human
Find all addresses, but return 'NO STREET' if :hasStreetName is missing.
gpt
```sparql
PREFIX :     <http://example.org/ontology#>
PREFIX rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#>

SELECT ?addr (COALESCE(?name, "NO STREET") AS ?street)
WHERE {
  ?addr rdf:type :Address .
  OPTIONAL { ?addr :hasStreetName ?name . }
}
```