쿼리의 정렬 조건을 가져옵니다.

def _order_queries(self):
        """쿼리의 정렬 조건을 가져옵니다."""
        from .condition import Order
        order = []
        for column in self.columns:
            if column.order_by:
                o = Order(self.cls, column.attr, column.order_by)
                order.append(o.__query__())
        if not order:
            k = self.columns[0].attr
            o = Order(self.cls, k)
            self.columns[0].order_by = o.order
            order.append(o.__query__())
        return order