10 Elevance Health SQL Interview Questions (Updated 2024)
Elevance Health employees write SQL queries to analyze patient data, helping them identify health trends and improve their wellness programs. They also optimize database queries to ensure quick and efficient data retrieval, which is crucial for providing timely care to patients, this is the reason why Elevance Health covers SQL query questions in interviews for Data Science, Data Engineering and Data Analytics jobs.
Thus, to help you practice, here's 10 Elevance Health SQL interview questions – can you answer each one?
10 Elevance Health SQL Interview Questions
SQL Question 1: Calculate Average Number of Appointments per Doctor
Elevance Health has a system where patients can book appointments with doctors. We have two tables, 'appointments' and 'doctors', which store information about each appointment and doctor, respectively.
A higher management is interested in how many appointments a doctor has on an average per month.
Write a SQL query to calculate the Average number of appointments per doctor for each month. The output should have the doctor id, month and average number of appointments per month.
Below are the table definitions and sample data for reference:
Example Input:
| appointment_id | doctor_id | appointment_date |
|---|---|---|
| 1 | 11 | 06/08/2022 00:00:00 |
| 2 | 22 | 06/10/2022 00:00:00 |
| 3 | 11 | 06/18/2022 00:00:00 |
| 4 | 33 | 07/26/2022 00:00:00 |
| 5 | 22 | 07/05/2022 00:00:00 |
Example Input:
| doctor_id | name |
|---|---|
| 11 | Max |
| 22 | Alex |
| 33 | Marry |
Example Output:
| month | doctor_id | avg_appointments |
|---|---|---|
| 6 | 11 | 2 |
| 6 | 22 | 1 |
| 7 | 22 | 1 |
| 7 | 33 | 1 |
Answer:
The query first JOINs the 'doctors' and 'appointments' tables on 'doctor_id'. Then it uses the window function to partition by 'doctor_id' and month of 'appointment_date' to calculate the 'avg_appointments' per doctor per month.
p.s. Window functions show up pretty often during SQL interviews, so practice the 27+ window function questions on DataLemur
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SQL Question 2: 2nd Highest Salary
Suppose there was a table of Elevance Health employee salary data. Write a SQL query to find the 2nd highest salary amongst all the .
Elevance Health Example Input:
| employee_id | salary |
|---|---|
| 1 | 2500 |
| 2 | 800 |
| 3 | 1000 |
| 4 | 1200 |
Example Output:
| second_highest_salary |
|---|
| 1200 |
Code your solution to this problem and run your code right in DataLemur's online SQL environment:
Answer:
You can find a detailed solution with hints here: 2nd Highest Salary.
SQL Question 3: What are the differences between an inner and a full outer join?
A full outer join returns all rows from both tables, including any unmatched rows, whereas an inner join only returns rows that match the join condition between the two tables.
For a tangible example, suppose you had a table of Elevance Health orders and Elevance Health customers.
Here's a SQL inner join using the orders and customers tables:
This query will return rows from the orders and customers tables that have matching values. Only rows with matching values will be included in the results.
Here is an example of a using the orders and customers tables:
This query will return all rows from both the orders and customers tables, including any rows that do not have matching values. Any rows with null values for either table will be included in the results.
SQL Question 4: Filter Patient Records based on Multiple Conditions
As a data analyst at Elevance Health, you are tasked to extract useful information from the patient records database. Write a PostgreSQL query to filter the records of patients who are above the age of 40, have a BMI higher than 25, and have been diagnosed with diabetes.
Expected input:
Example Input:
| patient_id | age | bmi | diabetes | last_checkup_date |
|---|---|---|---|---|
| 121 | 43 | 27.8 | True | 06/08/2022 |
| 242 | 35 | 23.5 | True | 06/10/2022 |
| 363 | 47 | 29.1 | True | 06/18/2022 |
| 484 | 39 | 26.5 | False | 07/26/2022 |
| 505 | 52 | 28.2 | True | 07/05/2022 |
Answer:
This query uses the clause to filter the patient records based on multiple conditions. It selects all columns from the database where the age is greater than , the BMI is higher than , and the patient has been diagnosed with . The operator is used to make sure all the conditions are met in the records that are returned.
SQL Question 5: What are the various forms of normalization?
Normalization is the process of organizing fields and tables of a database to minimize redundancy and dependency. While there are technically 5 levels (normal forms), the 3 most important normal forms you need to know about for SQL interviews at Elevance Health are:
- First Normal Form (1NF): This should fix remove a table's duplicate columns. Also, each column should contain only a single value (no lists or containers of data), and finally each row of table should have a unique identifier as well.
- Second Normal Form (2NF): A table is in its second normal form if it meets all requirements of the first normal form and places the subsets of columns in separate tables. The relationships between tables are created using primary/foreign keys.
- Third Normal Form (3NF): The table should be in the second normal form. There should be no dependency on another non-key attribute (meaning a primary key should be the only thing required to identify the row).
SQL Question 6: Calculate Click-Through Conversion Rates For Elevance Health
Elevance Health runs an online store that offers health products. The marketing team often looks at the click-through conversion rates. This measures the number of users who viewed a product to the number of users who added a product to the cart. You are required to calculate the click-through conversion rates for the past week.
Example Input:
| view_id | user_id | view_date | product_id |
|---|---|---|---|
| 101 | 10123 | 08/01/2023 | 10001 |
| 102 | 26500 | 08/02/2023 | 69852 |
| 103 | 36289 | 08/01/2023 | 10001 |
| 104 | 19234 | 08/03/2023 | 69852 |
| 105 | 98123 | 08/04/2023 | 10001 |
Example Input:
| add_id | user_id | add_date | product_id |
|---|---|---|---|
| 1001 | 10123 | 08/01/2023 | 10001 |
| 1002 | 26500 | 08/02/2023 | 69852 |
| 1003 | 36289 | 08/04/2023 | 10001 |
| 1004 | 19234 | 08/05/2023 | 69852 |
| 1005 | 36289 | 08/03/2023 | 10001 |
Answer:
This query will calculate click-through conversion rates for each product.
This query first identifies how many unique users viewed each product and added them to the cart. Then computes the conversion rate by dividing the distinct number of adds to cart by the number of unique product views. Using a left join ensures that all products that were viewed are included, even those not added to any cart. We are assuming views and additions to cart are within the same time period.
To solve a similar SQL interview question on DataLemur's free interactive coding environment, solve this Meta SQL interview question:
SQL Question 7: How does the LEAD() function differ from the LAG() function?
Both window functions are used to find rows at a given offset from the current row. However, will give you the rows AFTER the current row you. On the other hand, will give you the rows BEFORE the current row.
SQL Question 8: Calculating Average Number of Appointments per Doctor
Elevance Health, a digital health platform company, needs help understanding the appointment load on their doctors for better appointment management. Based on the company's data, you are tasked to write a query to return the average number of appointments each doctor had per month in 2022.
Here's a sample table:
Example Input:
| appointment_id | doctor_id | patient_id | appointment_date |
|---|---|---|---|
| 101 | 2001 | 3001 | 01/05/2022 |
| 102 | 2001 | 3002 | 01/08/2022 |
| 103 | 2002 | 3003 | 02/17/2022 |
| 104 | 2001 | 3004 | 03/21/2022 |
| 105 | 2003 | 3005 | 05/16/2022 |
Assuming that today's date is 05/16/2022.
Your job is to return the average number of appointments each doctor had per month from January to May.
Answer:
Here is the SQL query code block containing the solution:
This query first counts the number of appointments per doctor per month in a subquery. It then uses this data to calculate the average number of appointments for each doctor in the 2022 year.
SQL Question 9: Analyzing Customer Appointments and Health Issues
As a Data Analyst at Elevance Health, you have been given two tables, and .
The table contains data about all the appointments made by the customers including the appointment_id, customer_id, appointment_date and doctor_id.
| appointment_id | customer_id | appointment_date | doctor_id |
|---|---|---|---|
| 1001 | 475 | 01/08/2022 00:00:00 | 789 |
| 2005 | 857 | 04/10/2022 00:00:00 | 654 |
| 3002 | 634 | 06/18/2022 00:00:00 | 123 |
| 4003 | 857 | 07/26/2022 00:00:00 | 654 |
| 5006 | 475 | 07/05/2022 00:00:00 | 789 |
The table has information about the medical conditions of the customers including the issue_id, name of the issue, severity and the customer_id.
| issue_id | customer_id | issue_name | severity |
|---|---|---|---|
| 7081 | 475 | Hypertension | High |
| 9052 | 634 | Diabetes | Medium |
| 8043 | 857 | Asthma | Low |
| 7012 | 857 | Allergies | Low |
| 9017 | 634 | Heart Disease | High |
Write a SQL query to fetch all appointments made by the customers who have a 'High' severity health issue. List their appointment_id, appointment_date, doctor_id, and issue_name.
Answer:
This query is using a JOIN operation to combine the and tables based on the column. Then it's filtering out the results to only show the records where the of health issues is 'High'. The expected result would be the list of appointments along with their corresponding issue names that are of 'High' severity.
Because joins come up routinely during SQL interviews, take a stab at this SQL join question from Spotify:
SQL Question 10: What's the difference between a left and right join?
A join in SQL allows you to retrieve data from multiple tables and combine it into a single set of results.
To demonstrate the difference between left vs. right join, 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.
: 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.
How To Prepare for the Elevance Health SQL Interview
The key to acing a Elevance Health SQL interview is to practice, practice, and then practice some more! Besides solving the above Elevance Health SQL interview questions, you should also solve the 200+ DataLemur interview questions which come from companies like Microsoft, Google, Amazon, and tech startups.
Each problem on DataLemur has multiple hints, fully explained answers along with a discussion board to see how others solved it and most importantly, there is an interactive SQL code editor so you can instantly run your SQL query and have it graded.
To prep for the Elevance Health SQL interview you can also be a great idea to practice SQL problems from other healthcare and pharmaceutical companies like:
- Cardinal Health SQL questions
- Cigna SQL questions
- AmerisourceBergen SQL questions
- McKesson SQL questions
But if your SQL skills are weak, forget about diving straight into solving questions – improve your SQL foundations with this interactive SQL tutorial.
This tutorial covers SQL concepts such as working with string/text data and filtering groups with HAVING – both of these come up often in SQL interviews at Elevance Health.
Elevance Health Data Science Interview Tips
What Do Elevance Health Data Science Interviews Cover?
In addition to SQL query questions, the other topics tested in the Elevance Health Data Science Interview are:
- Probability & Stats Questions
- Python or R Coding Questions
- Product-Sense Questions
- ML Interview Questions
- Behavioral Interview Questions focussed on Elevance Health company values
How To Prepare for Elevance Health Data Science Interviews?
To prepare for Elevance Health Data Science interviews read the book Ace the Data Science Interview because it's got:
- 201 interview questions sourced from tech companies like Netflix, Google, & Airbnb
- a refresher on SQL, AB Testing & ML
- over 1000+ reviews on Amazon & 4.5-star rating
Don't forget about the behavioral interview – prep for that using this list of common Data Scientist behavioral interview questions.