human
Find buildings that do not have a number of units specified.
gpt
```sparql
PREFIX :    <http://example.org/ontology#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>

SELECT ?building
WHERE {
  ?building rdf:type :Building .
  FILTER NOT EXISTS {
    ?building :hasNumberOfUnits ?units .
  }
}
```