#14137: Django ORM adding unwanted parens when using extra()
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Reporter: mjs7231 | Owner: nobody
Status: new | Milestone:
Component: Uncategorized | Version: 1.2
Keywords: | Stage: Unreviewed
Has_patch: 0 |
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I have a table REPORTS containing the columns {id, user, date}. I was
attempting to get the row with the largest date for each user. Using
Django's ORM I can pretty much get what I want using the queryset
definition:
{{{
queryset = Report.objects.extra(select={'lastid':"DISTINCT ON (user_id)
id"})
queryset = queryset.order_by('user', '-date')
queryset = queryset.values('lastid')
}}}
This results in the query:
{{{
SELECT (DISTINCT ON (user_id) id) AS "lastid" FROM "report" ORDER BY
"report"."user_id" ASC, "report"."date" DESC;
}}}
Postgres spits out an exception with this query. However, if you remove
the extra parens around the DISTINCT clause, it works fine. So the query
should really look like:
{{{
SELECT DISTINCT ON (user_id) id AS "lastid" FROM "report" ORDER BY
"report"."user_id" ASC, "report"."date" DESC;
}}}
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Ticket URL: <http://code.djangoproject.com/ticket/14137>
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