From df7128bd34be68bccda90ab0ee011dffaccf0db0 Mon Sep 17 00:00:00 2001 From: Bruce Momjian <bruce@momjian.us> Date: Wed, 18 Jul 2007 03:12:42 +0000 Subject: [PATCH] Document that age() adds days, then full months. --- doc/src/sgml/func.sgml | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 387c4e81c8..5d5a86a0c7 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -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> -- 2.24.1