sql
Hosted by Interview Master
24 FREE SQL challenges starting December 1st 2025. Unlock a new challenge every day. Have fun while you level up your SQL skills.
Frequently Asked
Questions
What is a SQL advent calendar?
It's a 24-day countdown to Christmas, but instead of getting a small gift every day, you get a SQL question each day!
How much SQL experience is needed?
You just need to know the basics of SQL to sign up! The questions range from beginner to advanced. Plus, we have an AI assistant to help you out if you get stuck. I encourage to sign up no matter what level you are currently at!
Do you have an example of the SQL questions?
Of course! Here is an example of an easy question: Given a table called elves with columns name and age, write a query to find the average age of all the elves. An example of a more difficult question: Given a table called polar_bear_cubs with columns name, weight and day. Calculate the average day-over-day weight gain for the cubs. In the actual challenge, you will also receive the respective sample tables for the questions.
Will I get a certificate of completion?
Yes! You'll get a certificate of completion if you complete all 24 challenges within the challenge period (December 1st - December 31st).
When do new questions become available?
A new question becomes available each day at 9AM ET. You can complete the question as many times as you want.
Why is this free?
The holiday season is all about giving, and I wanted to create something fun and meaningful for anyone who loves—or is learning—SQL! Plus, I had lots of fun creating this last year and wanted to make it bigger and better this year.
What last year's Participants Say
“My favorite part of the SQL Advent Calendar challenge was how each day built upon the last — it was a perfect balance between learning and fun. I loved the hints and explanations when I got things wrong.”
“Every challenge came with its own story, and I felt like I was solving real business problems rather than generic SQL exercises. The creativity behind the setup made me look forward to each new day.”
“The challenges were well-written. The “Get a hint” feature was so helpful, and I learned more about window functions in 24 days than I did in months of tutorials.”
“I love the comment when I submit the wrong answer — it made the experience more human and less intimidating. Felt like I was learning with a friend!”
“I loved that the questions had different difficulty levels and touched on real-world use cases. It made me realize how much SQL can do.”
“I thoroughly enjoyed the challenge, and my favorite part was unlocking the next question each day — it gave me something to look forward to daily and helped me stay consistent with my SQL practice.”
“My favorite part of the SQL Advent Calendar challenge was how each day built upon the last — it was a perfect balance between learning and fun. I loved the hints and explanations when I got things wrong.”
“Every challenge came with its own story, and I felt like I was solving real business problems rather than generic SQL exercises. The creativity behind the setup made me look forward to each new day.”
Ready to Join?
Start your SQL journey this holiday season. 24 challenges, 24 days, infinite fun.