Thread

Re: BUG #19340: Wrong result from CORR() function

Oleg Ivanov <o15611@gmail.com> — 2025-12-02T14:05:23Z

Yes, must be NULL in all the queries I have provided!
But PostgreSQL curr() returns numbers, wich is incorrect.

On Tue, Dec 2, 2025 at 2:30 PM Laurenz Albe <laurenz.albe@cybertec.at>
wrote:

> On Tue, 2025-12-02 at 07:57 +0000, PG Bug reporting form wrote:
> > The following bug has been logged on the website:
> >
> > Bug reference:      19340
> > Logged by:          Oleg Ivanov
> > Email address:      o15611@gmail.com
> > PostgreSQL version: 18.1
> > Operating system:   all
> > Description:
> >
> > postgres=# SELECT corr( 0.09 , 0.09000001 ) FROM generate_series(1,24) ;
> >  corr
> > ------
> >
> > (1 row)
> >
> > If argument is the constant, function CORR() must give a 0 or NaN.
> > Consequences of this bug: statistic functions are used to make business
> > descision. Wrong and completely different results can lead to make
> mistakes.
>
> The documentation is pretty clear about that:
>
>   In all cases, null is returned if the computation is meaningless, for
> example when N is zero.
>
> Yours,
> Laurenz Albe
>