I think the crucial point is that the common IEEE floating point formats are unable to store an EXACT representation of common decimal fractions (such as .1) -- they can only store an APPROXIMATION.
>>> Peter Eisentraut <[EMAIL PROTECTED]> >>> Csaba Nagy wrote: > [snip] > > > Floating points numbers are accurate but not precise. > > OK, now this one beats me... what's the difference between "accurate" > and "exact" ? I thought both mean something like "correct", but > precise refers to some action and accurate applies to a situation or > description... Accurate means close to the real value, precise means having a lot of detail. So 3 is more accurate than 4 as a representation of "Pi", but both are not very precise. 5.32290753057207250735 is a very precise representation of "Pi" but totally inaccurate. This also means that the statement at the top is wrong. It should be the other way around. -- Peter Eisentraut http://developer.postgresql.org/~petere/ ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend