1.数据表
| event | camera_name |
|---|---|
| 30002 | 摄像头A |
| 30002 | 摄像头V |
| 30001 | 摄像头A |
| 30002 | 摄像头B |
| 30002 | 摄像头C |
| 30002 | 摄像头E |
2.mysql语句
select camera_name,event,count(*) from warning_event group by camera_name,event
3.django model写法
等效于
WarningEventModel.objects.values("camera_name","event").annotate(count=Count("camera_name"))
