Question

I would like to do a SUM on rows in a database and group by date.

I am trying to run this SQL query using Django aggregates and annotations:

select strftime('%m/%d/%Y', time_stamp) as the_date, sum(numbers_data)     from my_model     group by the_date; 

I tried the following:

data = My_Model.objects.values('strftime('%m/%d/%Y',            time_stamp)').annotate(Sum('numbers_data')).order_by() 

but it seems like you can only use column names in the values() function; it doesn’t like the use of strftime().

How should I go about this?

Answer 1

This works for me:

select_data = {'d': '''strftime('%%m/%%d/%%Y', time_stamp)'''}  data = My_Model.objects.extra(select=select_data).values('d').annotate(Sum('numbers_data')).order_by() 

Took a bit to figure out I had to escape the % signs.