Question

我应该写一个代码来查找具有以下条件的那些驾驶员的所有驾驶员（id）和旅行次数（n）： n：在这些行程中，汽车模型为x或刨丝器且行程持续时间超过t秒的行程次数。

我的模特：

class Rider(models.Model):
    account = GenericRelation(Account, related_query_name='riders')
    rating = models.FloatField()
    x = models.FloatField()
    y = models.FloatField()


class Driver(models.Model):
    account = GenericRelation(Account, related_query_name='drivers')
    rating = models.FloatField()
    x = models.FloatField()
    y = models.FloatField()
    active = models.BooleanField(default=False)


class RideRequest(models.Model):
    rider = models.ForeignKey(Rider, on_delete=models.CASCADE)
    x = models.FloatField()
    y = models.FloatField()
    car_type = models.CharField(max_length=3, choices=car_type_choices)


class Car(models.Model):
    owner = models.ForeignKey(Driver, on_delete=None)
    car_type = models.CharField(max_length=3, choices=car_type_choices)
    model = models.IntegerField()
    color = models.CharField(max_length=10)


class Ride(models.Model):
    pickup_time = models.IntegerField()
    dropoff_time = models.IntegerField()
    car = models.ForeignKey(Car, on_delete=models.CASCADE)
    request = models.OneToOneField(RideRequest, on_delete=models.CASCADE, null=False)
    rider_rating = models.FloatField()
    driver_rating = models.FloatField()

我的代码：

drivers = Driver.objects.values('id').annotate(
        travel_time=Sum(Case(
            When(car__ride__pickup_time__isnull=False,
                 then=(F('car__ride__dropoff_time') - F('car__ride__pickup_time'))),
            default=0
        )),
    ).annotate(
        n=Case(
            When(Q(travel_time__gt=t) & Q(car__model__gte=n), then=Count('car__ride')),
            output_field=IntegerField(),
            default=0
        )
    ).values('id', 'n')

当我打印结果时：

<QuerySet [{'id': 1, 'n': 0}, {'id': 2, 'n': 0}, {'id': 2, 'n': 1}, {'id': 3, 'n': 2}, {'id': 4, 'n': 0}, {'id': 5, 'n': 1}, {'id': 5, 'n': 0}]>

这接近真实答案，但仍然需要做更多。例如，我有两个id = 2。它应该是1，并且与之关联的n应该是1（对于id = 2，这两个n之和）

真实结果：

<QuerySet [{'id': 1, 'n': 0}, {'id': 2, 'n': 1}, {'id': 3, 'n': 2}, {'id': 4, 'n': 0}, {'id': 5, 'n': 1}]>

查找某些条件下的驾驶员和乘车次数

0 个答案: