SQL 取日期備忘錄－>

SQL 取日期備忘錄

取週日期

declare @mydate date='2013/11/29'
select CAST( CONVERT (varchar(8), DATEADD(wk, DATEDIFF(wk, 0, @mydate), -3),112 ) as int ) as '該週第1天'
,CAST( CONVERT (varchar(8), DATEADD(wk, DATEDIFF(wk, 0, @mydate), -2),112 ) as int ) as '該週第2天'
,CAST( CONVERT (varchar(8), DATEADD(wk, DATEDIFF(wk, 0, @mydate), -1),112 ) as int ) as '該週第3天'
,CAST( CONVERT (varchar(8), DATEADD(wk, DATEDIFF(wk, 0, @mydate), 0),112 ) as int ) as '該週第4天'
,CAST( CONVERT (varchar(8), DATEADD(wk, DATEDIFF(wk, 0, @mydate), 1),112 ) as int ) as '該週第5天'
,CAST( CONVERT (varchar(8), DATEADD(wk, DATEDIFF(wk, 0, @mydate), 2),112 ) as int ) as '該週第6天'
,CAST( CONVERT (varchar(8), DATEADD(wk, DATEDIFF(wk, 0, @mydate), 3),112 ) as int ) as '該週第7天'

SQL
--本周第一天
SELECT DATEADD(Day,1-(DATEPART(Weekday,getdate())+@@DATEFIRST-1)%7,getdate())
--or
select dateadd(wk, datediff(wk,0,getdate()), 0)
--本周第一天
select dateadd(wk, datediff(wk,0,getdate()), 6)

--上月第一天
SELECT CONVERT(CHAR(10),DATEADD(month,-1,DATEADD(dd,-DAY(GETDATE())+1,GETDATE())),111)
--上月最后一天
SELECT CONVERT(CHAR(10),DATEADD(ms,-3,DATEADD(mm, DATEDIFF(mm,0,getdate()),0)),111)+' 23:59:59'
--本月第一天
select dateadd(dd,-datepart(dd,getdate())+1,getdate())
--本月最后一天
select dateadd(dd,-datepart(dd,getdate()) ,dateadd(mm,1,getdate()))
--本月天?
select datediff(dd,dateadd(dd,-datepart(dd,getdate())+1,getdate()), dateadd(dd,-datepart(dd,getdate())+1,dateadd(mm,1,getdate())))
--or
select datepart(dd,dateadd(dd,-1,dateadd(mm,1,cast(cast(year(getdate()) as varchar)+'-'+cast(month(getdate()) as varchar)+'-01' as datetime))))

--下月第一天
select dateadd(dd,-datepart(dd,getdate())+1,dateadd(mm,1,getdate()))
--下月最后一天
SELECT CONVERT(CHAR(10),DATEADD(ms,-3,DATEADD(mm,DATEDIFF(m,0,getdate())+2,0)),111)+' 23:59:59'
--季度第一天
SELECT DATEADD(qq, DATEDIFF(qq,0,getdate()), 0)
--季度最后一天（直接推算法）
SELECT DATEADD(Day,-1,CONVERT(char(8),DATEADD(Month,1+DATEPART(Quarter,getdate())*3-Month(getdate()),getdate()),120)+'1')
--季度的最后一天（CASE判?法）
select DATEADD(Month,DATEPART(Quarter,getdate())*3-Month(getdate()),getdate())

--本月第一?星期一
SELECT DATEADD(wk, DATEDIFF(wk, '', DATEADD(dd, 6 - DAY(getdate()), getdate())), '')
--去年最后一天
SELECT   dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate()), 0))
--今年第一天
SELECT   DATEADD(yy,   DATEDIFF(yy,0,getdate()),   0)
--今年最后一天
SELECT dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1,0))

--指定日期所在周的任意一天
SELECT DATEADD(Day,@number-DATEPART(Weekday,@dt),@dt)--5．指定日期所在周的任意星期几
--A. 星期天做?一周的第1天
SELECT DATEADD(Day,@number-(DATEPART(Weekday,@dt)+@@DATEFIRST-1)%7,@dt)
--B. 星期一做?一周的第1天
SELECT DATEADD(Day,@number-(DATEPART(Weekday,@dt)+@@DATEFIRST-2)%7-1,@dt)
---周?的第几日
select datepart(weekday,getdate()) as 周?的第几日
--年?的第几周
select datepart(week,getdate()) as 年?的第几周
--年?的第几季
select datepart(quarter,getdate()) as 年?的第几季

--判?某天是?月的第几周的sql函?
CREATE   FUNCTION   WeekOfMonth(@day datetime)
RETURNS int
AS
begin

----declare @day datetime
declare @num int
declare @Start datetime
declare @dd int
declare @dayofweek char(8)
declare @dayofweek_num char(8)
declare @startWeekDays int
---set @day='2009-07-05'
if datepart(dd,@day)=1
return 1
else
set @Start= (SELECT   DATEADD(mm,   DATEDIFF(mm,0,@day),   0)) --一?月第一天的
set @dayofweek= (datename(weekday,@Start)) ---得到本月第一天是周几
set @dayofweek_num=(select (case @dayofweek when '星期一' then 2
when '星期二' then 3
when '星期三' then 4
when '星期四' then 5
when '星期五' then 6
when '星期六' then 7
when '星期日' then 1
end))
set @dayofweek_num= 7-@dayofweek_num+1 ---得到本月的第一周一共有几天
---print @dayofweek_num
   set @dd=datepart(dd,@day) ----得到今天是??月的第几天
--print @dd
if @dd<=@dayofweek_num --小于前一周的天?
return 1
else
set @dd=@dd-@dayofweek_num
if @dd % 7=0
     begin
       set @num=@dd / 7
        return @num+1

     end
   else --if @dd % 7<>0

     set @num=@dd / 7
set @num=@num+1+1
       return @num

end