The First Door

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

Domain

SQL

Difficulty

medium

Seniority

L3

Problem

Marketing credits each user's acquisition to their first-touch channel: whatever they did first. For each user, return the user_id and that first event's `event_type`, labeled `first_channel`.

Summary

The first interaction matters most. Or does it?

Practice This Problem

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