计算 loan_time 和curdate() 之间的日期差
DATEDIFF(date(loan_time), curdate())
- 1
loan_time 加上3个月 后的时间 IFNULL 判空处理
date_add(IFNULL(loan_time,0),NTERVAL 3 MONTH)
- 1
每十五分钟统计一次有多少数据,并按时间分组
SELECT
CONCAT(DATE_FORMAT(loan_time, '%Y-%m-%d %H:'),
FLOOR(DATE_FORMAT(loan_time, '%i') / 15)15) AS c,
count(*)
FROM
loan_record
WHERE
DATE(loan_time) = CURRENT_DATE()
GROUP BY c
ORDER BY loan_time DESC