Re: Passing distinct subquery solutions to aggregate outer query

Hi Paul,

Why would the outer query need any graph patterns other than the 
subquery? You ought to be able to do exactly what you have below without 
anything in the "what goes here" spot.


On 1/23/2013 3:56 PM, Paul Tyson wrote:
> Hi all,
> I'm wondering if there is a simple solution to this problem.
> I have a rather complicated query, consisting of several union 
> clauses, which by its nature will return duplicates. I need to get a 
> unique solution set so I can group them and sum a couple of fields.
> Simply wrapping the union query in a nested SELECT DISTINCT doesn't 
> work, because the outer query has no graph pattern to match the 
> variables projected from the subquery.
> I tried adding a series of BIND statements to simply rename the 
> subquery variables for use by the aggregate outer query, but that 
> didn't work (with jena, at least).
> The source dataset is nearly 500M triples. I'm using Jena 2.7.3. The 
> subquery will return anywhere from a few dozen to a few hundred 
> solutions, and by itself runs very quickly.
> Here's a skeleton view of the query. Is there something to fill "what 
> goes here" that will pass the subquery results up to the grouping 
> function?
> select ?var1 ?var2 (sum(?var3) as ?var3_total)
> where {
> { ??? what goes here ??? }
> {select distinct ?var1 ?var ?var3
> where { ... complicated union query ... }}
> }
> group by ?var1 ?var2
> Or any other suggestions on how to tackle this problem?
> Thanks,
> --Paul

Received on Thursday, 24 January 2013 06:45:19 UTC