What is {date of first performance} of {Lohengrin} that is {cast member} is {Karl Beck} ?
Give me the date of the first performance Karl Beck had with Lohengrin?
When was the first performance of Lohengrin that had Karl Beck?
SELECT ?r WHERE { resource:Lohengrin property:date_of_first_performance ?k . ?k property:date_of_first_performance ?r . ?k property:cast_member resource:Karl_Beck }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q23085> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1191> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P161> <http://wikidata.dbpedia.org/resource/Q6371612>
} 

SELECT ?obj WHERE { wd:Q23085 p:P1191 ?s . ?s ps:P1191 ?obj . ?s pq:P161 wd:Q6371612 }