How to use model variables in a view in Django

Question

I need to calculate the average of a school report where the data are filled in in Django Admin, I would like to take each value make the media and play on a table in View.

Code:

MODEL

class Cadastro_Boletim(models.Model):

    ra_aluno = models.ForeignKey(Aluno, models.DO_NOTHING, related_name='Nome')
    curso = models.ForeignKey(Curso, models.DO_NOTHING, db_column='Curso')   # Field name made lowercase.
    nome_disciplina = models.ForeignKey(Disciplina, models.DO_NOTHING, db_column='Nome_Discplina')
    MB1 = models.SmallIntegerField(blank=True, null=True)  # Field name made lowercase.
    SUB1 = models.SmallIntegerField(blank=True, null=True)
    MB2 = models.SmallIntegerField(blank=True, null=True)
    SUB2 = models.SmallIntegerField(blank=True, null=True)
    EX = models.SmallIntegerField(blank=True, null=True)
    regular = models.BooleanField("Ativo?",default=True)

VIEW

def boletim(request):    
    contexto = {
        'boletim': Cadastro_Boletim.objects.all()   
    }
    return render(request,"boletim.html", contexto)

That way it brings everything that has in the Model, but I can not do the average with the notes, could help me?

Answer 1

For the average between the bimonthes : MB1 and MB2 , you can do as follows:

from django.db import AVG, F 
Cadastro_Boletim.objects.aggregate(media_bimestres=AVG(F('MB1')*F('MB2')))

With this each element will have accessible a variable "media_bimesters" available for access.