What is {population} of {Warsaw} that is {point in time} is {1830-0-0} ?
In 1830 how many people resided in Warsaw?
What was the population of Warsaw in 1830?
SELECT ?f WHERE { resource:Warsaw property:population ?b . ?b property:point_in_time ?w . ?b property:population ?f . FILTER ( CONTAINS ( YEAR ( ?w ) , '1830' ) ) }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q270> .
?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:Q270 p:P1082 ?s . ?s ps:P1082 ?obj . ?s pq:P585 ?x filter(contains(YEAR(?x),'1830')) }