Use ROW_NUMBER() with PARTITION BY to isolate the most recent record per logical group. Example: SELECT rule_id, rule_status FROM (SELECT rule_id, rule_status, ROW_NUMBER() OVER (PARTITION BY rule_id ORDER BY updated_at DESC) AS rn FROM rules) ranked WHERE rn = 1. **Why**: Need recency column (created_at, updated_at). **Scalability**: Index partition/order columns. Use DISTINCT ON (PostgreSQL) or QUALIFY (Snowflake) where supported....
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