Re: Aggregating Ignores Slicing?

On Wed, Mar 4, 2009 at 9:24 AM, Waylan Limberg wrote: > > On Mar 3, 8:55 am, Ross 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: > > > >

Re: Aggregating Ignores Slicing?

On Mar 3, 8:55 am, Ross 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")) >

Re: Aggregating Ignores Slicing?

On Tue, Mar 3, 2009 at 11:46 AM, Ross wrote: > > As I thought about it more, I came up with something similar to what > both of you suggested. Django's query language has made my SQL > knowledge suffer a bit--your explanation about why the limit won't > work makes sense, Jeff.

Re: Aggregating Ignores Slicing?

As I thought about it more, I came up with something similar to what both of you suggested. Django's query language has made my SQL knowledge suffer a bit--your explanation about why the limit won't work makes sense, Jeff. Thanks a lot for the suggestions. On Mar 3, 10:39 am, Jeff FW

Re: Aggregating Ignores Slicing?

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

Re: Aggregating Ignores Slicing?

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

Re: Aggregating Ignores Slicing?

On Tue, Mar 3, 2009 at 11:32 AM, Ross wrote: > > Do you know a good way to do what I am trying to do? I can write a > quick for loop to do the work, but I was hoping to offload some of the > work to the database since it is much faster than a Python for loop. > > I have a set

Re: Aggregating Ignores Slicing?

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,

Re: Aggregating Ignores Slicing?

Do you know a good way to do what I am trying to do? I can write a quick for loop to do the work, but I was hoping to offload some of the work to the database since it is much faster than a Python for loop. I have a set of say 10,000 Product models. I want to get a list of the 100 with the

Re: Aggregating Ignores Slicing?

On Tue, Mar 3, 2009 at 8:55 AM, Ross 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"),

Aggregating Ignores Slicing?

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