On Fri, 2023-07-21 at 04:56 +0000, PG Doc comments form wrote: > The following documentation comment has been logged on the website: > > Page: https://www.postgresql.org/docs/15/functions-formatting.html > Description: > > I've encountered an issue with to_char(numeric type, text) > Apparently, it uses rounding instead of truncation which leads to > unpexpected results. This is not reflected in the documentation. > My specific example: > select to_Char(1235::real/(2::real+1235::real)*100, '99%') > The expected output was 99%. The output was ##% - since the number was > rounded to 100, there wasn't enough digits in the format. > If I add a digit after the decimal point > select to_char(1235::real/(2::real+1235::real)*100,'90D0%') > The output becomes 99.8% > > It would be nice to have this behavior explained in the documentation so > people get more predictable results.
+1 How about the following: diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 5a47ce4343..9421ace77e 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -8505,6 +8505,14 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}'); </para> </listitem> + <listitem> + <para> + If the format provides for fewer fractional digits than the number being + formatted has, <function>to_char()</function> will round the number to + the specified number of fractional digits. + </para> + </listitem> + <listitem> <para> The pattern characters <literal>S</literal>, <literal>L</literal>, <literal>D</literal>, Yours, Laurenz Albe