Django查询。计数和Group BY

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问题描述

我有一个查询，我正在尝试弄清" django"的方法: 我想接听最后100个电话.这很容易: 呼叫= call.objects.all().order_by(' - call_time')[:100]

但是，下一部分我找不到通过Django的ORM找到它的方法.我想获取一个call_types的列表，以及每个呼叫的呼叫数量在我刚刚做过的以前的QuerySet中.通常，我会进行这样的查询:"选择计数(id)，calltype从call where in where(通过call_time disc limit限制从呼叫订单中选择ID ID)组成calltype;"

我似乎找不到执行此特定查询的Django的方式.

这是我的2个型号:

class Call( models.Model ):
    call_time = models.DateTimeField( "Call Time", auto_now = False, auto_now_add = False )
    description = models.CharField( max_length = 150 )
    response = models.CharField( max_length = 50 )
    event_num = models.CharField( max_length = 20 )
    report_num = models.CharField( max_length = 20 )
    address = models.CharField( max_length = 150 )
    zip_code = models.CharField( max_length = 10 )
    geom = models.PointField(srid=4326)
    calltype = models.ForeignKey(CallType)

    objects = models.GeoManager()

class CallType( models.Model ):
    name = models.CharField( max_length = 50 )
    description = models.CharField( max_length = 150 )
    active = models.BooleanField()
    time_init = models.DateTimeField( "Date Added", auto_now = False, auto_now_add = True )

    objects = models.Manager()

其他推荐答案

使用Django 1.1.1这个令人惊讶的是;

from django.db.models import Count
calls = Call.objects.all().order_by('-call_time')[:100]
groups = calls.values('calltype').annotate(Count('calltype'))

它有效，但在整个对象上返回，不仅是所选的100个！无法理解.

但是，这种解决方法可以帮助(今天由Calltype分组的摘要):

import datetime
Call.objects.order_by('-call_time').filter(call_time__gte=datetime.datetime.today() - datetime.timedelta(days=1)).values('calltype').annotate(Count('calltype'))

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问题描述

I have a query that I'm trying to figure the "django" way of doing it: I want to take the last 100 calls from Call. Which is easy: calls = Call.objects.all().order_by('-call_time')[:100]

However the next part I can't find the way to do it via django's ORM. I want to get a list of the call_types and the number of calls each one has WITHIN that previous queryset i just did. Normally i would do a query like this: "SELECT COUNT(id),calltype FROM call WHERE id IN ( SELECT id FROM call ORDER BY call_time DESC LIMIT 100 ) GROUP BY calltype;"

I can't seem to find the django way of doing this particular query.

Here are my 2 models:

class Call( models.Model ):
    call_time = models.DateTimeField( "Call Time", auto_now = False, auto_now_add = False )
    description = models.CharField( max_length = 150 )
    response = models.CharField( max_length = 50 )
    event_num = models.CharField( max_length = 20 )
    report_num = models.CharField( max_length = 20 )
    address = models.CharField( max_length = 150 )
    zip_code = models.CharField( max_length = 10 )
    geom = models.PointField(srid=4326)
    calltype = models.ForeignKey(CallType)

    objects = models.GeoManager()

class CallType( models.Model ):
    name = models.CharField( max_length = 50 )
    description = models.CharField( max_length = 150 )
    active = models.BooleanField()
    time_init = models.DateTimeField( "Date Added", auto_now = False, auto_now_add = True )

    objects = models.Manager()

其他推荐答案

With django 1.1.1 this surprisingly doesnt work ;

from django.db.models import Count
calls = Call.objects.all().order_by('-call_time')[:100]
groups = calls.values('calltype').annotate(Count('calltype'))

it works but returns on the whole objects, not only the 100 selected! cant understand.

but this workaround could help (today calls summary grouped by calltype) :

import datetime
Call.objects.order_by('-call_time').filter(call_time__gte=datetime.datetime.today() - datetime.timedelta(days=1)).values('calltype').annotate(Count('calltype'))

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