Symmetric Reply Network

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

Domain

SQL

Difficulty

medium

Seniority

L3

Problem

The `chat_msgs` table logs team chat activity, where a reply stores the user ID of the person being replied to in `reply_to` while an original post leaves it empty. Map the symmetric reply network: whenever one person replied to another, list that pair of user IDs in both directions.

Summary

Every reply is an edge. Draw it both ways.

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