SQL Unique Users Last 30 Days | Dataford Interview Questions

Given a table of user events with columns user_id, event_name, and event_time, write a SQL query to find the number of unique users who performed each event in the last 30 days.

Use the current date as the reference point. Ignore rows where user_id, event_name, or event_time is NULL.

Output

One row per event, with columns event_name and unique_user_count
Include only events in the last 30 days
Sort alphabetically by event_name

Schema

user_events

Column	Type	Description
user_id	INT	Identifier of the user who performed the event
event_name	VARCHAR(50)	Name of the recorded user event
event_time	TIMESTAMP	Timestamp when the event occurred

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