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Write a query to find the top three customers by total revenue within each region.

SQLmedium0.2 min readPremium

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SELECT * FROM (SELECT customer_id, region, SUM(revenue) AS total, RANK() OVER (PARTITION BY region ORDER BY SUM(revenue) DESC) rn FROM orders GROUP BY customer_id, region) WHERE rn <= 3. **Why**: Aggregate then rank per region. RANK or DENSE_RANK per tie rule....

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