8 Baxter International SQL Interview Questions (Updated 2024)
Baxter International employees write SQL queries to analyze their patient database, helping them keep track of essential medical supplies and ensuring they have what’s needed for patient care. They also use SQL to get insights from clinical trial data, allowing them to develop better healthcare solutions, that is the reason why Baxter International includes SQL coding questions in interviews for Data Analytics, Data Science, and Data Engineering positions.
So, to help you practice for the Baxter International SQL interview, we've curated 8 Baxter International SQL interview questions in this blog.
8 Baxter International SQL Interview Questions
SQL Question 1: Identifying VIP Customer at Baxter International
Baxter International is a global medical products company and has a large number of customers. The company values its customers a lot, but it also has a category known as VIP customers. To the company, VIP customers are the ones who make large purchases, and they do so frequently.
This means, for a customer to be a VIP, they need to have at least $50,000 worth of purchases within the past year.
Assume we have a database table with the following columns:
- is the unique identifier of a purchase record.
- is the unique identifier of a customer.
- is the date a purchase was made.
- is the amount of money for that order.
Given the database table, write a SQL query that identifies the VIP customers.
Example Input:
| Id | CustomerId | PurchaseDate | Amount |
|---|---|---|---|
| 1 | 100 | 2021-01-01 | 5000 |
| 2 | 200 | 2021-02-01 | 2500 |
| 3 | 300 | 2021-03-01 | 75000 |
| 4 | 100 | 2021-04-01 | 45000 |
| 5 | 200 | 2021-05-01 | 5000 |
| 6 | 100 | 2021-06-01 | 5000 |
| 7 | 200 | 2021-07-01 | 5000 |
| 8 | 100 | 2021-08-01 | 5000 |
| 9 | 300 | 2021-09-01 | 2500 |
| 10 | 100 | 2021-10-01 | 5000 |
Answer:
The SQL query to do this would look like the following, in PostgreSQL:
The query looks at each purchase within the past year and groups them by . It then sums up the for each group and picks out the customers where the total is greater than or equal to 50,000.
This query returns all customers who have made a total purchase of at least $50,000 within the past year, hence, considered to be VIP users.
To practice a related super-user data analysis question on DataLemur's free interactive SQL code editor, try this Microsoft Teams Power User SQL Interview Question:
Visit Baxter International's newsroom to discover the latest updates on their commitment to improving patient care through innovative solutions! Understanding Baxter's initiatives can help you see how they are making a difference in the healthcare industry.
SQL Question 2: Employees Earning More Than Managers
Given a table of Baxter International employee salary data, write a SQL query to find employees who earn more than their own boss.
Baxter International 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 problem 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 confusing, you can find a step-by-step solution with hints here: Employees Earning More Than Their Boss.
SQL Question 3: What does the function do, and when would you use it?
The function can take in multiple paramaters, and returns the first input paramater that is not null. If all arguments are null, the function will return null too.
Suppose you have a table of Baxter International salespeople and the number of deals they closed. If a salesperson didn't close any deals, the data from the 3rd-party CRM system exports a NULL value.
| sales_person | closed_deals |
|---|---|
| Jason Wright | NULL |
| Drew Jackson | 3 |
| Chris Ho | NULL |
| Adam Cohen | 2 |
| Samantha Perez | 4 |
To change these NULLs to zeros, you can use the function in the following way:
This would result in the following data:
| sales_person | closed_deals |
|---|---|
| Jason Wright | 0 |
| Drew Jackson | 3 |
| Chris Ho | 0 |
| Adam Cohen | 2 |
| Samantha Perez | 4 |
SQL Question 4: Calculate the Average Sales of Each Product Over Time
As the business intelligence engineer at Baxter International, you are required to analyze the sales data for each product. Write a SQL query to calculate the average monthly sales for each product.
Also, calculate the moving average of sales over the last 3 months using a window function for each product and order the results by and .
For this question, we are provided with the table:
Example Input:
| sale_id | product_id | units_sold | sale_date |
|---|---|---|---|
| 1001 | 101 | 200 | 05/01/2022 |
| 1002 | 102 | 150 | 05/02/2022 |
| 1003 | 101 | 350 | 06/01/2022 |
| 1004 | 102 | 100 | 06/02/2022 |
| 1005 | 101 | 400 | 07/01/2022 |
| 1006 | 102 | 300 | 07/02/2022 |
| 1007 | 101 | 500 | 08/01/2022 |
| 1008 | 102 | 250 | 08/02/2022 |
Example Output:
| product_id | sale_month | avg_sales | 3_month_moving_avg |
|---|---|---|---|
| 101 | 05/2022 | 200 | NULL |
| 101 | 06/2022 | 350 | NULL |
| 101 | 07/2022 | 400 | 316.67 |
| 101 | 08/2022 | 500 | 416.67 |
| 102 | 05/2022 | 150 | NULL |
| 102 | 06/2022 | 100 | NULL |
| 102 | 07/2022 | 300 | 183.33 |
| 102 | 08/2022 | 250 | 216.67 |
Answer:
In this query, is used to separate the data based on . Then, the window function is used to calculate the average. The clause helps to define the window (range of rows) for each to calculate the moving average. is finally used to order the results by and .
For more window function practice, try this Uber SQL problem within DataLemur's interactive coding environment:
SQL Question 5: How do cross joins and natural joins differ?
Imagine you are organizing a party and have two database tables: one table of people you want to invite and another list of food items you want to serve.
A cross join would be like inviting every person on your list to the party and serving them every food item on the menu, regardless of whether they like the food or not. So, if you had 10 people on your invite list and 5 food items on the menu, you would generate all 50 different combinations of people and food (10 x 5 = 50).
On the other hand, a natural join would be like inviting only the people who like the food items on the menu (based on doing a inner/left/right/outer JOIN on a common key like ).
SQL Question 6: Baxter Equipment Utilization and Efficiency
Baxter International is a global diversified healthcare company that assists healthcare professionals and their patients with treatment of complex medical conditions. The company manages a fleet of healthcare equipment across various hospitals. Given the business scenario, please design a database that caters to the following business requirements:
- Be able to track all equipment including their respective types, purchase date, and conditions.
- Keep a record of which hospital each piece of equipment is currently located in.
- Track the usage of each piece of equipment (how many times it has been used, as well as when it was last used).
Subsequently, you would need to write a SQL query that retrieves the top 3 frequently used equipment in a hospital, for example in 'Hospital A'.
Example Input:
| equipment_id | type | purchase_date | condition |
|---|---|---|---|
| 1 | Ultrasound | 01/01/2018 | New |
| 2 | MRI Machine | 03/04/2017 | Used |
| 3 | X-Ray Machine | 12/11/2019 | New |
| 4 | CT Scanner | 08/01/2017 | Used |
| 5 | Ultrasound | 04/06/2020 | New |
Example Input:
| hospital_id | name | city | state |
|---|---|---|---|
| 1 | Hospital A | New York | NY |
| 2 | Hospital B | Chicago | IL |
| 3 | Hospital C | Dallas | TX |
| 4 | Hospital D | San Francisco | CA |
| 5 | Hospital E | Miami | FL |
Example Input:
| id | equipment_id | hospital_id | last_used |
|---|---|---|---|
| 1 | 1 | 1 | 08/08/2022 |
| 2 | 3 | 1 | 07/07/2022 |
| 3 | 5 | 1 | 06/06/2022 |
| 4 | 2 | 2 | 07/07/2022 |
| 5 | 4 | 2 | 06/06/2022 |
Example Input:
| id | equipment_id | usage_date |
|---|---|---|
| 1 | 1 | 03/11/2022 |
| 2 | 1 | 04/11/2022 |
| 3 | 1 | 05/11/2022 |
| 4 | 3 | 04/11/2022 |
| 5 | 3 | 05/11/2022 |
| 6 | 3 | 06/11/2022 |
| 7 | 2 | 05/11/2022 |
| 8 | 4 | 06/11/2022 |
| 9 | 5 | 07/11/2022 |
Answer:
This query retrieves the type of equipment and their usage frequency from Hospital A by joining the , , , and tables. The result is ordered in descending order by usage frequency and limited to the top 3 entries to get the most used equipment.
SQL Question 7: How do the SQL commands and differ?
No, in 99% of normal cases a and do NOT produce the same result.
You can think of more as set addition when it combines the results of two tables.
You can think of a more as set multiplication, producing all combos of table 1 with combos of table 2.
SQL Question 8: Analyzing average sales per customer and factoring industry type
Assume you have a customers table for Baxter International Inc. that contains information on different customers along with how much they have spent on Baxter's products. Also, you have an industries table that categorizes each customer by their industry. In this case, we want to find out the customer who made the maximum sales in each industry.
Please write a SQL query which will return each industry, the customer who made the maximum sales in each industry, and the total sales amount for that customer.
The table attributes:
| customer_id | name | total_sales |
|---|
The table attributes:
| industry_id | customer_id | industry_type |
|---|
Answer:
Here is a PostgreSQL query that can solve this problem:
This query first joins the and tables on . Then it groups the result by and , and for each group, it selects the maximum of . By doing this, we get each industry along with the customer who made the maximum sales in that industry and the total sales amount for that customer. Also note, for ties in the maximum sales, this query will return all customers who had the max sales. If we only want one record per industry in the case of such ties, we would need to decide on some mechanism of breaking the tie e.g. based on customer name or customer id etc.
Because joins come up routinely during SQL interviews, try this Snapchat JOIN SQL interview question:
Baxter International 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. Beyond just solving the above Baxter International SQL interview questions, you should also solve the 200+ DataLemur interview questions which come from companies like tech companies and healthcare and pharmaceutical companies like Baxter International.
Each DataLemur SQL question has hints to guide you, full answers and most importantly, there's an interactive SQL code editor so you can right in the browser run your SQL query answer and have it graded.
To prep for the Baxter International SQL interview it is also wise to practice SQL questions from other healthcare and pharmaceutical companies like:
But if your SQL query skills are weak, don't worry about going right into solving questions – refresh your SQL knowledge with this DataLemur SQL Tutorial.
This tutorial covers SQL topics like filtering data with WHERE and RANK vs. DENSE RANK – both of which show up frequently in SQL job interviews at Baxter International.
Baxter International Data Science Interview Tips
What Do Baxter International Data Science Interviews Cover?
Beyond writing SQL queries, the other question categories covered in the Baxter International Data Science Interview include:
- Probability & Stats Questions
- Python or R Coding Questions
- Product-Sense Questions
- ML Modelling Questions
- Behavioral Interview Questions centered on Baxter International values & principles
How To Prepare for Baxter International Data Science Interviews?
To prepare for Baxter International Data Science interviews read the book Ace the Data Science Interview because it's got:
- 201 interview questions taken from tech companies like Netflix, Google, & Airbnb
- a refresher on Product Analytics, SQL & ML
- over 1000+ 5-star reviews on Amazon
Don't forget about the behavioral interview – prepare for that using this Behavioral Interview Guide for Data Scientists.