What are the nicknames of the schools whose color is royal blue?
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/colour> <http://dbpedia.org/resource/Royal_blue> . ?x <http://dbpedia.org/property/nickname> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/School>}
Royal_blue