A medium SQL interview practice problem on DataDriven. Write and execute real sql code with instant grading.

Domain

SQL

Difficulty

medium

Problem

The product analytics team needs purchase counts for every user in the system, including those who have never bought anything. Show each user's username alongside their transaction count, with non-buyers showing zero.

Summary

Zero transactions is still a data point. Count everyone.

Practice This Problem

Solve this SQL problem with real code execution. DataDriven runs your SQL queries against a real database and grades it automatically.