Opened 4 years ago

Last modified 4 years ago

#31940 closed Cleanup/optimization

Order of WHERE clauses do not match the order of the arguments to .filter() — at Initial Version

Reported by: Tommy Li Owned by: nobody
Component: Database layer (models, ORM) Version: 3.0
Severity: Normal Keywords:
Cc: Triage Stage: Unreviewed
Has patch: no Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no

Description

With the following sample model

class MyModel(models.Model):
    a_field = models.IntegerField()
    b_field = models.IntegerField()

If I run the following query:

MyModel.objects.filter(b_field = 1, a_field = 2)

the SQL that it generates is 

SELECT "mymodel"."a_field", "mymodel"."b_field
FROM "mymodel"
WHERE ("mymodel"."a_field" = 2 AND "mymodel"."b_field" = 1)

I would expect the order of the clauses in the WHERE statement to match the order of arguments passed to the filter statement. In my case, b_field has a much higher cardinality than a_field and I want the query to use an index I have on (b_field, a_field)

After some experimentation, it looks like the WHERE clauses are ordered alphabetically by column name. Is that explicitly intended, or is it just a side effect of some implementation detail?

Change History (0)

Note: See TracTickets for help on using tickets.
Back to Top