Engagement Gap

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.

Practice This Problem

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