Solved lab

sql-aggregation-and-transformation.sql

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+USE sakila;
+
+-- 1.1 Determine the shortest and longest movie durations and name the values as max_duration and min_duration.
+SELECT MAX(length) AS max_duration, MIN(length) AS min_duration FROM sakila.film;
+
+-- 1.2. Express the average movie duration in hours and minutes. Don't use decimals.
+-- Hint: Look for floor and round functions.
+SELECT FLOOR(AVG(length)) AS average_duration FROM sakila.film;
+
+-- 2.1 Calculate the number of days that the company has been operating.
+-- Hint: To do this, use the rental table, and the DATEDIFF() function to subtract the earliest date in the rental_date column from the latest date.
+SELECT DATEDIFF(MAX(rental_date), MIN(rental_date)) FROM sakila.rental;
+
+-- 2.2 Retrieve rental information and add two additional columns to show the month and weekday of the rental. Return 20 rows of results.
+SELECT *, MONTHNAME(rental_date), DAYNAME(rental_date) FROM sakila.rental
+LIMIT 20;
+
+-- 2.3 Bonus: Retrieve rental information and add an additional column called DAY_TYPE with values 'weekend' or 'workday', depending on the day of the week.
+-- Hint: use a conditional expression.
+SELECT *, DAYNAME(rental_date) AS Day_of_Week,
+CASE 
+	WHEN DAYNAME(rental_date) = "Monday" THEN "Weekday"
+    WHEN DAYNAME(rental_date) = "Tuesday" THEN "Weekday"
+    WHEN DAYNAME(rental_date) = "Wednesday" THEN "Weekday"
+    WHEN DAYNAME(rental_date) = "Thursday" THEN "Weekday"
+    WHEN DAYNAME(rental_date) = "Friday" THEN "Weekday"
+    ELSE "Weekend"
+END AS DAY_TYPE
+FROM sakila.rental;
+
+-- 3. You need to ensure that customers can easily access information about the movie collection. 
+-- To achieve this, retrieve the film titles and their rental duration. If any rental duration value is NULL, replace it with the string 'Not Available'. 
+-- Sort the results of the film title in ascending order.
+-- Please note that even if there are currently no null values in the rental duration column, the query should still be written to handle such cases in the future.
+-- Hint: Look for the IFNULL() function.
+
+SELECT title, length,
+CASE 
+	WHEN ISNULL(rental_duration) THEN "Not Available"
+	ELSE "Available"
+END AS Information
+FROM sakila.film
+ORDER BY title ASC;
+
+-- 4. Bonus: The marketing team for the movie rental company now needs to create a personalized email campaign for customers. 
+-- To achieve this, you need to retrieve the concatenated first and last names of customers, along with the first 3 characters of their email address,
+-- so that you can address them by their first name and use their email address to send personalized recommendations. 
+-- The results should be ordered by last name in ascending order to make it easier to use the data.
+
+SELECT CONCAT(first_name, last_name) AS "concat", LEFT(email,3) FROM sakila.customer
+ORDER BY last_name ASC;
+
+-- Challenge 2
+
+-- Next, you need to analyze the films in the collection to gain some more insights. Using the film table, determine:
+-- 1.1 The total number of films that have been released.
+SELECT count(distinct film_id) as number_of_films FROM sakila.film;
+
+-- 1.2 The number of films for each rating.
+SELECT rating, COUNT(*) AS film_count
+FROM sakila.film
+GROUP BY rating;
+
+-- 1.3 The number of films for each rating, sorting the results in descending order of the number of films. 
+-- This will help you to better understand the popularity of different film ratings and adjust purchasing decisions accordingly.alter
+SELECT rating, COUNT(*) AS film_count
+FROM sakila.film
+GROUP BY rating
+ORDER BY film_count DESC;
+
+-- Using the film table, determine:
+-- 2.1 The mean film duration for each rating, and sort the results in descending order of the mean duration. 
+-- Round off the average lengths to two decimal places. This will help identify popular movie lengths for each category.
+SELECT rating, ROUND(AVG(length),2) AS film_duration FROM sakila.film
+GROUP BY rating
+ORDER BY film_duration DESC;
+
+-- 2.2 Identify which ratings have a mean duration of over two hours in order to help select films for customers who prefer longer movies.
+SELECT rating, ROUND(AVG(length),2) AS film_duration FROM sakila.film
+GROUP BY rating
+HAVING ROUND(AVG(length),2) > 120
+ORDER BY film_duration DESC;
+
+-- Bonus: determine which last names are not repeated in the table actor.
+SELECT distinct last_name FROM sakila.actor;
+
+