11 Interpublic Group SQL Interview Questions (Updated 2024)

Updated on

June 30, 2024

At Interpublic Group employees write SQL queries to help them analyze marketing data patterns to help them customize marketing initiatives to fit the customer profile. Unsurprisingly this is why Interpublic Group often tests SQL problems during interviews for Data Science and Data Engineering positions.

To help you study for the Interpublic Group SQL interview, here's 11 Interpublic Group SQL interview questions in this article.

Interpublic Group SQL Interview Questions

11 Interpublic Group SQL Interview Questions

SQL Question 1: Identify "Whale" Customers of Interpublic Group

For the company 'Interpublic Group', which offers advertising and marketing services, a 'whale' customer could be one who initiates numerous campaigns or whose ad spend is consistently high.

Write a SQL query to retrieve the customers who have either launched more than five marketing campaigns in the last six months or who have an average ad spend of over $10,000 per month for the same period.

You have two tables - and .

Example Input:
Example Input:
1001February 2022$4000
1002March 2022$5000
1001March 2022$6000
1003April 2022$20000
1001April 2022$7000
1001May 2022$13000
1002May 2022$12000
1001June 2022$16000
1002June 2022$15000
1003June 2022$18000


This query first creates two common table expressions (CTEs), and to count the number of campaigns and calculate the average ad spend for each customer over the past six months, respectively. Using a FULL OUTER JOIN, it then combines the CTEs and filters the data for customers with more than five campaigns or an average ad spend of more than $10,000. The COALESCE function ensures that each customer ID is displayed even if it only appears in one of the CTEs.

To work on another SQL customer analytics question where you can solve it right in the browser and have your SQL query automatically checked, try this Walmart SQL Interview Question: Walmart SQL Interview Question

SQL Question 2: Well Paid Employees

Assume there was a table of Interpublic Group employee salaries. Write a SQL query to find the employees who earn more than their direct manager.

Interpublic Group Example Input:

1Emma Thompson38001
2Daniel Rodriguez2230110
3Olivia Smith800018
4Noah Johnson680028
5Sophia Martinez1750110
8William Davis70002NULL
10James Anderson40001NULL

Example Output:

3Olivia Smith

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

Check your SQL query for this problem directly within the browser on DataLemur:

Employees Earning More Than Their Manager


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 hard to understand, you can find a step-by-step solution with hints here: Well Paid Employees.

SQL Question 3: In the context of a database transaction, what does ACID mean?

A DBMS (database management system), in order to ensure transactions are relaible and don't ruin the integrity of the data, tries to mantain the following ACID properties: Atomicity, Consistency, Isolation, and Durability.

To make this concept more concrete, here is what each of the ACID properties would mean in the context of banking transactions:

  • Atomicity: a transaction is either completed fully, or not complete at all. For example, if a customer is transferring money from one account to another, the transaction should either transfer the full amount or none at all.
  • Consistency: a transaction will only be completed if it follows all database constraints and checks. For example, if a customer is withdrawing money from an account, the transaction should only be completed if the account has sufficient funds available, otherwise the transaction is rejected
  • Isolation: ensures that concurrent transactions are isolated from each other, so that the changes made by one transaction cannot be seen by another transaction. This isolation prevents race conditions, like two customers trying to withdraw money from the same account at the same time.
  • Durability: ensures that once a transaction has been committed and completed, the changes are permanent. A reset / shutdown of the database shouldn't erase someone's savings accounts!

Interpublic Group SQL Interview Questions

SQL Question 4: Employee Performance Analysis Using Window Function

As an ad agency, Interpublic Group continuously monitors the performance of its employees in various advertising projects. Suppose they have an table that contains details of each project completed by employees. For each employee and project, they record the completion date and a score reflecting the quality, creativity, and impact of the work on a scale from 1 to 10.

Write a PostgreSQL query to find the average performance score for each employee over their last three projects. If an employee worked on fewer than three projects, evaluate their average performance score based on those projects.

Example Input:
Example Output:


The PostgreSQL query above uses a window function to compute the average () performance score for each employee over their last three projects. The clause is used to divide the data into partitions based on . Within each partition, rows are ordered by , and the clause specifies that for each row, the average performance score is calculated over the current row and the two preceding rows, representing the last three projects. If there are less than three projects, it calculates the average over available projects, due to the flexible nature of window functions.

p.s. Window functions show up pretty often during SQL interviews, so practice the 27+ window function questions on DataLemur

SQL Interview Questions on DataLemur

SQL Question 5: Can you explain what an index is and the various types of indexes?

A database index is a way to optimize the performance of a database by reducing the amount of data that needs to be searched to retrieve a record.

There are several types of indexes:

  • unique & non-inuqie indexes
  • primary & composite indexes
  • clustered & non-clustered indexes

SQL Question 6: Analyze Advertising Campaigns Performance

Assuming that Interpublic Group, being an advertising company, has run several advertising campaigns across different channels for its clients. Your task is to craft a SQL query that retrieves the total cost and total impressions for each client's campaign on each advertising channel.

Let's consider two tables, and , as outlined below:

Example Input:

11001TVSpring Sale500000
21001DigitalSummer Launch200000
31002RadioEnd of Year Clearance300000
41002TVBlack Friday400000

Example Input:


Using these tables, write a PostgreSQL query to retrieve the total cost and total impressions for each client's campaign on each advertising channel.


This query joins the campaigns and impressions tables based on the campaign_id. It then groups the results by client_id, channel, campaign_name, and cost. The total impressions per campaign are calculated using the SUM aggregate function.

Example Output:

1001TVSpring Sale5000005000000
1001DigitalSummer Launch2000001000000
1002RadioEnd of Year Clearance3000002000000
1002TVBlack Friday4000008000000

SQL Question 7: How do you identify records in one table that aren't in another?

To discover records in one table that are not present in another, you can utilize a and filter out any values in the right-side table.

For example, say you had a table of Interpublic Group customers and a 2nd table of all purchases made with Interpublic Group. To find all customers who did not make a purchase, you'd use the following

This query fetches all rows from the customers table, along with any rows that match in the purchases table. If there is no matching row in the purchases table, values will be returned for all of the right table's columns. The clause then filters out any rows where the purchases.id column is NULL, leaving only customers who have not made a purchase.

SQL Question 8: Calculating the Click-Through-Rate (CTR) on Ads

As a Data Analyst at Interpublic Group, your task is to analyze the click-through-rate (CTR) of digital ads. CTR is a highly important metric for assessing the effectiveness of a marketing campaign. You have been given two tables - 'Ad_impressions' and 'Ad_clicks'. The 'Ad_impressions' table includes each time an ad is displayed to a user, while 'Ad_clicks' tracks each time an ad is clicked by a user.

You are tasked with writing a SQL query that calculates the CTR for each ad_id as a ratio of the total number of clicks over the total number of impressions.

Example Input:

Example Input:


In the above query, we first create an between Ad_clicks and Ad_impressions on the and fields. Then, we use the function to calculate the total count of click events and impression events per each . By dividing these values, we calculate the Click-through-rate (CTR). The casting is to ensure a fractional output instead of integer division.

To practice a related problem on DataLemur's free interactive SQL code editor, try this Meta SQL interview question: Facebook App CTR SQL Interview question

SQL Question 9: Ad Campaign Performance Analysis

As part of Interpublic Group, an advertising company, your task is to analyse ad campaigns of our clients. Given a table listing ad impressions (times an ad was displayed) and clicks (times an ad was clicked), can you write a SQL query to retrieve the campaign name, the total impressions and clicks, and calculate the click-through-rate (CTR) for each campaign?

Provide the results sorted by CTR in descending order.

Sample Data:
101Campaign A5000400
202Campaign B7500330
303Campaign C2100200
404Campaign D9000300
505Campaign E3500220


Here is your answer written in PostgresSQL:

This query groups the data by campaign name, then it sums up the impressions and clicks. The click-through-rate (CTR) is calculated as (total clicks / total impressions) * 100. The resulting rows are then ordered by the CTR in descending order so we can instantly see which campaign has the highest effectiveness in terms of the percentage of impressions that lead to clicks.

SQL Question 10: Can you explain what SQL constraints are, and why they are useful?

In a database, constraints are rules that the DBMS (database management system) follows when performing operations such as inserting, updating, or deleting data.

For example, consider a table of employee records at Interpublic Group. Some constraints that you might want to implement include:

  • NOT NULL: This constraint ensures that certain columns, such as the employee's first and last name, cannot be NULL.
  • UNIQUE: This constraint ensures that each employee has a unique employee ID.
  • PRIMARY KEY: This constraint combines the NOT NULL and UNIQUE constraints to create a primary key for the employee table. The primary key is a column or set of columns that uniquely identifies each row in the table.
  • FOREIGN KEY: This constraint establishes a relationship 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.
  • DEFAULT: This constraint specifies a default value for a column in case no value is specified when a new row is inserted into the table.

SQL Question 11: Joining Customer and Campaigns Tables

Interpublic Group is involved in marketing and advertising, they would likely maintain databases for their clients and various advertising campaigns. Imagine you're given these two tables in your SQL server:

Example Input:
4312JohnDoejohndoe@email.comNew YorkNY
7852JaneSmithjanesmith@email.comLos AngelesCA
2461EmilyJohnsonemilyjohnson@email.comLas VegasNV
Example Input:
001431205/01/202205/31/2022Spring Sale
002785206/01/202206/30/2022Summer Blowout
003653109/01/202209/30/2022Back to School
004246111/25/202212/01/2022Black Friday Week
005937612/01/202212/31/2022Holiday Sale

Your task is to write a SQL query that displays all customers' names, email addresses and the names of the campaigns they participated in. If a customer did not participate in any campaign, display 'No Campaign'.


The answer involves postgreSQL's "LEFT JOIN" clause, which gathers records from the "customers" table and any matching records from the "campaigns" table. If there's no match, the result is NULL, which is then replaced with 'No Campaign' using "COALESCE". This way, you get a complete list of every customer, regardless of their participation in a campaign.

Also read about how Huge (a advertising firm part of IPG) uses AI and Data Science to support their creatives!

Since join questions come up frequently during SQL interviews, take a stab at this Snapchat SQL Interview question using JOINS: Snapchat Join SQL question

How To Prepare for the Interpublic Group SQL Interview

The best way to prepare for a Interpublic Group SQL interview is to practice, practice, practice. In addition to solving the earlier Interpublic Group SQL interview questions, you should also solve the 200+ FAANG SQL Questions on DataLemur which come from companies like Google, Facebook, Microsoft and Amazon. DataLemur Questions

Each DataLemur SQL question has multiple hints, full answers and most importantly, there is an interactive SQL code editor so you can right online code up your SQL query answer and have it checked.

To prep for the Interpublic Group SQL interview you can also be useful to practice SQL questions from other advertising companies like:

However, if your SQL skills are weak, forget about going right into solving questions – improve your SQL foundations with this interactive SQL tutorial.

DataLemur SQL Course

This tutorial covers SQL topics like turning a subquery into a CTE and filtering on multiple conditions using AND/OR/NOT – both of these come up often during Interpublic Group SQL interviews.

Interpublic Group Data Science Interview Tips

What Do Interpublic Group Data Science Interviews Cover?

In addition to SQL interview questions, the other topics to prepare for the Interpublic Group Data Science Interview are:

Interpublic Group Data Scientist

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