Document that age() adds days, then full months.

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Bruce Momjian 2007-07-18 03:12:42 +00:00
parent 27d074923d
commit df7128bd34
1 changed files with 12 additions and 1 deletions

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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.382 2007/06/06 23:00:35 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.383 2007/07/18 03:12:42 momjian Exp $ -->
<chapter id="functions">
<title>Functions and Operators</title>
@ -5895,6 +5895,17 @@ SELECT (DATE '2001-02-16', INTERVAL '100 days') OVERLAPS
<literal>CST7CDT</literal>.
</para>
<para>
Note that when the <function>age</> function operates on multi-month
intervals, <productname>PostgreSQL</> adds days to the earlier date
until full months can be added. This yields a different result than
adding full months first if the interval crosses from one month to the
next. For example, <literal>age('2004-06-01', '2004-04-30')</> yeilds
<literal>1 mon 1 day</> using the <productname>PostgreSQL</> method,
while adding the month first would yield <literal>1 mon 2 days</>
because May has 31 days, while April has only 30.
</para>
<sect2 id="functions-datetime-extract">
<title><function>EXTRACT</function>, <function>date_part</function></title>