Perhaps I'm missing something, but if you count all the defined foreign keys AND all the null values, won't you just end up with a count of the parent model? Or are you saying that you explicitly want to count how many values are null *instead of* defined?
On Jan 25, 2:39 pm, Sergiy Kuzmenko <s.kuzme...@gmail.com> wrote: > Hi there! > > Annotating a nullable foreign field with Count seems to always return > the count of null values as zero (at least in MySQL environment). A > quick look into this problem reveals that the corresponding SQL clause > is generated as `count(<field_name>)` [1]. This causes to exclude null > values from annotation in MySQL [2]. I believe the same applies to > PostgreSQL [3] and likely to other backends. > > In my mind, current behaviour is bit of a bug (it is definitely quirky > in MySQL). But it is possible that not counting null values was > intentional. In this case there should be at least a way for user to > specify that null values must also be counted. Perhaps something like: > > Count(field_name, count_nulls=True) > > [1]http://code.djangoproject.com/browser/django/trunk/django/db/models/s... > [2]http://dev.mysql.com/doc/refman/5.1/en/group-by-functions.html#functi... > [3]http://www.postgresql.org/docs/9.0/static/sql-expressions.html > > Thanks > Sergiy -- You received this message because you are subscribed to the Google Groups "Django developers" group. To post to this group, send email to django-developers@googlegroups.com. To unsubscribe from this group, send email to django-developers+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-developers?hl=en.
