【django】django的orm的分组查询

前言：django当中分组查询如何实现？   annotate

from myapp import models
from django.db.models.functions import TruncMonth
from django.db.models import Count,Avg# 分组  values 就是取值作用
model.Book.objects.values('month').annotate(count=Count('id'))# 等同于  select month,count(id) from book group by month;model.Book.objects.values('month').annotate(count=Avg('price'))# 等同于  select month,avg(price) from book group by month;# 多表分组model.A.objects.annotate(a=Avg('B__price')).values('a')# 等同于select avg(B.price) as a from A join B on A.B_id =B.id group by A.id;

from myapp import models
from django.db.models.functions import TruncMonth
from django.db.models import Count# 一个日期字段按月分组result = model.Book.objects.annotate(month=TruncMonth('date_field')).values('month').annotate(count=Count('id'))