association_join

# File activerecord/lib/active_record/associations.rb, line 1013
        def association_join(reflection)
          case reflection.macro
            when :has_and_belongs_to_many
              " LEFT OUTER JOIN #{reflection.options[:join_table]} ON " +
              "#{reflection.options[:join_table]}.#{reflection.options[:foreign_key] || table_name.classify.foreign_key} = " +
              "#{table_name}.#{primary_key} " +
              " LEFT OUTER JOIN #{reflection.klass.table_name} ON " +
              "#{reflection.options[:join_table]}.#{reflection.options[:association_foreign_key] || reflection.klass.table_name.classify.foreign_key} = " +
              "#{reflection.klass.table_name}.#{reflection.klass.primary_key} "
            when :has_many, :has_one
              " LEFT OUTER JOIN #{reflection.klass.table_name} ON " +
              "#{reflection.klass.table_name}.#{reflection.options[:foreign_key] || table_name.classify.foreign_key} = " +
              "#{table_name}.#{primary_key} "
            when :belongs_to
              " LEFT OUTER JOIN #{reflection.klass.table_name} ON " +
              "#{reflection.klass.table_name}.#{reflection.klass.primary_key} = " +
              "#{table_name}.#{reflection.options[:foreign_key] || reflection.klass.table_name.classify.foreign_key} "
            else
              ""
          end          
        end