9 Select Medical Holdings SQL Interview Questions (Updated 2024)
At Select Medical Holdings, SQL is used to analyze patient data to figure out the best care strategies for individuals, ensuring they receive the most effective treatments. The company also relies on SQL to handle vast amounts of healthcare data, making sure they meet all the necessary regulatory compliance requirements, this is the reason why Select Medical Holdings ask SQL questions during interviews for Data Science, Analytics, and Data Engineering jobs.
Thus, to help you prep, here's 9 Select Medical Holdings SQL interview questions – can you solve them?
9 Select Medical Holdings SQL Interview Questions
SQL Question 1: Calculate the Average Rating of Each Medical Facility
As a data analyst at Select Medical Holdings, you are tasked with finding out the average patient satisfaction rating of each of their medical facilities for each month. This will help the company identify the performance of their facilities and make informed decisions to improve patient experience.
To do this, you will need to write a SQL query that calculates the average rating of each facility for each month. The data is stored in a table, with rows being individual feedbacks containing a , , , and (1 to 5).
Example Input:
| feedback_id | patient_id | submit_date | facility_id | stars |
|---|---|---|---|---|
| 6171 | 123 | 2021-08-06 | 20001 | 4 |
| 7802 | 265 | 2021-10-06 | 30002 | 3 |
| 5293 | 362 | 2021-06-18 | 20001 | 5 |
| 6352 | 192 | 2021-06-26 | 30002 | 2 |
| 4517 | 981 | 2021-05-05 | 30002 | 4 |
Example Input:
| facility_id | facility_name |
|---|---|
| 20001 | Philly General Hospital |
| 30002 | New York City Medical |
Answer:
This query first truncates the to the month, effectively treating all days in the same month as equal. It then partitions the table by and by month, then computes the average stars within each partition. Note the use of window function .
The use of JOIN is required to get the from the table based on the from the table.
Finally, it sorts the result by month and in descending order, showing the highest-rated facilities first.
To solve a similar window function interview problem which uses RANK() on DataLemur's free online SQL coding environment, solve this Amazon SQL question asked in a BI Engineer interview:
Check out Select Medical Holdings' media center for the latest articles and news that highlight their dedication to providing high-quality healthcare services! Understanding their initiatives can give you a better perspective on how they are making a difference in patient care.
SQL Question 2: Department Salaries
You're given a table of Select Medical Holdings employee and department salary data. Write a SQL query to find departments where the departments average salary is higher than the company's average salary.
Write a SQL query for this question directly within the browser on DataLemur:
The answer is LONG – 30+ lines of SQL. You can find a detailed solution with hints here: Department Salaries.
SQL Question 3: What's a database view, and when would you use one?
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 just like a regular table?
Views are useful for creating a simplified version of your data for specific users, or for hiding sensitive data from certain users while still allowing them to access other data.
SQL Question 4: Filter Patients Based on Conditions
In Select Medical Holdings, we have patients coming in from various cities suffering from different health conditions. Write a SQL query to filter patients who are from 'New York' or 'Chicago' and have a health condition 'Heart Disease' or 'Diabetes' from the customer records.
Here are the definition and example records for the table:
Example Input:
| patient_id | name | city | health_condition |
|---|---|---|---|
| 1100 | John Doe | New York | Heart Disease |
| 1101 | Jane Smith | Chicago | Diabetes |
| 1102 | Bob Johnson | Los Angeles | Cancer |
| 1103 | Alice Williams | New York | Diabetes |
| 1104 | Charlie Brown | Chicago | Heart Disease |
| 1105 | David Jones | Dallas | High Blood Pressure |
We would like to get the following output:
Example Output:
| patient_id | name | city | health_condition |
|---|---|---|---|
| 1100 | John Doe | New York | Heart Disease |
| 1101 | Jane Smith | Chicago | Diabetes |
| 1103 | Alice Williams | New York | Diabetes |
| 1104 | Charlie Brown | Chicago | Heart Disease |
Answer:
This query filters the rows from the table where the column is either 'New York' or 'Chicago' and the column is either 'Heart Disease' or 'Diabetes'. The operator ensures that both conditions must be satisfied. The operator within the conditions allows for any of the specified options to be true.
SQL Question 5: Why would you use the SQL constraint?
The 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 constraint's rule, the operation will fail.
For example, say you had a database that stores ad campaign data from Select Medical Holdings's Google Analytics account.
Here's what some constraints could look like:
In this example, the constraint is used to ensure that the and fields have positive values. This helps to ensure that the data in the database is valid and makes sense in the context of ad campaigns.
You can also use the constraint to ensure that data meets other specific conditions. For example, you could use a constraint to ensure that the is before the for each ad campaign.
SQL Question 6: Analyzing Click-Through Rate and Conversion for Select Medical Holdings
For Select Medical Holdings, which specializes in providing long term acute care, rehabilitation services, and outpatient care in the U.S., we might be interested in their online marketing campaign effectiveness to drive more appointments booking.
For simplicity, let's assume we have two tables and . The table records the clicks on the ads, with ,, , and . The table records the booked appointments, with , , and .
Sample table:
| click_id | ad_id | user_id | click_date |
|---|---|---|---|
| 1543 | 001 | 101 | 07/12/2022 00:00:00 |
| 1578 | 002 | 102 | 07/13/2022 00:00:00 |
| 1590 | 001 | 101 | 07/14/2022 00:00:00 |
| 1611 | 002 | 103 | 07/14/2022 00:00:00 |
| 1800 | 001 | 104 | 07/15/2022 00:00:00 |
Sample table:
| appointment_id | user_id | ad_id | booking_date |
|---|---|---|---|
| 713 | 101 | 001 | 07/14/2022 00:00:00 |
| 765 | 102 | 002 | 07/14/2022 00:00:00 |
| 787 | 101 | 001 | 07/15/2022 00:00:00 |
| 823 | 103 | 002 | 07/16/2022 00:00:00 |
| 851 | 104 | 001 | 07/17/2022 00:00:00 |
The question could be: Given these two tables, calculate the daily click-through rate (i.e., the number of unique users who clicked on an ad divided by the total number of clicks) and the conversion rate (i.e., the number of unique users who booked an appointment after clicking on an ad divided by the number of unique users who clicked on an ad), for each ad.
Answer:
This query calculates the daily click-through rate and conversion rate for each ad by first determining the number of total and unique clicks by ad and date, and the number of unique appointments (where the user clicked on an ad) by ad and date. It then divides the number of unique clicks by the total number of clicks to get the click-through rate, and the number of unique appointments by the number of unique clicks to get the conversion rate.
To solve a related SQL interview question on DataLemur's free interactive SQL code editor, solve this SQL interview question asked by Facebook:
SQL Question 7: What's the difference between a left and right join?
In SQL, both a left and right join is used to combine rows from different tables based on a shared key or set of keys, resulting in a single merged table of data. However, here's the difference:
LEFT (OUTER) JOIN: Retrieves all the records/rows from the left and the matched records/rows from the right table.
RIGHT (OUTER) JOIN: Retrieves all the records/rows from the right and the matched records/rows from the left table.
SQL Question 8: Average Treatment Cost Per Department
For "Select Medical Holdings", a company that specializes in clinical rehabilitation, we would like to investigate how the treatments costs vary across different departments within each hospital. In particular, can you calculate the Average cost of treatments performed by each department in each hospital based on the given sample data?
Example Input:
| treatment_id | hospital_id | department_id | treatment_cost |
|---|---|---|---|
| 5012 | 1 | 201 | 500 |
| 5013 | 1 | 202 | 1000 |
| 5014 | 2 | 203 | 1500 |
| 5015 | 1 | 201 | 700 |
| 5016 | 2 | 202 | 200 |
Example Output:
| hospital_id | department_id | average_cost |
|---|---|---|
| 1 | 201 | 600 |
| 1 | 202 | 1000 |
| 2 | 202 | 200 |
| 2 | 203 | 1500 |
Answer:
This query takes the table and calculates the average treatment cost () for each department () in each hospital (). The result is a table with each hospital_id, its departments and the average cost of treatments in that department.
SQL Question 9: Customer and Payments Analysis
As a Data Analyst at Select Medical Holdings, you are tasked with understanding the payment behavior of the customers. You've been given access to the and tables. The table has details about each payment such as , , and paid. The table has , , , and .
You need to write a SQL query that lists all customers together with their total payment amount. If a customer has no records in the table, they should still be included in the output with a total payment amount of 0.
Example Input:
| customer_id | first_name | last_name | |
|---|---|---|---|
| 123 | John | Doe | john.doe@example.com |
| 265 | Jane | Smith | jane.smith@example.com |
| 362 | Jim | Brown | jim.brown@example.com |
| 192 | Jill | Jones | jill.jones@example.com |
| 981 | Jack | Johnson | jack.johnson@example.com |
Example Input:
| payment_id | customer_id | payment_date | amount |
|---|---|---|---|
| 1 | 123 | 06/08/2022 00:00:00 | 150.00 |
| 2 | 265 | 06/10/2022 00:00:00 | 200.50 |
| 3 | 192 | 06/18/2022 00:00:00 | 350.70 |
| 4 | 123 | 07/26/2022 00:00:00 | 125.00 |
| 5 | 981 | 07/05/2022 00:00:00 | 300.00 |
Answer:
This SQL query uses a to combine the and tables. By grouping on the customer's details and using the function on the column, we calculate the total payment for each customer. The function is used to ensure that if a customer has no related payments in the table, their total payment will be 0 rather than .
Because join questions come up routinely during SQL interviews, try this Spotify JOIN SQL question:
Preparing For The Select Medical Holdings SQL Interview
The best way to prepare for a Select Medical Holdings SQL interview is to practice, practice, practice. In addition to solving the above Select Medical Holdings SQL interview questions, you should also solve the 200+ SQL questions from real Data Science & Analytics interviews which come from companies like Microsoft, Google, Amazon, and tech startups.
Each DataLemur SQL question has hints to guide you, step-by-step solutions and most importantly, there is an interactive coding environment so you can easily right in the browser your query and have it checked.
To prep for the Select Medical Holdings SQL interview it is also a great idea to practice interview questions from other healthcare and pharmaceutical companies like:
- Vertex Pharmaceuticals SQL questions
- Zoetis SQL questions
- Zimmer Biomet Holdings SQL questions
- Owens & Minor SQL questions
In case your SQL query skills are weak, forget about going right into solving questions – refresh your SQL knowledge with this DataLemur SQL tutorial.
This tutorial covers SQL concepts such as aggregate functions like SUM()/COUNT()/AVG() and handling timestamps – both of which pop up frequently in Select Medical Holdings SQL interviews.
Select Medical Holdings Data Science Interview Tips
What Do Select Medical Holdings Data Science Interviews Cover?
In addition to SQL interview questions, the other types of problems tested in the Select Medical Holdings Data Science Interview are:
- Statistics and AB Testing Questions
- Python or R Programming Questions
- Product Data Science Interview Questions
- ML Interview Questions
- Behavioral Questions based on Select Medical Holdings company values
How To Prepare for Select Medical Holdings Data Science Interviews?
To prepare for Select Medical Holdings Data Science interviews read the book Ace the Data Science Interview because it's got:
- 201 interview questions taken from FAANG (FB, Apple, Amazon, Netflix, Google)
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