PREFIX  rdf:    <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX  :       <http://example/>
PREFIX  dc:     <http://purl.org/dc/elements/1.1/>

SELECT * # ?p ( 2*count(distinct ?t) AS ?cd) 
{
    # :x2 has :p = 2 so UNION is asymmetric in what it generates
    { ?x rdf:type :X . } UNION { ?x rdf:type :X . FILTER (?x != :x2 )}
    ?x rdf:type ?t .
    OPTIONAL { ?x :p ?p . }
    OPTIONAL { ?x :r ?r . }
}
GROUP BY ?p (1/?p AS ?q)
#HAVING (count(*) > 1)
## # ORDER BY ?q ?count