LeetCode（数据库）- 每天的最大交易

-- 解决方案(1)
SELECT
    transaction_id
FROM transactions
WHERE (DATE(day), amount) in (
    SELECT DATE(day), MAX(amount)
    FROM transactions GROUP BY DATE(day)
)
ORDER BY 1;
-- 解决方案(2)
-- 非 MAX 函数版
SELECT transaction_id
FROM (SELECT transaction_id, RANK() OVER(PARTITION BY DATE_FORMAT(day, '%Y-%m-%d') ORDER BY amount DESC) rk FROM Transactions) t
WHERE rk = 1
ORDER BY transaction_id