Get distinct values of Queryset by field
What you want is:
Visit.objects.filter(stuff).values("ip_address").annotate(n=models.Count("pk"))
What this does is get all ip_addresses and then it gets the count of primary keys (aka number of rows) for each ip address.
With Alex Answer I also have the n:1 for each item. Even with a distinct() clause.
It's weird because this is returning the good numbers of items :
Visit.objects.filter(stuff).values("ip_address").distinct().count()
But when I iterate over "Visit.objects.filter(stuff).values("ip_address").distinct()" I got much more items and some duplicates...
EDIT :
The filter clause was causing me troubles. I was filtering with another table field and a SQL JOIN was made that was breaking the distinct stuff.I used this hint to see the query that was really used :
q=Visit.objects.filter(myothertable__field=x).values("ip_address").distinct().count()print q.query
I then reverted the class on witch I was making the query and the filter to have a join that doesn't rely on any "Visit" id.
hope this helps
The question is different from what the title suggests. If you want set-like behavior from the database, you need something like this.
x = Visit.objects.all().values_list('ip_address', flat=True).distinct()
It should give you something like this for x
.
[1.2.3.4, 2.3.4.5, ...]
Where
len(x) == len(set(x))
Returns True