Monthly Transactions I _ Medium. LeetCode *

SELECT SUBSTR(trans_date, 1, 7) AS month,
    country,
    COUNT(id) AS trans_count,
    SUM(CASE WHEN state='approved' THEN 1 ELSE 0 END) AS approved_count,
    SUM(amount) AS trans_total_amount,
    SUM(CASE WHEN state='approved' THEN amount ELSE 0 END) AS approved_total_amount
FROM Transactions
GROUP BY month, country;

 

SELECT에서 필터링한 것도 GROUP BY에서 사용할 수 있는 것을 몰랐다.