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@@ -40,7 +40,8 @@ There are two phases of the exercises for ths project.
 
 `select * from film natural join inventory;`
 
-The solutions to these are in [sakila-queries-answers.sql](doc/sakila-queries-answers.sql) (But don't look at them until you've really tried to solved them all yourself.)
+The solutions to these are in [
+](doc/sakila-queries-answers.sql) (But don't look at them until you've really tried to solved them all yourself.)
 
 ### Phase 2. Longer, Harder, More Realistic.
 

ph1-solutions.sql

@@ -4,3 +4,148 @@
 USE sakila;
 
 -- Your solutions...
+
+--* Write an SQL script with queries that answer the following questions:
+
+--* 1. Which actors have the first name ‘Scarlett’
+
+SELECT * FROM sakila.actor
+WHERE first_name = "Scarlett";
+
+--Answers:  Scarlett Damon and Scarlett Bening
+
+--* 2. Which actors have the last name ‘Johansson’
+
+SELECT *
+FROM sakila.actor a
+WHERE a.last_name = "Johansson";
+
+--Answer: Matthew, Ray and Albert Johansson
+
+--* 3. How many distinct actors last names are there? 121
+
+SELECT DISTINCT last_name FROM sakila.actor;
+
+--Answer: 121
+
+--* 4. Which last names are not repeated? 66
+
+SELECT *
+FROM sakila.actor a
+WHERE NOT EXISTS (
+SELECT 1
+FROM sakila.actor b
+WHERE a.last_name=b.last_name
+HAVING COUNT(*)>1
+)
+
+--Answer: 66
+
+--* 5. Which last names appear more than once? 200
+
+SELECT *
+FROM sakila.actor a
+WHERE NOT EXISTS (
+SELECT 1
+FROM sakila.actor b
+WHERE a.last_name=b.last_name
+HAVING COUNT(*)<1
+)
+
+--Answer: 200
+
+--* 6. Which actor has appeared in the most films?
+SELECT actor_id, count(actor_id) as Total
+FROM sakila.film_actor
+GROUP BY actor_id
+ORDER BY Total DESC;
+
+SELECT first_name, last_name
+FROM sakila.actor
+WHERE actor_id = 107
+GROUP BY first_name, last_name;
+
+--Answer: Actor_ID 107, Gina Degeneres
+
+--* 7. Is ‘Academy Dinosaur’ available for rent from Store 1?
+SELECT film_id, title
+FROM sakila.film
+GROUP BY film_id, title;
+-- "Academy Dinosaur" film id is 1
+SELECT film_id, store_id
+FROM sakila.inventory
+WHERE film_id = 1
+AND store_id = 1;
+-- Yes, there are 4 copies available from store 1
+
+--* 8. Insert a record to represent Mary Smith renting ‘Academy Dinosaur’ from Mike Hillyer at Store 1 today .
+
+SELECT staff_id, first_name, last_name
+FROM sakila.staff
+WHERE first_name = 'Mike'
+AND last_name = 'Hillyer'
+GROUP BY staff_id, first_name, last_name;
+
+INSERT INTO sakila.rental (rental_date, inventory_id, customer_id, staff_id)
+VALUES (NOW(), 1, 1, 1)
+
+--Double checking...
+SELECT * FROM sakila.rental
+WHERE inventory_id = 1;
+
+--* 9. When is ‘Academy Dinosaur’ due?
+
+SELECT * FROM sakila.rental
+WHERE inventory_id = 1
+AND customer_id = 1;
+
+--Due: 'Null'
+
+SELECT film_id, rental_duration
+FROM sakila.film
+WHERE film_id = 1
+GROUP BY film_id, rental_duration;
+
+--Rental duration = 6
+--Due: '2020-12-12'
+
+--* 10. What is that average running time of all the films in the sakila DB?
+
+SELECT AVG(length)
+FROM sakila.film;
+
+Answer: '115.2720'
+
+--* 11. What is the average running time of films by category?
+
+SELECT category.name, avg(f.length)
+FROM sakila.film f
+JOIN sakila.film_category USING (film_id)
+JOIN sakila.category USING (category_id)
+GROUP BY category.name
+ORDER BY avg(length) DESC;
+
++-------------+---------------+
+| name        | avg(f.length) |
++-------------+---------------+
+| Sports      |      128.2027 |
+| Games       |      127.8361 |
+| Foreign     |      121.6986 |
+| Drama       |      120.8387 |
+| Comedy      |      115.8276 |
+| Family      |      114.7826 |
+| Music       |      113.6471 |
+| Travel      |      113.3158 |
+| Horror      |      112.4821 |
+| Classics    |      111.6667 |
+| Action      |      111.6094 |
+| New         |      111.1270 |
+| Animation   |      111.0152 |
+| Children    |      109.8000 |
+| Documentary |      108.7500 |
+| Sci-Fi      |      108.1967 |
++-------------+---------------+
+
+--* 12. Why does this query return the empty set?
+
+-- I don't understand... The previous exercise did not return an empty set.