code: def parse_order(text):
          
          orders = []
          for i in map(str.strip, text.split(',')):
              items = i.split('.', 2)
  
              if len(items) == 1: column, order = items[0], 'default'
              elif len(items) == 2: column, order = items
              else: raise InvalidParams("Invalid order syntax")
  
              order = order.lower()
              if order not in ('asc', 'desc', 'default'):
                  raise InvalidParams('Invalid order mode: %s' % order)
  
              if order != 'default':
                  orders.append(SQLQueryOrder(column, order))
          return orders
docs: :param text: order=id.desc, xxx.asc
          :return: [
              [<column>, asc|desc|default],
              [<column2>, asc|desc|default],
          ]