On Fri, Feb 13, 2009 at 6:54 PM, Alessandro <alessandro.ron...@gmail.com> wrote:
>
>
> 2009/2/10 Alessandro <alessandro.ron...@gmail.com>
>>
>>
>> 2009/2/10 Russell Keith-Magee <freakboy3...@gmail.com>
>>>
>>>
>>> i.e., plural modules, not singular module, in the Max lookup. It's the
>>> reverse lookup name for the module relationship on Module_scheme. For
>>> future reference, the message on the FieldError tells you the right
>>> name - modules.
>
> Is it possible to do a group by of a time selection, like GROUP BY
> DAY(time_field) ?
Enabling grouping on fields modified by a function wasn't explicitly
part of the original design specification. However, once I fix #10132,
you may be able to do this by putting the DAY(time_field) portion into
an extra column, and naming the extra column in a values clause;
something like:
Model.objects.extra(select={'giorno':''DAY(time_field)'}).values('giorno').annotate(SUM('peak'))
#10132 is the ticket I'm working on right now, but fixing it has
revealed a few other problems along the way. I hope to commit a fix in
the next day or so.
> I need to make a query like this:
>
> SELECT SUM(peak), giorno FROM (SELECT MAX(power_peakdaily) AS peak
> ,DAY(time) AS giorno FROM fotovoltaico_modules, fotovoltaico_module_scheme
> WHERE fotovoltaico_module_scheme.plant_id=%s AND year(time)= %s AND
> month(time)=%s AND scheme_id=fotovoltaico_module_scheme.id GROUP BY
> fotovoltaico_module_scheme.id, DAY(time) ORDER BY DAY(time)) AS tabella
> GROUP BY giorno ;"%( year, month, self.id))
Annotating over subqueries wasn't explicitly part of the design spec,
either; again, you will probably need to fall back onto an extra
clause, this time with a 'tables' parameter. You're going to need to
play around a bit to see what works, though.
Yours,
Russ Magee %-)
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