Django filter queryset only if variable is not null

Question

I have a queryset it filter by 2 variables

family = ModelsClass.objects.filter(foo=var1).filter(bar=var2)

If var1 and var2 are not null everything work but var1 and var2 can be Null.
In this case i need to exclude the Null one.

For example, if var1 is Null it must filter only by var2 and the other way around.

Is there a way to insert an if condition inside the filter queryset or something else?

TY

Asked By: JuConte

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Source

Answer 1

Why don’t you check if variable is null and then filter it? You don’t have to do it in one line. Django’s queryset objects are lazy evaluated and you can filter or do other things in separate lines.

family_queryset = ModelClass.objects.all()

if var1:
    family_queryset = family_queryset.filter(foo=var1)

if var2:
    family_queryset = family_queryset.filter(bar=var2)

Answered By: Cagatay Barin

Answer 2

More generally, you can create a filter dictionary and filter the dictionary keys for null values using a dict comprehension.

filters = {
  'foo': var1,
  'bar': var2,
}
filters = {k:v for k,v in filters.items() if v is not None}
family_queryset = ModelClass.objects.filter(**filters)

You can even use if v instead of if v is not None to also exclude empty strings, for example.

Answered By: arcstur

Answer 3

A different approach using Q

Q object encapsulates a SQL expression in a Python object that can be used in database-related operations. Using Q objects we can make complex queries with less and simple code.

filters = Q()
if my_first_param:
   filters &= Q(my_first_param=my_first_param)
if my_second_param:
   filters &= Q(my_second_param=my_second_param)

# Perform filtration
family_queryset = ModelClass.objects.filter(filters)

Answered By: griffins

Django filter queryset only if variable is not null

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