can be rented from Store 1.
+SELECT film.title
+FROM sakila.film
+JOIN sakila.inventory ON film.film_id = inventory.film_id
+JOIN sakila.store ON inventory.store_id = store.store_id
+WHERE film.title = "Academy Dinosaur" AND store.store_id = 1;
+
+-- 8. Provide a list of all distinct film titles, along with their availability status in the inventory. Include a column indicating whether each title is 'Available' or 'NOT available.' Note that there are 42 titles that are not in the inventory, and this information can be obtained using a CASE statement combined with IFNULL."
+SELECT DISTINCT film.title,
+	CASE 
+		WHEN inventory.film_id IS NULL THEN 'NOT available'
+		ELSE 'Available'
+	END AS availability_status
+FROM sakila.film
+LEFT JOIN sakila.inventory ON film.film_id = inventory.film_id;
+
+
+