CARS ONLINE SQL PROJECT

Questions and Answers

Author: Aytekin Can

Email: aytekincan92@gmail.com

LinkedIn: https://www.linkedin.com/in/aytekincan

A SQL analysis of cars sold on Carsonline and the prices of car models by year, the average price of each transmission, number of hybrid cars for each car make, manual-gearbox cars by each car year and customers information such as number of customers by each gender and age and what are the countries of these customers.

Displaying the car id, price, car model, and car year for each car ORDER BY price?

SELECT c.car_id, c.price, ct.car_make, ct.car_model, ct.car_year 
FROM cars c JOIN car_types ct 
ON   c.car_type_id = ct.car_type_id 
ORDER BY price DESC

Results:

car_id	price	car_make	car_model	car_year
55927	159999	mercedes	G Class	2020

Only cars made by bmw in 2019?

SELECT TOP 10 c.car_id, c.price, ct.car_make, ct.car_model, ct.car_year 
FROM cars c 
INNER JOIN car_types ct 
ON c.car_type_id = ct.car_type_id
WHERE ct.car_make = 'bmw' 
AND ct.car_year = 2019
ORDER BY price DESC

Results:

car_id	price	car_make	car_model	car_year
12481	88980	bmw	8 Series	2019
17114	78386	bmw	X7	2019
13606	77880	bmw	X7	2019
11477	74990	bmw	X7	2019
12516	74480	bmw	X7	2019
17680	73990	bmw	M5	2019
15995	73950	bmw	X7	2019
20496	72000	bmw	i8	2019
17653	69995	bmw	X5	2019
20652	69948	bmw	M5	2019

Average price of audi models for the 2018?

SELECT ct.car_model, AVG(c.price) AS 'average_price'
FROM cars c JOIN car_types ct 
ON   c.car_type_id = ct.car_type_id
WHERE ct.car_make = 'audi' AND ct.car_year = 2020
GROUP BY ct.car_model

Results:

car_model	average_price
A1	23781
A3	26275
A4	36920
A5	31766
A7	45890
A8	49800
Q2	28634
Q3	33073
Q5	41146
Q7	63179
R8	133900
RS3	42490
SQ5	56450
TT	37425

The number of cars by each fuel type name and sort output by the numbers of cars descending?

SELECT ft.fuel_type_name, COUNT(*) AS 'number_of_cars'
FROM cars c JOIN fuel_types ft 
ON   c.fuel_type_id = ft.fuel_type_id
GROUP BY ft.fuel_type_name
ORDER BY COUNT(*) DESC

Results:

fuel_type_name	number_of_cars
Petrol	7900
Diesel	6673
Hybrid	564
Other	31
Electric	2

Average price for each transmission name. Output by the average price?

SELECT tt.transmission_name, AVG(c.price) AS 'average_price' 
FROM cars c JOIN transmission_types tt 
ON   c.transmission_type_id = tt.transmission_type_id
GROUP BY tt.transmission_name
ORDER BY AVG(c.price) DESC

Results:

transmission_name	average_price
Semi-Auto	25200
Automatic	21703
Manual	12381

Number of hybrid cars for each car make. Sort the output by the number of cars?

SELECT ct.car_make, COUNT(DISTINCT ct.car_model) AS 'number_of_hybrid_cars' 
FROM cars c JOIN fuel_types ft 
ON   c.fuel_type_id = ft.fuel_type_id
			JOIN car_types ct 
ON   c.car_type_id = ct.car_type_id
WHERE ft.fuel_type_name = 'Hybrid'
GROUP BY car_make
ORDER BY COUNT(DISTINCT car_model) DESC

Results:

car_make	number_of_hybrid_cars
bmw	7
toyota	7
mercedes	4
hyundi	3
audi	2
ford	2
skoda	1

What is the number of customers by each gender?

SELECT g.gender, COUNT(*) AS 'number_of_customers'
FROM customers c JOIN genders g
ON   c.gender_code = g.gender_code
GROUP BY g.gender

Results:

gender	number_of_customers
Female	2849
Male	6151

Restrict query to for customers above the age 59?

SELECT g.gender, DATEDIFF(YEAR, c.birth_date, GETDATE()) AS 'age', COUNT(*) AS 'number_of_customers'
FROM customers c JOIN genders g
ON   c.gender_code = g.gender_code
WHERE DATEDIFF(YEAR, c.birth_date, GETDATE()) > 59
GROUP BY g.gender, DATEDIFF(YEAR, c.birth_date, GETDATE())
ORDER BY COUNT(*) DESC

Results:

gender age	number_of_customers
Male	62
Male	61
Male	60
Male	63
Female	62
Female	61
Female	60
Female	63

Display the number of customers living in Australia?

SELECT COUNT(*) AS 'number_of_customers'
FROM customers c JOIN locations l 
ON   c.location_code = l.location_code
WHERE l.country = 'Australia'

Results:

number_of_customers
281

Display the number of customers living in Australia?

SELECT city, COUNT(*) AS 'number_of_customers'
FROM customers c JOIN locations l 
ON   c.location_code = l.location_code
WHERE l.country = 'Australia' AND phone_number IS NULL
GROUP BY city
ORDER BY COUNT(*) DESC

Results:

city	number_of_customers
Sydney	19
Adelaide Mail Centre	6
Eastern Suburbs Mc	5
Sydney South	3
Launceston	2
Melbourne	2
Perth	1
Hobart	1
Australia Square	1
Brisbane	1

Full name of customers who bought more than 5 cars?

SELECT c.customer_id, CONCAT(c.first_name, ' ', c.last_name) AS 'full_name', COUNT(*) AS 'number_of_cars'
FROM sales s JOIN customers c 
ON s.customer_id = c.customer_id
GROUP BY c.customer_id, CONCAT(c.first_name, ' ', c.last_name)
HAVING COUNT(*) > 5 

Results:

customer_id	full_name	number_of_cars
3942	Addie Pickover	6
1522	Bram Barrass	6
2758	Francois Houlson	6
7620	Jessey Geeve	6
7587	Kimberley Heard	6
4154	Madlen Brennenstuhl	6
7810	Maridel Stembridge	6

Display the percent of sold cars?

SELECT COUNT(s.customer_id) / CAST(COUNT(*) AS DECIMAL) * 100 AS 'percent_of_sold_cars'
FROM sales s RIGHT OUTER JOIN cars c 
ON s.car_id = c.car_id

Results:

percent_of_sold_cars
65.9195781147000659100

What was the average price of sold cars made by Audi?

SELECT AVG(cr.price) AS 'average_price'
FROM sales s JOIN cars cr 
ON s.car_id = cr.car_id
JOIN car_types ct
ON  ct.car_type_id = cr.car_type_id
WHERE YEAR(s.purchase_date) = 2019 AND ct.car_make = 'Audi'

Results:

average_price
22620