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Posted to dev@jena.apache.org by "Andy Seaborne (Jira)" <ji...@apache.org> on 2022/02/24 13:46:00 UTC

[jira] [Resolved] (JENA-2288) Counting aggregation inside SERVICE provides wrong result

     [ https://issues.apache.org/jira/browse/JENA-2288?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andy Seaborne resolved JENA-2288.
---------------------------------
      Assignee: Andy Seaborne
    Resolution: Cannot Reproduce

> Counting aggregation inside SERVICE provides wrong result
> ---------------------------------------------------------
>
>                 Key: JENA-2288
>                 URL: https://issues.apache.org/jira/browse/JENA-2288
>             Project: Apache Jena
>          Issue Type: Bug
>    Affects Versions: Jena 4.4.0
>            Reporter: Dmitry Zhelobanov
>            Assignee: Andy Seaborne
>            Priority: Major
>
> Here is a query which retrieves museums in the specific city:
> {code:java}
> PREFIX wd: <http://www.wikidata.org/entity/>
> PREFIX wdt: <http://www.wikidata.org/prop/direct/>
> SELECT ?wikidata_iri ?museum
> WHERE {
>   VALUES (?wikidata_iri) { (<http://www.wikidata.org/entity/Q612>) } .
>     
>   SERVICE <https://query.wikidata.org/sparql> {
>     {
>       select ?wikidata_iri ?museum
>       where {
>         OPTIONAL {
>           ?museum (wdt:P131)+ ?wikidata_iri ;
>                    wdt:P31/(wdt:P279)* wd:Q33506 .
>         }
>       }
>     }
>   }
> } {code}
> This query returns 3 results:
> |<http://www.wikidata.org/entity/Q612>|<http://www.wikidata.org/entity/Q2125281>|
> |<http://www.wikidata.org/entity/Q612>|<http://www.wikidata.org/entity/Q28736367>|
> |<http://www.wikidata.org/entity/Q612>|<http://www.wikidata.org/entity/Q67737768>|
> And here is a query which is supposed to count the number of the same museums in the same city:
> {code:java}
> PREFIX wd: <http://www.wikidata.org/entity/>
> PREFIX wdt: <http://www.wikidata.org/prop/direct/>
> SELECT ?wikidata_iri ?museum_count_in_city
> WHERE {
>   VALUES (?wikidata_iri) { (<http://www.wikidata.org/entity/Q612>) } .
>   
>   SERVICE <https://query.wikidata.org/sparql> {
>     {
>       select ?wikidata_iri (COUNT(?museum) as ?museum_count_in_city)
>       where {
>         OPTIONAL {
>           ?museum (wdt:P131)+ ?wikidata_iri ;
>                    wdt:P31/(wdt:P279)* wd:Q33506 .
>         }
>       } group by ?wikidata_iri
>     }
>   }
> }{code}
> But the count value produced by the query is wrong:
> |<[http://www.wikidata.org/entity/Q612]>|"201"{^}^^<[http://www.w3.org/2001/XMLSchema#integer]>{^}|
> It outputs *201* instead of expected *3.*



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