Opened 12 years ago
Closed 9 years ago
#19434 closed Bug (wontfix)
Some QuerySet methods not aware of fields added on "extra"
Reported by: | Henrique C. Alves | Owned by: | nobody |
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Component: | Database layer (models, ORM) | Version: | dev |
Severity: | Normal | Keywords: | QuerySet.extra |
Cc: | flo@… | Triage Stage: | Accepted |
Has patch: | yes | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | yes |
Easy pickings: | no | UI/UX: | no |
Description
Some examples to illustrate the issue:
(Pdb) CUSTOM_SQL = "SELECT some_function(some_field) FROM some_table" # This works (Pdb) qs = qs.extra(select={'some_alias': CUSTOM_SQL}, order_by=['some_alias']) # This fails (Pdb) qs.filter(some_alias__gt=0) *** FieldError: Cannot resolve keyword 'some_alias' into field. Choices are: ... # This works (Pdb) qs.values() [{'some_alias': 1}, {'some_alias': 2}] # This fails (Pdb) qs.values('some_alias') *** FieldError: Cannot resolve keyword 'some_alias' into field. Choices are: ...
There's a situation where half of the API supports extra
queries correctly, the other half fails with a FieldError
, and there's no clear indication to what should be the right behavior.
Change History (8)
comment:2 by , 12 years ago
Triage Stage: | Unreviewed → Accepted |
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Yes, it isn't possible to filter on a field added in a .extra(select={...})
. I've hit this problem too.
comment:3 by , 12 years ago
Cc: | added |
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Has patch: | set |
Version: | 1.4 → master |
I've started a patch that adds support for filtering fields added by extra and created a pull request: https://github.com/django/django/pull/735
I think something similar has been done to provide support for filtering annotations/aggregations
qs.extra(select={'num_plus_one': 'num + 1'} qs.filter(num_plus_one=2)
will result in following query:
SELECT (num+1) AS "num_plus_on" ... WHERE (num+1) = 2 ....
In order to avoid quoting of the lvalue of the term in the WHERE part I modified WhereNode.add to accept a QueryWrapper (contains the extra sql). There's probably a much better way to add an unqouted lvalue to the WhereNode, any suggestions/feedback are very appreciated.
qs.values('some_alias')
worked for me (without modification), but I've added a test to check it.
comment:4 by , 11 years ago
Triage Stage: | Accepted → Ready for checkin |
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<commented on incorrect ticket>
comment:5 by , 11 years ago
Triage Stage: | Ready for checkin → Accepted |
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comment:8 by , 9 years ago
Keywords: | QuerySet.extra added |
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Resolution: | → wontfix |
Status: | new → closed |
We are no longer fixing bugs with QuerySet.extra()
per discussion on django-developers.
Might be related to ticket #8784.