MySQL

MySQL commonly used time functions detailed of recommendations

2.6 DATE_SUB/DATE_ADD

DATE_SUB(date,INTERVAL expr type)

The date argument is a valid date expression. The expr parameter is the interval you want to add.

SELECT id FROM my_table WHERE create_time >= date_sub(now(), INTERVAL 3 HOUR) AND create_time < now();

Type value

•MICROSECOND •SECOND •MINUTE •HOUR •DAY •WEEK •MONTH •QUARTER •YEAR •SECOND_MICROSECOND •MINUTE_MICROSECOND •MINUTE_SECOND •HOUR_MICROSECOND •HOUR_SECOND •HOUR_MINUTE •DAY_MICROSECOND •DAY_SECOND •DAY_MINUTE •DAY_HOUR •YEAR_MONTH

2.7 Time addition and subtraction

When we give now () +-1 time, we should understand it like this:

+1/+01: Add 1 second +101/+0101: Add 1 minute and 1 second +10101/+010101: Plus 1 hour, 1 minute, 1 second +1010101/+01010101: Plus 1 hour, 1 minute, 1 second per day +101010101/+0101010101: Plus January 1 day 1:00, 1 minute, 1 second +1101010101/+010101010101: plus 1 January 1, 1 day, 1 hour, 1 minute, 1 second. Note here that this part of year can be 4 digits (if there is no high position, zero will be added) : 00010101010101

2.8 DATE_DIFF/TIME_DIFF

DATEDIFF(date1,date2)

The DATEDIFF() function returns the number of days between two dates (days only). The date1 and date2 arguments are valid datetime/date expressions.

select datediff('2016-03-29','2016-03-29');

select datediff('2016-03-29 00:00:00','2016-03-29 23:59:59');

TIMEDIFF(date1,date2)

The TIMEDIFF() function returns the number of minutes and seconds between two dates (HH:MM:ss). The date1 and date2 arguments are datetime/time expressions.

select timediff('2016-03-30 00:00:00','2016-03-28 11:11:11');

select timediff('00:00:00','11:11:11');

2.9 DATE_FORMAT

DATE_FORMAT(date,format) The DATE_FORMAT() function is used to display date/time data in different formats.

SELECT DATE_FORMAT(insert_time,'%Y-%m-%d %H:%i:%S') AS insert_time FROM user;

SELECT DATE_FORMAT(insert_time,'%Y-%m-%d') AS day, COUNT(id) AS count FROM user GROUP BY day;
格式描述
%a缩写星期名
%b缩写月名
%c月，数值
%D带有英文前缀的月中的天
%d月的天，数值(00-31)
%e月的天，数值(0-31)
%f微秒
%H小时 (00-23)
%h小时 (01-12)
%I小时 (01-12)
%i分钟，数值(00-59)
%j年的天 (001-366)
%k小时 (0-23)
%l小时 (1-12)
%M月名
%m月，数值(00-12)
%pAM 或 PM
%r时间，12-小时（hh:mm:ss AM 或 PM）
%S秒(00-59)
%s秒(00-59)
%T时间, 24-小时 (hh:mm:ss)
%U周 (00-53) 星期日是1周的第1天
%u周 (00-53) 星期1是1周的第1天
%V周 (01-53) 星期日是1周的第1天，与 %X 使用
%v周 (01-53) 星期1是1周的第1天，与 %x 使用
%W星期名
%w周的天 （0=星期日, 6=星期6）
%X年，其中的星期日是周的第1天，4 位，与 %V 使用
%x年，其中的星期1是周的第1天，4 位，与 %v 使用
%Y年，4 位
%y年，2 位