SQL for Most Active Users | Dataford Interview Questions

Write a query to identify our most active users over the last 30 days on Quizlet.

Treat each row in activity_events as one activity. Use the last 30 calendar days, including today, and return users with the three highest activity ranks. Users tied on activity count share a rank.

Output

One row per qualifying user with activity_rank, user_id, username, activity_count, and active_days.
Sort by activity_rank, then activity_count descending, then user_id ascending.

Schema

users

Column	Type	Description
user_idPK	INT	Unique Quizlet user identifier
username	VARCHAR(100)	Quizlet username

activity_events

Column	Type	Description
event_idPK	INT	Unique activity event identifier
user_id	INT	User who generated the activity event
event_type	VARCHAR(50)	Type of Quizlet activity
occurred_at	TIMESTAMPTZ	Timestamp when the activity occurred

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