涉及的函數
date_format(date, format) 函數
unix_timestamp() 函數
str_to_date(str, format) 函數
from_unixtime(unix_timestamp, format) 函數
1.字符串轉化成時間
select
str_to_date('2019-09-12 00:16:50','%Y-%m-%d %H:%i:%s'),
str_to_date('2019-09-12 00:16:50','%Y-%m-%d %H')
2019-09-12 00:16:50 2019-09-12 00:00:00
2.字符串轉化成時間戳
select
unix_timestamp('2019-09-12 00:00:50'),
unix_timestamp('2019-09-12 00:01:00');
1568217650 1568217660
3.時間轉換成字符串
select
date_format(now(), '%Y-%m-%d'),
date_format(now(), '%Y-%m-%d %H:%i:%s')
2020-08-24 2020-08-24 14:51:26
4.時間轉換成時間戳
select
unix_timestamp(now());
1598251906
5.時間戳轉換成時間
select from_unixtime(1598250986);
2020-08-24 14:36:26
6.時間戳轉成成字符串
select from_unixtime(1598250986,'%Y-%m-%d');
2020-08-24
要想獲得正確的時間相減秒數，有以下三張方式：
1、time_to_sec(timediff(t2, t1))
2、timestampdiff(second, t1, t2)
3、unix_timestamp(t2) -unix_timestamp(t1)
列子：
select time_to_sec(timediff(str_to_date('2019-09-12 00:17:50','%Y-%m-%d %H:%i:%s'), str_to_date('2019-09-12 00:16:50','%Y-%m-%d %H:%i:%s')))
60
select timestampdiff(second, str_to_date('2019-09-12 00:17:50','%Y-%m-%d %H:%i:%s'), str_to_date('2019-09-12 00:16:50','%Y-%m-%d %H:%i:%s'))
-60
select unix_timestamp(str_to_date('2019-09-12 00:17:50','%Y-%m-%d %H:%i:%s')) -unix_timestamp(str_to_date('2019-09-12 00:16:50','%Y-%m-%d %H:%i:%s'))
60