query: SELECT ?Org ?OrgLabel ?StockExchange ?StockExchangeLabel ?Ceo ?CeoLabel ?Subsidiary ?SubsidiaryLabel ?SubsidiaryCEO ?SubsidiaryCEOLabel ?Ticker
  WHERE {
    ?Org p:P414 ?SE . # look for an entity with a "stock exchange" statement
    ?SE ps:P414 ?StockExchange . # of which we get the value
    ?SE pq:P249 ?Ticker . # and the "ticker symbol" qualifier
    # Add new fields
    ?Org wdt:P169 ?Ceo .        # Entity has Ceo
    ?Org wdt:P355 ?Subsidiary . # Entity has Subsidiary
    ?Subsidiary wdt:P169 ?SubsidiaryCEO . # no OPTIONAL means that bit is mandatory
    FILTER(?Ticker="BA") . #and we restrict the value of that qualifier to "FB"
    SERVICE wikibase:label {
      bd:serviceParam wikibase:language "en" .
    }
  }