build_through_conditions

# File activerecord/lib/active_record/associations/through_association_scope.rb, line 136
      def build_through_conditions
        conditions = @reflection.through_reflection.options[:conditions]
        if conditions.is_a?(Hash)
          interpolate_sql(@reflection.through_reflection.klass.send(:sanitize_sql, conditions)).gsub(
            @reflection.quoted_table_name,
            @reflection.through_reflection.quoted_table_name)
        elsif conditions
          interpolate_sql(sanitize_sql(conditions))
        end
      end