Django annotate with conditional expression, how to apply distinct()

Question

I have a little bit complex query and I use annotate with a conditional expression, the code is below:

from django.db.models import Q, F, When, CharField, Value, Case
from django.contrib.auth.models import User


ATT_PREFIX = 'f'

def get_it(mymodel, fields):

    q = Q(modelone__modeltwo__mymodel=mymodel)

    query_set = {
        'aid': F('modelone__id'),
        'name': F('modelfour__name'),
    }

    for f in fields:
        query_set[ATT_PREFIX + str(f.id)] = Case(
            When(Q(modelfive__modelsix=f) &
                 Q(modelfive__user__email=F('email')),
                 then='modelfive__entry'),
            default=Value(''),
            output_field=CharField(),
        )

    return User.objects.filter(q).annotate(**query_set)

Attributes aid and name collected with F() have expected values. Second part which use conditional expression have a problem: If feilds list contain 2 objects, then I have 2 User objects created by Case() when condition is meet. So instead of one object with atributes (aid, name, f17, f18) I got two objects:

obj1 attributes (aid, name, f17)
obj2 attributes (aid, name, f18)

Django 1.10, Python3.5

score 0 · Answer 1 · answered Jan 06 '22 at 18:02

0

try this

q = Q(modelone__modeltwo__mymodel=mymodel).distinct()

answered Jan 06 '22 at 18:02

Mario_z04

51
6

Django annotate with conditional expression, how to apply distinct()

1 Answers1