diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 7765af05d14..3d45eff040e 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -1,5 +1,5 @@
@@ -601,6 +601,13 @@ SELECT name FROM distributors ORDER BY code;
specific ordering operator name may be specified. ASC is equivalent
to USING < and DESC is equivalent to USING >.
+
+
+ The null value sorts higher than any other value in a domain. In other
+ words, with ascending sort order nulls sort at the end and with
+ descending sort order nulls sort at the beginning.
+
+