Top 3 Users by Activity | Dataford Interview Questions

The Nio Robotics Fleet Console team wants to identify its most active users during August 2026. Write a PostgreSQL query using the users and activity_events tables.

Requirements

Count each user's activity events from August 1 through August 31, 2026, including the start date and excluding September 1.
Return the top three users with their user_id, display name, and activity count.
Use user_id ascending as the deterministic tie-breaker when users have the same activity count.
Include only registered users, and ensure users without matching events do not create incorrect counts.

Schema

users

Column	Type	Description
user_idPK	INTEGER	Unique registered user identifier
display_name	VARCHAR(100)	User's Fleet Console display name
role	VARCHAR(40)	User role in the robotics operation

activity_events

Column	Type	Description
event_idPK	INTEGER	Unique activity event identifier
user_id	INTEGER	User associated with the activity event
event_type	VARCHAR(40)	Type of Fleet Console activity
occurred_at	TIMESTAMP	Timestamp when the activity occurred

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