column_aliases

# File activerecord/lib/active_record/associations.rb, line 1382
        def column_aliases(join_dependency)
          join_dependency.joins.collect{|join| join.column_names_with_alias.collect{|column_name, aliased_name|
              "#{connection.quote_table_name join.aliased_table_name}.#{connection.quote_column_name column_name} AS #{aliased_name}"}}.flatten.join(", ")
        end