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.
