11 Aflac SQL Interview Questions (Updated 2024)

Data Analysts and Data Engineers at Aflac uses SQL to analyze customer behavior patterns in insurance claims, including claim frequency and severity, as well as creating predictive models for future insurance offerings, such as identifying new business opportunities. That is the reason behind why Aflac asks SQL problems during job interviews.

Thus, to help you prepare for the Aflac SQL interview, here’s 11 Aflac SQL interview questions – scroll down to start solving them!

11 Aflac SQL Interview Questions

SQL Question 1: Identify the Top Insurance Policy Holders

Assume that "Aflac" wants you to identify their top insurance policy holders. These are the customers who have the most number of insurance policies registered under their name. Write a SQL query that would analyze the customer database, specifically look for the customers with most number of insurance policies registered under their name.

Example Input:

Example Input:

Answer:

In this query, we first join the 'customers' table with the table on . Then, we count the number of policies per customer by using the function on in the table and we use the 'GROUP BY' clause on the . Finally, we order the results by in descending order to fetch the users with most policies. We limit the results to top 10 for simplicity. This query will help "Aflac" identify their top insurance policy holders, which could be very valuable for their customer engagement activities.

To solve a similar VIP customer analysis question on DataLemur's free interactive SQL code editor, try this Microsoft SQL Interview problem:

SQL Question 2: Well Paid Employees

Imagine you had a table of Aflac employee salary data. Write a SQL query to find the employees who earn more than their direct manager.

Aflac Example Input:

Example Output:

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

Test your SQL query for this question directly within the browser 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 code above is confusing, you can find a step-by-step solution with hints here: Well Paid Employees.

SQL Question 3: In SQL, Are NULL values the same as a zero or blank space?

A NULL value represents a missing or unknown value. It is different from a zero or a blank space, which are actual values. It is important to handle NULL values properly in SQL because they can cause unexpected results if not treated correctly.

SQL Question 4: Calculate Average Policy Premium by State

Aflac sells insurance policies across various U.S states. The premiums for these policies may vary based on the coverage, specific terms and the state in which the policyholder resides. As part of their regular analytics and reporting, Aflac needs to understand how the average policy premium varies by state over time.

Please write a SQL query that calculates the overall average policy premium by state for each month of a given year. Use window function.

Table:

Answer:

This query first extracts the month portion of the start_date for each policy in a subquery . Then it calculates the overall average premium for each state and each month using the window function. The clause specifies which rows are grouped together for calculation, in this case those having the same state and month. The result is sorted by month and state.

Pro Tip: Window functions are a frequent SQL interview topic, so practice every window function problem on DataLemur

SQL Question 5: What are SQL constraints, and can you give some examples?

Constraints are just rules for your DBMS to follow when updating/inserting/deleting data.

Say you had a table of Aflac employees, and their salaries, job titles, and performance review data. Here's some examples of SQL constraints you could implement:

NOT NULL: This constraint could be used to ensure that certain columns in the employee table, such as the employee's first and last name, cannot contain NULL values.

UNIQUE: This constraint could be used to ensure that the employee ID is unique. This would prevent duplicate entries in the employee table.

PRIMARY KEY: This constraint could be used to combine the NOT NULL and UNIQUE constraints to create a primary key for the employee table. The employee ID could serve as the primary key.

FOREIGN KEY: This constraint could be used to establish relationships between the employee table and other tables in the database. For example, you could use a foreign key to link the employee ID to the department ID in a department table to track which department each employee belongs to.

CHECK: This constraint could be used to ensure that certain data meets specific conditions. For example, you could use a CHECK constraint to ensure that salary values are always positive numbers.

DEFAULT: This constraint could be used to specify default values for certain columns. For example, you could use a DEFAULT constraint to set the employee hire date to the current date if no value is provided when a new employee is added to the database.

SQL Question 6: Calculate Average Insurance Plan Rating

Aflac offers a variety of insurance plans to its customers. These plans are rated by the customers on a scale of 1 to 5, where 5 is the best score representing highest satisfaction. Aflac's management wants to understand the monthly average rating of each insurance plan over a span of time in order to glean insights into plan performance.

The exercise is this - given a table with columns , , , , , write a SQL query to calculate the average rating of each plan on a monthly basis.

Example Input:

Answer:

This query utilizes the function to retrieve the year and month from the field. The function is used to limit the average rating, , to two decimal places. The query groups the reviews by year, month, and insurance plan, so it will return the average monthly rating for each insurance plan. The insurance plans are then ordered by their year, month and plan_id in ascending order.

SQL Question 7: Can you describe the difference between a correlated and a non-correlated sub-query?

A correlated sub-query is a sub-query that depends on the outer query and cannot be executed separately. It uses the outer query to filter or transform data by referencing a column from it, and the outer query uses the results of the inner query. In contrast, a non-correlated sub-query is independent of the outer query and can be executed on its own. It does not reference any columns from the outer query and is used to retrieve additional data needed by the outer query.

Here is an example of a correlated sub-query:

This query selects the and total sales of all Aflac 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.

Performance-wise, correlated sub-queries are generally 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 8: Filter Customers records for Aflaq

As a Database Analyst at Aflaq, your project manager wants you to obtain relevant customer details who have insurance policy of 'Life Insurance' and who reside in 'New York' or their policy is about to expire in 'December 2022'. Based on these requirements, write a SQL query to filter the necessary information.

Example Input:

Answer:

The above query checks for three conditions stated in the question. It looks for customers who have 'Life Insurance', are residing in 'New York' or whose policy is expiring in December 2022. The OR operator combines the last two conditions so the query would return a customer who belongs to 'New York' or whose policy is expiring in December 2022 and has a 'Life Insurance'.

SQL Question 9: Calculate Click Through Conversion Rates for Aflac's Policies

Aflac wants to analyze the effectiveness of their online ads. They especially want to understand the click-through conversion rates for their insurance policies. Given two tables - and , write an SQL query to calculate the click-through conversion rate for each insurance policy type. The rate is calculated as the number of unique users that eventually purchased a policy of a type, divided by the number of unique users clicked on an advertisement for that policy type.

The table records all the clicks each user made on digital ads showcasing different policies and the table records all the users that completed a purchase after clicking on the ads.

Example Input:

Example Input:

Answer:

This query joins the and tables on the and fields, to get pairs of ads and purchases for the same policy and user. The WHERE clause ensures that only purchases made after an advertisement click will be considered. The output of the query gives the and the click-through conversion rate for each policy. This rate is calculated by dividing the number of unique users that made a purchase () by the number of unique users that clicked on an ad ().

To practice a similar problem on DataLemur's free interactive coding environment, solve this Facebook SQL Interview question:

SQL Question 10: Could you explain what a self-join is and provide examples of when it might be used?

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 FROM clause, and give each instance of the table a different alias. You can then join the two instances of the table using a JOIN clause, and use a WHERE clause to specify the relationship between the rows.

Self-joins are the go-to technique for any data analysis that involves pairs of the same thing, like identifying pairs of products that are frequently purchased together like in this Walmart SQL interview question.

For another example, say you were doing an HR analytics project and needed to analyze how much all Aflac employees in the same department interact with each other. Here's a self-join query you could use to retrieve all pairs of Aflac employees who work in the same department:

This query returns all pairs of Aflac employees who work in the same department, and excludes pairs where the employee's id is the same (since this would represent the same Aflac employee being paired with themselves).

SQL Question 11: Filter Aflac Customers by Address Pattern

As a data analyst at Aflac, one of your tasks is to filter customer records based on the address. The business requires a list of all customers residing in specific states. Can you write a SQL query to generate a list of all customers residing in states that begin with 'New'?

Here's your input table:

Example input:

Answer:

This query selects all columns from the 'Customers' table where the 'State' column starts with 'New'. In our example, it would return all records for customers who live in New York, New Jersey, and New Hampshire, and New Mexico.

How To Prepare for the Aflac SQL Interview

The best way to prepare for a Aflac SQL interview is to practice, practice, practice. In addition to solving the earlier Aflac SQL interview questions, you should also solve the 200+ tricky sql questions on DataLemur which come from companies like Amazon, Microsoft, Meta, and smaller tech companies.

Each DataLemur SQL question has hints to guide you, full answers and crucially, there's an interactive SQL code editor so you can right online code up your query and have it graded.

To prep for the Aflac SQL interview you can also be useful to practice SQL questions from other insurance companies like:

• The Hartford SQL questions
• Travelers SQL questions
• MassMutual SQL questions
• Northwestern Mutual SQL questions

Dive into the latest news and stories from Aflac and discover how they're making a difference in the world of insurance!

In case your SQL query skills are weak, forget about diving straight into solving questions – improve your SQL foundations with this interactive SQL tutorial.

This tutorial covers topics including aggregate window functions and filtering strings using LIKE – both of these pop up often during Aflac SQL interviews.

Aflac Data Science Interview Tips

What Do Aflac Data Science Interviews Cover?

In addition to SQL interview questions, the other question categories tested in the Aflac Data Science Interview are:

• Probability & Stats Questions
• Python or R Programming Questions
• Data Case Study Questions
• Machine Learning Questions
• Behavioral Interview Questions centered on Aflac cultural values

How To Prepare for Aflac Data Science Interviews?

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

• 201 interview questions sourced from FAANG (FB, Apple, Amazon, Netflix, Google)
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Don't forget about the behavioral interview – prep for that using this Behavioral Interview Guide for Data Scientists.