# 9 Travelers SQL Interview Questions (Updated 2024)

Updated on

August 11, 2024

Data Analytics, Data Science, and Data Engineering employees at Travelers uses SQL to analyze massive travel-related datasets, including trip itineraries and travel patterns, for risk assessment. It is also used to create predictive models for customer behavior patterns, such as identifying frequent travelers, which is why Travelers often asks jobseekers SQL interview questions.

Thus, to help you study, we've curated 9 Travelers SQL interview questions – how many can you solve?

## 9 Travelers SQL Interview Questions

### SQL Question 1: Calculate the Average Rating Per Destination Monthly

As a data analyst for a travel company, you're asked to provide insights into the review performance of different holiday destinations. Write a SQL query to calculate the average review per destination for each month. The aim is to determine the best rated destination on a monthly basis over time to make recommendations for travellers.

Assume you have a table that holds data about the reviews made by users for each destination they travel to. The table schema and data looks like this:

#### Example Input:

review_iduser_idsubmit_datedestination_idstars
317102106/08/2022 00:00:00100015
402205006/15/2022 00:00:00100014
329308406/20/2022 00:00:00450013
125207207/22/2022 00:00:00450014
541709407/30/2022 00:00:00450015

You can calculate the average review per destination for each month by grouping the reviews by month and destination, then calculating the average stars. Here's how:

The function is used to extract the month from the timestamp. The is a window function that calculates the average stars for each destination on a monthly basis. The query results are then ordered by descending order of the month and average rating to present the best rated destinations first for each month.

For more window function practice, try this Uber SQL Interview Question on DataLemur's online SQL coding environment:

### SQL Question 2: 2nd Largest Salary

Imagine there was a table of Travelers employee salary data. Write a SQL query to find the 2nd highest salary amongst all the .

#### Travelers Example Input:

employee_idsalary
12500
2800
31000
41200

#### Example Output:

second_highest_salary
1200

Solve this problem directly within the browser on DataLemur:

You can find a step-by-step solution here: 2nd Highest Salary.

### SQL Question 3: Can you explain the concept of database normalization?

Database normalization is the process of breaking down a table into smaller and more specific tables and defining relationships between them via foreign keys. This minimizes redundancy, and creates a database that's more flexible, scalable, and easier to maintain. It also helps to ensure the integrity of the data by minimizing the risk of data inconsistencies and anomalies.

### SQL Question 4: Travel Booking Analysis

As a Data Analyst at Travelers, your task is to derive insights into the travel booking patterns of customers. The company maintains a database with tables for Customers, Flights, Airlines, Hotels, and Bookings.

The Customers table holds the customer details with as the primary key. The Flights table stores flight details with as primary key, as the foreign key referring to the Airlines table, and representing the flight departure time. The Hotels table keeps records of hotels with as the primary key. The Bookings table contains booking records, with as primary key, and foreign keys , and referring to respective tables.

Analyze the tables and write a query to find out the total number of bookings made by each customer per airline.

##### Example Input:
customer_idfirst_namelast_name
1JohnDoe
2JaneDoe
3JamesSmith
##### Example Input:
flight_idairline_iddeparture_datetime
1012012022-03-01 10:00:00
1022012022-03-02 14:00:00
1032022022-03-01 08:00:00
##### Example Input:
airline_idairline_name
201Airline A
202Airline B
##### Example Input:
hotel_idhotel_name
301Hotel C
302Hotel D
##### Example Input:
booking_idcustomer_idflight_idhotel_id
11101301
21102302
32103301

This query joins the , , , and tables using appropriate keys. Then it counts the number of for each customer per airline. Finally, it groups the results by , , and to get the total bookings made by each customer per airline.

### SQL Question 5: How does a left join differ from a right join?

A join in SQL allows you to retrieve data from multiple tables and combine it into a single set of results.

To demonstrate the difference between left vs. right join, imagine you had two database tables, an advertising campaigns table which had information on Google Ads keywords and how much was bid for each keyword, and a sales table, which has data on how many products were sold and which Google Ads keyword drove that sale.

: A LEFT JOIN retrieves all rows from the left table (in this case, the table) and any matching rows from the right table (the Sales table). If there is no match in the right table, values will be returned for the right table's columns.

: A RIGHT JOIN retrieves all rows from the right table (in this case, the Sales table) and any matching rows from the left table (the table). If there is no match in the left table, values will be returned for the left table's columns.

### SQL Question 6: Find the Average Duration of Booked Trips

At Travelers, we want to maintain a high level of satisfaction for all our customers. To do this, we need to continuously understand our statistics surrounding trip bookings. Please find the average duration of booked trips for each destination.

Consider the table with the following structure:

##### Example Input:
booking_iduser_idstart_dateend_datedestination
10011012022-09-012022-09-05New York
10021022022-09-152022-09-20London
10031012022-10-012022-10-05New York
10041032022-09-202022-09-22New York
10051052022-09-152022-09-25London

We are particularly interested in the average duration of trips per destination (in days). The start and end dates of the bookings are of date format and you can assume that all bookings are within the same year.

##### Example Output:
destinationaverage_duration
New York4.33
London7.50

The posted SQL script calculates the average duration of booked trips for each destination by subtracting the start date from the end date for each booking, and then takes the average of these values per destination.

To practice a very similar question try this interactive Microsoft Teams Power Users Question which is similar for requiring statistics for user activities or this Facebook Average Post Hiatus (Part 1) Question which is similar for requiring a time duration calculation.

### SQL Question 7: Could you provide a list of the join types in SQL and explain what each one does?

A join in SQL allows you to retrieve data from multiple tables and combine it into a single set of results.

In SQL, there are four different types of JOINs. To demonstrate each kind, imagine you had two database tables, an advertising campaigns table which had information on Google Ads keywords and how much was bid for each keyword, and a sales table, which has data on how many products were sold and which Google Ads keyword drove that sale.

: An INNER JOIN retrieves rows from both tables where there is a match in the shared key or keys. For example, an INNER JOIN between the table and the table could be performed using the keyword column as the shared key. This would retrieve only the rows where the keyword in the table matches the keyword in the table.

: A LEFT JOIN retrieves all rows from the left table (in this case, the table) and any matching rows from the right table (the Sales table). If there is no match in the right table, values will be returned for the right table's columns.

: A RIGHT JOIN retrieves all rows from the right table (in this case, the Sales table) and any matching rows from the left table (the table). If there is no match in the left table, values will be returned for the left table's columns.

: A FULL OUTER JOIN retrieves all rows from both tables, regardless of whether there is a match in the shared key or keys. If there is no match, values will be returned for the columns of the non-matching table.

### SQL Question 8: Analyzing Click Through Rates for Travelers

Travelers, a travel service company, has two main tables.

One, the table, records each time a user clicks on an ad:

##### Example Input:
100173206/12/2021 15:45:005000
100243506/15/2021 10:23:006000
100373207/10/2021 17:02:005000
100473207/12/2021 09:33:006000
100543507/26/2021 14:45:006000

The other, the table, records every booking a user makes:

##### Example Input:
booking_iduser_idbooking_timeproduct_id
800173206/12/2021 16:00:0050000
800243506/15/2021 11:00:0060000
800373207/10/2021 18:00:0050000
800443507/26/2021 16:00:0060000

Write a SQL query that calculates the click through rate (CTR), which is defined as the number of bookings divided by the number of ad clicks, for each ad_id on a monthly basis.

This SQL statement joins the table with the table based on the and the condition that the ad click must have happened before the booking. It then groups the data by month and to calculate the CTR.

To practice a similar SQL problem on DataLemur's free interactive coding environment, attempt this Meta SQL interview question:

### SQL Question 9: Find the total amount spent by each customer on hotel bookings

As a data analyst for Travelers, your task is to join and analyze the customer and booking tables. Write a SQL query to find the total amount spent by each customer on their hotel bookings.

The table has the following structure:

##### Example Input:
customer_idfirst_namelast_name
1JohnDoe
2JaneSmith
3SamBrown
4EmilyClark

The table has the following structure:

##### Example Input:
booking_idcustomer_idhotel_nameprice
1021Dream Palace\$400
1032Sunny Inn\$200
1053Dream Palace\$400

This query joins the table with the table on the common field. It then groups by and computes the sum of for each group. The result is a list of customers along with the total amount they have spent on hotel bookings. As a result, you will be able to identify who your biggest spenders are.

Because joins come up so often during SQL interviews, take a stab at this interactive Snapchat Join SQL question:

### How To Prepare for the Travelers SQL Interview

The key to acing a Travelers SQL interview is to practice, practice, and then practice some more! Beyond just solving the earlier Travelers SQL interview questions, you should also solve the 200+ tricky sql questions on DataLemur which come from companies like FAANG tech companies and tech startups.

Each DataLemur SQL question has hints to guide you, step-by-step solutions and most importantly, there's an online SQL coding environment so you can right online code up your SQL query answer and have it checked.

To prep for the Travelers SQL interview you can also be wise to solve SQL questions from other insurance companies like:

Learn how Travelers is leveraging AI to stay ahead of the curve in the insurance industry!

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

This tutorial covers topics including Subqueries and manipulating date/time data – both of which show up often in Travelers SQL assessments.

### Travelers Data Science Interview Tips

#### What Do Travelers Data Science Interviews Cover?

Beyond writing SQL queries, the other types of questions covered in the Travelers Data Science Interview are:

#### How To Prepare for Travelers Data Science Interviews?

To prepare for Travelers Data Science interviews read the book Ace the Data Science Interview because it's got:

• 201 interview questions taken from FAANG tech companies
• a refresher covering Python, SQL & ML
• over 1000+ reviews on Amazon & 4.5-star rating

Don't forget about the behavioral interview – prep for that using this guide on behavioral interview questions.