Django F() expressions Execute Arithmetic operations between fields
Example
F() expressions can be used to execute arithmetic operations (+, -, * etc.) among model fields, in order to define an algebraic lookup/connection between them.
-
Let model be:
class MyModel(models.Model): int_1 = models.IntegerField() int_2 = models.IntegerField() -
Now lets assume that we want to retrieve all the objects of
MyModeltable who'sint_1andint_2fields satisfy this equation:int_1 + int_2 >= 5. Utilizingannotate()andfilter()we get:result = MyModel.objects.annotate( diff=F(int_1) + F(int_2) ).filter(diff__gte=5)resultnow contains all of the aforementioned objects.
Although the example utilizes Integer fields, this method will work on every field on which an arithmetic operation can be applied.
