# 10 Avis Car Rental SQL Interview Questions (Updated 2024)

Updated on

June 30, 2024

Data Analysts and Data Engineers at Avis Car Rental use SQL for analyzing car rental trends, and for optimizing vehicle inventory. That's the reason behind why Avis Car Rental asks prospective hires SQL interview questions.

So, to help you practice, here’s 10 Avis Budget Group SQL interview questions – able to answer them all?

## 10 Avis Budget Group SQL Interview Questions

### SQL Question 1: Identify Avis Car Rental Power Users

For our car rental company "Avis Car Rental" we care very much about the customers that rent cars frequently.

One important detail about our business is that customers can rent cars for different periods of time. The rental period can anywhere from a single day rental to a rental for an entire week or even longer.

To define our "power users" (VIP users, whale users), we would like to identify the customers that have rented the most during the last 3 months.

##### Example Input:
rental_idcustomer_idrental_start_daterental_end_datecar_id
502421406/02/2022 00:00:0006/05/2022 00:00:008001
629714506/10/2022 00:00:0006/15/2022 00:00:008023
390137106/22/2022 00:00:0006/26/2022 00:00:008042
921621407/04/2022 00:00:0007/05/2022 00:00:008011
753914507/10/2022 00:00:0007/20/2022 00:00:008001

Please write a SQL query to identify power users over the last 3 months.

In this query we first filter out the rentals within the last three months. Then, we group the data by customer_id and calculate the total number of rentals and total rental days for each customer. Finally, we order the result by the total rental days in descending order to get the top power users. We limit the result to the top 10 power users.

To solve a related customer analytics question on DataLemur's free online SQL code editor, try this recently asked Microsoft SQL interview question:

### SQL Question 2: Department Salaries

You're given a table of Avis Car Rental employee and department salaries. Write a SQL query to find departments where the departments average salary is higher than the company's average salary.

Code your solution to this problem directly within the browser on DataLemur:

The solution is LONG – 30+ lines of SQL. You can find a step-by-step solution with hints here: Department vs. Company Salary.

### SQL Question 3: What does do, and when would you use this SQL command?

If you have two tables and want to retrieve only the rows that are present in both tables, just use the operator!

For example, let's use to find all of Avis Car Rental's Facebook video ads that are also being run on YouTube:

### SQL Question 4: Analyze Rental Frequencies with Window Functions

For Avis Car Rental, you have been provided with two datasets. One contains details of all car rental transactions, named and the other contains details of all available cars in the fleet, named .

includes details such as rental_id, car_id, customer_id, start_date and end_date of the rental. includes details such as car_id, car_make, car_model and car_year.

As an analyst for Avis, you are tasked to analyze the rental frequencies for each car make and model and rank them within their respective years.

Write a SQL query to find the top 3 most frequently rented car make and car_model for each car_year using window functions.

##### Example Input:
rental_idcar_idcustomer_idstart_dateend_date
100110100212022-06-012022-06-10
100220300522022-06-052022-06-08
100310100422022-06-152022-06-20
100410200152022-06-102022-06-15
100520300282022-06-202022-06-25
##### Example Input:
car_idcar_makecar_modelcar_year
101ToyotaCamry2018
102HondaAccord2017
203ChevroletMalibu2016

The above SQL query first joins the and tables on the field. It then groups by , , and and counts the number of rentals for each grouping. This result serves as a subquery for the main query, the main query uses a window function to rank each car make and model within each year based on the count of rentals. The final clause filters the result to only include the top 3 most frequently rented cars for each year.

To solve another window function question on DataLemur's free interactive coding environment, solve this Google SQL Interview Question:

### SQL Question 5: In SQL, are blank spaces the same as a NULL?

A value represents a missing or unknown value. It is different from a zero or a blank space, which are actual values.

It's important to handle values properly in SQL because they can cause unexpected results if not treated correctly. For example, comparisons involving values always result in . Also values are not included in calculations. For example, will ignore values in the column.

### SQL Question 6: Average Rental Price Per Car Type

For Avis Car Rental, let's consider a scenario where we have a database with two tables -- and . The table contains information about all rentals, including rental_id, car_id, rental_date and rental_price. The table contains details about cars like car_id, car_type and number_of_seats. The question could be:

"Find the average rental price for each type of car from the rentals table."

##### Example Input:
rental_idcar_idrental_daterental_price
123412021/08/18100
125622021/08/1875
125922021/08/2380
132432021/09/10200
139742021/08/18150
##### Example Input:
car_idcar_typenumber_of_seats
1Sedan5
2SUV7
3Luxury4
4Truck2
##### Example Output:
car_typeavg_rental_price
Sedan100.00
SUV77.50
Luxury200.00
Truck150.00

To find the average rental price for each car type, you can join the and tables on the field and then group by car type, calculating the average rental price using the function in PostgreSQL.

This script works by joining the table and the table on the column. It then groups all the joined rows by the column. For each group of rows with the same car type, it calculates the average , thus giving us the average rental price per car type.

### SQL Question 7: What's a database view, and what's it used for?

A database view is a virtual table that is created based on the results of a SELECT statement, and provides you a customized, read-only version of your data that you can query just like a regular table.

You'd want to use a view for a few reasons:

• views allow you to create a simpler versions of your data based on whose running the query (such as hiding un-important columns/rows from business analysts if they're just random noisy artifricats of your Data Infrastructure pipelines)
• views can help you comply with information security requirements by hiding sensitive data from certain users (important for regulated industries like govermnet and healthcare!)
• views often improve performance for complicated queries by pre-computing the results and saving them in a view (which is often faster than re-executing the original query)... just be careful since static views don't update if the underlying data changes!

Check out the Avis Car Rental job areas and see which one would be the best fit for you.

### SQL Question 8: Filter Customer records for Avis Car Rental

Avis Car Rental has an extensive customer database containing customer details and their rental histories. The management wants to filter down this database to find the records of customers who rented a specific vehicle model. They are particularly interested in customers who rented any version of "Ford Mustang", those records can contain different version of "Ford Mustang" like "2022 Ford Mustang", "2019 Ford Mustang GT" etc.

##### Example Input:
rental_idcustomer_idrental_datevehicle_modelrental_duration
892310106/08/20222022 Ford Mustang7
713525606/10/20222015 Subaru Forester10
379210106/18/20222019 Ford Mustang GT14
982336907/26/20222022 Toyota Camry3
624919207/05/20222019 Ford Mustang7

You need to create a SQL query that will filter down the customer_rentals records where the vehicle_model column contains string 'Mustang'.

This query uses the SQL keyword LIKE to filter and return all records from the customer_rentals table where the 'vehicle_model' contains the string 'Mustang'. The '%' is a wildcard operator that matches any sequence of characters. This means that the query will catch any version of "Ford Mustang", like "2022 Ford Mustang", "2019 Ford Mustang GT" etc.

### SQL Question 9: Analyze and Compare Rental Duration and Cost

Assume that Avis Car Rental maintains two tables in their database - and . The table keeps track of every car rental reservation including the rental date, return date, customer_id, car_id and cost. The table keeps track of every customer including their ID, name, and email.

Write a SQL query to calculate the total rental duration and total rental cost for each customer.

Note: Assume all dates are formatted in 'YYYY-MM-DD' and the rental cost is stored as a floating point number.

Here are example input tables:

##### Example Input:
rental_idcustomer_idrental_datereturn_datecar_idrental_cost
10112022-07-012022-07-155001350.00
10222022-08-052022-08-155010450.25
10312022-09-012022-09-105020300.00
10432022-10-012022-10-115030400.10
##### Example Input:
customer_idcustomer_namecustomer_email
1John Doejohndoe@gmail.com
2Jane Smithjanesmith@hotmail.com
3Bob Datebobdate@yahoo.com

This query joins the table with the table based on the . Then it calculates the total rental cost for each customer by using the aggregate function on the column. The total rental days are calculated by subtracting the from the , extracting the days using , and summing the result. The result is grouped by the and .

Since join questions come up frequently during SQL interviews, practice this Snapchat SQL Interview question using JOINS:

### SQL Question 10: How do you identify records in one table that are not present in a second table?

To discover records in one table that are not present in another, you can utilize a and filter out any values in the right-side table.

For example, say you had a table of Avis Car Rental customers and a 2nd table of all purchases made with Avis Car Rental. To find all customers who did not make a purchase, you'd use the following

This query returns all rows from the customers table, along with any matching rows from the purchases table. If there is no matching row in the purchases table, values will be returned for all of the right table's columns. The clause then filters out any rows where the purchases.id column is , leaving only customers who have not made a purchase.

### How To Prepare for the Avis Car Rental SQL Interview

Assuming that you've already got basic SQL skills, the next best tip we have to prepare for the Avis Car Rental SQL interview is to solve as many practice SQL interview questions as you can! Beyond just solving the earlier Avis Car Rental SQL interview questions, you should also solve the 200+ FAANG SQL Questions on DataLemur which come from companies like Google, Facebook, Microsoft and Amazon.

Each problem on DataLemur has hints to guide you, fully explained answers along with a discussion board to see how others solved it and best of all, there's an online SQL code editor so you can right online code up your SQL query answer and have it executed.

To prep for the Avis Car Rental SQL interview you can also be helpful to solve SQL problems from other automotive companies like:

In case your SQL skills are weak, forget about going right into solving questions – refresh your SQL knowledge with this SQL interview tutorial.

This tutorial covers SQL concepts such as CASE/WHEN statements and LEAD/LAG – both of these show up often in Avis Car Rental interviews.

### Avis Budget Group Data Science Interview Tips

#### What Do Avis Car Rental Data Science Interviews Cover?

In addition to SQL interview questions, the other types of questions covered in the Avis Car Rental Data Science Interview are:

#### How To Prepare for Avis Car Rental Data Science Interviews?

I'm a tad biased, but I believe the optimal way to prepare for Avis Car Rental Data Science interviews is to read the book Ace the Data Science Interview.

The book solves 201 data interview questions taken from Microsoft, Amazon & startups. It also has a crash course covering Stats, ML, & Data Case Studies. And finally it's helped a TON of people, which is how it's gotten to be an Amazon best-seller with over 1000+ 5-star reviews.