CODEWITHSUNDEEP
djangodjango-views
Mark
Mark

Reputation: 2542

Django Order_by blank

I have a simple model

title = models.CharField(max_length=250)
url = models.CharField(max_length=250)
title_french = models.CharField(max_length=250)

I want to order it via title_french, however when it orders in A-Z in this way, all the blank values are at the top. In the case ot blank values I display the English title.

So I get A-Z for the French titles, but at the top there is a load of English title unordered.

Any advice?

Upvotes: 2

Views: 2102

Answers (5)

LMB
LMB

Reputation: 464

Django has the option to order nulls_first and nulls_last, for details see the docs.

In your case it would be something like this (not tested):

MyModel.objects.order_by(Coalesce('title_french', 'title').asc(nulls_last=True))

You would still have to do some logic in Python to display the title when the french title is None.

Upvotes: 1

bjornbajs
bjornbajs

Reputation: 701

Here is a way to order blank value last while only using the ORM:

from django.db.models import Case, When, Value

...

title_french_blank_last = Case(
    When(title_french="", then=Value(1)),
    default=Value(0)
)

...

queryset.order_by(title_french_blank_last, "title_french", "title")

Upvotes: 0

madewulf
madewulf

Reputation: 1910

For your case, I think you should do the sorting in your python code (currently, as it is, the sorting is made in the database). It is not possible, imho, to do what you want in the db, at least without writing some sql by hand.

So the idea would be to do something like this in your view : 

your_objects = list(YourObject.objects.filter(....))

your_objects.sort(key=lambda ob:  ob.title_french if ob.title_french else  ob.title)

As long as you sort small lists, this should not be a too problematic performance issue.

Upvotes: 2

Ashok
Ashok

Reputation: 10603

specify both the columns, title_french and title in order_by

queryset.order_by('title_french', 'title')

title_french will be given first preference and if there are two entries with the same title_french then those two entries will be sorted by their title

Upvotes: 0

second
second

Reputation: 28637

have you tried ordering by multiple fields (doc):

ordering = ('title_french', 'title')

Upvotes: 1

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