mysql 关于时间查询的条件

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