django queryset相加和筛选教程

a = {1,2,3}
b = {3,4,5}
print(type(a))
print(a|b)

from django.db import models

class Author(models.Model):
  name = models.CharField(max_length=100)
  age = models.IntegerField()

class Publisher(models.Model):
  name = models.CharField(max_length=300)
  num_awards = models.IntegerField()

class Book(models.Model):
  name = models.CharField(max_length=300)
  pages = models.IntegerField()
  price = models.DecimalField(max_digits=10, decimal_places=2)
  rating = models.FloatField()
  authors = models.ManyToManyField(Author)
  publisher = models.ForeignKey(Publisher)
  pubdate = models.DateField()

class Store(models.Model):
  name = models.CharField(max_length=300)
  books = models.ManyToManyField(Book)
  registered_users = models.PositiveIntegerField()

>>> from django.db.models import Count
>>> pubs = Publisher.objects.aggregate(num_books=Count('book'))
>>> pubs
{'num_books': 27}

>>> from django.db.models import Avg
>>> Book.objects.all().aggregate(Avg('price'))
{'price__avg': 34.35}



# Cost per page 输出的名字同样可以指定，比如price_per_page
>>> from django.db.models import F, FloatField, Sum
>>> Book.objects.all().aggregate(
... price_per_page=Sum(F('price')/F('pages'), output_field=FloatField()))
{'price_per_page': 0.4470664529184653}

# python:2.7.9
# django:1.7.8

class MessageTab(models.Model):
  msg_sn = models.CharField(max_lenth=20, verbose_name=u'编号')
  msg_name = models.CharField(max_length=50, verbose_name=u'消息名称')
  message_time = models.DateTimeField(verbose_name=u'消息出现时间')
  msg_status = models.CharField(max_length=50, default='未处理', verbose_name=u'消息状态')
  class Meta:
    db_table = 'message_tab'

date_end = now().date() + timedelta(days=1)
date_start = date_end - timedelta(days=7)
messageTimeRange = (date_start, date_end)
GroupList = getGroupIdLis(request.user) # 返回当前用户能查询的group的一个列表。。仅做参考用
qQueryList = [Q(message_time__range=messageTimeRange), Q(message_name__in=GroupList)] # 可以有多个Q函数查询条件

msgS = MessageTab.objects.filter(reduce(operator.and_, qQueryList)).values_list('msg_status').annotate(msg_num=Count('id'))

SELECT `message_tab`.`msg_status`, COUNT(`message_tab`.`id`) AS `msg_num` FROM `message_tab` WHERE (`message_tab`.`message_time` BETWEEN 2017-03-27 00:00:00 AND 2017-04-03 00:00:00 AND `message_tab`.`message_name` IN (1785785, 78757, 285889, 2727333, 7272957, 786767)) GROUP BY
 `message_tab`.`msg_status` ORDER BY NULL