How many {mobile country code} are for {United States of America} ?
Give me the number of area codes in the USA.
How many mobile country codes are in the USA?
SELECT ( COUNT ( ?o ) AS ?y ) { resource:United_States_of_America property:mobile_country_code ?o }
SELECT (COUNT(?obj) AS ?objs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q30> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P2258> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
} 

SELECT (COUNT(?obj) AS ?value ) { wd:Q30 wdt:P2258 ?obj }
5