Django通过自定义方法排序

Question

我的自定义方法实际上是一种计算，我试图通过管理器避免排序，如果可能的话只使用order_by。有没有一种方法或一行语法来实现这一点？这里是我的模型：

class Bet(models.Model): 


    provider = models.ForeignKey(Provider) 
    member = models.ForeignKey(Member) 
    game = models.ForeignKey(Game) 
    status = models.ForeignKey(Status) 
    bet_id = models.CharField(max_length=200) 
    bet_time = models.DateTimeField() 
    bet_amount = models.FloatField() 
    valid_bet_amount = models.FloatField() 
    settlement_amount = models.FloatField() 

    def get_profit(self): 
     return self.settlement_amount - self.valid_bet_amount 

Answer 1

您正在寻找注释

profit = F('settlement_ammount') - F('valid_bet_amount') 
my_query.annotate(profit=profit).order_by('profit') 

见Using F() with annotations