Problem: 1193. 每月交易 I

👨‍🏫 参考题解

Code

select DATE_FORMAT(trans_date, '%Y-%m') AS month,
    country,
    count(*) as trans_count,
    count(if(state = 'approved', 1, NULL)) as approved_count,
    sum(amount) as trans_total_amount,
    sum(if(state = 'approved', amount, 0)) as approved_total_amount
FROM Transactions
Group by month, country;