SELECT
TIME_TO_SEC(TIMEDIFF('2018-09-30 19:38:45', '2018-08-23 10:13:01')) AS DIFF_SECOND1, -- 秒
UNIX_TIMESTAMP('2018-09-30 19:38:45')-UNIX_TIMESTAMP('2018-08-23 10:13:01') AS DIFF_SECOND2, -- 秒
TIMESTAMPDIFF(SECOND,'2018-08-23 10:13:01','2018-09-30 19:38:45') AS DIFF_SECOND3, -- 秒
TIMESTAMPDIFF(MINUTE,'2018-08-23 10:13:01','2018-09-30 19:38:45') AS DIFF_MINUTE, -- 分
TIMESTAMPDIFF(HOUR,'2018-08-23 10:13:01','2018-09-30 19:38:45') AS DIFF_HOUR, -- 小时
TIMESTAMPDIFF(DAY ,'2018-08-23 10:13:01','2018-09-30 19:38:45') AS DIFF_DATE1, -- 天
DATEDIFF('2018-09-30 19:38:45','2018-08-23 10:13:01') AS DIFF_DATE2, -- 天
TIMESTAMPDIFF(MONTH,'2018-08-23 10:13:01','2018-09-25 19:38:45') AS DIFF_MONTH, -- 月
TIMESTAMPDIFF(YEAR,'2018-08-23 10:13:01','2020-07-25 19:38:45') AS DIFF_YEAR -- 年
FROM DUAL;