diff --git a/W4L4.sql b/W4L4.sql
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+++ b/W4L4.sql
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+#1.List the number of films per category.
+use sakila;
+
+select name
+from category;
+
+#2 Retrieve the store ID, city, and country for each store.
+select *
+from store;
+select *
+from city;
+select *
+from country;
+
+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.
+select *
+from payment;
+select *
+from rental;
+select *
+from store;
+select *
+from staff;
+select *
+from address;
+
+
+SELECT 
+    s.store_id,
+    SUM(p.amount) AS total_revenue
+FROM 
+    payment p
+JOIN 
+    rental r ON p.rental_id = r.rental_id
+JOIN 
+    inventory i ON r.inventory_id = i.inventory_id
+JOIN 
+    store s ON i.store_id = s.store_id
+GROUP BY 
+    s.store_id;
+    
+#4 Determine the average running time of films for each category.
+
+select *
+from film;
+select *
+from payment;
+select *
+from rental;
+select *
+from store;
+select *
+from staff;
+select *
+from address;
+select *
+from category;
+select *
+from film_category;
+
+SELECT 
+    category.category_id,
+    AVG(film.length) AS avg_running_time
+    from film
+join 
+category on category.film_id = film.film_id
+group by film.length;
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