[Leetcode] Sales Analysis III

문제 링크

정답

SELECT DISTINCT P.product_id, P.product_name
FROM Product P
JOIN Sales S
ON P.product_id = S.product_id
WHERE P.product_id NOT IN (
    SELECT product_id
    FROM Sales
    WHERE sale_date NOT BETWEEN '2019-01-01' AND '2019-03-31'
)
AND S.sale_date BETWEEN '2019-01-01' AND '2019-03-31';

✅ Point

• 1분기 외 판매된 적이 없고 (NOT IN) & 1분기에만 판매된 상품
• Sales 는 중복된 row를 가질 수 있으므로, DISTINCT 로 product_id 중복 없이 SELECT