View source for Q0.8

=Query=

{{Query
|id=8
|name=Duplicate URNs
|title=Duplicate URNs of [[Concept:Proceedings|proceedings]]
|description=List all proceedings with duplicate URN ids
|sparql=# Query 8 of Task 0
# see https://cr.bitplan.com/index.php?title=Q0.8
PREFIX pq: <http://www.wikidata.org/prop/qualifier/>
PREFIX p: <http://www.wikidata.org/prop/>
PREFIX schema: <http://schema.org/>
PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
PREFIX wikibase: <http://wikiba.se/ontology#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

SELECT ?urn (GROUP_CONCAT(DISTINCT ?proceeding; separator=", ") AS ?proceedings) (COUNT(?proceeding) AS ?count)
WHERE {
   # Instance of Proceedings
   ?proceeding wdt:P31 wd:Q1143604.
   # with english label
   ?proceeding rdfs:label ?proceedingLabel.
   FILTER(LANG(?proceedingLabel) = "en")
   # Part of the series
   ?proceeding p:P179 ?partOfTheSeries.
   # CEUR Workshop proceedings
   ?partOfTheSeries ps:P179 wd:Q27230297.
   # URN-NBN
   OPTIONAL { ?proceeding wdt:P4109 ?urn. }
   FILTER(BOUND(?urn))  # Ensure URN is available
}
GROUP BY ?urn
HAVING (COUNT(?proceeding) > 1)  # Only select URNs that appear more than once
ORDER BY DESC(?count)
|tryiturl=PPiY9f
|wdqsurl=8eX3
|relevance=1
|task=Task0
|storemode=property
}}
=Freitext=