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Implement a CASE WHEN condition - medium difficulty

SQLmedium0.7 min readPremium

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Expert AnswerPremium

131 wordsInterview-ready

CASE WHEN implements conditional logic. Medium example—categorize sales: SELECT customer_id, amount, CASE WHEN amount >= 1000 THEN 'High' WHEN amount >= 100 THEN 'Medium' WHEN amount > 0 THEN 'Low' ELSE 'Zero' END AS tier FROM orders. Nested CASE: CASE WHEN region = 'US' THEN CASE WHEN state IN ('CA','NY') THEN 'Tier1' ELSE 'Tier2' END ELSE 'International' END. Use for bucketing, NULL handling, and derived columns....

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