django--orm--011

聚合函数引包：

from django.db.models import Avg,Sum,Min,Max,Count

查询

count1 = Article.objects.all().aggregate(Count("title"))

加筛选条件查询：

count2 = Article.objects.filter(context='xt').aggregate(Count("title"))

分组之后查询：

count3 = Article.objects.values("context").annotate(Count("title"))

多表查询：

count3=Account.objects.filter(password="123456").aggregate(Count('article__context'))

account 是外键的表，对应sql

SELECT COUNT(`myapp_article`.`context`) AS `article__context__count` FROM `myapp_account` LEFT OUTER JOIN `myapp_article` ON (`myapp_accoun
t`.`id` = `myapp_article`.`account_id`) WHERE `myapp_account`.`password` = '123456'; args=('123456',)