sparql/concat/bind/replace/str

SELECT count( distinct concat(?s, "|", ?o) as ?row) {GRAPH <http://yago3> {
?s rdfs:subClassOf ?o.
FILTER (REGEX(str(?o), 'http://yago-knowledge.org/resource/wikicat') || REGEX(str(?o), 'http://yago-knowledge.org/resource/wordnet') || ?o = <http://www.w3.org/2002/07/owl#Thing>)
}}
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SELECT CONCAT(?s, "|", ?o) as ?row {GRAPH <http://yago3> {
?s owl:sameAs ?o.
FILTER(REGEX(?s, "http://yago-knowledge.org/resource") && REGEX(?o, "http://dbpedia.org/resource"))
}}
LIMIT 10
=============================================================================================
SELECT ?s {GRAPH <http://dbpedia.org> {
?s <http://xmlns.com/foaf/0.1/isPrimaryTopicOf> ?o.
{
SELECT IRI(?bind) as ?o {GRAPH <http://wikidata.org> {
?o <http://schema.org/about> <http://www.wikidata.org/entity/Q76>.
BIND(REPLACE(STR(?o), "https", "http") as ?bind)
FILTER(REGEX(?o, 'https://en.wikipedia.org/wiki'))
}}
}}}