Django - How To Sort Queryset By Number Of Character In A Field

MyModel: name = models.CharField(max_length=255) I try to sort the queryset. I just think about this: obj = MyModel.objects.all().sort_by(-len(name)) #??? Any idea?

Solution 1:

The new hotness (as of Django 1.8 or so) is Length()

from django.db.models.functions import Length
obj = MyModel.objects.all().order_by(Length('name').asc())

Solution 2:

you might have to sort that in python..

sorted(MyModel.objects.all(),key=lambda o:len(o.name),reverse=True)

or I lied ( A quick google search found the following)

MyModel.objects.extra(select={'length':'Length(name)'}).order_by('length')

Solution 3:

You can of course sort the results using Python's sorted, but that's not ideal. Instead, you could try this:

MyModel.objects.extra(select={'length':'Length(name)'}).order_by('length')

Solution 4:

You'll need to use the extra argument to pass an SQL function:

obj = MyModel.objects.all().extra(order_by=['LENGTH(`name`)']) 

Note that this is db-specific: MySQL uses LENGTH, others might use LEN.