## 时间函数 now()：返回当前时间，日期 时间. curdate()：返回当前日期. curtime()：返回当前时间. ~~~ select now(),curdate(),curtime(); ~~~ 结果: ~~~ +---------------------+------------+-----------+ | now() | curdate() | curtime() | +---------------------+------------+-----------+ | 2018-03-14 10:07:40 | 2018-03-14 | 10:07:40 | +---------------------+------------+-----------+ ~~~ * * * * * datediff()：判断两个日期之间的天数差距，参数日期必须使用字符串格式（用引号） ~~~ select datediff('2018-01-01','2010-01-01'); ~~~ 结果: ~~~ +-------------------------------------+ | datediff('2018-01-01','2010-01-01') | +-------------------------------------+ | 2922 | +-------------------------------------+ ~~~ * * * * * date_add(日期,interval 时间数字 type)：进行时间的增加,type:day/hour/minute/second. ~~~ select date_add('2010-01-01',interval 10 day); ~~~ 结果: ~~~ +----------------------------------------+ | date_add('2010-01-01',interval 10 day) | +----------------------------------------+ | 2010-01-11 | +----------------------------------------+ ~~~ * * * * * unix_timestamp()：获取时间戳 ~~~ select unix_timestamp(); ~~~ 结果: ~~~ +------------------+ | unix_timestamp() | +------------------+ | 1521077300 | +------------------+ ~~~ * * * * * from_unixtime()：将指定时间戳转换成对应的日期时间格式 ~~~ select from_unixtime(1499567890); ~~~ 结果: ~~~ +---------------------------+ | from_unixtime(1499567890) | +---------------------------+ | 2017-07-09 10:38:10 | +---------------------------+ ~~~