带有日期计数器的sql while循环

Question

我需要在sql中做这样的事情:

declare @StartDate varchar(10)
declare @EndDate varchar(10)
set @StartDate='12/31/2008'
set @EndDate='1/11/2009'

Declare @date varchar = @StartDate
while (@date <= @EndDate)
begin
 -- some statements
set @date += 1 -- basically increment by 1 day
end

如何在SQL中正确执行上述操作？基本上,我的startdate和enddate是字符串而不是日期时间,因为我的业务逻辑在另一个表中引用字符串列,日期作为列的名称 - 但我需要遍历一堆列,每列的名称都是第二天的约会.

如果日期是11/07/2009,那么列的名称将是'11/7/2009'(7中没有0),所以我也要注意这一点.

任何帮助表示赞赏!

谢谢.

Answer 1

您可以将日期参数转换为日期时间.

SELECT convert(datetime, @StartDate) into datetimevariable

然后你可以使用日期函数来添加天数.

select DATEADD(day,1,datetimevariable) into datetimevariable

作为获得am/d/yyyy格式的解决方案,我几周前从一些网站上获得了C&P这个功能.使用此代码创建一个函数并以这种方式调用:

 SELECT dbo.fnFormatDate (@DateTimeVariable, 'M/DD/YYYY') into stringVariable 

CREATE FUNCTION dbo.CustomFormatDate (@Datetime DATETIME, @FormatMask VARCHAR(32))
RETURNS VARCHAR(32)
AS
BEGIN

    DECLARE @StringDate VARCHAR(32)
    SET @StringDate = @FormatMask
    IF (CHARINDEX (‘YYYY’,@StringDate) > 0)
       SET @StringDate = REPLACE(@StringDate, ‘YYYY’,
                         DATENAME(YY, @Datetime))
    IF (CHARINDEX (‘YY’,@StringDate) > 0)
       SET @StringDate = REPLACE(@StringDate, ‘YY’,
                         RIGHT(DATENAME(YY, @Datetime),2))
    IF (CHARINDEX (‘Month’,@StringDate) > 0)
       SET @StringDate = REPLACE(@StringDate, ‘Month’,
                         DATENAME(MM, @Datetime))
    IF (CHARINDEX (‘MON’,@StringDate COLLATE SQL_Latin1_General_CP1_CS_AS)>0)
       SET @StringDate = REPLACE(@StringDate, ‘MON’,
                         LEFT(UPPER(DATENAME(MM, @Datetime)),3))
    IF (CHARINDEX (‘Mon’,@StringDate) > 0)
       SET @StringDate = REPLACE(@StringDate, ‘Mon’,
                                     LEFT(DATENAME(MM, @Datetime),3))
    IF (CHARINDEX (‘MM’,@StringDate) > 0)
       SET @StringDate = REPLACE(@StringDate, ‘MM’,
                  RIGHT(‘0?+CONVERT(VARCHAR,DATEPART(MM, @Datetime)),2))
    IF (CHARINDEX (‘M’,@StringDate) > 0)
       SET @StringDate = REPLACE(@StringDate, ‘M’,
                         CONVERT(VARCHAR,DATEPART(MM, @Datetime)))
    IF (CHARINDEX (‘DD’,@StringDate) > 0)
       SET @StringDate = REPLACE(@StringDate, ‘DD’,
                         RIGHT(‘0?+DATENAME(DD, @Datetime),2))
    IF (CHARINDEX (‘D’,@StringDate) > 0)
       SET @StringDate = REPLACE(@StringDate, ‘D’,
                                    DATENAME(DD, @Datetime))   

RETURN @StringDate
END
GO