如何使用年份的周数来获取周日期 [英] how to get week dates by using week number of the year

问题描述

您好b $ b

我们提供当周的周数如何获得该周的日期



谢谢和问候

Lakshman

Hi
we are providing present week number how to get dates in that week

Thanks & Regards
Lakshman

推荐答案

这很复杂，因为周数与固定的开始日期无关：1月特定年份的第一年可以在上一年的第50周，第51周或第52周，或当年的第1周 - 并且取决于何时控制当前一周的开始日期。

https://en.wikipedia.org/wiki/ISO_week_date [ ^ ]



我要做的是设置一个按年份编制索引并提供的表格每年第1周的开始日期，然后将周数乘以7以获得实际日期。

或者您可以按照链接中的算法进行操作！

That's complicated, because "week number" doesn't relate to a fixed start date: January the first of a particular year can be in week 50, 51, or 52 of the previous year, or week 1 of the current year - and depending on when that is controls what date the current week starts with.
https://en.wikipedia.org/wiki/ISO_week_date[^]

What I would do set up a table which indexes by year and provides the start date for week 1 of each year, and then add the week number times 7 to that to get the actual date.
Or you could follow the algorithm in the link!

DECLARE @WeekNo in t = 15

DECLARE @Year int = 2013



SELECT DATEADD（周刊，@ WeekNo-1，DATEADD（yy，@ Year-） 1900,0））AS WeekStart，

DATEADD（wk，@ WeekNo，DATEADD（yy，@ Year-1900,0）） - 1 AS WeekEnd

DECLARE @WeekNo int= 15
DECLARE @Year int=2013

SELECT DATEADD(wk,@WeekNo-1,DATEADD(yy,@Year-1900,0)) AS WeekStart,
DATEADD(wk,@WeekNo,DATEADD(yy,@Year-1900,0))-1 AS WeekEnd

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