Crucial Exams

AWS Certified Data Engineer Associate DEA-C01 Practice Question

An Amazon Redshift table named order_events contains multiple versions of each order identified by order_id. Each new version has a higher event_ts timestamp. You must write a single-pass SQL query that returns only the latest version of every order for a downstream ETL step. Which statement meets the requirement?

  • SELECT * FROM ( SELECT *, LEAD(event_ts) OVER (PARTITION BY order_id ORDER BY event_ts DESC) AS next_ts FROM order_events ) WHERE next_ts IS NULL;

  • SELECT DISTINCT ON (order_id) * FROM order_events ORDER BY event_ts DESC;

  • SELECT order_id, MAX(event_ts) AS event_ts FROM order_events GROUP BY order_id;

  • SELECT * FROM order_events QUALIFY ROW_NUMBER() OVER (PARTITION BY order_id ORDER BY event_ts DESC) = 1;

AWS Certified Data Engineer Associate DEA-C01
Data Ingestion and Transformation
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