Question

I’ve got an object that have the counts for connections in twitter and facebook saved in the object’s table. I’m trying to sort a list of these objects by the combined sum of the facebook and twitter counts using the .extra field.

Some of the twitter / facebook fields are empty (None) so the combined is blank. This is causing some issues, and these blank ones are being sorted first. Is there any way to have these blank fields sorted as if they were 0?

pages = Page.objects.filter(
    setup_complete=1, active=1
).exclude(
    Q(background_image__isnull=True) | Q(background_image__exact='')
).extra(
    select={'total_count':'twitter_count + facebook_count'},order_by=['-total_count']
)[:99]

Answer 1

This is not tested, but can you do this?

annotate(total_count=Sum(twitter_count) + Sum(facebook_count))

If not, you may need to do it in the model. For example, in the model add a

def get_total(self):
    if twitter_count == None and facebook_count == None:
        return 0
    elif twitter_count != None and facebook_count != None:
        return twitter_count + facebook_count
    elif twitter_count != None:
        return twitter_count
    else:
        return facebook_count
total_count = property(get_total)

Then in your query:

pages = Page.objects.filter(
    setup_complete=1, active=1
).exclude(
    Q(background_image__isnull=True) | Q(background_image__exact='')
).annotate(
    total_count=Sum(total)
).order_by=('-total')
)[:99]