Uploaded October 2020 | Updated September 2026, 24 minutes ago

---

This SQL data science interview question was asked by Microsoft. I’ll cover both the question and answer and give a detailed explanation of the approach. I walkthrough each step of my answer, assumptions, approach, and explain every line of code I write. This is literally how I would answer every data science interview question and prepare for every data science interview at FAANG companies and others.

Link to the question: platform.stratascratch.com/coding/10301-expensive-projects?python=&utm_source=youtube&utm_medium=click&utm_campaign=YT+description+link (the question on the platform has been revised)

The question covers the basic concept of a SQL INNER JOIN and calculating a ratio in the SELECT clause. Technically, it’s an easy data science interview question to solve but understanding the assumptions to the questions to then select the right JOIN and ratio formula is what can make this interview questions difficult. Once you understand how to translate the business question to the technical implementation, this data science interview question becomes easy. This question covers concepts that are commonly found in data science interviews at Facebook and Google.

______________________________________________________________________

This series is for both beginner and intermediate data scientists and analysts interested in learning how to solve common data science interview questions in SQL. These are real data science interview questions. For some background context and an intro about what this series is about: bit.ly/36kKbxG

👉 Subscribe to my channel: bit.ly/2GsFxmA
👉 Playlist for more data science interview questions and answers: bit.ly/3jifw81
👉 Playlist for data science interview tips: bit.ly/2G5hNoJ
👉 Practice more real data science interview questions: platform.stratascratch.com/coding?utm_source=youtube&utm_medium=click&utm_campaign=YT+description+link

______________________________________________________________________
Timestamps:

Intro: (0:00)
Interview Question: (0:09)
Exploring The Data: (0:41)
Developing The Framework For The Solution: (1:14)
INNER JOIN The Tables: (3:08)
Calculating budget-to-employee Count Ratio: (3:45)
Finishing off with ORDER BY and LIMIT 5: (4:46)

______________________________________________________________________
About The Platform:

I'm using StrataScratch, a platform that allows you to practice real data science interview questions. There are over 1000+ interview questions that cover coding (SQL and python), statistics, probability, product sense, and business cases.

I created this platform because I wanted to build a resource to specifically help prepare data scientists for their technical interviews and to generally improve their analytical skills. Over my career as a data scientist, I never was able to find a dedicated platform for data science interview prep. LeetCode and HackerRank were the closest but these platforms specifically serve the computer developer community so their questions focus more on algorithms that working with data.

So, if you want more interview practice with real data science interview questions, visit platform.stratascratch.com/coding?utm_source=youtube&utm_medium=click&utm_campaign=YT+description+link. All questions are free and you can even execute SQL and python code in the IDE, but if you want to check out the solutions from me or from other users, you can use ss15 for a 15% discount on the premium plans.

______________________________________________________________________
Contact:

If you have any questions, comments, or feedback, please leave them here!
Feel free to also email me at nathan@stratascratch.com
______________________________________________________________________