id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
7070	Query.get_ordering doesn't support foreign key related ordering when combined with distinct()	matt@…	nobody	"As per my comment on django-users:

If you have a query set which has had distinct() called and then order_by() on a foreign key
field you don't get the ordering on that foreign key field - the
resulting generated sql query has the joins for the foreign table
ready to be used for the order_by, but the ""if not distinct or elt in
select_aliases"" bit inside get_ordering() prevents the actual ORDER BY
portion being added.

The following example case illustrates. The models are:

{{{
from django.db import models

class FKTest(models.Model):
        name = models.CharField()

class Test(models.Model):
        fk = models.ForeignKey('FKTest')
        name = models.CharField()
}}}

Using those models:

{{{
print str(Test.objects.all().order_by('fk__name').query)
print str(Test.objects.all().order_by('fk__name').distinct().query)
print str(Test.objects.all().order_by('name').query)
print str(Test.objects.all().order_by('name').distinct().query)
}}}

This gives the output (with psycopg being my database driver):

{{{
SELECT ""crs_test"".""id"", ""crs_test"".""fk_id"", ""crs_test"".""name"" FROM ""crs_test"" INNER JOIN ""crs_fktest"" ON (""crs_test"".""fk_id"" = ""crs_fktest"".""id"") ORDER BY ""crs_fktest"".""name"" ASC
SELECT DISTINCT ""crs_test"".""id"", ""crs_test"".""fk_id"", ""crs_test"".""name"" FROM ""crs_test"" INNER JOIN ""crs_fktest"" ON (""crs_test"".""fk_id"" = ""crs_fktest"".""id"")
SELECT ""crs_test"".""id"", ""crs_test"".""fk_id"", ""crs_test"".""name"" FROM ""crs_test"" ORDER BY ""crs_test"".""name"" ASC
SELECT DISTINCT ""crs_test"".""id"", ""crs_test"".""fk_id"", ""crs_test"".""name"" FROM ""crs_test"" ORDER BY ""crs_test"".""name"" ASC
}}}

As you can see the DISTINCT version of the sort on a foreign object's name is missing the ORDER BY clause.
"		closed	Uncategorized	queryset-refactor		fixed			Unreviewed	0	0	0	0	0	0