CODEWITHSUNDEEP
djangodjango-queryset
Ricardo
Ricardo

Reputation: 442

Django not in other table (Not using id)

I have:

Models:

class Category(models.Model):
    description = models.CharField(unique=True, max_length=200)                        
    myfield = models.CharField(unique=True, max_length=200)                        

class Car(models.Model):
    categorys = models.ManyToManyField(Category)   
    myfield = models.CharField(unique=True, max_length=200)

I am trying to execute the following query:

Car.objects.filter(category__id = c.id )
           .exclude(myfield__in =                      
                    Category.objects.all()
                            .only('myfield')
                    )
           .order_by("id")
           .first()

I expected to find a result like this:

SELECT ...
 FROM `myapp_car` 
 INNER JOIN `myapp_car_categorys` 
        ON (`myapp_car`.`id` = `myapp_car_categorys`.`car_id`)    
WHERE ( ...
  AND NOT (`myapp_car`.`myfield` IN 
           (SELECT `myapp_category`.`myfield` FROM `myapp_category`))) 
ORDER BY `myapp_car`.`id` ASC LIMIT 1;

But i find:

SELECT ...
 FROM `myapp_car` 
 INNER JOIN `myapp_car_categorys` 
        ON (`myapp_car`.`id` = `myapp_car_categorys`.`car_id`)    
WHERE ( ...
  AND NOT (`myapp_car`.`myfield` IN 
           (SELECT `myapp_category`.`id` FROM `myapp_category`))) 
ORDER BY `myapp_car`.`id` ASC LIMIT 1;

I need use myfield in select, not id:

(SELECT `myapp_category`.`myfield` FROM `myapp_category`)

How would I get this result?

Upvotes: 0

Views: 953

Answers (1)

AKS
AKS

Reputation: 19861

Even if you use only it will return the objects of Category model. So if you use it in in filtering the category objects will be used for filtering and for SQL the ids of those category objects.

If you need to filter on the myfield values on all the category objects, then use values instead:

....exclude(myfield__in=Category.objects.values('myfield'))

Upvotes: 1

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