Convert from sql to Django ORM

Question

Help me, please! How to convert this SELECT hotel_id FROM hotelrooms GROUP BY hotel_id HAVING COUNT(room_id) < 20 to Django ORM?

Model:

class hotelrooms(models.Model):
  room_id = models.IntegerField()
  hotel_id = models.IntegerField()
  price = models.IntegerField()

@WillemVanOnsem there is only one model, I updated the question — , May 21 '20 at 12:16
You can have a look @ https://stackoverflow.com/questions/45547674/how-to-execute-a-group-by-count-or-sum-in-django-orm/45547675 — chirag soni, May 21 '20 at 12:21

score 0 · Accepted Answer · answered May 21 '20 at 12:18

You can query with:

HotelRoom.objects.values('hotel_id').annotate(
    nhotel=Count('room_id')
).filter(nhotel__lt=20).order_by('hotel_id')

That being said, it looks like these should be **ForeignKey**s [Django-doc]. ForeignKeys refer to another model, and thus can enforce referential integrity for example.

Convert from sql to Django ORM

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