当前时间
select now()
select now()+0
时间戳和timestamp切换
select unix_timestamp(now());
select from_unixtime(1525263383, '%Y-%m-%d %H:%i:%s');
select from_unixtime(1525263383);
select unix_timestamp('2018-05-02 20:24:10');
计算时间差 date_sub 和 date_add
select date_sub(now(),interval 1 day);
select date_sub(now(),interval 1 year);
select date_sub(now(),interval 1 week);
select date_sub(now(),interval 1 month);
select date_add(now(),interval 1 day);
select date_add(now(),interval 1 year);
select date_add(now(),interval 1 week);
select date_add(now(),interval 1 month);
提取时间中年月日时分秒
SELECT EXTRACT(YEAR FROM '2017-05-15 10:37:14.123456'); 2017
SELECT EXTRACT(MONTH FROM '2017-05-15 10:37:14.123456'); 5
SELECT EXTRACT(DAY FROM '2017-05-15 10:37:14.123456'); 15
SELECT EXTRACT(HOUR FROM '2017-05-15 10:37:14.123456'); 10
SELECT EXTRACT(MINUTE FROM '2017-05-15 10:37:14.123456'); 37
SELECT EXTRACT(SECOND FROM '2017-05-15 10:37:14.123456'); 14
SELECT EXTRACT(MICROSECOND FROM '2017-05-15 10:37:14.123456'); 123456