获取给定年份和周数的上周数字

Question

如何从给定的年份和周数中获取上一周的周数（和年份数）？

e.g。

declare @year int = 2014;
declare @week int = 53;

我想获得2014年和52年。

Answer 1

与@AFract一样，根据您使用的RDBMS，您可以这样做。

DECLARE @year int;
DECLARE @week int;
DECLARE @date datetime;

SET @year = 2014;
SET @week = 53;
SET @date = '01/01/' + CAST ( @year AS varchar ) ;
SET @date = DATEADD ( week , @week - 2 , @date ) ;

SELECT DATEPART ( year , @date ) AS 'Year' ,
       DATEPART ( week , @date ) AS 'Week';