Django计算截止日期的年龄，单位为DB

Question

我是Django的新手。请帮我解决这个问题

这就是我要在其上编写查询的模型

class ReservationFrame(models.Model):
    id = models.AutoField(primary_key=True)
    start_at = models.DateTimeField(db_index=True)
    information = models.JSONField(default=dict)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

json字段（ReservationFrame.information）的格式如下

{
    upper_age_limit: 22,
    lower_age_limit: 30
}

我想计算登录用户的年龄，直到ReservationFrame.start\u在，如果较低的\u年龄\u限制<；=user.age<；=年龄上限

我用来计算年龄的公式是

start_at.year - born.year - ((start_at.month, start_at.day) < (born.month, born.day))

我正在使用annotate，但出现了错误

person_birthday = request.user.person.birthday
frames_without_age_limit = reservation_frames.exclude(Q(information__has_key = 'upper_age_limit')&Q(information__has_key = 'lower_age_limit'))
reservation_frames = reservation_frames.annotate(
    age=ExtractYear('start_at') - person_birthday.year - Case(When((ExtractMonth('start_at'), ExtractDay('start_at')) < (person_birthday.month, person_birthday.day), then=1), default=0))
reservation_frames = reservation_frames.filter(
    Q(information__lower_age_limit__lte = F('age'))|
    Q(information__lower_age_limit=None)
)
reservation_frames = reservation_frames.filter(
    Q(information__upper_age_limit__gte = F('age'))|
    Q(information__upper_age_limit=None)
)

TypeError: '<' not supported between instances of 'ExtractMonth' and 'int'

Answer 1

关系运算符，如<><；=>；=，==在Django conditional expressions中不允许使用。 因此，您应该使用查询集和链条件来实现您的逻辑。 此外，您还可以将词汇比较更改为更简单的逻辑比较。 像这样：

(A,B) < (X,Y) -> (A<X) OR ((A==X) AND (B<Y))

像这样试试。它应该有用

reservation_frames = reservation_frames.annotate(
age=ExtractYear('start_at') - person_birthday.year - Case(
    When(Q(start_at__month__lt=person_birthday.month)|(Q(start_at__month=person_birthday.month) & Q(start_at__day__lt=person_birthday.day)), then=1),
    default=0))