Peter,
A pragmatic way would be to use a nested SELECT first, where you can define
aggregates that you would latter use in CONSTRUCT as usual.
Regards,Milorad
From: Martynas Jusevičius <marty...@graphity.org>
To: users@jena.apache.org
Sent: Monday, November 2, 2015 12:23 PM
Subject: Re: use aggregates in CONSTRUCT query
You can, but they need to go in the WHERE part, not CONSTRUCT. And you
need to GROUP BY first:
http://rdf.myexperiment.org/howtosparql?page=GROUP%20BY
On Mon, Nov 2, 2015 at 12:20 PM, Wetz Peter <peter.w...@tuwien.ac.at> wrote:
> This is more of a SPARQL question, so sorry, if it not perfectly fits here:
> I wonder, if it's possible to use aggregates in SPARQL CONSTRUCT queries.
>
> For instance, I have the following query:
>
> CONSTRUCT {
> ?s ei:number ?number .
> }
> FROM <http://example.org>
> WHERE {
> ?s ei:number ?number
> }
>
> However, since `?number` has multiple solutions, I would like to calculate
> the aggregate. I tried it like this:
>
> CONSTRUCT {
> ?s ei:number AVG(?number) .
> }
> FROM <http://example.org>
> WHERE {
> ?s ei:number ?number
> }
>
> The [SPARQL Query Validator][1] raises the following error:
>
> Encountered " "avg" "AVG "" at line 3, column 14.
> Was expecting one of:
> ...
> "true" ...
> "false" ...
> ...
> "(" ...
> ...
> "[" ...
>
> Hence, my question is: (How) can I use aggregates in SPARQL CONSTRUCT queries
> efficiently?
