diff --git a/app/models/query.rb b/app/models/query.rb
index 9e5071e6c..0e38b47d8 100644
--- a/app/models/query.rb
+++ b/app/models/query.rb
@@ -300,7 +300,7 @@ class Query < ActiveRecord::Base
     :text => [  "~", "!~", "^", "$", "!*", "*" ],
     :integer => [ "=", ">=", "<=", "><", "!*", "*" ],
     :float => [ "=", ">=", "<=", "><", "!*", "*" ],
-    :relation => ["=", "=p", "=!p", "!p", "*o", "!o", "!*", "*"],
+    :relation => ["=", "!", "=p", "=!p", "!p", "*o", "!o", "!*", "*"],
     :tree => ["=", "~", "!*", "*"]
   }