[英]Django, how to set a filter based on a queryset?
I have a queryset given by three different models:我有一个由三个不同模型给出的查询集:
class Sottocategoria(models.Model):
name = models.CharField('Nome del sottoprodotto', max_length=30)
class A(models.Model):
codice_commessa=models.ForeignKey()
prodotto=models.ForeignKey()
sottocategoria=models.ForeignKey(Sottocategoria)
class B(models.Model):
quantity=models.ForeignKey()
price=models.DecimalField()
sottocategoria=models.ForeignKey(Sottocategoria)
Now I have set the following for loop:现在我设置了以下 for 循环:
for sottocategoria_id, totale in
(B.objects.values_list('sottocategoria__id').annotate(totale=(Sum(F('quantity') * F('price')))):
....
I have the need to filter sottocategoria__id
in the models B, that are present in the model A.我需要在模型 B 中过滤sottocategoria__id
,这些模型存在于 model A 中。
Ad example If I have in the model A
sottocategoria equal to {'abc','abcd','abcdf'}
and model B sottocategoria equal to {'abc','abcd','abcdf', '1234'}
, in my for loop I want to filter only {'abc','abcd','abcdf'}
.广告示例 如果我在model A
sottocategoria 等于{'abc','abcd','abcdf'}
和 model B sottocategoria 等于{'abc','abcd','abcdf', '1234'}
,我的 for 循环我只想过滤{'abc','abcd','abcdf'}
。
You can filter with an __in
lookup [Django-doc] :您可以使用__in
查找 [Django-doc]进行过滤:
B.objects.filter(
sottocategoria__name__in={'abc','abcd','abcdf'}
).values_list(
'sottocategoria_id'
).annotate(
totale=Sum(F('quantity') * F('price'))
)
You also might want to .order_by('sottocategoria_id')
, such that if you subscript, you subscript on a sottocategoria_id
, not on the primary key of a B
object:您可能还需要.order_by('sottocategoria_id')
,这样如果您下标,您将在sottocategoria_id
标,而不是在B
object 的主键上下标:
B.objects.filter(
sottocategoria__name__in={'abc','abcd','abcdf'}
).values_list(
'sottocategoria_id'
).annotate(
totale=Sum(F('quantity') * F('price'))
).order_by('sottocategoria_id')
For example if you look for sottocategoria
s that are referenced by an A
you can use:例如,如果您查找由A
引用的sottocategoria
,您可以使用:
B.objects.filter(
sottocategoria__in=Sottocategoria.objects.filter(a__isnull=False).distinct()
).values_list(
'sottocategoria_id'
).annotate(
totale=Sum(F('quantity') * F('price'))
).order_by('sottocategoria_id')
for certain databases, like MySQL, it might be better to first materialize the ids:对于某些数据库,例如 MySQL,最好先实现 id:
sottocategoria_ids = list(Sottocategoria.objects.filter(a__isnull=False).values_list('pk', flat=True).distinct())
B.objects.filter(
sottocategoria__in=sottocategoria_ids
).values_list(
'sottocategoria_id'
).annotate(
totale=Sum(F('quantity') * F('price'))
).order_by('sottocategoria_id')
We can also query from the A
model:我们也可以从A
model查询:
sottocategoria_ids = list(A.objects.values_list('sottocategoria_id', flat=True).distinct())
B.objects.filter(
sottocategoria__in=sottocategoria_ids
).values_list(
'sottocategoria_id'
).annotate(
totale=Sum(F('quantity') * F('price'))
).order_by('sottocategoria_id')
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.