User 360

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

Domain

SQL

Difficulty

hard

Seniority

L6

Problem

The product team wants a one-row-per-user activity summary, including users with zero activity. For every user, count their rows in transactions and their rows in user_sessions, substituting 0 when either side is empty. Return the username, transaction count, and session count.

Summary

One row per user. Everything they did, or didn't do.

Practice This Problem

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