From: Laurenz Albe <laurenz.albe@cybertec.at>
To: barsikdacat@gmail.com
To: pgsql-docs@lists.postgresql.org
Subject: Re: to_char(numeric type, text) rounding instead of truncating
Date: Wed, 26 Jul 2023 07:53:36 +0200
Message-ID: <bab04d8c091629a3f17d476af5eda6982d7e0e0d.camel@cybertec.at> (raw)
In-Reply-To: <168991536429.626.9957835774751337210@wrigleys.postgresql.org>
References: <168991536429.626.9957835774751337210@wrigleys.postgresql.org>
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.sgmlindex 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
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To: pgsql-docs@postgresql.org
Cc: laurenz.albe@cybertec.at, barsikdacat@gmail.com, pgsql-docs@lists.postgresql.org
Subject: Re: to_char(numeric type, text) rounding instead of truncating
In-Reply-To: <bab04d8c091629a3f17d476af5eda6982d7e0e0d.camel@cybertec.at>
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