当日期在一个范围内时计算每次出现的次数

Question

我试图计算每次 created_on 中月份的值落在不同的月份，使用下面的 django orm：

    result_qs = Model.objects.all().annotate(
        spring=Count(Case(When(ExtractMonth("created_on") in [1, 2, 3, 4, 5], then=1))),
        summer=Count(Case(When(ExtractMonth("created_on") in [6, 7], then=1))),
        fall=Count(Case(When(ExtractMonth("created_on") in [8, 9, 10, 11, 12], then=1))),
        year=ExtractYear("created_on")
)

我遇到了错误

When() supports a Q object, a boolean expression, or lookups as a condition.

当我对其中一种情况应用 Q 符号时，例如：

spring=Count(Case(When(Q(ExtractMonth("created_on") in [1, 2, 3, 4, 5], then=1)))),

cannot unpack non-iterable bool object

有什么建议吗？

Answer 1

您可以尝试这样的操作：

result_qs = Model.objects.all().annotate(
        spring=Count(Case(When(created_on__month__in=[1, 2, 3, 4, 5], then=1))),
        summer=Count(Case(When(created_on__month__in=[6, 7], then=1))),
        fall=Count(Case(When(created_on__month__in=[8, 9, 10, 11, 12], then=1))),
        year=ExtractYear("created_on")
)

当日期在一个范围内时计算每次出现的次数

count each occurrences when date falls within a range

python

django

postgresql

orm