Re: Inconsistent results for division and multiplication operations

Erik Brandsberg <erik@heimdalldata.com> writes:
> This is a common issue with using floating point math.  You will see the
> same issue with many systems.  Basically, the order of operations can
> trigger very minor differences in results, but if you round the first
> result to the same number of significant digits as the input, it would be
> identical.
> https://learn.microsoft.com/en-us/office/troubleshoot/access/floating-calculations-info

Yeah.  The OP is actually working with PG's "numeric" type, not
floating-point, but the principle is the same.  Some division
results can't be represented exactly in any finite number of
digits, so you get roundoff error.

			regards, tom lane