00:00:00'GMT开始的秒数,date默认值为当前时间)
mysql> select UNIX_TIMESTAMP();
-> 882226357
mysql> select UNIX_TIMESTAMP('1997-10-04
22:23:00');
-> 875996580
FROM_UNIXTIME(unix_timestamp)
以'YYYY-MM-DD
HH:MM:SS'或YYYYMMDDHHMMSS格式返回时间戳的值(根据返回值所处上下文是字符串或数字)
mysql> select
FROM_UNIXTIME(875996580);
-> '1997-10-04 22:23:00'
mysql>
select FROM_UNIXTIME(875996580) + 0;
-> 19971004222300
FROM_UNIXTIME(unix_timestamp,format)
以format字符串格式返回时间戳的值
mysql>
select FROM_UNIXTIME(UNIX_TIMESTAMP(),'%Y %D %M %h:%i:%s %x');
'1997 23rd December 03:43:30 x'
SEC_TO_TIME(seconds)
以'HH:MM:SS'或HHMMSS格式返回秒数转成的TIME值(根据返回值所处上下文是字符串或数字)
mysql> select
SEC_TO_TIME(2378);
-> '00:39:38'
mysql> select
SEC_TO_TIME(2378) + 0;
-> 3938
TIME_TO_SEC(time)
返回time值有多少秒
mysql> select
TIME_TO_SEC('22:23:00');
-> 80580
mysql> select
TIME_TO_SEC('00:39:38');
-> 2378