Session Duration by Platform

SQLMediumMid levelGoogle~15 min

Problem

**[Asked at Google]**

Google tracks user sessions across devices. Each session has a start and end time.
Calculate the **average session length in minutes** per platform, rounded to 2 dp.

Return `platform` and `avg_duration_min`, ordered by platform.

Tables

Example rows — the live problem includes the full dataset.

user_sessions

session_id	user_id	platform	start_time	end_time

Expected output

Your answer should return 3 rows with the columns platform, avg_duration_min.

Starter code (SQL)

SELECT *
FROM user_sessions;

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Solution & explanation

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