Yeah, I know :\, but still maybe someone have a good idea :), lot of people still using old Django versions.
I tried the expressions, the `F()` but it not worked well and I had no time to debug why, but in next weeks I'll probably create a slug field to compare directly. I post here if have updates. Thx Tim. Felipe Prenholato. Home page: http://devwithpassion.com | http://chronosbox.org/blog GitHub: http://github.com/chronossc/ | Twitter: http://twitter.com/chronossc LinkedIn: http://br.linkedin.com/in/felipeprenholato/ 2016-09-23 13:36 GMT-03:00 Tim Graham <[email protected]>: > Not sure, this is using lots of private API and QuerySet.extra() which is > discourage these days. I'm afraid you won't get much help for unsupported > Django versions. > > After you upgrade to Django 1.9+, hopefully you can construct your query > using the new expressions API! > > https://docs.djangoproject.com/en/stable/ref/models/expressions/ > > > On Friday, September 23, 2016 at 11:40:04 AM UTC-4, Felipe 'chronos' > Prenholato wrote: >> >> Hello folks! >> >> I have a complex queryset here that do joins in at least 8 tables. The >> query is fast, but has use of Postgresql `concat` method, and to make it >> have correct aliases I'm using `qs.query.alias_map` where qs is my queryset >> instance: >> >> def my_complex_queryset(self): >> qs = self.filter(*lot_of_stuff_with_lot_of_joins) >> alias_map = { >> j.table_name: a for a, j in qs.query.alias_map.items() >> if j.table_name in ['table_a', 'table_b'] >> } >> concat_str = ( >> 'concat("{table_a}"."city", "{table_a}"."state") ' >> '!= concat("{table_b}"."city", "{table_b}"."state")' >> ).format( >> table_a=alias_map['table_a'], >> table_b=alias_map['table_b'] >> ) >> qs = qs.extra(where=[concat_str]) >> return qs >> >> The problem is when the query is re-executed with some other table in the >> joins because it will change the alias_map but won't run my method again >> to update the concat_str: >> >> my_qs = MyModel.objects.my_complex_queryset() >> print my_qs >> # now it will fail because alias changed: >> print my_qs.filter(another_table_1__another_table_2__id__in=[1, 2, 3]) >> >> The error I receive is: >> >> * ProgrammingError: invalid reference to FROM-clause entry for table >> "table_a"* >> *LINE 1: ... AND U0."some_id" IN (13361, 9820) AND (concat("table_a...* >> * ^* >> *HINT: Perhaps you meant to reference the table alias "u9".* >> >> The great question is: Is possible to do the query with dynamic aliases >> to be used in concat string? Maybe the `tables` argument to extra? I not >> saw much doc about it :\. >> >> My Django version is 1.6.x, not because my choice but because software >> here still a bit legacy about Django versions and we won't change until >> January. >> >> Thanks for your attention! >> >> Felipe Prenholato. >> Home page: http://devwithpassion.com | http://chronosbox.org/blog >> GitHub: http://github.com/chronossc/ | Twitter: http://twitter.com/ch >> ronossc >> LinkedIn: http://br.linkedin.com/in/felipeprenholato/ >> > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/django-users. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/django-users/77febd31-5b71-4ce2-a794-dab2f7c5e3e7%40googlegroups.com > <https://groups.google.com/d/msgid/django-users/77febd31-5b71-4ce2-a794-dab2f7c5e3e7%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CADdUj3HxrWLJai5_wQaKWBKtBOi%2B9d_zZwCi0%3DPUm8yps_-gLA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
