Doc: document the tie-breaking behavior of the round() function.

Back-patch to v13; the table layout in older branches is unfriendly
to adding such details.

Laurenz Albe

Discussion: https://postgr.es/m/161881920775.685.12293798764864559341@wrigleys.postgresql.org
This commit is contained in:
Tom Lane 2021-04-22 14:47:26 -04:00
parent a71cfc56bf
commit 00037d8d00

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@ -1617,7 +1617,10 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
<returnvalue>double precision</returnvalue>
</para>
<para>
Rounds to nearest integer
Rounds to nearest integer. For <type>numeric</type>, ties are
broken by rounding away from zero. For <type>double precision</type>,
the tie-breaking behavior is platform dependent, but
<quote>round to nearest even</quote> is the most common rule.
</para>
<para>
<literal>round(42.4)</literal>
@ -1632,7 +1635,7 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
</para>
<para>
Rounds <parameter>v</parameter> to <parameter>s</parameter> decimal
places
places. Ties are broken by rounding away from zero.
</para>
<para>
<literal>round(42.4382, 2)</literal>