Add mention of NULL for COMMENT.

diff --git a/doc/src/sgml/ref/comment.sgml b/doc/src/sgml/ref/comment.sgml
index c59ea744e73c29d57f8645567ce219e29dbe0583..21f1e7b993d5155ca8c30dd6a56fa43d1bb35eb4 100644 (file)
--- a/doc/src/sgml/ref/comment.sgml
+++ b/doc/src/sgml/ref/comment.sgml
@@ -1,5 +1,5 @@
 
 
@@ -102,7 +102,7 @@ COMMENT
    COMMENT adds a comment to an object that can be 
     easily retrieved with psql's
     \dd command.
-    To remove a comment, use ''.
+    To remove a comment, use NULL.
     Comments are automatically dropped when the object is dropped.