MySQL 時間差、每15分鐘統計一次數據

計算 loan_time 和curdate() 之間的日期差

  DATEDIFF(date(loan_time), curdate()) 

loan_time 加上3個月 後的時間 IFNULL 判空處理

date_add(IFNULL(loan_time,0),NTERVAL 3  MONTH)

每十五分鐘統計一次有多少數據,並按時間分組

SELECT 
    CONCAT(DATE_FORMAT(loan_time, '%Y-%m-%d %H:'),
           FLOOR(DATE_FORMAT(loan_time, '%i') / 15)) AS c,
           count(*)
FROM
    loan_record
WHERE
    DATE(loan_time) = CURRENT_DATE()
GROUP BY c
ORDER BY loan_time DESC