-<!-- $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>
<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>