SQL 获取第一天、最后一天

–本周第一天
select dateadd(WEEK, datediff(WEEK, 0, getdate()), 0);

–本周最后一天
select dateadd(WEEK, datediff(WEEK, 0, getdate()), 7);

–本月第一天
select dateadd(month, datediff(month, 0, getdate()), 0);
SELECT CONVERT(datetime,CONVERT(char(8),GETDATE(),120)+‘1’);

–本月最后一天
select dateadd(month, datediff(month, -1, getdate()), -1);
select dateadd(d,-day(getdate()),dateadd(m,1,getdate()))；

–上月第一天
SELECT DATEADD(mm,DATEDIFF(mm,0,dateadd(month,-1,getdate())),0);

–上月最后一天
select dateadd(ms,-3,DATEADD(mm,DATEDIFF(mm,0,getdate()),0)) ;

–本季第一天
select dateadd(QUARTER , datediff(QUARTER ,0, getdate()), 0);

–本季最后一天
select dateadd(QUARTER , datediff(QUARTER , -1, getdate()), -1);

–本年第一天
select dateadd(year, datediff(year, 0, getdate()), 0);

–本年最后一天
select dateadd(year, datediff(year, -1, getdate()), -1);

–获取当天的最后一刻
select DATEADD(SS,-1,dateadd(day,1,CONVERT(varchar(15) , getdate(), 102 )))