Django框架models使用group by的方法

Django框架models使用group by的方法：

首先，看下列代码：

UserData.objects.filter(hubid=sensorid,time__range=(time2,time1)).values('hour').annotate(sum_out=Sum('outdoor'), sum_in=Sum('indoor'), sum_eat=Sum('kitchen'), sum_wash=Sum('toilet')).order_by('hour')
 
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上述代码相当于sql语句：

select Sum('outdoor') as sum_out,Sum('indoor') as sum_in,Sum('kitchen') as sum_eat,Sum('toilet') as sum_wash,hour
where hubid='sensorid' and (time between time1 and time2)
group by hour
order by hour asc
 
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另外，在Django中order_by(‘hour’)表示按生序排列，若要按降序排列，则使用order_by(‘-hour’)

参考：

http://blog.youkuaiyun.com/tianweitao/article/details/50161445