8 IDEXX Laboratories SQL Interview Questions (Updated 2024)
IDEXX Laboratories employees use SQL to analyze pet health data trends, helping them identify common health issues and improve treatment options for animals. They also rely on SQL to enhance veterinary diagnostic tools and services, ensuring that veterinarians have access to the most accurate and timely information, that is the reason why IDEXX Laboratories includes SQL questions in interviews for Data Analytics, Data Science, and Data Engineering roles.
Thus, to help you study for the IDEXX Laboratories SQL interview, we've collected 8 IDEXX Laboratories SQL interview questions – scroll down to start solving them!
8 IDEXX Laboratories SQL Interview Questions
SQL Question 1: Analyzing VIP Customers at IDEXX Laboratories
IDEXX Laboratories, a multinational corporation involved in the pet healthcare industry, wants to understand their top tier customers better. These "VIP Customers" are defined as customers who have ordered labs tests more than 100 times within the last year.
Write a SQL query to identify VIP customers. The dataset provided for this, includes a table that records all lab tests ordered by a customer.
Example Input:
| order_id | customer_id | order_date | test_id |
|---|---|---|---|
| 001 | 176 | 06/08/2021 | t001 |
| 002 | 256 | 06/09/2021 | t002 |
| 003 | 176 | 06/10/2021 | t003 |
| 004 | 456 | 06/11/2021 | t004 |
| 005 | 176 | 06/12/2021 | t005 |
Note: Each row in the table represents a test ordered by a customer on a particular date.
The resulting output should contain the and (i.e., total number of orders a customer has made) for all VIP Customers.
Example Output:
| customer_id | total_orders |
|---|---|
| 176 | 3 |
Answer:
With the following PostgreSQL SQL query, we can identify these VIP customers:
This query works by grouping all orders by and counting the number of orders made by each customer within the last year, which is achieved with the clause. The clause is then used to filter out customers who made fewer than 100 orders within the last year.
To work on a similar customer analytics SQL question where you can solve it interactively and have your SQL query instantly executed, try this Walmart Labs SQL Interview Question:
Uncover the exciting ways IDEXX Laboratories is using artificial intelligence to revolutionize veterinary medicine and improve animal health outcomes! Learning about their groundbreaking efforts can give you a fresh perspective on the intersection of technology and animal care.
SQL Question 2: Top 3 Department Salaries
Given a table of IDEXX Laboratories employee salaries, write a SQL query to find the top three highest paid employees within each department.
IDEXX Laboratories 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 |
Solve this problem directly within the browser on DataLemur:
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 detailed solution with hints here: Top 3 Department Salaries.
SQL Question 3: What are the similarities and differences between correlated and non-correlated sub-queries?
A correlated sub-query is one that relies on the outer query and cannot be run independently. It uses the outer query to filter or transform data by referencing a column from it, while the outer query uses the results of the inner query. On the other hand, a non-correlated sub-query is not linked to the outer query and can be run on its own. It does not reference any columns from the outer query and is used to retrieve additional data for the outer query.
Here is an example of a correlated sub-query:
This query selects the and total sales of all IDEXX Laboratories customers in the sales table whose are greater than the average of their own customer group. The sub-query in this case is correlated with the outer query, as it references the column from the outer query ().
Here is an example of a non-correlated sub-query:
The sub-query in this case is non-correlated, as it does not reference any columns from the outer query.
Correlated sub-queries are slower to execute, as they have to be re-evaluated for each row of the outer query, while non-correlated sub-queries are faster, as they only have to be executed once.
SQL Question 4: Analyzing Veterinary Tests
IDEXX Laboratories provides comprehensive diagnostic products and services to veterinary practices. One of their offerings is tests like Complete Blood Count (CBC), Heartworm tests etc. Suppose you have tables containing information about these tests conducted at various veterinary clinics.
We need to analyze these datasets to help the company gather insights about the trends of tests conducted. Specifically, the company wants to know the total tests conducted for each type on a month to month basis. For a given test, they also want to compare the current month's performance with the previous month (if there's data available for that month) using a SQL query.
Given below are two markdown-formatted tables, one for and another for .
Example Input:
| test_id | clinic_id | test_type_id | test_date |
|---|---|---|---|
| 20001 | 903 | 2 | 06/07/2022 |
| 30052 | 805 | 1 | 06/09/2022 |
| 40093 | 712 | 2 | 06/18/2022 |
| 10132 | 614 | 3 | 07/26/2022 |
| 50174 | 921 | 1 | 07/30/2022 |
Example Input:
| test_type_id | test_name |
|---|---|
| 1 | CBC |
| 2 | Heartworm |
| 3 | FIV/FeLV |
Your task is to write a SQL query that generates the total count of tests performed for each test type per month and compares it with the previous month (if applicable).
Answer:
This query involves using a window function (the and parts) to figure out the test count for each test type for each month, and then to compare it with the test count of the previous month. The clause constructs a table with monthly test counts, which is then used in the main query. The function is used to access data from a previous row in the partition.
p.s. Window functions show up super frequently during SQL interviews, so practice the 27+ window function questions on DataLemur
SQL Question 5: What's a self-join, and when would you use one?
A self-join is a type of join in which a table is joined to itself. To perform a self-join, you need to specify the table name twice in the clause, and give each instance of the table a different alias. You can then join the two instances of the table using a clause, and use a clause to specify the relationship between the rows.
For example, say you were doing an HR analytics project and needed to analyze how much all IDEXX Laboratories employees in the same department interact with each other. Here's a self-join query you could use to retrieve all pairs of IDEXX Laboratories employees who work in the same department:
This query returns all pairs of IDEXX Laboratories employees who work in the same department, and excludes pairs where the employee's id is the same (since this would represent the same IDEXX Laboratories employee being paired with themselves).
SQL Question 6: Design a database to track veterinary visits
IDEXX Laboratories, Inc. is a leader in pet healthcare innovation, serving practicing veterinarians around the world with a broad range of diagnostic and information technology-based products and services.
Assume IDEXX Laboratories has a new venture that provides software for veterinary clinics. You need to design a database to record pet owners, their pets, and the visits to the vet.
Here are the key considerations:
- Each pet belongs to a specific owner.
- Each pet can have many visits to the vet.
- Each visit has a date, a reason for the visit, and the treatment given.
- We need to keep track of the type of pet (e.g., dog, cat, bird).
Design the tables and their relationships and list down the columns that will belong to each table.
Example Input:
| owner_id | owner_name | address |
|---|---|---|
| 1 | John Doe | 123 Main St |
| 2 | Jane Smith | 456 Oak St |
| 3 | Tom Jones | 789 Pine St |
Example Input:
| pet_id | pet_name | pet_type | owner_id |
|---|---|---|---|
| 1 | Fido | Dog | 1 |
| 2 | Whiskers | Cat | 2 |
| 3 | Polly | Bird | 3 |
Example Input:
| visit_id | visit_date | reason | treatment | pet_id |
|---|---|---|---|---|
| 1 | 2022-01-01 | Annual Checkup | Vaccinations | 1 |
| 2 | 2022-02-01 | Sneezing | Antibiotics | 2 |
| 3 | 2022-03-01 | Feather Loss | Vitamin Supplements | 3 |
Answer:
Based on the business problem and the data given, we can design the database with three tables: , , and . Here are the definitions for the these tables:
To find all the visits for a specific pet and the owner's information, we could use following SQL:
This will give us all visits of 'Fido', along with treatments provided in those visits, and Fido's owner information.
SQL Question 7: What is a database index, and what are the different types of indexes?
An index in a database is a data structure that helps to quickly find and access specific records in a table.
For example, if you had a database of IDEXX Laboratories customers, you could create a primary index on the column.
Having a primary index on the column can speed up performance in several ways. For example, if you want to retrieve a specific customer record based on their , the database can use the primary index to quickly locate and retrieve the desired record. The primary index acts like a map, allowing the database to quickly find the location of the desired record without having to search through the entire table.
Additionally, a primary index can also be used to enforce the uniqueness of the column, ensuring that no duplicate values are inserted into the table. This can help to prevent errors and maintain the integrity of the data in the table.
SQL Question 8: Filtering Client Records
In IDEXX Laboratories, the marketing team frequently needs to extract specific customer data for targeted campaigns. As a database manager, can you write a query to extract the full names (concatenated and ) of the customers in the customer database who have an 'a' in their first name and their name ends with 'son'?
To illustrate, consider the following example:
Example Input:
| customer_id | first_name | last_name | registration_date |
|---|---|---|---|
| 1 | Jackson | Smith | 02/25/2022 |
| 2 | David | Johnson | 04/15/2022 |
| 3 | Sam | Williams | 05/28/2022 |
| 4 | Jason | Miller | 01/31/2022 |
| 5 | William | Brown | 03/20/2022 |
Example Output:
| customer_full_name |
|---|
| Jackson Smith |
| David Johnson |
| Jason Miller |
Answer:
The given SQL block will return the fully concatenated name of customers who meet both conditions: their first name contains 'a' and ends in 'son'. The '%' wildcard symbol is used to fetch records that contain any characters in the specified locations.
How To Prepare for the IDEXX Laboratories SQL Interview
The key to acing a IDEXX Laboratories SQL interview is to practice, practice, and then practice some more! Besides solving the above IDEXX Laboratories SQL interview questions, you should also solve the 200+ SQL Interview Questions on DataLemur which come from companies like FAANG (FB, Apple, Amazon, Netflix, Google).
Each SQL question has hints to guide you, detailed solutions and crucially, there is an online SQL coding environment so you can instantly run your query and have it graded.
To prep for the IDEXX Laboratories SQL interview you can also be useful to practice interview questions from other healthcare and pharmaceutical companies like:
- Option Care Health SQL questions
- Charles River SQL questions
- Align Technology SQL questions
- AMN Healthcare SQL questions
But if your SQL query skills are weak, don't worry about going right into solving questions – go learn SQL with this free SQL for Data Analytics course.
This tutorial covers topics including SQL joins with practice exercises and GROUP BY – both of which show up frequently during SQL interviews at IDEXX Laboratories.
IDEXX Laboratories Data Science Interview Tips
What Do IDEXX Laboratories Data Science Interviews Cover?
Besides SQL interview questions, the other types of problems tested in the IDEXX Laboratories Data Science Interview include:
- Experimental Design & AB Testing Questions
- Python or R Coding Questions
- Product-Sense and Business Case Questions
- Machine Learning Questions
- Behavioral Interview Questions focussed on IDEXX Laboratories culture and values
How To Prepare for IDEXX Laboratories Data Science Interviews?
To prepare for IDEXX Laboratories Data Science interviews read the book Ace the Data Science Interview because it's got:
- 201 interview questions taken from companies like Microsoft, Google & Amazon
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Don't forget about the behavioral interview – prepare for it using this behavioral interview question bank.