Re: float conversion / presentation problem ?

John R Pierce <pierce@hogranch.com> writes:
> Tom Lane wrote:
>> You do realize that float4/real is only good to six decimal places
>> on most platforms?

> and importantly, are stored as binary fractions.  0.10000 decimal is a
> repeating fraction in binary, its like .1100110011.... x 2^-2 or
> something as a FLOAT.

Right, and conversely a fraction that's cut off at a certain number of
base-2 digits often corresponds to a repeating pattern of base-10
digits.  I once had a clue about the exact laws for this, but it was
many years ago :-(

            regards, tom lane