Ruby on rails下，一句话进行多条件模糊搜索

conditions = []
      [:mail_from, :mail_to, :subject, :attachment, :domain, :ip, :location, :date, :mailer].each{
        |attr| conditions << Employee.send(:sanitize_sql, ["#{attr} LIKE ?", "%#{params[attr]}%"]) unless params[attr].blank? }
      conditions = conditions.any? ? conditions.collect { |c| "(#{c})" }.join(' AND ') : nil

      @emails = Email.where(conditions).order("date DESC")