On 14 Dec 2013 15:40, "Tom Lane" <t...@sss.pgh.pa.us> wrote: > > David Rowley <dgrowle...@gmail.com> writes: > > The attached patch is not quite finished yet, I've not yet fully covered > > SUM and AVG for all types. > > I think you *can't* cover them for the float types; roundoff error > would mean you don't get the same answers as before.
I was going to say the same thing. But then I started to wonder.... What's so special about the answers we used to give? They are also subject to round off and the results are already quite questionable in those cases.