On Thu, Jan 6, 2011 at 7:35 AM, Vlastimil Zima <vlastimil.z...@gmail.com> wrote: > Recently I found out that distinct() can not be called on queries that > are ordered as the result query is kind of > > SELECT DISTINCT table.id, table.ordering_column FROM table ORDER BY > table.ordering_column ASC > > In ticket http://code.djangoproject.com/ticket/11568 was said that > this will not be fixed, bacuse this is intentional behaviour of > ordering. > > > So code > > SomeModel.objects.order_by('ordering_column').values_list('pk') > > leads to SQL > > SELECT table.id, table.ordering_column FROM table ORDER BY > table.ordering_column ASC > > instaed of simple > > SELECT table.id FROM table ORDER BY table.ordering_column ASC > > My question is, what is the intention? I could not find out any > advantage that comes from this kind of query.
It is not valid SQL to order by a column that is not in the result set. MySQL allows you to do that, but that is a MySQL-specific feature. PostgreSQL, certainly, does not allow this, and there is no real advantage gained (aside from a slightly smaller response) by excluding the ordering column. Regards, Ian Clelland <clell...@gmail.com> -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-us...@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
