From 11e12b5a770e7575c7191d1a1973f3fb703fd19c Mon Sep 17 00:00:00 2001
From: AnaP2020 <anarita.preto@gmail.com>
Date: Sat, 4 Jul 2026 13:51:56 +0100
Subject: [PATCH] lab 3 from unit 9 done

---
 Lab 3.sql | 114 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 Lab 3.sql

diff --git a/Lab 3.sql b/Lab 3.sql
new file mode 100644
index 0000000..7fc2811
--- /dev/null
+++ b/Lab 3.sql	
@@ -0,0 +1,114 @@
+USE sakila;
+
+-- Shortest and Longest Movie Durations
+SELECT 
+    MIN(length) AS min_duration, 
+    MAX(length) AS max_duration
+FROM film;
+
+-- Average Movie Duration in Hours and Minutes
+SELECT 
+    FLOOR(AVG(length) / 60) AS average_hours, 
+    FLOOR(AVG(length) % 60) AS average_minutes
+FROM film;
+
+-- Number of Days the Company Has Been Operating
+SELECT 
+    DATEDIFF(MAX(rental_date), MIN(rental_date)) AS days_operating
+FROM rental;
+
+-- Rental Information with Month and Weekday
+
+SELECT 
+    rental_id,
+    rental_date,
+    MONTH(rental_date) AS rental_month,
+    DAYNAME(rental_date) AS rental_weekday
+FROM rental
+LIMIT 20;
+
+-- Adding a DAY_TYPE Column Indicating 'weekend' or 'workday'
+
+SELECT 
+    rental_id,
+    rental_date,
+    CASE
+        WHEN DAYOFWEEK(rental_date) IN (1, 7) THEN 'weekend' -- 1 is Sunday, 7 is Saturday
+        ELSE 'workday'
+    END AS day_type
+FROM rental
+LIMIT 20;
+
+-- film titles and their rental duration
+SELECT 
+    title,
+    IFNULL(rental_duration, 'Not Available') AS rental_duration
+FROM 
+    film
+ORDER BY 
+    title ASC;
+    
+    -- personalized email campaign for customers
+    SELECT 
+    CONCAT(first_name, ' ', last_name) AS full_name,
+    LEFT(email, 3) AS email_prefix
+FROM 
+    customer
+ORDER BY 
+    last_name ASC;
+    
+-- Total Number of Films Released
+SELECT COUNT(*) AS total_films
+FROM film;
+
+-- Number of Films for Each Rating
+SELECT 
+    rating, 
+    COUNT(*) AS number_of_films
+FROM 
+    film
+GROUP BY 
+    rating;
+    
+-- Number of Films for Each Rating, Sorted by Number of Films
+SELECT 
+    rating, 
+    COUNT(*) AS number_of_films
+FROM 
+    film
+GROUP BY 
+    rating
+ORDER BY 
+    number_of_films DESC;
+    
+-- Mean Film Duration for Each Rating, Descending Order
+SELECT 
+    rating, 
+    ROUND(AVG(length), 2) AS mean_duration
+FROM 
+    film
+GROUP BY 
+    rating
+ORDER BY 
+    mean_duration DESC;
+    
+-- Ratings with a Mean Duration Over Two Hours
+SELECT 
+    rating, 
+    ROUND(AVG(length), 2) AS mean_duration
+FROM 
+    film
+GROUP BY 
+    rating
+HAVING 
+    mean_duration > 120;
+    
+-- Unique Last Names in the Actor Table
+SELECT 
+    last_name
+FROM 
+    actor
+GROUP BY 
+    last_name
+HAVING 
+    COUNT(*) = 1;
\ No newline at end of file