arel columns can be used for grouping so that "weird" column names are usable

3 files changed, 11 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index 8054294954..f02ed62275 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -335,6 +335,10 @@ module ActiveRecord
     #   column_alias_for("count(*)")                 # => "count_all"
     #   column_alias_for("count", "id")              # => "count_id"
     def column_alias_for(keys)
+      if keys.respond_to? :name
+        keys = "#{keys.relation.name}.#{keys.name}"
+      end
+
       table_name = keys.to_s.downcase
       table_name.gsub!(/\*/, 'all')
       table_name.gsub!(/\W+/, ' ')
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index c02d8f7760..8644f2f496 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -616,6 +616,12 @@ class BasicsTest < ActiveRecord::TestCase
     assert_equal 'value2', weird.read_attribute('a$b')
   end
 
+  def test_group_weirds_by_from
+    Weird.create('a$b' => 'value', :from => 'aaron')
+    count = Weird.group(Weird.arel_table[:from]).count
+    assert_equal 1, count['aaron']
+  end
+
   def test_attributes_on_dummy_time
     # Oracle, and Sybase do not have a TIME datatype.
     return true if current_adapter?(:OracleAdapter, :SybaseAdapter)
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index eec06754a5..35778d008a 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -770,6 +770,7 @@ ActiveRecord::Schema.define do
   end
   create_table :weirds, :force => true do |t|
     t.string 'a$b'
+    t.string 'from'
   end
 
   except 'SQLite' do