merge_conditions

# File activerecord/lib/active_record/base.rb, line 1519
      def merge_conditions(*conditions)
        segments = []

        conditions.each do |condition|
          unless condition.blank?
            sql = sanitize_sql(condition)
            segments << sql unless sql.blank?
          end
        end

        "(#{segments.join(') AND (')})" unless segments.empty?
      end