9 PROS Holdings SQL Interview Questions (Updated 2024)

Updated on

March 3, 2024

At PROS, SQL is typically used for analyzing vast pricing and revenue management datasets, especially for airlines. Because of this, PROS Holdings often tests SQL problems during interviews for Data Science, Data Engineering and Data Analytics jobs.

Thus, to help you ace the PROS Holdings SQL interview, we've collected 9 PROS SQL interview questions – able to solve them?

9 PROS SQL Interview Questions

SQL Question 1: Identify Most Active Customers

PROS Holdings, a company providing AI-based solutions to optimize sales, wants to analyze its customer database to identify customers who are very important to the business because of their high-frequency activity. To be more precise, PROS wants to identify customers who have logged into their system most frequently during the last month. Use the table to identify these power users.

Example Input:

And we also have the table as such:

Example Input:


This query identifies the top 10 users with the most number of logins during the current month. The query starts by joining the and tables on . It then filters the activities to only include 'login' activities from the current month. The results are grouped by and , and then ordered in descending order of the count of login activity. The clause restricts the output to only include the top 10 users.

To solve a related customer analytics question on DataLemur's free online SQL coding environment, try this Microsoft Azure Cloud SQL Interview Question: Microsoft SQL Interview Question: Super Cloud Customer

SQL Question 2: Analyzing Average Sale Price Per Month

Let's suppose PROS Holdings is interested in analyzing their average sale price for each product on a monthly basis. The task is to write an SQL query which calculates the average price of products sold in each month. Products with no sales in a month should not be in the output.

The dataset includes the table with the following schema:

Example Input:
Example Output:


The SQL query to solve this problem utilizes the function and clause:

This SQL query calculates the average sale price of products in each month.

is used to extract the month from the sale_date column.

The AVG() function calculates the average price of products.

The GROUP BY clause groups the results by the month and product_id, and the ORDER BY clause sorts the results by month and product_id.

p.s. Window functions show up super frequently during SQL interviews, so practice the 27+ window function questions on DataLemur

SQL Interview Questions on DataLemur

SQL Question 3: How do foreign and primary keys differ?

To clarify the distinction between a primary key and a foreign key, let's examine employee data from PROS Holdings's HR database:


+------------+------------+------------+------------+ | employee_id| first_name | last_name | manager_id | +------------+------------+------------+------------+ | 1 | Aubrey | Graham | 3 | | 2 | Marshal | Mathers | 3 | | 3 | Dwayne | Carter | 4 | | 4 | Shawn | Carter | | +------------+------------+------------+------------+

In this table, serves as the primary key. It uniquely identifies each employee and cannot be null.

functions as a foreign key, linking to the of the employee's manager. This establishes a relationship between PROS Holdings employees and their managers, allowing for easy querying to find an employee's manager or see which employees report to a specific manager.

The table may also have multiple foreign keys that reference primary keys in other tables. For example, and foreign keys could be used to connect each employee to their respective department and location.

PROS SQL Interview Questions

SQL Question 4: Filter Customers with High Revenue and Active Accounts

As an employee of PROS Holdings, your task is to write an SQL query that filters the customer database to show only records of active customers who have spent more than $5000 in the last 12 months and had no refunds in this period.

"Active" customers are defined as those who have had their account longer than 3 months, and have purchased something in the last month.

Example Input:
Example Input:


This query first joins the Customers and Orders tables on customer_id and then filters based on several conditions. The WHERE clause finds customers who have been active for more than 3 months and have made a purchase in the last month. The purchase must have been made within the last year and should not be a refund. Finally, the HAVING clause filters for customers that spent more than $5000. The result is a list of customer_ids and the total amount they spent.

SQL Question 5: What does the clause do vs. the clause?

The clause is used to filter the groups created by the clause. It's similar to the clause, but it is used to specify conditions on the groups created by the clause, rather than on the individual rows of the table.

For example, say you were analyzing salaries for analytics employees at PROS Holdings:

This query retrieves the total salary for each Analytics department at PROS Holdings and groups the rows by the specific department (i.e. ""Marketing Analytics"", ""Business Analytics"", ""Sales Analytics"" teams).

The clause then filters the groups to include only PROS Holdings departments where the total salary is greater than $1 million

SQL Question 6: Calculate Click-through Conversion Rate

PROS Holdings is a company that offers a range of solutions to help businesses with their revenue and profit realization. Suppose PROS Holdings is selling digital products and want to understand the clickthrough conversion rates from viewing a product to adding a product to the cart to improve their marketing strategies. Specifically, they want to know the overall click-through conversion rate and the daily click-through conversion rates for the last 6 months.

You have given two types of user activity data. table records when a user viewed a product, and table records when a user added a product to the cart.

Your task is to write a query that calculates the click-through conversion rate, which is the number of times a product was added to the cart divided by the number of times it was viewed.

Example Input:
Example Input:


In the query above, the clause firstly creates a temporary result set called . In this subset, we calculate the number of product views and adds for each product per day in the last 6 months. In the main statement, we calculate the daily click-through conversion rate by dividing the number of product adds by the number of product views, and the function prevents division by zero when a product has been viewed but not added to the cart.

To practice another question about calculating rates, try this SQL interview question from TikTok on DataLemur's interactive coding environment: TikTok SQL Interview Question

SQL Question 7: How does the constraint function, and in what scenarios might it be useful?

The CHECK constraint is used to enforce rules on the data in a specific column. If a row is inserted or updated with data that does not follow the CHECK constraint's rule, the operation will fail.

For example, say you had a marketing analytics database that stores ad campaign data from PROS Holdings's Google Analytics account.

Here's what some constraints could look like:

The CHECK constraint is used in the above example to make sure that the "budget" and "cost_per_click" fields contain only positive values. This helps to maintain the validity and integrity of the data in the context of ad campaigns.

The CHECK constraint can also be used to enforce other specific conditions on data. For example, you can use it to ensure that the "start_date" for each ad campaign is earlier than the "end_date."

SQL Question 8: Filter Customers From A Specific Region.

PROS Holdings is a company that develops and sells software and services to pricing and revenue management professionals. They have a global footprint with diverse customer base. As an SQL developer for PROS, you are given a task to filter out customer records from the customer database that reside in a specific region.

You have a table with the following fields: , , , , . Your task is to write a query that filters out all the customers who reside in the 'North America' region.

Example Input:
111JohnDoejohn@example.comNorth America
113CarlosGomezcarlos@example.comLatin America
115PatrickO'Brienpatrick@example.comNorth America
Example Output:
111JohnDoejohn@example.comNorth America
115PatrickO'Brienpatrick@example.comNorth America


This PostgreSQL query filters out records from the table where the column matches the string 'North America'. As SQL is case-insensitive, it will return all the records where region is 'North America' regardless of the capitalization in the actual data. The keyword is used in the clause to search for the specified pattern in a column.

SQL Question 9: Retrieve the Most Purchased Product by Each Customer

As a data analyst on P.R.O.S Holdings company, you manage the customers' and products' databases. You need to retrieve a list of all customers along with the product that each has purchased most. In case of a tie, each product needs to be presented in the list.

For this task, you should join and aggregate the table that contains purchase history and the table that holds all the product information.

Example Input:
Example Input:
Example Input:
Expected Output:


This PostgreSQL query joins , , and tables together, creating a subquery that summarizes the number of purchases for each product by each customer. Then, it finds and lists the most purchased item per customer by using the clause.

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

PROS Holdings SQL Interview Tips

The best way to prepare for a SQL interview, besides making sure you have strong SQL fundamentals, is to practice a ton of real SQL questions that were asked in recent job interviews. In addition to solving the earlier PROS Holdings SQL interview questions, you should also solve the 200+ SQL questions from real Data Science & Analytics interviews which come from companies like Facebook, Google and unicorn tech startups. DataLemur SQL Interview Questions

Each exercise has multiple hints, step-by-step solutions and most importantly, there's an interactive coding environment so you can right online code up your SQL query and have it executed.

To prep for the PROS Holdings SQL interview it is also helpful to solve SQL problems from other tech companies like:

But if your SQL skills are weak, forget about diving straight into solving questions – go learn SQL with this free SQL tutorial.

SQL tutorial for Data Scientists & Analysts

This tutorial covers SQL concepts such as creating pairs via SELF-JOINs and aggregate functions – both of these show up routinely during PROS Holdings SQL assessments.

PROS Data Science Interview Tips

What Do PROS Holdings Data Science Interviews Cover?

In addition to SQL interview questions, the other topics to practice for the PROS Holdings Data Science Interview are:

PROS Holdings Data Scientist

How To Prepare for PROS Holdings Data Science Interviews?

The best way to prepare for PROS Holdings Data Science interviews is by reading Ace the Data Science Interview. The book's got:

  • 201 Interview Questions from tech companies like Netflix, Google, & Airbnb
  • A Refresher on Python, SQL & ML
  • Great Reviews (900+ 5-star reviews on Amazon)

Acing Data Science Interview