[yunqa.de] Re: Rounding of REAL and DISQLite3Api.DateTimeToJulianDate
- From: Delphi Inspiration <delphi@xxxxxxxx>
- To: yunqa@xxxxxxxxxxxxx
- Date: Wed, 25 Feb 2009 13:01:25 +0100
Edwin Yip wrote:
>The problem is that the above select statement does not return any records, I
>think this is because of the difference after rounding (calling of
>DateTimeToJulianDate), but I HAVE use this datetime value to match the
>records, it's of the the combined primary keys. Any suggestion to solve my
>problem? Thank you.
Precision is an inherited problem in floating point arithmetic. See
http://en.wikipedia.org/wiki/Floating_point
Therefore the recommendation is not to use double / floating point types for
exact record matches. If you must do so, consider using ROUND(number,
precision) on both sides of the comparison to compensate for rounding errors or
compare against a range of values to satisfy for potential rounding errors.
Ralf
_______________________________________________
Delphi Inspiration mailing list
yunqa@xxxxxxxxxxxxx
//www.freelists.org/list/yunqa
Other related posts:
