Casting Char Field to Integer in Django ORM
When querying with Django ORM, you may encounter scenarios where you need to cast a character field to an integer. This can arise when the field is stored as a CharField but you want to perform calculations or comparisons using integer values.
Why CAST is Unavailable?
In earlier versions of Django, raw SQL queries or database functions were necessary for such scenarios. However, with the introduction of Cast function in Django 1.10, you can achieve this casting within the ORM itself.
Using the Cast Function
To cast a CharField to an integer, use the following syntax:
<code class="python">from django.db.models import Cast, IntegerField students.objects.annotate( student_id_int=Cast('student_id', IntegerField()) ).filter(student_id_int__contains=97318).order_by('-student_id_int')</code>
This will annotate the queryset with a new field called student_id_int, which is cast to an integer type. You can then use this new field for filtering and ordering as desired.
Benefits of Using Cast
Using Cast provides several benefits:
Reference
For more information on casting in Django ORM, refer to the documentation:
The above is the detailed content of How to Cast a CharField to an Integer in Django ORM?. For more information, please follow other related articles on the PHP Chinese website!