如何在Django中获取相关模型上字段的最新值?
我有以下型号:如何在Django中获取相关模型上字段的最新值?,django,django-queryset,annotate,Django,Django Queryset,Annotate,我有以下型号: class Timestamped(models.Model): created = models.DateTimeField(auto_now_add=True) modified = models.DateTimeField(auto_now=True) class Meta: abstract = True class Thread(Timestamped): user1 = models.ForeignKey(User,
class Timestamped(models.Model):
created = models.DateTimeField(auto_now_add=True)
modified = models.DateTimeField(auto_now=True)
class Meta:
abstract = True
class Thread(Timestamped):
user1 = models.ForeignKey(User, related_name='user1')
user2 = models.ForeignKey(User, related_name='user2')
class Message(Timestamped):
thread = models.ForeignKey(Thread)
text = models.CharField(max_length=255)
sender = models.ForeignKey(User)
我有一个查询集来获取所有线程,但我还想在循环它们时显示每个线程的最新消息
我提出了以下内容来显示消息的最新时间戳
threads = Thread.objects.filter(Q(user1=request.user) | Q(user2=request.user))\
.annotate(latest_msg=Max('message__modified')).order_by('-latest_msg')
如何显示消息文本?如果我使用
值(“消息文本”)
,它将返回所有消息。我只想要最后发送或接收的消息。理想情况下,我想要类似于值('message\uu text')。latest()
。您可以使用limit来完成此操作,获取最新消息,检查编辑的答案
threads = Thread.objects.filter(
Q(user1=request.user) | Q(user2=request.user)
).annotate(
latest_msg=Max('message__modified')
).values(
'message__text',
'fields you want to fetch'
).order_by('-latest_msg')[:1]