This time I didn't, apparently, read what you wanted exactly. Here I was, talking about sums, when all you want are the minimum and maximum. Apparently, I shouldn't answer mailing lists in the morning.
Anyway, *most* of what I said holds true, as min and max work pretty much the same way as sum--in Python, and in SQL. On Mar 3, 11:36 am, Jeff FW <jeff...@gmail.com> wrote: > Responded too quickly :-) > > If you're already getting a list of the top 100 products (and > displaying them, I assume, in a loop,) then totalling up the prices in > Python really won't hurt at all. I'd only suggest going with my > *previous* suggestion if you *weren't* already fetching the top 100 > products. > > -Jeff > > On Mar 3, 11:34 am, Jeff FW <jeff...@gmail.com> wrote: > > > The behavior is there because you can't limit an aggregate function in > > (AFAIK) SQL in that way. It just doesn't make sense--what would this > > actually mean? > > > select sum(price) from product limit 100; > > > Really, you'd be limiting the number of *rows* of sum returned, which, > > unless you're using GROUP, is going to be 1. To do what you want, > > you'd need a subselect, which (correct me if I'm wrong,) you'd have to > > manually write in SQL. Like so: > > > select sum(price) from (select price from product order by price desc > > limit 100) as q; > > > (That's postgres; your DB may vary.) > > > I could be completely off-base here, as I haven't delved very far into > > the aggregate code, but from what I can tell, this is the case. > > > -Jeff > > > On Mar 3, 11:08 am, Alex Gaynor <alex.gay...@gmail.com> wrote: > > > > On Tue, Mar 3, 2009 at 8:55 AM, Ross <real...@gmail.com> wrote: > > > > > I have started using aggregation, but it seems to ignore any slicing I > > > > do on a QuerySet before calling aggregate. This is what I'm doing: > > > > > Product.objects.order_by("-price")[:100].values("price").aggregate(Max > > > > ("price"), Min("price")) > > > > > I want the maximum and minimum price for the products with the top 100 > > > > largest prices. The aggregate function, however, returns the maximum > > > > and minimum price for all Products--it ignores the [:100] slice. > > > > > Is this an improper use of aggregation, or am I doing something wrong > > > > with my query? > > > > Before an aggregation is preformed all limits are removed, so you are > > > seeing > > > expected behavior. I can't remember why this behavior exists though :/ > > > > Alex > > > > -- > > > "I disapprove of what you say, but I will defend to the death your right > > > to > > > say it." --Voltaire > > > "The people's good is the highest law."--Cicero > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---