Threads Excluding User

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

Domain

SQL

Difficulty

easy

Seniority

L3

Problem

The trust and safety team needs to audit messaging activity that doesn't involve user 1. A thread is defined as a unique sender_id and reply_to pair. Count how many threads exist where neither the sender_id nor the reply_to is user 1, considering only messages that have a non-null reply_to.

Summary

Every thread they're not part of.

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