Thank you for your answer. I am convinced. Thank you for replying to my question in poor English.
2022年12月3日(土) 23:19 Tom Lane <t...@sss.pgh.pa.us>: > Laurenz Albe <laurenz.a...@cybertec.at> writes: > > On Sat, 2022-12-03 at 08:54 +0000, PG Doc comments form wrote: > >> I am thinking that the value of the ROUND function with NUMERIC as an > >> argument is rounded off, not rounded away from zero. > > > It is rounded away from zero, since 43 is farther away from 0 than 42.5. > > This may be a language problem. > > Perhaps, since I don't see anything wrong with that text either. > (Of course, it's moderately likely that I wrote that text, > or at least copy-edited it at some point ;-). Don't remember.) > > The point is that for 42.5, or anything-point-5, the basic > "round to nearest integer" rule is insufficient because 42 and > 43 are equally near. We need a tie-breaking rule, and for numeric > that rule has historically been to round to the larger absolute > value (or "away from zero", as the text puts it to avoid two-dollar > terminology). Sadly, that is not what IEEE has established as > best practice for floating-point rounding, so round(float8) > acts differently. > > regards, tom lane >
