mysql求最近一段时间的日期

用户密码过期策略

ALTER USER ‘testuser``'@‘localhost' PASSWORD EXPIRE INTERVAL 30 DAY``;

禁用密码过期：

ALTER USER 'testuser'``@``'localhost' PASSWORD EXPIRE NEVER;

基本原理：to_days后方便计算

SELECT TO_DAYS(CURDATE()), id , TO_DAYS(CURDATE())-id, FROM_DAYS (TO_DAYS(CURDATE())-id)  FROM seq_help

to_days(CURDATE())  id  TO_DAYS(CURDATE())-id   from_days (TO_DAYS(CURDATE())-id)
737136  1   737135  2018-03-17
737136  2   737134  2018-03-16
737136  3   737133  2018-03-15
737136  4   737132  2018-03-14
737136  5   737131  2018-03-13
737136  6   737130  2018-03-12
737136  7   737129  2018-03-11

求月初日期

select from_days(to_days(CURDATE())-DAYOFMONTH(CURDATE()-1));


2018-03-01

求日期序列

构造一个表seq_help, 只要id字段，id自增长，填充100行。

SELECT  TO_DAYS(CURDATE())-id dd, FROM_DAYS (TO_DAYS(CURDATE())-id)  FROM seq_help