本文介绍了Django ORM:Group by和Max的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个如下所示的模型:
请求:user,req_time,req_text $在数据库中,记录可以如下所示: id,user_id,req_time,req_text 1 1 TIMESTAMP YES 2 1 TIMESTAMP NO 3 2 TIMESTAMP YES / pre>等。
如何编写一个Django ORM查询:按用户分组请求,基于req_text过滤请求,还可以选择最终结果集的最大值。所以对于每个用户,我将返回一行与过滤条件匹配,并且也有最大的id。
解决方案from django.db.models.aggregates import Max request_values = Requests.objects.filter(req_text ='YES')\ .values('user')\ .annotate(max_id = Max('id'))
I have a model that looks like this:
Requests: user, req_time, req_textIn the DB, the records can look like this:
id, user_id, req_time, req_text 1 1 TIMESTAMP YES 2 1 TIMESTAMP NO 3 2 TIMESTAMP YESetc.
How do I write a Django ORM query that: groups the Requests by user, filters the Requests based on req_text, and also, select the max id of the resulting result set. So for each user, I will return one row which matches the filter condition and also has the greatest id.
解决方案 from django.db.models.aggregates import Max request_values = Requests.objects.filter(req_text='YES') \ .values('user') \ .annotate(max_id=Max('id'))
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Django ORM:Group by和Max
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