what is the {point in time} for {Portsmouth} has {population} as {248440} ?
What was the date when 248,440 people lived in Portsmouth?
When did Portsmouth have a population of 248440?
SELECT ?j WHERE { ?z property:population ?m . FILTER ( CONTAINS ( ?m , '248440' ) ) . ?z property:point_in_time ?j . resource:Portsmouth property:population ?z }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q72259> .
?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> <248440> .
?statement <http://www.wikidata.org/entity/P585> ?value. 
} 

SELECT ?value WHERE { wd:Q72259 p:P1082 ?s . ?s ps:P1082 ?x filter(contains(?x , '248440')) . ?s pq:P585 ?value}