[Answered ]-How to count quantity with data in table, depending on status?

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Give this a try

Override you get_queryset() and annotate paper_left which is the calculated sum of Arrived-Given,

# views.py
from .models import PaperReport
from django.db.models import Sum, F, Case, When, IntegerField

class PaperReportView(ListView): 
    model = PaperReport
    template_name = 'paper_list.html'

    def get_queryset(self):
        queryset = super().get_queryset()
        queryset = queryset.annotate(
            paper_left=Sum(
                Case(
                    When(status='Arrived', then=F('amount')),
                    When(status='Given', then=-F('amount')),
                    default=0,
                    output_field=IntegerField(),
                    )
                )
            )
        return queryset

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['paper_left_sum'] = self.get_queryset().aggregate(Sum('paper_left'))['paper_left__sum']
        return context

and in you template file,

<h2>Printer paper left: {{ paper_left_sum }}<h2>
<div>
    {% for case in object_list %}
        <div>
            <p>{{ case.amount }} pcs {{ case.status}} for {{ case.name }}</p>
        </div>
    {% endfor %}
</div>

Read more about conditional expressions in Django

👤Sumithran

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