query: SELECT 
     (wd:Q847 as ?item) 
     (SAMPLE(?a) as ?sample) 
     (COUNT(DISTINCT ?a) as ?ct)
     (wd:Q7700500 as ?type)
  ("0 A" as ?level)
  ("tennis tour AKA tennis circuit" as ?descr)
  WHERE
     { ?a (wdt:P31