'Sum of two calculated annotation in django

.annotate(
        waste=Sum("processings__chunks__waste"),
        completed_waste=models.Task.get_completed_waste_annotation(),
        tooling_time=Sum("processings__chunks__tooling_time"),
        completed_tooling_time=models.Task.get_completed_tooling_time_annotation(),
        processing_time=Sum("processings__chunks__processing_time"),
        completed_processing_time=models.Task.get_completed_processing_time_annotation(),
        total_time=F("tooling_time") + F("processing_time"),
        completed_total_time=F("completed_tooling_time") + F("completed_processing_time"),
    )

I've this annotate, the problem is in the last two fields total_time and completed_total_time, when one of the fields tooling_time, processing_time is None, I get None in both of the fields.

django django-database

Solution 1:^[1]

The solution at the end was to calculate that two fields in the serializer with serializers.SerializerMethodField()

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Solution	Source
Solution 1	Stefano

'Sum of two calculated annotation in django

Solution 1:[1]

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Related Questions

Solution 1:^[1]