Deduplicate Latest Session Records | Dataford Interview Questions

Given a scenario with duplicate user event logs, write a deduplication query that retains only the latest record per session.

Use the user_event_logs table. Treat the greatest event_timestamp as latest; if timestamps tie, retain the row with the greatest event_id.

Output

Return one row per non-null session.
Include event_id, user_id, session_id, event_type, and event_timestamp.
Order by session_id ascending.

user_event_logs

Column	Type	Description
event_idPK	INT	Unique identifier for the logged event
user_id	INT	Identifier of the user associated with the event
session_id	VARCHAR(50)	Identifier of the user session
event_type	VARCHAR(50)	Type of event recorded
event_timestamp	TIMESTAMP	Timestamp when the event was recorded

Your question is Deduplicate Latest Session Records. Start with the requirements and the one table in the Question tab.

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Given a scenario with duplicate user event logs, write a deduplication query that retains only the latest record per session.

Use the user_event_logs table. Treat the greatest event_timestamp as latest; if timestamps tie, retain the row with the greatest event_id.

Return one row per non-null session.
Include event_id, user_id, session_id, event_type, and event_timestamp.
Order by session_id ascending.

user_event_logs

Column	Type	Description
event_idPK	INT	Unique identifier for the logged event
user_id	INT	Identifier of the user associated with the event
session_id	VARCHAR(50)	Identifier of the user session
event_type	VARCHAR(50)	Type of event recorded
event_timestamp	TIMESTAMP	Timestamp when the event was recorded

Your question is Deduplicate Latest Session Records. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.