MySql常用日期时间查询

-- 某一天所在周的第一天： 
-- 我们知道国外的星期的第一天是从星期天开始的，所以DAYOFWEEK(\'2017-3-10\')函数的第一天是星期天： 
SELECT 
CASE WHEN DAYNAME(DATE(\'2017-3-10\'))=\'Sunday\' 
THEN DATE_SUB(DATE(\'2017-3-10\'),INTERVAL 6 DAY) 
ELSE DATE_ADD(\'2017-3-10\',INTERVAL -DAYOFWEEK(DATE(\'2017-3-10\'))+2 DAY) END

-- 某一天所在周的最后一天：
SELECT CASE WHEN DAYNAME(DATE(\'2017-3-11\'))=\'Sunday\' THEN DATE(\'2017-3-11\') ELSE DATE_ADD(\'2017-3-11\',INTERVAL 7-DAYOFWEEK(\'2017-3-11\')+1 DAY) END

-- 某一天的所在月的第一天： 
SELECT DATE_ADD( DATE_ADD(LAST_DAY(\'2017-03-03\'),INTERVAL 1 DAY ),INTERVAL -1 MONTH );

-- 或
SELECT DATE_SUB(DATE_ADD(LAST_DAY(\'2017-03-03\'),INTERVAL 1 DAY),INTERVAL 1 MONTH)

-- 或
SELECT DATE_SUB(LAST_DAY(\'2017-03-03\'),INTERVAL TIMESTAMPDIFF(DAY,\'2017-03-03\',(DATE_ADD(\'2017-03-03\',INTERVAL 1 MONTH)))-1 DAY)

-- 某一天所在月的最后一天： 
SELECT LAST_DAY(\'2017-03-03\'); 

select DATE_FORMAT(NOW(),\'%Y-%m-%d %h:%i:%s\');

-- 某一天所在月的天数： 
SELECT TIMESTAMPDIFF(DAY,\'2017-03-03\',(DATE_ADD(\'2017-03-03\',INTERVAL 1 MONTH)));


set @dt = now();  
select date_add(@dt, interval 1 day);   - 加1天  
select date_add(@dt, interval 1 hour);   -加1小时  
select date_add(@dt, interval 1 minute);    - 加1分钟  
select date_add(@dt, interval 1 second); -加1秒  
select date_add(@dt, interval 1 microsecond);-加1毫秒  
select date_add(@dt, interval 1 week);-加1周  
select date_add(@dt, interval 1 month);-加1月  
select date_add(@dt, interval 1 quarter);-加1季  
select date_add(@dt, interval 1 year);-加1年  

select TIMESTAMPDIFF(DAY,\'2019-06-01\',\'2019-06-05\');

select DATE_FORMAT(\'20190606\',\'%Y-%m-%d\');

-- 遍历指定时间段集合
select t.date from (
SELECT DATE_FORMAT(DATE_ADD(date_sub(\'2019-06-01\',INTERVAL 1 day), INTERVAL num DAY), \'%Y-%m-%d\') as date
FROM ( 
	SELECT @num:=@num+1 as num from 
	(SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5) a, 
	(SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5) b, 
	(SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5) c, 
	(SELECT 1 UNION SELECT 2 UNION SELECT 3 ) d,   
	(SELECT @num:=0) m 
) x)t where t.date<=\'2019-12-01\';


-- 遍历指定时间段集合2
select a.date,DAYOFWEEK(a.date)-1,WEEKDAY(a.date)+1,DAYNAME(DATE(a.date)) from
(
select @num:=@num+1,
date_format(adddate(date_sub(\'2020-01-02\',INTERVAL 1 day),INTERVAL @num day),\'%Y-%m-%d\') as date
from t_student,
(select @num:=0) t
where ADDDATE(\'2020-01-02\',INTERVAL @num day)<= date_format(\'2020-03-01\',\'%Y-%m-%d\')
) a;