diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 15774a3a00a..2de07c04ae8 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1,5 +1,5 @@
@@ -4412,6 +4412,13 @@ substring('foobar' from 'o(.)b') o
1230 microseconds = 2.021230 seconds.
+
+
+ to_char's day of the week numbering
+ (see the 'D' formatting pattern) is different from that of the
+ extract function.
+
+
@@ -5146,6 +5153,11 @@ SELECT EXTRACT(DECADE FROM TIMESTAMP '2001-02-16 20:38:40');
SELECT EXTRACT(DOW FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 5
+
+ Note that extract's day of the week numbering is
+ different from that of the to_char function.
+
+