The Faithful Few

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

Domain

SQL

Difficulty

medium

Seniority

L4

Problem

We track sessions across many devices for a multi-platform product. For each device type, count the users who have only ever used that single device type across all of their sessions, and return the device type with that exclusive user count, most loyal type first.

Summary

Loyal to one platform only.

Practice This Problem

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