From 74f4881d7cc9c69cb0e0b236f06d1ebf9859a737 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Wed, 15 Aug 2012 16:03:58 -0400
Subject: [PATCH] Document why you can't use date_trunc("week") on intervals.

---
 doc/src/sgml/func.sgml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d5ad4718b1..5d0c71a8b9 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -7050,6 +7050,11 @@ date_trunc('<replaceable>field</replaceable>', <replaceable>source</replaceable>
     </simplelist>
    </para>
 
+   <para>
+    <literal>week</literal> is not supported for <type>interval</>
+    values because months usually have fractional weeks.
+   </para>
+
    <para>
     Examples:
 <screen>
-- 
2.40.0