From e8d8f3d651d190fc187f520cfe25b0ce3ad0f0e3 Mon Sep 17 00:00:00 2001
From: Matt Duncan <mrduncan@gmail.com>
Date: Fri, 7 Aug 2009 22:55:19 -0400
Subject: [PATCH] Adding :from scoping to ActiveRecord calculations

---
 activerecord/lib/active_record/calculations.rb |    2 ++
 activerecord/test/cases/calculations_test.rb   |    6 ++++++
 activerecord/test/models/organization.rb       |    2 ++
 3 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/activerecord/lib/active_record/calculations.rb b/activerecord/lib/active_record/calculations.rb
index 7af97d7..6eee401 100644
--- a/activerecord/lib/active_record/calculations.rb
+++ b/activerecord/lib/active_record/calculations.rb
@@ -190,6 +190,8 @@ module ActiveRecord
           sql << ", #{options[:group_field]} AS #{options[:group_alias]}" if options[:group]
           if options[:from]
             sql << " FROM #{options[:from]} "
+          elsif scope && scope[:from]
+            sql << " FROM #{scope[:from]} "
           else
             sql << " FROM (SELECT #{distinct}#{column_name}" if use_workaround
             sql << " FROM #{connection.quote_table_name(table_name)} "
diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
index b4f76cb..f428052 100644
--- a/activerecord/test/cases/calculations_test.rb
+++ b/activerecord/test/cases/calculations_test.rb
@@ -5,6 +5,8 @@ require 'models/edge'
 require 'models/owner'
 require 'models/pet'
 require 'models/toy'
+require 'models/club'
+require 'models/organization'
 
 Company.has_many :accounts
 
@@ -226,6 +228,10 @@ class CalculationsTest < ActiveRecord::TestCase
     assert_equal 15, companies(:rails_core).companies.sum(:id)
   end
 
+  def test_should_sum_scoped_field_with_from
+    assert_equal Club.count, Organization.clubs.count
+  end
+
   def test_should_sum_scoped_field_with_conditions
     assert_equal 8,  companies(:rails_core).companies.sum(:id, :conditions => 'id > 7')
   end
diff --git a/activerecord/test/models/organization.rb b/activerecord/test/models/organization.rb
index d79d503..c857261 100644
--- a/activerecord/test/models/organization.rb
+++ b/activerecord/test/models/organization.rb
@@ -1,4 +1,6 @@
 class Organization < ActiveRecord::Base
   has_many :member_details
   has_many :members, :through => :member_details
+
+  named_scope :clubs, { :from => 'clubs' }
 end
\ No newline at end of file
-- 
1.6.0