Re: Strange round behaviour w/ more than 2 decimals - Mailing list pgsql-general

"Fernando Madruga Pinheiro" <fernando.madrugapinheiro@gmail.com> writes:
> If I use ROUND(1.8947, 2), it should return 1.90, but it does return 1.89.

Why do you consider that wrong?  It's the closest approximation.
Do you know of any other software that would produce 1.90 from a
similar query?

> Rounding to 3 decimal places, then 2 (eg.: ROUND(ROUND(1.8947, 3), 2) ) then
> I get 1.90!

Since ROUND() is a lossy process by definition, you cannot expect
that different multi-step paths will always yield the same result.

            regards, tom lane