| re: Rounding errors with the ROUND()
Thomas Bartkus wrote:[color=blue]
> "Matias Silva" <matt@nospam.com> wrote in message
> news:1119iaqmp8bak3a@corp.supernews.com...
>[color=green]
>>Can anybody tell me why I am getting rounding errors
>>using the ROUND function.
>>
>>3.7125 rounds to 3.70 when I use the following:
>>TRUNCATE(ROUND(units_pay_amount * fees_amount, 2),2)))
>>The correct value should be 3.71
>>
>>I could round to the 3rd decimal place ROUND(X,3) and
>>that would round it correctly to 3.71 but that would
>>mean I would have to change the ROUND function in another
>>part of the query in order to make it uniform (to 3 decimal
>>places).
>>
>>The kick in the ass is if I try to make it uniform (to 3
>>places) then another value is wrong and when this one
>>is right...[/color]
>
>
> Why are you blaming ROUND()?
>
> It appears that it is TRUNCATE() that is a bit funky and ROUND() does indeed
> give the correct results according to it's definition.
>
> ROUND(3.7125,2) = 3.71 <- correct
> TRUNCATE(3.71, 2) = 3.70 <- *wrong* according to TRUNCATEs definition.
>
> And - Since ROUND is a truncation to the number of decimal places you
> specified anyway, why in heck do you need to TRUNCATE?
>
> ROUND(x, n)
> should *always* return the exact same value as the needlessly complicated -
> TRUNCATE(ROUND(x, n), n))
> because you have already discarded your extraneous digits using ROUND alone.
>
> So why deal with the TRUNCATE() bug?
> Even if it returned the correct result, it does nothing for you!
>
> Although we do like to know about these bugs :-)
> Thomas Bartkus
>
>
>
>[/color]
Thanks for straightening me out, your absolutly right. When
I removed the TRUNCATE it works.
Thanks for help,
Matias
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