Re: The 85/0.0085 mistery ?

Hannu Krosing wrote:
>
> Tom Lane wrote:
> >
> > "Frederick W. Reimer" <fwr(at)ga(dot)prestige(dot)net> writes:
> > > In general, it's recommended you don't check for exact equivalence when
> > > doing calculations on real numbers and instead check for "almost exactness."
> >
>
> perhaps "where trunc(85/0.0085) = 10000" works better.

ok I tested it and it does not work ;(

hannu=# select trunc(85.0::float4/0.0085::float4) = '10000';
ERROR: Function 'trunc(float4)' does not exist
Unable to identify a function that satisfies the given argument types
You may need to add explicit typecasts
hannu=# select trunc(float8(85.0::float4/0.0085::float4));
trunc
-------
9999
(1 row)

But this does work

hannu=# select text(85.0::float4/0.0085::float4) = '10000';
?column?
----------
t
(1 row)

As does this

hannu=# select round(float8(85.0::float4/0.0085::float4));
round
-------
10000
(1 row)

--------------
Hannu