如何篩選日期時間字段上的對象？

Question

我有以下型號：

def announcements(request): 
    announcements = Announcement.objects.all().filter(
     is_active = True 
    ) 
    return HttpResponse(
     serializers.serialize("json", announcements)) 

這工作得很好：

class Announcement(models.Model): 
    name = models.CharField(max_length=500) 
    content = models.CharField(max_length=1000) 
    is_active = models.BooleanField(default=False) 
    date_start = models.DateTimeField() 
    date_end = models.DateTimeField() 

    def __str__(self): 
     return self.name 

我可以像is_active字段進行篩選的對象。但是，當我要過濾這些基於date_start場這樣的：

def announcements(request): 
    announcements = Announcement.objects.all().filter(
     date_start >= datetime.now() 
    ) 
    return HttpResponse(
     serializers.serialize("json", announcements)) 

我得到global name 'date_start' is not defined錯誤。

Answer 1

您需要使用queryset過濾器查找，__gte (greater than or equal)：

announcements = Announcement.objects.all().filter(date_start__gte = datetime.now()) 

Answer 2

這個語法是錯誤的：

announcements = Announcement.objects.all().filter(date_start >= datetime.now()) 

filter需要Python關鍵字參數。所以實際上你可以：

announcements = Announcement.objects.all().filter(date_start__gte=datetime.now()) 

更多關於Django docs: Making queries: Field lookups。