How to Calculate Percentage?

Using Django Using the ORM
1

I have the following models

class Club(Adresse):
    ...

class Member(Adresse):
    club = ForeignKey(Club, on_delete=models.CASCADE)
    type = PositiveSmallIntegerField(default=1)
    points = PositiveSmallIntegerField(default=0)

I want to collect some statistics and I used annotate to count the numbers of members with several types and points. Lastly, I want to see the ratio between members of type 1 and 2. The ratio is always returned as 0.0, even if all other values are greater than 0. Why?

type1 = Count("member", filter=Q(member__type=1))
type2_gt0 = Count("member", filter=Q(member__type=2) & Q(member__points__gt=0))
type2_eq0 = Count("member", filter=Q(member__type=2) & Q(member__points=0))

statistics = Club.objects.annotate(
    all=Count("member"),  # Works!
    type1=type1,          # Works!
    type2_gt0=type2_gt0,  # Works!
    type2_eq0=type2_eq0,  # Works!
    
    ratio=ExpressionWrapper(
        F("type1") / (F("type2_gt0") + F("type2_eq0")),
        output_field=FloatField()
    ),                    # Always 0.0
)
2

Because you’re performing integer math. The result isn’t cast to a float until after the calculation has been performed. You need to cast these individual values to floats in the expression.