On Fri, Oct 30, 2009 at 1:39 AM, Gray <g...@ms-irk.ru> wrote: > > The following bug has been logged online: > > Bug reference: 5150 > Logged by: Gray > Email address: g...@ms-irk.ru > PostgreSQL version: 8.2.6 > Operating system: i686-pc-linux-gnu > Description: math bug > Details: > > select 1/3*3,(1.0/3.0)*3.0,floor((1.0/3.0)*3.0); > > returns > 0, 1, 0
Well, the first answer is correct, because 1/3 is a request for integer division, so you get 0, and 0 * 3 is still zero. I don't believe the second answer is really what you got, because surely if you requested floating-point division the answer would be a floating point number, not just 1. On pg 8.3.8, I get 0.999999999999999999990, which explains why the third answer comes out to zero. In general, floating point arithmetic is inaccurate and sucky. That has nothing to do with PostgreSQL; it's just life. http://en.wikipedia.org/wiki/Floating_point#Accuracy_problems ...Robert -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
