Django Complicated Query - django

Question

I am using django restframework with my Django app and I need to create quite specific query.
Here is the models.py:
class TaskHours(models.Model):
name = models.CharField(max_length=100)
hours = models.FloatField()
task = models.CharField(max_length=100)
date = models.DateField()
views.py:
class TaskHoursView(generics.ListAPIView):
serializer_class = TaskHoursSerializer
queryset = TaskHours.objects.all()
def get_queryset(self):
start_date = self.request.query_params.get('start_date')
end_date = self.request.query_params.get('end_date')
return TaskHours.filter(date__range=[start_date, end_date])
and serializer is default one with class Meta with all fields.
This query is working fine but I need to alter it. In the data there are entries which have same name and same date, but different tasks. What I would need is get all the tasks and hours worked with the same name and date to one object like this:
{
"name": "John",
"date": "2021-04-14",
"task": "cleaning",
"hours": "4.5",
"task": "hoovering",
"hours": "2.0"
}
Now I am receiving it like this:
{
"name": "John",
"date": "2021-04-14",
"task": "cleaning",
"hours": "4.5",
},
{
"name": "John",
"date": "2021-04-14",
"task": "hoovering",
"hours": "2.0"
}
Is there any way how to merge the two objects into one?

Answer 1

You need to slightly modify your serializer in order to create a subquery for each object you're going to serialize.
class TaskHoursSerializer(serializers.ModelSerializer):
tasks = serializers.SerializerMethodField()
class Meta:
model = TaskHours
exclude = ['task', 'hour']
def get_tasks(self, obj):
tasks = TaskHours.objects.filter(name=obj.name, date=obj.date).values_list("task", "hour")
return list(tasks)
And also, you need to change the queryset in your view in order to not have object duplicates.
class TaskHoursView(generics.ListAPIView):
serializer_class = TaskHoursSerializer
queryset = TaskHours.objects.all()
def get_queryset(self):
start_date = self.request.query_params.get('start_date')
end_date = self.request.query_params.get('end_date')
return TaskHours.filter(date__range=[start_date, end_date]).values('name', 'date').distinct()
That should output a field called "tasks" containing each task with the matching hour.