soled lab

.gitignore

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+sakila-data.sql
+sakila-schema.sql

challenges.sql

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+USE sakila;
+
+SELECT 
+    max(LENGTH) as max_duration, min(LENGTH) as min_duration
+FROM film;
+
+select 
+    FLOOR(AVG(LENGTH)/60) as average_duration_hour,
+    FLOOR(AVG(LENGTH)%60) as average_duration_min
+from FILM;
+
+select
+    DATEDIFF(max(rental_date), min(rental_date)) as days_of_operation
+from rental;
+
+select *,
+    MONTHNAME(rental_date) as month_name,
+    DAYNAME(rental_date) as day_name,
+    CASE 
+        WHEN WEEKDAY(rental_date) in (5, 6) THEN 'Weekend'
+        ELSE 'Workday'
+    END as day_type
+from rental
+limit 20;
+
+select 
+    title,
+    IFNULL(rental_duration, 'Not available') as rental_duration
+from film
+ORDER BY title ASC;
+
+select 
+    CONCAT(first_name,' ', last_name, ', ', SUBSTR(email, 1, 3))
+from customer
+ORDER BY last_name ASC;
+
+-- The total number of films that have been released
+select count(*) as total_films from film;
+
+-- The number of films for each rating, sorting the results in descending order of the number of films
+select rating, count(*) from film
+group by rating
+order by count(*) desc;
+
+--  The mean film duration for each rating, and sort the results in descending order of the mean duration
+select rating, ROUND(AVG(LENGTH), 2) as mean_film_duration from film
+group by rating
+order by AVG(LENGTH) desc;
+
+-- Identify which ratings have a mean duration of over two hours
+select rating, ROUND(AVG(LENGTH), 2) as mean_film_duration from film
+group by rating
+HAVING AVG(LENGTH) >= 120
+order by AVG(LENGTH) desc;
+
+SELECT last_name, count(*)
+FROM actor
+GROUP BY last_name
+HAVING COUNT(*) = 1;