Solved Lab

lab-sql-aggregation-and-transformation.sql

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+-- Setting the working database
+USE sakila;
+
+-- Display all available tables in the Sakila database.
+SHOW TABLES;
+
+-- 1.1 Determine the shortest and longest movie durations and name the values as max_duration and min_duration.
+-- select title, MIN(length) as min_duration from sakila.film group by title order by min_duration asc LIMIT 1;
+-- select title,  MAX(length) as max_duration from sakila.film group by title order by min_duration desc LIMIT 1;
+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.
+select  SEC_TO_TIME(ROUND(AVG(length)) * 60) AS formatted_duration FROM sakila.film;
+
+-- 2.1 Calculate the number of days that the company has been operating
+select Max(datediff(last_update,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 *, DATE_FORMAT(CONVERT(rental_date, DATE), '%W') as weekday, DATE_FORMAT(CONVERT(rental_date, DATE), '%M') as month 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 *,
+  CASE
+    WHEN UPPER(DATE_FORMAT(CONVERT(rental_date, DATE), '%W')) IN ('SATURDAY', 'SUNDAY') THEN 'weekend'
+    -- WHEN UPPER(DATE_FORMAT(CONVERT(rental_date, DATE), '%W')) IN ('MONDAY', 'TUSDAY', 'WEDNESDAY', 'THURSDAY', 'FRIDAY') THEN 'weekend'
+    ELSE 'workday'
+  END AS DAY_TYPE
+FROM sakila.rental;
+
+-- 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 rental_id, f.title, IFNULL(datediff(return_date, rental_date), 'Not Available') as day_diff
+	from sakila.rental as r
+JOIN sakila.film as f
+	ON r.rental_id = f.film_id
+ORDER BY f.title ASC;
+
+-- 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 'Full Name', LEFT(email, 3) as email_start FROM sakila.customer;
+
+-- 1.1 The total number of films that have been released.
+SELECT count(*) FROM sakila.film;
+
+-- 1.2 The number of films for each rating.
+SELECT rating, count(*) FROM sakila.film group by rating;
+
+-- .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(*) as films FROM sakila.film group by rating order by films DESC;
+
+-- 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 Average FROM sakila.film group by rating order by Average 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 Average 
+FROM sakila.film 
+GROUP BY rating 
+HAVING Average > 120
+ORDER BY Average DESC;
+
+-- Bonus: determine which last names are not repeated in the table actor.
+Select distinct(last_name) as last_name from sakila.actor order by last_name ASC;
+
+
+