使用左连接的 Django 注释

Question

型号：

class Operator_online(models.Model):
    name             =  models.TextField()
    role             =  models.TextField()

class Reservations(models.Model):
    consultant_id     = models.ForeignKey(Operator_online, on_delete=models.CASCADE)
    voip_number       = models.IntegerField()

尝试过：

consultants_operators = Operator_online.objects.filter(
    Q(role='consultant') | Q(role='support'), status='1'
)

consultant_id_queryset = Reservations.objects.filter(
    consultant_id__in=consultants_operators
).select_related('consultant_id').annotate(role=F('consultant_id__role')).values(
    'consultant_id',
    'consultant_id__name',
    'voip_number',
    'role'
)

需求：

Steel 返回与上面相同的

consultant_id_queryset

查询集值：

返回所有已创建的

Operator_online

（即

role

和

name

字段）加上现有的已分配

Reservations

（即

consultant_id

和

voip_number

）反对 在返回之前仅存在的

Reservations

已分配实例

 Operator_online

。

因此，对于未建立的

Reservations

实例，其

consultant_id

字段 (

foreignkey

) 与

Operator_online

返回

null

为

voip_number

和

consultant_id

Answer 1

consultants_operators = Operator_online.objects.filter(
    Q(role='consultant') | Q(role='support'), status='1'
)

reservations_id_subquery = Reservations.objects.filter(
    consultant_id=OuterRef('pk')
).values('id')[:1]

reservations_subquery = Reservations.objects.filter(
    consultant_id=OuterRef('pk')
).values('voip_number')[:1]

consultant_id_queryset = consultants_operators.annotate(
     reservation_consultant_id=Coalesce(Subquery(reservations_id_subquery), Value(None)),
    reservation_voip_number=Coalesce(Subquery(reservations_subquery), Value(None))
).values(
    'role',
    'reservation_voip_number',
    'reservation_consultant_id',
    consultant_id__name=F('name')
)

尝试工作正常，但我看到的问题是将最后一个查询集字段命名为相同的波纹管，并抛出与响应相同的波纹管：

"The annotation 'voip_number' conflicts with a field on the model."

发出的尝试

consultant_id_queryset = consultants_operators.annotate(
    reservation_consultant_id=Coalesce(Subquery(reservations_id_subquery), Value(None)),
    reservation_voip=Coalesce(Subquery(reservations_voip_subquery), Value(None))
).values(
    'role',
    consultant_id=F('reservation_consultant_id'),
    voip_number=F('reservation_voip'),
    consultant_id__name=F('name')
)