Kaiting Chen <ktchen14@gmail.com> writes:
> Hi everyone. I’m trying to perform some exact precision arithmetic with PostgreSQL’s NUMERIC type. However I can’t
seemto get the unparameterized NUMERIC type to perform exact precision arithmetic:
Division is inherently inexact, except in special cases. If you think
that 1/(2^64) should be carried out to enough digits to be exact,
what would you have us do with 1/3?
The actual behavior is that it will choose a result scale (number of
digits after the decimal point) that is dependent on the scales of the
input arguments, but not on their precise values. I don't recall the
details beyond that.
regards, tom lane