我的model.py是
class Place(models.Model):
id = models.IntegerField(primary_key=True)
location = models.CharField(max_length=100)
class Meta:
db_table = 'place'
managed=False
class Session(models.Model):
id = models.IntegerField(primary_key=True)
place = models.ForeignKey(Place,related_name='session',on_delete=models.CASCADE, null=True)
start = models.DateField(auto_now=True)
counts = models.IntegerField()
class Meta:
db_table = 'session'
managed=False
class Animal(models.Model):
id = models.IntegerField(primary_key=True)
sess = models.ForeignKey(Session,related_name='details',on_delete=models.CASCADE, null=True)
type = models.CharField(max_length=100)
is_active = models.BooleanField()
length = models.DecimalField(max_digits=6, decimal_places=2)
class Meta:
db_table = 'animal'
managed=False
我需要根据特定日、周、月或年的选择获得一个汇总表，其中包含特定位置的最小、最大、标准偏差、平均值和动物数量。我尝试使用聚合和注释，但结果并不如预期。请向我建议如何实现？
Serilaizer.py
class AnimalSerializers(FlexFieldsModelSerializer):
class Meta:
model = Animal
fields = ["is_active","type"]
class SessionSerializers(FlexFieldsModelSerializer):
class Meta:
model = Session
fields = ["start","count"]
expandable_fields = {
'details': (AnimalSerializers, {'many': True})
}
class PlaceSerializers(FlexFieldsModelSerializer):
# countsessiontotank = serializers.PrimaryKeyRelatedField(read_only=True)
length_max = serializers.DecimalField(max_digits=10, decimal_places=2)
length_min = serializers.DecimalField(max_digits=10, decimal_places=2)
length_avg = serializers.DecimalField(max_digits=10, decimal_places=2)
length_std = serializers.DecimalField(max_digits=10, decimal_places=2)
active_percent = serializers.IntegerField()
total_counts = serializers.IntegerField()
class Meta:
model = Place
fields = ["location","length_max","length_min","length_avg","length_std","total_counts","active_percent"]
expandable_fields = {
'session': (SessionSerializers, {'many': True})
}
视图.py
class PlaceModelViewSets(ModelViewSet):
queryset = Place.objects.values('location')
serializer_class = PlaceSerializer
def get_queryset(self):
queryset = Place.objects.values('location').annotate(total_count=Count('session__details__is_active'), def_count = Count('session__details__is_active',filter=Q(session__details__is_active=True)))
queryset = queryset.annotate(def_percent = ExpressionWrapper(F('def_count')/F('total_count'), output_field=FloatField())) //For percentage of active counts out of total counts
queryset = queryset.annotate(
total_counts = Count('session__details__is_active'),
length_max=Max('session__details__length'),
length_min=Min('session__details__length'),
length_avg=Avg('session__details__length'),
length_std=StdDev('session__details__length')
)
return queryset
我想得到的输出是
[
{
"location": "Loc 1",
"length_max": "38.74",
"length_min": "38.74",
"length_avg": "38.74",
"length_std": "2.37",
"total_counts": 4,
"active_percent": 50,
"session": [
{
"start": "2021-01-01",
"count": 900,
"details": [
{
"type": "dog"
}
]
},
]
},
{
"location": "Loc 1",
"length_max": "43.47",
"length_min": "38.74",
"length_avg": "41.10",
"length_std": "2.37",
"total_counts": 4,
"active_percent": 50,
"session": [
{
"start": "2021-01-02",
"count": 400,
"details": [
{
"type": "dog"
}
]
},
]
},
{
"location": "Loc 4",
"length_max": "28.47",
"length_min": "28.47",
"length_avg": "28.47",
"length_std": "5.60",
"total_counts": 4,
"active_percent" : 50,
"session": [
{
"start": "2021-01-02",
"count": 800,
"details": [
{
"type": "cat"
},
]
}
]
},
{
"location": "Loc 4",
"length_max": "22.45",
"length_min": "22.45",
"length_avg": "22.45",
"length_std": "5.60",
"total_counts": 4,
"active_percent" : 50,
"session": [
{
"start": "2021-01-03",
"count": 750,
"details": [
{
"type": "cat"
},
]
}
]
}
]
但是我得到的输出是
[
{
"location": "Loc 1",
"length_max": "43.47",
"length_min": "38.74",
"length_avg": "41.10",
"length_std": "2.37",
"total_counts": 8,
"session": [
{
"start": "2021-01-01",
"count": 600,
"details": [
{
"is_active": true,
"type": "dog"
},
{
"is_active": false,
"type": "dog"
},
{
"is_active": true,
"type": "dog"
},
{
"is_active": false,
"type": "dog"
}
]
},
{
"start": "2021-01-02",
"count": 400,
"details": [
{
"is_active": false,
"type": "dog"
},
{
"is_active": true,
"type": "dog"
},
{
"is_active": false,
"type": "dog"
},
{
"is_active": true,
"type": "dog"
}
]
},
{
"start": "2021-01-01",
"count": 300,
"details": []
}
]
},
{
"location": "Loc 4",
"length_max": "34.85",
"length_min": "20.56",
"length_avg": "26.58",
"length_std": "5.60",
"total_counts": 8,
"session": [
{
"start": "2021-01-02",
"count": 800,
"details": [
{
"is_active": false,
"type": "cat"
},
{
"is_active": true,
"type": "cat"
},
{
"is_active": false,
"type": "cat"
},
{
"is_active": true,
"type": "cat"
}
]
},
{
"start": "2021-01-03",
"count": 750,
"details": [
{
"is_active": true,
"type": "cat"
},
{
"is_active": false,
"type": "cat"
},
{
"is_active": true,
"type": "cat"
},
{
"is_active": false,
"type": "cat"
}
]
}
]
}
]
有额外的字段。当我尝试计算“active_percent”时，我得到的只是“active_percent”字段不存在。