From 2fd385d47163149ec74029731bc29370fa768735 Mon Sep 17 00:00:00 2001
From: Aaron Patterson <aaron.patterson@gmail.com>
Date: Wed, 8 Dec 2010 10:29:52 -0800
Subject: [PATCH] reducing use of custom joins

---
 activerecord/lib/active_record/relation/query_methods.rb | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index df41f756ce..705bf21eae 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -296,7 +296,12 @@ module ActiveRecord
       if Arel::Table === relation
         relation.from(ast || relation)
       else
-        relation.join(custom_joins)
+        if relation.froms.length > 0 && ast
+          ast.left = relation.froms.first
+          relation.from ast
+        else
+          relation.join(custom_joins)
+        end
       end
     end