tables argument of QuerySet.extra should be allow a subquery.

[bear330]

If I call extra with tables parameter:

queryset.extra(tables=['(select * from table) as k'])

The result SQL will be:

select ........ from `self_table`, `(select * from table) as k`

the subquery will be invalid.

That will be nice if we can determine whether we need qn or not.
For a normal table:

queryset.extra(tables=[qn('tableA'), qn('tableB')])

But for a subquery I can just omit qn to do that.

Thanks.

[Samuel Cormier-Iijima]

Attaching a patch for one possible solution: allow the tables argument to be a dictionary-like object mapping table names to subqueries, where the subquery is not quoted. Your example could therefore be re-written as

queryset.extra(tables={
    'k': '(select * from table)'
})

[Shaun Cutts]

update of the previous patch -- conforms to new sql compilation

[Jacob]

Now that we've got .raw(), .extra() should be used less and less. I'm against adding any more abilities to it -- it's a bad feature and should be used as little as possible.