Django的查詢，GROUPBY，計數（）

Question

如何爲以下MySQL查詢執行的Django查詢：

This is Django model 
class Passengers(models.Model):  
    id = models.CharField(max_length=128)   
    ref = models.CharField(max_length=128) 
    orgId = models.ForeignKey(Organization) 
    number = models.CharField(max_length=128) 

MYSQL 
------ 
SELECT `ref` , count('id') 
FROM `dispatcher_passengers` 
WHERE `orgId_id` =1 
GROUP BY `ref` 

我有ID，參考列的模型。

我想用'ref'得到count（id）。

所以我怎麼能寫在Django查詢集格式上面的查詢。

Answer 1

怎麼樣這樣：

refs = Passengers.objects.values('ref') 
refs = set(refs) 
ref_count = lambda ref: Passengers.objects.filter(ref = ref).count 
counts = [ (ref, ref_count(ref)) for ref in refs ] 

更新：

from django.db.models import Count 
count = Passengers.objects.values('ref').annotate(Count('id')).order_by()