Solved Lab 3

solutions_lab3.sql

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+USE sakila;
+--   CHALLENGE 1
+
+/* 1.1 Shortest and longest movie durations (minutes) */
+SELECT MAX(rental_duration) AS max_duration, MIN(rental_duration) AS min_duration
+FROM film;
+
+/* 1.2 Average movie duration in hours and minutes  */
+SELECT 
+  FLOOR(AVG(length) / 60) AS avg_hours,
+  FLOOR(AVG(length)) % 60 AS avg_minutes
+FROM film;
+
+/* 2.1 Days the company has been operating (based on rentals) */
+SELECT 
+  DATEDIFF(MAX(rental_date), MIN(rental_date)) AS days_operating
+FROM rental;
+
+/* 2.2 Show month and weekday for rentals (20 rows) */
+SELECT 
+  rental_id,
+  rental_date,
+  DATE_FORMAT(rental_date, '%M') AS rental_month,
+  DATE_FORMAT(rental_date, '%W') AS rental_weekday
+FROM rental
+ORDER BY rental_date
+LIMIT 20;
+
+/* 2.3 Add DAY_TYPE = 'weekend' or 'workday' (20 rows) */
+SELECT 
+  rental_id,
+  rental_date,
+  CASE 
+    WHEN DAYOFWEEK(rental_date) IN (1,7) THEN 'weekend'  -- 1=Sun, 7=Sat
+    ELSE 'workday'
+  END AS day_type
+FROM rental
+ORDER BY rental_date
+LIMIT 20;
+
+/* 3. Film titles and rental duration, replace NULL with 'Not Available' */
+
+SELECT 
+  title,
+  IFNULL(CAST(rental_duration AS CHAR), 'Not Available') AS rental_duration
+FROM film
+ORDER BY title ASC;
+
+/* 4. Full name + first 3 chars of email, order by last name */
+SELECT 
+  CONCAT(first_name, ' ', last_name) AS full_name,
+  SUBSTRING(email, 1, 3) AS email_prefix
+FROM customer
+ORDER BY last_name ASC, first_name ASC;
+
+   -- CHALLENGE 2
+
+/* 1.1 Total number of films released */
+SELECT COUNT(*) AS total_films FROM film;
+
+/* 1.2 Number of films for each rating */
+SELECT 
+  rating,
+  COUNT(*) AS films
+FROM film
+GROUP BY rating
+ORDER BY rating;
+
+/* 1.3 Number of films for each rating, sorted by count descending */
+SELECT 
+  rating,
+  COUNT(*) AS films
+FROM film
+GROUP BY rating
+ORDER BY films DESC, rating ASC;
+
+/* 2.1 Mean film duration per rating, rounded to 2 decimals */
+SELECT 
+  rating,
+  ROUND(AVG(length), 2) AS mean_duration_minutes
+FROM film
+GROUP BY rating
+ORDER BY rating;
+
+/* 2.2 Ratings with mean duration > 2 hours (120 minutes) */
+SELECT 
+  rating,
+  ROUND(AVG(length), 2) AS mean_duration_minutes
+FROM film
+GROUP BY rating
+HAVING AVG(length) > 120
+ORDER BY mean_duration_minutes DESC;
+
+/* 3. Last names that are NOT repeated in actor table */
+-- Challenge 2 - 3 Bonus
+SELECT 
+  last_name
+FROM actor
+GROUP BY last_name
+HAVING COUNT(*) = 1
+ORDER BY last_name;
+