当选择格式时间列时django

Question

django model JobError（id int pk，create_time datetime [2017-07-24 00:00:14]） sql如下：

SELECT time_format,count(id) as total
from (SELECT
id,
date_format(create_time, '%Y-%m-%d %H:%i') AS time_format
FROM monitor_job_error
WHERE create_time > '2017-7-24')as tab
GROUP BY time_format

我现在想使用django orm，当selct create_time执行date_format时该怎么办。

JobError.objects.filter(create_time__gte=(datetime.now()-relativedelta(hours=15))).order_by('create_time').values('create_time').annotate(total=Count('id'))`

伙计们，请帮忙。感谢：！）