10 Universal Health Services SQL Interview Questions (Updated 2024)

At Universal Health Services, SQL is essential for extracting and analyzing patient data to enhance healthcare delivery, allowing the organization to track patient recovery rates and optimize treatment plans. It is also used to predict healthcare trends, enabling better resource allocation and improved hospital operations, which is why Universal Health Services evaluates jobseekers with SQL questions during interviews for Data Analyst, Data Science, and BI jobs.

Thus, to help you ace the Universal Health Services SQL interview, we've collected 10 Universal Health Services SQL interview questions in this blog.

10 Universal Health Services SQL Interview Questions

SQL Question 1: Analyze Patients' Average Recovery Time

As a data analyst at Universal Health Services, you have been asked to analyze the average recovery time of patients after going through different types of treatments. The database contains two tables, and , which include information about the patients and their recovery times, respectively.

The table contains patient information, with each patient having a unique , along with their , , , and .

Example Input:

The table records the recovery period in days for each , detailing the duration from the to the .

Example Input:

Your task is to write a SQL query that returns the and the average recovery time in days for each type of treatment, ordered by the average recovery time in ascending order.

Answer:

This query first joins and on . It then uses a window function to calculate the average time for each type. The result is ordered by in ascending order. This query provides information on how long, on average, patients take to recover from a specific treatment.

To solve a similar window function question on DataLemur's free interactive SQL code editor, solve this Google SQL Interview Question:

Explore Universal Health Services' newsroom to discover their latest initiatives and updates in the healthcare sector! This is relevant for understanding how they are working to improve health services and support community well-being.

SQL Question 2: Employees Earning More Than Managers

Given a table of Universal Health Services employee salary data, write a SQL query to find employees who make more than their direct manager.

Universal Health Services Example Input:

Example Output:

This is the output because Olivia Smith earns $8,000, surpassing her manager, William Davis who earns 7,800.

Code your solution to this question interactively on DataLemur:

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 confusing, you can find a detailed solution here: Employees Earning More Than Managers.

SQL Question 3: What are the different kinds of joins in SQL?

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 retrieves rows from both tables where there is a match in the shared key or keys. For example, an 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 retrieves all rows from the left table (in this case, the table) and any matching rows from the right table (the table). If there is no match in the right table, values will be returned for the right table's columns.

: A retrieves all rows from the right table (in this case, the 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 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 4: Health Services Data Analysis

Universal Health Services wishes to analyze the patient visit data for its various hospitals. During a typical visit, a patient visits a doctor at a hospital. Data is collected about the patient including their age and gender, the hospital and doctor they visited, and the date of the visit.

Your task is to design a database to store this information and write a SQL query to find the total number of visits each doctor had in 2021.

Additional data collected includes:

• Doctor details (ID, name, specialty)
• Hospital details (ID, name, location)
• Patient details (ID, name, age, gender)

You may assume each visit corresponds to a unique record.

Sample Data:

Table:

Table:

Table:

Table:

Answer:

Here is a PostgreSQL query to find the total number of visits each doctor had in 2021.

This query joins the table with the table on . It then groups by and counts the total visits each doctor had in 2021. The condition filters the visits for the year 2021 and arranges the doctors in decreasing order of their total visits.

SQL Question 5: What are the similarities and difference between relational and NoSQL databases?

While knowing this answer is beyond the scope of most Data Analyst & Data Science interviews, Data Engineers at Universal Health Services should be at least aware of SQL vs. NoSQL databases.

Relational databases and non-relational (NoSQL) databases have some key differences, particularly in terms of how data is stored. Whereas relational databases have tables, made up of rows and columns, NoSQL databases use various data models like:

• Wide-Column Stores – this database uses tables, rows, and columns, but unlike a relational database, the names and format of the columns can vary from row to row within the same table
• Key-Value Stores – instead of rows and columns, you have keys, where each key is associated with only one value in a collection (similar to a Python dictionary data structure!)
• Graph Stores – instead of rows of data, you have nodes, and then can also have edges between entities (much like a Graph Data Structure for those who've taken a Computer Science data structures & algorithms class)

This added flexibility makes NoSQL databases well-suited for handling non-tabular data or data with a constantly changing format. However, this flexibility comes at the cost of ACID compliance, which is a set of properties (atomic, consistent, isolated, and durable) that ensure the reliability and integrity of data in a database. While most relational databases are ACID-compliant, NoSQL databases may not provide the same level of guarantees.

SQL Question 6: Filtering Patient Data by Specific Conditions

Universal Health Services would like to analyze patient data to better understand trends and provide improved care. Write a SQL query that filters patient records based on the following conditions: patients are above 60 years old, their most recent visit was within the last 30 days, and they have a diagnosis of diabetes (Code 250.00).

Here is the required data in the patients and visits tables:

Example Input:

Example Input:

Answer:

This query will select patient details from the patients table where their age is more than 60, and their latest visit with a diabetes diagnosis was within the last month. We first create a subquery to select each patient's latest visit with a diabetes diagnosis, and then join this with the patient table, filtering on the age and visit date conditions.

SQL Question 7: Can you explain the difference between and ?

The clause is used to filter rows from the result set of a , , or statement. It allows you to specify a condition that must be met for a row to be included in the result set.

The clause is used to filter groups created by the clause. It is similar to the clause, but it is used to specify conditions on the groups created by the clause, rather than on the individual rows of the table.

Say you were working on a social media analytics project for Universal Health Services.

Here is an example of a SQL query that you might write which uses both the and clauses:

This query retrieves the total impressions and average conversions for each platform in the table, the date of the campaign is in January 2023. The rows are grouped by platform and the clause filters the groups to include only those with more than 5000 impressions and an average conversion rate above 0.2.

SQL Question 8: Average Length of Patients' Stay

As a data analyst at Universal Health Services, you are asked to find the average length of stay in days of patients in each of their hospitals. You have the and tables available to you. Please write a PostgreSQL query that will provide this information.

Consider the following database tables:

Example Input:

Example Input:

Example Output:

Answer:

This SQL query joins the and table on the column, calculates the average length of stay for each hospital, and presents the results in descending order by average length of stay. The length of a patient's stay is calculated by subtracting the from . PostgreSQL date subtraction returns the result in the form of days, which is what we expected.

To practice a very similar question try this interactive CVS Health Pharmacy Analytics (Part 1) Question which is similar for calculating profit metrics from transactions or this Amazon Average Review Ratings Question which is similar for averaging metrics over different categories.

SQL Question 9: Find the average rating per treatment type

As an analyst in Universal Health Services, we need to consistently monitor patient satisfaction levels for different types of treatments. Using the provided table, can you write a SQL query to find the average rating (scale of 1 to 5) for each type of treatment handled by the healthcare service?

Example Input:

Please write a query to get the average rating for each treatment type.

Answer:

The query takes each unique type of treatment from the table and returns an average rating of the patient feedback for the corresponding treatment. It uses the function to calculate the average and to separate the results by treatment type. The result would be a table showing each treatment type with its average patient rating.

SQL Question 10: What does do in a SQL query?

In SQL, the operator combines the result of two or more SELECT statements into a single result set. Note that each statement within the UNION must have the same number of columns and the columns must have similar data types. The operator removes duplicates from the final result set. If you want to include duplicates in the final result set, you can use the operator instead.

Here's an example of using the operator to combine the results of two statements that retrieve data from tables of Universal Health Services's Facebook ads and their Google ads:

This statement would return a combined result set of both Facebook and Google ads that have a spend greater than $500.

How To Prepare for the Universal Health Services SQL Interview

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. In addition to solving the earlier Universal Health Services SQL interview questions, you should also solve the 200+ SQL questions on DataLemur which come from companies like Netflix, Airbnb, and Amazon.

Each exercise has hints to guide you, 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 easily right in the browser your SQL query and have it graded.

To prep for the Universal Health Services SQL interview it is also helpful to practice SQL questions from other healthcare and pharmaceutical companies like:

• Baxter International SQL questions
• IQVIA SQL questions
• Regeneron SQL questions
• LabCorp SQL questions

In case your SQL foundations are weak, don't worry about jumping right into solving questions – go learn SQL with this DataLemur SQL Tutorial.

This tutorial covers SQL topics like filtering on multiple conditions using AND/OR/NOT and joining a table to itself – both of which come up routinely in SQL interviews at Universal Health Services.

Universal Health Services Data Science Interview Tips

What Do Universal Health Services Data Science Interviews Cover?

In addition to SQL interview questions, the other topics covered in the Universal Health Services Data Science Interview include:

• Probability & Statistics Questions
• Python or R Programming Questions
• Business Sense and Product-Sense Questions
• ML Modelling Questions
• Behavioral Interview Questions focussed on Universal Health Services cultural values

How To Prepare for Universal Health Services Data Science Interviews?

To prepare for Universal Health Services Data Science interviews read the book Ace the Data Science Interview because it's got:

• 201 interview questions taken from FAANG & startups
• a crash course on SQL, AB Testing & ML
• over 1000+ reviews on Amazon & 4.5-star rating

Also focus on the behavioral interview – prepare for it using this behavioral interview question bank.