#11881: ORDER BY in aggregate subqueries is not necessary and might causes on
some
SQL servers
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Reporter: egenix_viktor |
Owner: nobody
Status: new |
Milestone:
Component: Database layer (models, ORM) |
Version: 1.1
Keywords: aggregate subquery order_by optimization incompatibility |
Stage: Unreviewed
Has_patch: 1 |
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Some SQL servers, like `MS SQL 2005` does not allow `ORDER BY` in
subqueries without a `TOP` modifier. (It might apply to other database
servers as well.) It is also suboptimal to use `ORDER BY` in the subquery
of an aggregate `SELECT`, since it does not affect the result.
It might be better to just clear ordering in the subquery in this case. I
suggest adding the following line in the `BaseQuery.get_aggregation`
method before the `query.add_subquery(obj)` call:
{{{
obj.clear_ordering(True)
}}}
Patch against the `db\models\sql\query.py` file of the 1.1 release version
has been attached.
--
Ticket URL: <http://code.djangoproject.com/ticket/11881>
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