1 files changed, 9 insertions, 0 deletions
diff --git a/lib/arel/engines/sql/relations/table.rb b/lib/arel/engines/sql/relations/table.rb
index dd9000d660..b31df7a6d0 100644
--- a/lib/arel/engines/sql/relations/table.rb
+++ b/lib/arel/engines/sql/relations/table.rb
@@ -82,6 +82,15 @@ module Arel
       @columns = nil
       @attributes = Header.new([])
     end
+
+    private
+    def matching_attributes
+      @matching_attributes ||= Hash[attributes.map { |a| [a.root, true] }]
+    end
+
+    def has_attribute?(attribute)
+      matching_attributes.key? attribute.root
+    end
   end
 end