What is {population} of {Barcelona} that is {point in time} is {1830-0-0} ?
Barcelona's population was what in 1830?
What was the population of Barcelona in 1830?
SELECT ?o WHERE { ?c property:point_in_time ?m . resource:Barcelona property:population ?c . FILTER ( CONTAINS ( YEAR ( ?m ) , '1830' ) ) . ?c property:population ?o }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q1492> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1082> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P585> <1830-0-0>
} 

SELECT ?obj WHERE { wd:Q1492 p:P1082 ?s . ?s ps:P1082 ?obj . ?s pq:P585 ?x filter(contains(YEAR(?x),'1830')) }