finished lab sql joins day 3

lab-sql-joins.sql

@@ -0,0 +1,48 @@
+#Challenge - Joining on multiple tables
+#Write SQL queries to perform the following tasks using the Sakila database:
+# 1. List the number of films per category.
+Use Sakila;
+#Let's join the table category (where we have the movie categories) with film_category(with the multiple id's)
+SELECT film_id
+FROM film_category;
+SELECT 
+	category.name,
+    COUNT(film_category.film_id) AS films_per_category
+FROM category
+JOIN film_category
+ON category.category_id = film_category.category_id
+GROUP BY category.name;
+# 2. Retrieve the store ID, city, and country for each store.
+SELECT
+    store.store_id,
+    city.city,
+    country.country
+FROM store
+JOIN address
+ON store.address_id = address.address_id
+JOIN city
+ON address.city_id = city.city_id
+JOIN country
+ON city.country_id = country.country_id;
+# 3. Calculate the total revenue generated by each store in dollars.
+#I need SUM() for the total revenue. I need to GROUP BY store. I need to find the column amount.
+SELECT
+    store.store_id,
+    SUM(payment.amount) AS total_revenue
+FROM store
+JOIN customer
+ON store.store_id = customer.store_id
+JOIN payment
+ON customer.customer_id = payment.customer_id
+GROUP BY store.store_id;
+# 4. Determine the average running time of films for each category.
+#I need the length from Film. I need to do AVG. I need to join per category.
+SELECT
+    category.name,
+    AVG(film.length) AS average_running_time
+FROM film
+JOIN film_category
+ON film.film_id = film_category.film_id
+JOIN category
+ON film_category.category_id = category.category_id
+GROUP BY category.name;