9 Boston Scientific SQL Interview Questions (Updated 2024)
Data Analysts & Data Scientists at Boston Scientific write SQL queries to analyze medical device usage data, helping them identify patient trends and improve treatment outcomes. They also use SQL to manage complex clinical trial datasets, ensuring they meet regulatory compliance and maintain high standards of safety and effectiveness, which is why Boston Scientific includes SQL questions during job interviews.
To help you ace the Boston Scientific SQL interview, here’s 9 Boston Scientific SQL interview questions in this article.
9 Boston Scientific SQL Interview Questions
SQL Question 1: Monthly Average Star Rating Per Product
Boston Scientific would like to understand how their products are performing in terms of customer satisfaction. One measure they use is the average star rating given by users for each product, evaluated on a monthly basis. You are asked to write a SQL query that will compute the said metric: the average star rating per product for each month.
Given the table as,
Example Input:
| review_id | user_id | submit_date | product_id | stars |
|---|---|---|---|---|
| 6171 | 123 | 2020-06-08 | 50001 | 4 |
| 7802 | 265 | 2020-06-10 | 69852 | 4 |
| 5293 | 362 | 2020-06-18 | 50001 | 3 |
| 6352 | 192 | 2020-07-26 | 69852 | 3 |
| 4517 | 981 | 2020-07-05 | 69852 | 2 |
Please calculate the average star rating per product for each month.
Example Output:
| mth | product | avg_stars |
|---|---|---|
| 6 | 50001 | 3.50 |
| 6 | 69852 | 4.00 |
| 7 | 69852 | 2.50 |
Answer:
Here is a PostgreSQL-friendly query that computes the above. Notice how we extract the month from using the function. We then use the function to round to two decimal places for presentation:
This solution works by first extracting the month from each date, and grouping all star ratings by both the extracted month and . It thus effectively computes the average star rating by product for each individual month. The results are finally sorted first by month, and then by average star rating in descending order.
Pro Tip: Window functions are a popular SQL interview topic, so practice all the window function problems on DataLemur
Check out Boston Scientific's news to learn about their innovative approaches and advancements in medical technology! This information can provide valuable insights into how they are enhancing patient care and driving healthcare innovation.
SQL Question 2: Top 3 Department Salaries
Given a table of Boston Scientific employee salaries, write a SQL query to find the top three highest paid employees in each department.
Boston Scientific Example Input:
| employee_id | name | salary | department_id |
|---|---|---|---|
| 1 | Emma Thompson | 3800 | 1 |
| 2 | Daniel Rodriguez | 2230 | 1 |
| 3 | Olivia Smith | 2000 | 1 |
| 4 | Noah Johnson | 6800 | 2 |
| 5 | Sophia Martinez | 1750 | 1 |
| 8 | William Davis | 6800 | 2 |
| 10 | James Anderson | 4000 | 1 |
Example Input:
| department_id | department_name |
|---|---|
| 1 | Data Analytics |
| 2 | Data Science |
Example Output:
| department_name | name | salary |
|---|---|---|
| Data Analytics | James Anderson | 4000 |
| Data Analytics | Emma Thompson | 3800 |
| Data Analytics | Daniel Rodriguez | 2230 |
| Data Science | Noah Johnson | 6800 |
| Data Science | William Davis | 6800 |
You can solve this problem and run your code right in DataLemur's online SQL environment:
Answer:
We use the DENSE_RANK() window function to generate unique ranks for each employee's salary within their department, with higher salaries receiving lower ranks. Then, we wrap this up in a CTE and filter the employees with a ranking of 3 or lower.
If the code above is hard to understand, you can find a step-by-step solution with hints here: Top 3 Department Salaries.
SQL Question 3: Can you explain the difference between a foreign and primary key in a database?
To explain the difference between a primary key and foreign key, let's start with an example Boston Scientific sales database:
:
| order_id | product_id | customer_id | quantity |
|---|---|---|---|
| 1 | 303 | 1 | 2 |
| 2 | 404 | 1 | 1 |
| 3 | 505 | 2 | 3 |
| 4 | 303 | 3 | 1 |
In this table, could be a primary key. It is unique for each row in the table and cannot contain null values.
and could both be foreign keys. They reference the primary keys of other tables, such as a table and a table, respectively. This establishes a relationship between the table and the other tables, ensuring that each row in the sales database corresponds to a specific product and a specific customer.
SQL Question 4: Designing Database for Medical Device Inventory
Boston Scientific is a leading innovator of medical devices. You are assigned the task of designing a database to manage their inventory. The features they're interested in include logging every time a device moves out, the ability to track devices based on their batch number and the manufacturing date, and the hospital the devices are sent to.
For simplicity, assume each device's and are unique. And each hospital's is also unique.
Please design the tables required for the above problem and create some sample data for these tables. Once you've done that, write a SQL query to retrieve all devices sent to Hospital ID 002 during the month of August, 2022.
Below are the tables, and .
Example Input:
| device_id | batch_number | manufacture_date |
|---|---|---|
| 01 | Batch001 | 01/20/2022 00:00:00 |
| 02 | Batch001 | 01/20/2022 00:00:00 |
| 03 | Batch002 | 03/17/2022 00:00:00 |
| 04 | Batch003 | 04/29/2022 00:00:00 |
| 05 | Batch003 | 04/29/2022 00:00:00 |
Example Input:
| log_id | device_id | date_moved_out | hospital_id |
|---|---|---|---|
| 001 | 01 | 08/02/2022 00:00:00 | 001 |
| 002 | 02 | 08/05/2022 00:00:00 | 002 |
| 003 | 03 | 08/13/2022 00:00:00 | 002 |
| 004 | 04 | 08/21/2022 00:00:00 | 003 |
| 005 | 05 | 08/28/2022 00:00:00 | 002 |
Answer:
This PostgreSQL query first joins the and the tables using the key. It then applies a filter to retrieve only those rows where is '002' and falls in August, 2022. The function is used to truncate the to the month, so it can be compared directly to '08/01/2022 00:00:00'. This query returns the device ID, batch number and manufacture date of all such devices.
SQL Question 5: What's the difference between a one-to-one and one-to-many relationship?
In database schema design, a one-to-one relationship between two entities is characterized by each entity being related to a single instance of the other. An example of this is the relationship between a US citizen and their social-security number (SSN) - each citizen has one SSN, and each SSN belongs to one person.
On the other hand, a one-to-many relationship is when one entity can be associated with multiple instances of the other entity. A teacher's relationship with their classes is an example of this - a teacher can teach many classes, but each class is only associated with one teacher.
SQL Question 6: Filter Customers with Specific Conditions
Boston Scientific has a massive database of customer purchases. You are asked to filter out those customers who purchased a particular product, let's say Product X, between January 2022 and July 2022, and whose total expenditure is greater than $5000 during this period. You also need to exclude any customers who are not from the USA. For this task, you will be provided two tables - and .
Example Input:
| purchase_id | customer_id | product | purchase_date | amount |
|---|---|---|---|---|
| 1 | 102 | Product A | 01/15/2022 | $150 |
| 2 | 102 | Product X | 02/20/2022 | $1000 |
| 3 | 283 | Product X | 03/10/2022 | $600 |
| 4 | 102 | Product B | 03/25/2022 | $4500 |
| 5 | 473 | Product X | 05/01/2022 | $500 |
| 6 | 283 | Product Y | 06/21/2022 | $800 |
| 7 | 190 | Product X | 07/15/2022 | $1000 |
| 8 | 102 | Product X | 07/20/2022 | $1000 |
| 9 | 190 | Product Z | 01/01/2022 | $400 |
| 10 | 190 | Product X | 04/05/2022 | $1200 |
Example Input:
| customer_id | name | country |
|---|---|---|
| 102 | John Smith | USA |
| 283 | Maria Rodriguez | USA |
| 473 | Chen Wei | China |
| 190 | Oliver Jones | USA |
Answer:
This query first filters out the customer IDs who have purchased 'Product X' between January and July 2022, and whose total expenditure during this period exceeds $5000 (from the table). Then, from this filtered list, it selects the customers who are from the USA (from the table).
SQL Question 7: What's a database view, and what's their purpose?
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 government 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 8: Find The Average Sale Price by Sales Rep
As a data analyst at Boston Scientific, your manager wants to understand the sales performance with respect to the average sale price of each sales representative in the current year. Can you write a SQL query to find the average sale price of each sales representative?
:
| sales_person_id | first_name | last_name |
|---|---|---|
| 512 | John | Doe |
| 783 | Jane | Doe |
| 179 | Jake | Smith |
| 234 | Julia | Jones |
:
| sale_id | sales_person_id | sale_date | sale_price |
|---|---|---|---|
| 4182 | 512 | 01/06/2022 00:00:00 | 2500 |
| 5783 | 783 | 02/08/2022 00:00:00 | 3500 |
| 3184 | 179 | 01/10/2022 00:00:00 | 1500 |
| 2451 | 512 | 03/05/2022 00:00:00 | 3000 |
| 4891 | 783 | 04/07/2022 00:00:00 | 2000 |
Answer:
Each sales representative's first and last name will be selected, along with the average of their sale price over the current year. This average is displayed as . Here, is used to only consider the sales happening in the current year. The clause is applied on both and to calculate the average for each sales representative. If a sales representative has made no sales in the current year, they will not be included in the result set.
To practice a very similar question try this interactive Amazon Highest-Grossing Items Question which is similar for using calculations within sales data or this Wayfair Y-on-Y Growth Rate Question which is similar for focusing on metrics related to sales.
SQL Question 9: Analyze Customer Purchases and Feedback
Boston Scientific wants to analyze the relationship between customer purchases and product reviews. They have a 'customers' table detailing customer demographics and a 'reviews' table with customer reviews of the various products they have purchased.
We want to write a SQL query to join these tables and provide insights on the feedback given by customers from different states. The output should include the state, product_id, and average stars given.
table:
| customer_id | name | state |
|---|---|---|
| 123 | John Doe | Massachusetts |
| 265 | Jane Smith | Minnesota |
| 362 | Emma Johnson | California |
| 192 | Michael Brown | Florida |
| 981 | Olivia Davis | Texas |
table:
| review_id | customer_id | submit_date | product_id | stars |
|---|---|---|---|---|
| 6171 | 123 | 06/08/2022 00:00:00 | 50001 | 4 |
| 7802 | 265 | 06/10/2022 00:00:00 | 69852 | 4 |
| 5293 | 362 | 06/18/2022 00:00:00 | 50001 | 3 |
| 6352 | 192 | 07/26/2022 00:00:00 | 69852 | 3 |
| 4517 | 981 | 07/05/2022 00:00:00 | 69852 | 2 |
Answer:
This SQL query performs an operation between the and tables based on the field. It then groups the result by and , calculating the average for each group using the function.
Since joins come up routinely during SQL interviews, try this interactive Snapchat SQL Interview question using JOINS:
How To Prepare for the Boston Scientific SQL Interview
The best way to prepare for a Boston Scientific SQL interview is to practice, practice, practice. Besides solving the earlier Boston Scientific SQL interview questions, you should also solve the 200+ SQL questions on DataLemur which come from companies like FAANG (FB, Apple, Amazon, Netflix, Google).
Each SQL question has multiple hints, detailed solutions and crucially, there's an interactive coding environment so you can instantly run your SQL query answer and have it executed.
To prep for the Boston Scientific SQL interview it is also wise to practice SQL problems from other healthcare and pharmaceutical companies like:
- Community Health Systems SQL questions
- Henry Schein SQL questions
- Universal Health Services SQL questions
- Baxter International SQL questions
However, if your SQL coding skills are weak, don't worry about jumping right into solving questions – improve your SQL foundations with this DataLemur SQL tutorial.
This tutorial covers SQL concepts such as filtering data with WHERE and handling strings – both of these pop up routinely during SQL interviews at Boston Scientific.
Boston Scientific Data Science Interview Tips
What Do Boston Scientific Data Science Interviews Cover?
Beyond writing SQL queries, the other topics to practice for the Boston Scientific Data Science Interview are:
- Probability & Stats Questions
- Python or R Programming Questions
- Product Analytics Questions
- Machine Learning Questions
- Resume-Based Behavioral Questions
How To Prepare for Boston Scientific Data Science Interviews?
I believe the best way to study for Boston Scientific Data Science interviews is to read the book I wrote: Ace the Data Science Interview.
It covers 201 data interview questions taken from Google, Microsoft & tech startups. The book's also got a crash course covering Python, SQL & ML. And finally it's helped thousands of people land their dream job in data, which is why it's earned 1000+ reviews on Amazon and a 4.5-star rating.
While the book is more technical, it's also crucial to prepare for the Boston Scientific behavioral interview. Start by reading the company's cultural values.