Daily problem
One problem a day
The same free problem for everyone, new every day at midnight India time. Ten minutes is enough.
Tue, 2026-10-27PySparkbeginner
Inner Join
Interview-style drill: Inner join orders to users on user_id.
- Time
- About 12 minutes
- Pattern
- Joins
- Cost
- Free, no signup to run
0day streak
Best run: 0 days
Solve today's problem to start your streak.
This week
Missed a day? The last 6 daily problems are still open.
0 of 6 solved
- Mon, 2026-10-26Validate a discount code formatPython · beginner · 10 min
- Sun, 2026-10-25GroupBy with Multiple AggregationsPySpark · beginner · 12 min
- Sat, 2026-10-24Running sum of daily signupsPython · beginner · 10 min
- Fri, 2026-10-23Distinct CountPySpark · beginner · 12 min
- Thu, 2026-10-22Coordinates as immutable recordsPython · beginner · 10 min
- Wed, 2026-10-21Profile every column of a framePandas · beginner · 12 min
How the daily problem works
- A new problem each dayEveryone gets the same free problem. It changes at midnight India time.
- Ten minutes is enoughBeginner and intermediate only, so it fits before a class or after work.
- Keep the streakSolving a problem, finishing a lesson or a plan day counts as an active day.
Want more than one a day? Browse all practice problems.