我想得到星期天 WeekNo？答案

【问题标题】：I want to get the sunday WeekNo?我想得到星期天 WeekNo？
【发布时间】：2013-01-24 12:02:00
【问题描述】：

我使用的是 SQL Server 2008 R2。我需要获得周日 weekno 并且我已经有了查询，但它显示了错误的数据。我能做什么？

它显示 2 而不是 1。例如，06-Jan-2013(WeekNo - 1)

我的查询是

SELECT DATEPART (week, '01-13-2013 23:59:59.000' ) As WeekNo1 ,  
  DATEPART (week, '01-06-2013 23:59:59.000' ) As WeekNo2 ,  
  DATEPART (week, '12-30-2012 23:59:59.000' ) As WeekNo3 ,  
  DATEPART (week, '12-23-2012 23:59:59.000' ) As WeekNo4 ,  
  DATEPART (week, '12-16-2012 23:59:59.000' ) As WeekNo5 ,  
  DATEPART (week, '12-09-2012 23:59:59.000' ) As WeekNo6

【问题讨论】：

标签： sql sql-server sql-server-2008 sql-server-2005 sql-server-2008-r2

【解决方案1】：

您需要将DATEFIRST 属性设置为一周的开始日期。这指定了一周的第一天。

要确定服务器一周的第一天是什么，您将使用：

SELECT @@DATEFIRST

那么如果你需要改变这个值，你会使用：

SET DATEFIRST 1;

SELECT DATEPART (week, '01-13-2013 23:59:59.000' ) As WeekNo1 ,  
  DATEPART (week, '01-06-2013 23:59:59.000' ) As WeekNo2 ,  
  DATEPART (week, '12-30-2012 23:59:59.000' ) As WeekNo3 ,  
  DATEPART (week, '12-23-2012 23:59:59.000' ) As WeekNo4 ,  
  DATEPART (week, '12-16-2012 23:59:59.000' ) As WeekNo5 ,  
  DATEPART (week, '12-09-2012 23:59:59.000' ) As WeekNo6

见SQL Fiddle with Demo。

【讨论】：

【解决方案2】：

查询：

SQLFIDDLEExample

SET DATEFIRST 1
SELECT DATEPART (week, '01-13-2013 23:59:59.000' ) As WeekNo1 ,  
       DATEPART (week, '01-06-2013 23:59:59.000' ) As WeekNo2 , 
       DATEPART (week, '12-30-2012 23:59:59.000' ) As WeekNo3 ,  
       DATEPART (week, '12-23-2012 23:59:59.000' ) As WeekNo4 ,  
       DATEPART (week, '12-16-2012 23:59:59.000' ) As WeekNo5 ,  
       DATEPART (week, '12-09-2012 23:59:59.000' ) As WeekNo6

结果：

| WEEKNO1 | WEEKNO2 | WEEKNO3 | WEEKNO4 | WEEKNO5 | WEEKNO6 |
-------------------------------------------------------------
|       2 |       1 |      53 |      52 |      51 |      50 |

【讨论】：

初始/原始DATEFIRST设置应在SELECT ...之后恢复。