我寫了一個導(dǎo)出數(shù)據(jù)的視圖，我的模型是這樣的：class Event(models.Model):    KIND_CHOICES = (('doing', 'doing'),                    ('done', 'done'),                    ('cancel', 'cancel'))    created_at = models.DateTimeField(auto_now_add=True)    created_by = models.ForeignKey('auth.User')    kind = models.CharField(max_length=20, choices=KIND_CHOICES)事件是三種中的一種，每個用戶每月可能有3?10個事件，首先我查詢本月的事件：events_this_month = Event.objects.filter(created_at__year=2013,                                         created_at__month=5)然后找到所有用戶：users = User.objects.all()我這樣導(dǎo)出數(shù)據(jù)：for user in users:    # 1000 users with 5 events each    user_events = events_this_month.filter(created_by=user)    doing_count = user_events.filter(kind='doing').count()    done_count = user_events.filter(kind='done').count()    cancel_count = user.events.filter(kind='cancel').count()    append_to_csv([user.username, doing_count, done_count, cancel_count])然后我嘗試使用collections.Counter，我認為這將減少SQL計數(shù)（實際上，它從3000多個減少到1200）：for user in users:    user_events = events_this_month.filter(created_by=user)    counter = Counter(user_events.values_list('kind', flat=True))    doing_count = counter['doing']    done_count = counter['done']    cancel_count = counter['cancel']    ...哪種方法更好？是一種更慣用的方式來更有效地對此類數(shù)據(jù)進行計數(shù)嗎？