SQL-日期时间函数

日期格式

SELECT
	uid,
	start_time,
	CURRENT_DATE,
	CURRENT_DATE(),
	CURDATE(),
	NOW(),
	DATE(NOW()) date,
	DATE_FORMAT(NOW(),"%Y-%m-%d") as date_format,
	DATEDIFF( CURRENT_DATE, start_time ) AS datediff,
	-- DATEDIFF(结束日期，开始日期) 返回值是相隔天数
	WEEKDAY(start_time) weedday,
	WEEK(start_time) week,
	WEEKOFYEAR(start_time) weekofyear,
	DATE_SUB( start_time, INTERVAL 1 DAY ) AS datesub,
	DATE_ADD( start_time, INTERVAL 2 MONTH ) AS dateadd
FROM
	exam_record

时间格式

SELECT
	start_time,
	TIME( start_time ) time,
	CURRENT_TIME,
	CURRENT_TIME () cur,
	CURRENT_TIMESTAMP () cur1,
	TIMESTAMP(2) stamp,
	TIME_FORMAT( start_time, "%H:%I:%S" ) format,
	TIME_FORMAT( start_time, "%h:%I:%S" ) format3,
	TIME_FORMAT( start_time, "%T" ) format1,
	TIME_FORMAT( start_time, "%r" ) format2,
	TIMEDIFF( submit_time, start_time ) diff,-- 	TIMESTAMP,
	TIMESTAMPDIFF( MINUTE, submit_time, start_time ) diff1,
	TIMESTAMPDIFF( SECOND, submit_time, start_time ) diff2,
	TIMESTAMPDIFF( HOUR, submit_time, start_time ) diff3,
	TIMESTAMPDIFF( YEAR, submit_time, start_time ) diff4,
	TIMESTAMPDIFF( MONTH, submit_time, start_time ) diff5,
	TIMESTAMPDIFF( DAY, submit_time, start_time ) diff6,
	TIMESTAMPDIFF( QUARTER, submit_time, start_time ) diff7,
	TIMESTAMPDIFF( WEEK, submit_time, start_time ) diff8,
	TIME_TO_SEC( start_time ) timesec,-- 时间转秒
	SEC_TO_TIME(90) sectime -- 数字转时间
FROM
	exam_record;