Solved lab

lab-sql-aggregation-and-transformation.sql

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+
+-- CHALLENGE 1
+-- 1. You need to use SQL built-in functions to gain insights relating to the duration of movies:
+-- 1.1 Determine the shortest and longest movie durations and name the values as max_duration and min_duration.
+SELECT
+MIN(length) AS min_duration,
+MAX(length) AS max_duration
+FROM film;
+
+-- 1.2. Express the average movie duration in hours and minutes. Don't use decimals.
+SELECT
+AVG(length) AS avg_duration
+FROM film;
+
+SELECT
+FLOOR(AVG(length) / 60) AS hours,
+FLOOR(AVG(length) % 60) AS minutes
+FROM film;
+
+-- 2. You need to gain insights related to rental dates:
+-- 2.1 Calculate the number of days that the company has been operating.
+SELECT
+DATEDIFF(MAX(rental_date), MIN(rental_date)) AS operating_days
+FROM 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 *
+FROM rental;
+
+SELECT
+rental_id,
+inventory_id,
+customer_id,
+staff_id,
+rental_date,
+MONTHNAME(rental_date) AS rental_month,
+DAYNAME(rental_date) AS rental_weekday
+FROM rental
+LIMIT 20;
+
+-- 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.
+SELECT
+title,
+IFNULL(rental_duration, 'No dispnible') AS rental_duration
+FROM film
+ORDER BY title
+LIMIT 20;
+
+-- CHALLENGE 2
+-- 1. 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(release_year)
+FROM film;
+
+-- 1.2 The number of films for each rating.
+SELECT
+rating,
+COUNT(title)
+FROM 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.
+SELECT
+rating,
+COUNT(title) AS num_films
+FROM film
+GROUP BY rating
+ORDER BY num_films DESC;
+
+-- 2. 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 avg_length
+FROM film
+GROUP BY rating
+ORDER BY avg_length 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 avg_length
+FROM film
+GROUP BY rating
+HAVING avg_length > 120
+ORDER BY avg_length DESC;