9 Capgemini SQL Interview Questions (Updated 2024)
At Capgemini, SQL is used to analyze customer purchase behavior and sales data from large retail databases to identify trends and optimize marketing strategies. It is also used to manage data storage for efficient processing of large datasets in IT consulting projects, the reason why Capgemini asks SQL questions during interviews for Data Science, Analytics, and & Data Engineering jobs.
Thus, to help prep you for the Capgemini SQL interview, we've collected 9 Capgemini SQL interview questions – scroll down to start solving them!
9 Capgemini SQL Interview Questions
SQL Question 1: Identifying Power Users in Capgemini
Capgemini provides multiple services to its clients, one of which is the use of its custom software. From Capgemini's database of clients using this software, identify the "Power Users". Power Users are defined as clients who use Capgemini's software more than 5 times per week on average.
Consider the following tables that show some details of the clients and their respective logins.
Example Input:
| employee_id | client_name |
|---|---|
| 2431 | ABC Consultants |
| 3716 | Zeta Corporation |
| 4293 | Gamma Enterprises |
| 5632 | Delta Services |
| 6427 | Beta Technologies |
Example Input:
| log_id | employee_id | login_date |
|---|---|---|
| 7381 | 2431 | 07/05/2022 |
| 8127 | 3716 | 07/06/2022 |
| 6743 | 4293 | 07/06/2022 |
| 9823 | 5632 | 07/07/2022 |
| 6257 | 6427 | 07/07/2022 |
For the above SQL question, write a PostgreSQL query to identify these power users.
Answer:
This query first calculates the number of times each client has logged in during the last week. It then determines the average number of logins across all the weeks by each client, and filters out those with the average usage greater than 5, which is our criterion for a 'Power User'.
To work on another SQL customer analytics question where you can solve it right in the browser and have your SQL solution instantly graded, try this Walmart Labs SQL Interview Question:
SQL Question 2: Highly-Paid Employees
Given a table of Capgemini employee salaries, write a SQL query to find all employees who make more money than their direct boss.
Capgemini 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.
Test your SQL query for 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 solution above is tough, you can find a detailed solution here: Highly-Paid Employees.
SQL Question 3: How are left and right joins different from each other?
Both left and right joins in SQL allow you to combine data from different tables based on a shared key or set of keys. For a concrete example of the difference between these two join types, say you had sales data exported from Capgemini's Salesforce CRM stored in a PostgreSQL database, and had access to two tables: and .
: retrieves all rows from the left table (in this case, the sales table) and any matching rows from the right table (the table). If there is no match in the right table, NULL values will be returned for the right table's columns.
: retrieves all rows from the right table (in this case, the customers table) and any matching rows from the left table (the sales table). If there is no match in the left table, NULL values will be returned for the left table's columns.
SQL Question 4: Calculating Monthly Average Review Score per Product
In a business setting, it is essential for a company like Capgemini to keep track on how their products are performing in terms of customer reviews. Moreover, understanding the changes in the review scores over time is equally critical.
You are given a table with a list of user reviews submitted for different products. The table has the following 5 columns:
- (integer): a unique identifier for each review.
- (integer): a unique identifier for each user.
- (timestamp): the date and time when the review was submitted.
- (integer): a unique identifier for each product.
- (integer): the scores of the review (from 1 to 5).
Could you write a SQL query to calculate the monthly average review score for each product? Your output should be sorted in the order of the month (ascending) and then the product_id (ascending).
Example Input:
| review_id | user_id | submit_date | product_id | stars |
|---|---|---|---|---|
| 6171 | 123 | 2022-06-08 00:00:00 | 50001 | 4 |
| 7802 | 265 | 2022-06-10 00:00:00 | 69852 | 4 |
| 5293 | 362 | 2022-06-18 00:00:00 | 50001 | 3 |
| 6352 | 192 | 2022-07-26 00:00:00 | 69852 | 3 |
| 4517 | 981 | 2022-07-05 00:00:00 | 69852 | 2 |
Answer:
In this query, we use the function to get the month from the . The aggregate function is used to calculate the average , and we round it to two decimals with . We both and , and finally and field in ascending order.
Example Output:
| mth | product_id | avg_stars |
|---|---|---|
| 6 | 50001 | 3.50 |
| 6 | 69852 | 4.00 |
| 7 | 69852 | 2.50 |
p.s. Window functions show up pretty often during SQL interviews, so practice the 27+ window function questions on DataLemur
SQL Question 5: Can you explain the meaning of database denormalization?
Denormalization is the practice of altering a database schema in a way that breaks the normalization rules (1st, 2nd, 3rd normal forms).
Denormalization is done to improve the performance of the database when it is being used for online analytics processing (OLAP), rather than online transaction processing (OLTP) use cases.
For these OLAP use cases, you're bottleneck frequently is joining multiple tables, but de-normalizing your database cuts these outs.
Denormalization can improve query performance by reducing the number of expensive joins required to retrieve data, but it comes with its own drawbacks too. By adding redundant columns, you incur more data storage costs, and there's need for more complex update and delete operations in order to maintain data integrity across all the duplicated data. Thus, it's important to carefully consider the trade-offs involved before implementing denormalization.
SQL Question 6: Average Consulting Service Rating for Capgemini
As a data analyst at Capgemini, you've been asked to provide a summary of client feedback on different consulting services for each month. Specifically, your manager wants to see the average client rating for each service provided by Capgemini every month.
Example Input:
| feedback_id | client_id | submit_date | service_id | rating |
|---|---|---|---|---|
| 101 | 324 | 06/08/2022 00:00:00 | 1001 | 4 |
| 202 | 265 | 06/10/2022 00:00:00 | 2002 | 5 |
| 303 | 362 | 06/15/2022 00:00:00 | 1001 | 3 |
| 404 | 192 | 07/26/2022 00:00:00 | 1001 | 4 |
| 505 | 981 | 07/29/2022 00:00:00 | 2002 | 5 |
Each row corresponds to a client's feedback about a consulting service. The column uses a 1-to-5 scale, with 5 being the highest.
Answer:
This PostgreSQL query groups the feedback entries by month and service, calculating the average rating for each pair. The function is used to get the month part of the submission date. With this query, we can monitor how well we are doing in terms of different services on a monthly basis.
Example Output:
| month | service_id | avg_rating |
|---|---|---|
| 6 | 1001 | 3.5 |
| 6 | 2002 | 5.0 |
| 7 | 1001 | 4.0 |
| 7 | 2002 | 5.0 |
SQL Question 7: Name the different types of joins in SQL. What does each one do?
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: Find Customers Matching Specified Pattern
Capgemini has a large customer base and you are required to filter the customers whose names starts with 'CAP'. For this task, you are given a customer records database. Write an SQL query to find all records where starts with 'CAP'.
Here's the database table for your reference:
Example Input:
| CustomerID | CustomerName | ContactName | Country |
|---|---|---|---|
| 0001 | CAPSmith | John Smith | USA |
| 0002 | JohnsonCAP | Johnson Jones | UK |
| 0003 | CAPStevenson | Steve Stevenson | USA |
| 0004 | FreemanCAP | Morgan Freeman | Canada |
| 0005 | CapitoneMaria | Maria Capitone | Italy |
Answer:
This PostgreSQL query searches the table and filters out those records where starts with 'CAP'. The '%' character in the LIKE clause is a wildcard that matches any sequence of characters. So 'CAP%' matches any string that starts with 'CAP'.
SQL Question 9: Analyzing Product Sales and Joining with Customer Information
Suppose Capgemini has a database with a table capturing the sales data, and a table capturing customer data. The database needs to analyze the sales data by joining the and tables to find out the total sales generated by customers from each city.
The table captures the , , , and . The table, on the other hand, holds customer details including , , , and .
Write a SQL query to return the total sales generated from each city.
Example Input:
| sale_id | customer_id | product_id | sale_price | sale_date |
|---|---|---|---|---|
| 1 | 45 | 89012 | 450.00 | 06/08/2022 |
| 2 | 32 | 43560 | 213.00 | 06/10/2022 |
| 3 | 45 | 89012 | 450.00 | 06/18/2022 |
| 4 | 56 | 78452 | 270.00 | 07/26/2022 |
| 5 | 32 | 43560 | 213.00 | 07/05/2022 |
Example Input:
| customer_id | first_name | last_name | city |
|---|---|---|---|
| 45 | John | Doe | New York |
| 32 | Jane | Smith | Chicago |
| 56 | Marie | Johnson | Los Angeles |
Answer:
This query joins the and tables on the column which is common to both tables. It then groups the results by the column in the table and sums up the for each grouped city, resulting in the total sales for each city. Running this query on the given data would return the total sales generated from New York, Chicago, and Los Angeles.
Since joins come up so often during SQL interviews, try this Spotify JOIN SQL question:
Capgemini SQL Interview Tips
Assuming that you've already got basic SQL skills, the next best tip we have to prepare for the Capgemini SQL interview is to solve as many practice SQL interview questions as you can! Beyond just solving the earlier Capgemini SQL interview questions, you should also solve the 200+ SQL coding questions which come from companies like Google, Uber, and Microsoft.
Each SQL question has multiple hints, step-by-step solutions and best of all, there is an online SQL code editor so you can right in the browser run your SQL query and have it graded.
To prep for the Capgemini SQL interview you can also be wise to solve SQL problems from other consulting and professional service companies like:
Discover how Capgemini is helping businesses harness the potential of data and AI to drive growth!
But if your SQL foundations are weak, don't worry about diving straight into solving questions – improve your SQL foundations with this SQL tutorial for Data Scientists & Analysts.
This tutorial covers things like cleaning text data and CASE/WHEN/ELSE statements – both of which come up often in Capgemini interviews.
Capgemini Data Science Interview Tips
What Do Capgemini Data Science Interviews Cover?
In addition to SQL interview questions, the other types of problems to practice for the Capgemini Data Science Interview include:
- Statistics and Probability Questions
- Python Pandas or R Coding Questions
- Product Metrics Interview Questions
- ML Interview Questions
- Behavioral Questions centered on Capgemini culture and values
How To Prepare for Capgemini Data Science Interviews?
To prepare for Capgemini Data Science interviews read the book Ace the Data Science Interview because it's got:
- 201 interview questions sourced from Facebook, Google, & Amazon
- a refresher on Python, SQL & ML
- over 1000+ 5-star reviews on Amazon
Also focus on the behavioral interview – prepare for it using this guide on acing behavioral interviews.