[Django]-Django query equivalent of MySQL GREATEST function?

by

3👍

Have you looked into using the extra method?

Month.objects.extra(select={'max_income': 'greatest(income_actual, income_projected)'})

EDIT:

You’re not going to be able to use that through the ORM without writing raw SQL. Although you could use some python magic:

sum(month['max_income'] for month in Month.objects.extra(select={'max_income': 'greatest(income_actual, income_projected)'}).values('max_income'))
👤drewman

2👍

You may use Django’s Database Function Greatest.

For example you may use such a query:

>>> from django.db.models.functions import Greatest

>>> months = Month.objects.annotate(greatest_income=Greatest('income_actual', 'income_projected').all()

# now you can access the greatest value using something like this:
>>> months[0].greatest_income
👤Chirag Maheshwari

0👍

@drewman already gave you the version when you want to use strictly SQL. I would do things a bit differently, and add a property to the model which dynamically calculates the correct version.

class model(models.Model):
    ....

    @property
    def income(self):
        return max(self.income_actual, self.income_real)
👤user234932

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