Django PostgreSQL：填写范围内的缺失日期

date         .....
-----------  -----
2015-07-20     ..
2015-07-20     ..
2015-07-23     ..
2015-07-24     ..

我想使用Django ORM和PostgreSQL作为数据库后端,以下面的形式获取数据：

date         count(date)
-----------  -----------
2015-07-20        2
2015-07-21        0       (missing after aggregation)
2015-07-22        0       (missing after aggregation)
2015-07-23        1
2015-07-24        1

对应的PostgreSQL查询：

WITH RECURSIVE date_view(start_date,end_date) 
AS ( VALUES ('2015-07-20'::date,'2015-07-24'::date) 
     UNION ALL SELECT start_date::date + 1,end_date 
     FROM date_view 
     WHERE start_date < end_date ) 
SELECT start_date,count(date) 
FROM date_view LEFT JOIN my_table ON date=start_date 
GROUP BY date,start_date 
ORDER BY start_date ASC;

我将此原始查询转换为Django ORM查询时遇到问题.

如果有人可以使用PostgreSQL作为数据库后端,使用/不使用公用表表达式的解决方法来提供样本ORM查询,那将是很棒的.

引用here的简单原因是：

My preference is to do as much data processing in the database,short of really involved presentation stuff. I don’t envy doing this in application code,just as long as it’s one trip to the database

根据this answer,django本身不支持CTE,但答案似乎已经过时了.

参考文献：

> MySQL: Select All Dates In a Range Even If No Records Present
> WITH Queries (Common Table Expressions)

谢谢