8 Euronet SQL Interview Questions (Updated 2024)
Euronet employees write SQL queries for analyzing transactional data, including payment processing, card transactions, and merchant activity, as well as managing data warehousing in financial technology operations, including data integration and data quality control. Because of this, Euronet frequently asks SQL problems in interviews for Data Science and Data Engineering positions.
So, to help you prepare, here's 8 Euronet Worldwide SQL interview questions – how many can you solve?
8 Euronet Worldwide SQL Interview Questions
SQL Question 1: Calculate the Most Frequently Used Payment Method by each User
Euronet provides a wide variety of payment methods for its users. As a data analyst, your task is to write a SQL query that will calculate the most frequently used payment method by each user for their transactions in the year 2020. You have the table which has the following schema:
| Column | Type |
|---|---|
| transaction_id | integer |
| user_id | integer |
| payment_method | string |
| transaction_date | timestamp |
| amount | float |
And contains the following sample data:
Example Input:
| transaction_id | user_id | payment_method | transaction_date | amount |
|---|---|---|---|---|
| 1001 | 300 | Credit Card | 2020-01-12 00:00:00 | 50.0 |
| 1002 | 300 | Debit Card | 2020-01-15 00:00:00 | 20.0 |
| 1003 | 300 | Credit Card | 2020-02-18 00:00:00 | 80.0 |
| 1004 | 300 | PayPal | 2020-03-26 00:00:00 | 60.0 |
| 1005 | 300 | Credit Card | 2020-04-05 00:00:00 | 30.0 |
| 1006 | 400 | PayPal | 2020-01-26 00:00:00 | 120.0 |
| 1007 | 400 | PayPal | 2020-02-15 00:00:00 | 100.0 |
| 1008 | 400 | Debit Card | 2020-03-02 00:00:00 | 140.0 |
| 1009 | 400 | PayPal | 2020-05-18 00:00:00 | 90 |
Answer:
This query first calculates the frequency of each payment method per user in the year 2020 and stores the result in CTE. Then, it finds the maximum frequency for each user ( CTE). Finally, it joins and to get the most frequently used payment method by each user. If there is a tie in frequency, this query will return all payment methods with the highest frequency.
Pro Tip: Window functions are a frequent SQL interview topic, so practice every window function problem on DataLemur
SQL Question 2: Employees Earning More Than Managers
Imagine there was a table of Euronet employee salaries. Write a SQL query to find the employees who earn more than their direct manager.
Euronet Example Input:
| employee_id | name | salary | department_id | manager_id |
|---|---|---|---|---|
| 1 | Emma Thompson | 3800 | 1 | |
| 2 | Daniel Rodriguez | 2230 | 1 | 10 |
| 3 | Olivia Smith | 8000 | 1 | 8 |
| 4 | Noah Johnson | 6800 | 2 | 8 |
| 5 | Sophia Martinez | 1750 | 1 | 10 |
| 8 | William Davis | 7000 | 2 | NULL |
| 10 | James Anderson | 4000 | 1 | NULL |
Example Output:
| employee_id | employee_name |
|---|---|
| 3 | Olivia Smith |
This is the output because Olivia Smith earns $8,000, surpassing her manager, William Davis who earns 7,800.
Code your solution to this interview question and run your code right in DataLemur's online SQL environment:
Answer:
First, we perform a SELF-JOIN where we treat the first table () as the managers' table and the second table () as the employees' table. Then we use a clause to filter the results, ensuring we only get employees whose salaries are higher than their manager's salary.
If the code above is hard to understand, you can find a step-by-step solution with hints here: Employee Salaries Higher Than Their Manager.
SQL Question 3: What are database views, and when would you use them?
Database views are created to provide customized, read-only versions of your data that you can query just like a regular table. So why even use one if they're so similar to a regular table?
Views are advantageous for several reasons:
- views allow you to create a simpler versions of your data for specific users (such as hiding extraneous columns/rows from business analysts since they're relics of the Data Engineering pipelines setup)
- views help you comply with data security requirements by hiding sensitive data from certain users (important for regulated industries like govermnet and healthcare!)
- views can improve performance for complicated queries by pre-computing the results and caching them in a view (which is often faster than re-executing the original query)
SQL Question 4: Analysis of ATM Transactions
Euronet is a provider of electronic payment services and operates one of the largest independent ATM networks in Europe. A key performance metric for Euronet is the total number of transactions occurring on its network of ATMs. As a database designer, you have been asked to design a database to store transactions data and write a query to retrieve the total number of ATM transactions per country for the current month. The transaction data includes transaction_id, ATM_id, user_id, transaction_date, transaction_amount, and transaction_type (withdrawal, deposit, or balance inquiry).
Here is an example of how the table may look:
| transaction_id | ATM_id | user_id | transaction_date | transaction_amount | transaction_type |
|---|---|---|---|---|---|
| 1001 | 3001 | 2001 | 08/17/2022 10:30:00 | 100.00 | withdrawal |
| 1002 | 3002 | 2002 | 08/18/2022 11:00:00 | 250.00 | deposit |
| 1003 | 3001 | 2003 | 08/18/2022 11:30:00 | 0.00 | balance inquiry |
| 1004 | 3003 | 2001 | 08/19/2022 09:00:00 | 50.00 | withdrawal |
| 1005 | 3002 | 2002 | 08/20/2022 08:30:00 | 200.00 | deposit |
And the table is:
| ATM_id | country |
|---|---|
| 3001 | Germany |
| 3002 | France |
| 3003 | Spain |
Answer:
This query joins the table with the table on the field. It then filters the data to only include transactions from the current year and month. The function is used to calculate the total number of transactions for each country. The result is a list of countries and their corresponding transaction counts for the current month.
SQL Question 5: What is a foreign key?
A foreign key is a field in a database table that links to the primary key of another table, establishing a connection between the two tables.
To demonstrate this concept, let's analyze Euronet's marketing analytics database which stores data from Google Ads campaigns:
:
| ad_id | campaign_id | keyword | click_count |
|---|---|---|---|
| 1 | 100 | Euronet pricing | 10 |
| 2 | 100 | Euronet reviews | 15 |
| 3 | 101 | Euronet alternatives | 7 |
| 4 | 101 | buy Euronet | 12 |
is a foreign key. It references the of the Google Ads campaign that each ad belongs to, establishing a relationship between the ads and their campaigns. This foreign key allows you to easily query the table to find out which ads belong to a specific campaign, or to find out which campaigns a specific ad belongs to.
It is also possible for a table to have multiple foreign keys that reference different primary keys in other tables. For example, the table could have additional foreign keys for the of the ad group that each ad belongs to, and the of the Google Ads account that the campaigns belong to.
SQL Question 6: Calculate Average Transaction Amount Per Currency
As a data analyst at Euronet, a company that provides payment processing solutions and software for electronic payments, you are asked to examine average transaction amounts for each currency processed. Using the following table structure, create a SQL query that returns the average transaction amount by currency.
Example Input:
| transaction_id | currency | transaction_date | transaction_amount |
|---|---|---|---|
| 1251 | USD | 09/08/2022 00:00:00 | 3050.60 |
| 2352 | EUR | 09/10/2022 00:00:00 | 1500.80 |
| 7643 | GBP | 08/18/2022 00:00:00 | 2050.00 |
| 9842 | USD | 06/26/2022 00:00:00 | 1548.40 |
| 5125 | EUR | 07/05/2022 00:00:00 | 1090.75 |
Answer:
This query groups the transactions by their respective currencies (). The function is then used to calculate the average transaction amount within each group. The result will provide the average transaction amount per each currency used in the transactions.
To practice a very similar question try this interactive Stripe Repeated Payments Question which is similar for dealing with transaction-based analytics or this Uber User's Third Transaction Question which is similar for focusing on specific transaction behavior.
SQL Question 7: DBMS transactions are expected to follow the ACID properties. What are they, and what does each property mean?
A transaction is a one or more SQL commands which are executed as a singular unit if the transaction -commits- (or no execution hapens if the transaction -aborts-).
For transactions, a DBMS is supposed to enforce the follwing ACID properties: Atomicity, Consistency, Isolation, & Durability.
Here's what each one means:
- Atomicity: the transaction is completed in an all-or-nothing way (no partial commits)
- Consistency: the transaction is valid and follows all constraints and restrictions
- Isolation: the transaction doesn't affect another transaction
- Durability: the committed transactions is stored permanently in the DB (it doesn't dissapear!)
As you can see, it's pretty important for the multiple databases where Euronet store's it's data to be ACID-compliant!
SQL Question 8: Find Customers Whose First Name Starts With 'Jo'
As a data analyst at Euronet, our database contains detailed information about our customers. One of our duties is to perform ad-hoc data retrieval tasks upon request. For instance, the marketing team might be interested in targeting customers whose first names start with 'Jo' for a personalized promotional campaign.
Consequently, you are tasked to write a SQL query that selects all customer records from the table where the first name of the customer starts with 'Jo'. This list will be used to send promotional newsletters and offers to these targeted customers.
Example Input:
| customer_id | first_name | last_name | signup_date | |
|---|---|---|---|---|
| 1 | John | Doe | john.doe@example.com | 2017-10-05 |
| 2 | Jordan | Smith | jordan.smith@example.com | 2018-06-21 |
| 3 | Simon | Brown | simon.brown@example.com | 2019-02-18 |
| 4 | Joanne | Taylor | joanne.taylor@example.com | 2020-02-28 |
| 5 | Tim | White | tim.white@example.com | 2021-11-04 |
Answer:
This query returns the full records of John, Jordan and Joanne. The SQL LIKE keyword in the WHERE clause is used to search for a specified pattern in a column. Here, we are looking for any value that starts with 'Jo' in the column. The '%' sign is used to define wildcards (missing letters) both before and after the pattern. In this case, we use it only after 'Jo', meaning that the first name must start with 'Jo', followed by any sequence of characters. This query is case-sensitive, so it will not match names like 'joanne'. To make it case-insensitive, you could use the lower function --
How To Prepare for the Euronet SQL Interview
The best way to prepare for a Euronet SQL interview is to practice, practice, practice. Besides solving the above Euronet SQL interview questions, you should also solve the 200+ FAANG SQL Questions on DataLemur which come from companies like Microsoft, Google, and Meta.
Each interview question has hints to guide you, step-by-step solutions and crucially, there's an online SQL coding environment so you can right online code up your SQL query and have it checked.
To prep for the Euronet SQL interview you can also be wise to practice SQL questions from other fintech companies like:
Dive into the latest news and announcements from Euronet and stay ahead of the curve in the fintech industry!
But if your SQL foundations are weak, forget about diving straight into solving questions – refresh your SQL knowledge with this SQL tutorial for Data Analytics.
This tutorial covers SQL concepts such as advantages of CTEs vs. subqueries and UNION vs. joins – both of which come up frequently in SQL job interviews at Euronet.
Euronet Worldwide Data Science Interview Tips
What Do Euronet Data Science Interviews Cover?
In addition to SQL interview questions, the other question categories covered in the Euronet Data Science Interview include:
- Probability & Statistics Questions
- Python or R Programming Questions
- Open-Ended Data Case Studies
- ML Interview Questions
- Resume-Based Behavioral Questions
How To Prepare for Euronet Data Science Interviews?
To prepare for the Euronet Data Science interview have a strong understanding of the company's values and company principles – this will be clutch for acing the behavioral interview. For technical interviews get ready by reading Ace the Data Science Interview. The book's got:
- 201 Interview Questions from Microsoft, Amazon & startups
- A Refresher on SQL, AB Testing & ML
- Amazing Reviews (1000+ 5-star reviews on Amazon)