Six Degrees

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

Domain

SQL

Difficulty

hard

Seniority

L5

Problem

Across the company chat history, every reply ties together two people, the sender and the person being replied to, and that tie runs both ways. For each person, count how many different people they are tied to, then turn that into a percentage of everyone who has ever sent or received a message. Show the most connected people first.

Summary

Every reply ties two names together. Find whose web reaches the furthest.

Practice This Problem

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