sql 根據某年某周獲取對應日期
--建立乙個標量值函式
--例：weektoday(2018,18)
create function [dbo].[weektoday](@year int,@week int)
returns varchar(50)
asbegin
declare @year1 datetime
declare @stratweek datetime
declare @endweek datetime
set @year1=convert(smalldatetime,convert(varchar(4),@year) + '-1-1')
set @stratweek=dateadd(day,1-datepart(weekday,@year1),dateadd(week,@week-1,@year1))
set @endweek=dateadd(day,6,@stratweek)
return convert(varchar(10),@stratweek,111)
endc# 根據某年某周獲取對應日期
例： getfirstdayofweek(year, week, system.globalization.cultureinfo.invariantculture);
/// 根據一年中的第幾周獲取該週的開始日期
public static datetime getfirstdayofweek(int year, int week, system.globalization.cultureinfo culture)
system.globalization.calendar calendar = culture.calendar;
datetime firstofyear = new datetime(year, 1, 1, calendar);
datetime targetday = calendar.addweeks(firstofyear, week - 1);
dayofweek firstdayofweek = culture.datetimeformat.firstdayofweek;
while (targetday.dayofweek != firstdayofweek)
targetday = targetday.adddays(-1);
return targetday;
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