如何将双倍转换为时间？ [英] How do I convert a double to a time?

问题描述

42998.578472222223

应该在太平洋标准时间今天下午1点左右？

should be around 1PM PST today??

DateTime.FromOADate(42998.578472222223)

没有给出正确答案



我尝试过：



尝试了各种时间戳转换

doesn't give the right answer

What I have tried:

tried various time stamp conversions

推荐答案

这看起来像是编码值的本地化时间。如果在澳大利亚布里斯班转换：

This looks like a localized time to where the value was encoded. If converted here in Brisbane, Australia:

double dateValue = 42998.578472222223;
DateTime convertedDate = DateTime.FromOADate(dateValue); // 20/09/2017 1:53:00 PM
DateTime localDate = convertedDate.ToLocalTime();        // 20/09/2017 11:53:00 PM
DateTime utcDate = convertedDate.ToUniversalTime();      // 20/09/2017 3:53:00 AM

Quote：

42998.578472222223

42998.578472222223

这是一个'Excel DateTime编码'。

整数部分是自开始日起的天数，应该是01/01/1900左右。

小数部分是当天的时间。

1是24小时

0.75是18小时

0.50是12小时

0.25是6小时

等等。

0.578472222223是13:53或1:53 PM

This is an 'Excel DateTime encoding'.
The integer part is number of days since starting day which should be around 01/01/1900.
the decimal part is the time in the current day.
1 is 24 hours
0.75 is 18 hours
0.50 is 12 hours
0.25 is 6 hours
and so on.
0.578472222223 is 13:53 or 1:53 PM

在之前的答案之后，我只是尝试了以下内容SQL Server 2014

After the previous answers, I just tried the following in SQL Server 2014

DECLARE @d DECIMAL = 42998
DECLARE @t DECIMAL = 0.578472222223 * ( 60*60*24 )
SELECT DATEADD(ss,@t,DATEADD(dd,@d,'1900-01-01'))

它的收益率 2017-09-22 13：53：00.000 这不是今天的日期。



但这可能是有意义的：

https://support.microsoft.com/en-us/help/ 214326 / excel-incorrect-assume-that-the-year-1900-a-aap-year [ ^ ]



那么这个呢？

and it yields 2017-09-22 13:53:00.000 which is not today's date.

But this may be of interest:
https://support.microsoft.com/en-us/help/214326/excel-incorrectly-assumes-that-the-year-1900-is-a-leap-year[^]

So then this?

SELECT DATEADD ( ss , @t , DATEADD ( dd , @d - CASE WHEN @d < 60 THEN 1 ELSE 2 END , '1900-01-01' ) )

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