Re: [GENARAL] round() bug

On 15/04/2014 17:20, David G Johnston wrote:
> Willy-Bas Loos-3 wrote
>> Hi, I ran into some strange behavior. Seems like a bug to me?
>>
>> wbloos=# select round(0.5::numeric), round(0.5::double precision);
>> round | round -------+------- 1 | 0 (1 row)
>
> Not a bug; and likely to simple to have escaped notice this long so
> the first reaction should be "what am I missing here?"
>
> [google: round .5 postgresql]
>
> http://grokbase.com/t/postgresql/pgsql-hackers/03ap11tckn/round-function-wrong/oldest
>
> Round( numeric ) - 0.5 rounds away from zero Round( float ) -
> platform dependent, IEEE 0.5 rounds toward even
>
> You can argue the decision but at this point it's not likely to
> change.

Interestingly, I get different results (on both 9.1.4 and 9.3.0) on Windows:

postgres=# select round(0.5::numeric), round(0.5::double precision);
round | round
-------+-------
1 | 1
(1 row)

postgres=# select version();
version
-------------------------------------------------------------
PostgreSQL 9.1.4, compiled by Visual C++ build 1500, 64-bit
(1 row)

.... Same on 9.3.0.

Ray.

--
Raymond O'Donnell :: Galway :: Ireland
rod(at)iol(dot)ie