Is the Amazon river longer than the Nile river?
You can also try this one against DBPedia…
PREFIX prop: <http://dbpedia.org/property/>
ASK
{
<http://dbpedia.org/resource/Amazon_River> prop:length ?amazon .
<http://dbpedia.org/resource/Nile> prop:length ?nile .
FILTER(?amazon > ?nile) .
}
The answer is: false.
Note: The WHERE keyword is optional–not only in ASK queries but in all SPARQL queries.
Does a triple with the given subject URI exist?
ASK { <http://example.org/carbon/ldp/main/people> ?p ?o> }
Returns true or false.
Does Fred have grandchildren?
PREFIX: <http://bedrock/>
ASK
WHERE { :fred :hasChild :?child . :?child :hasChild :?grandchild. }
Where :fred has any child, see if that child has any child identified by the placeholder, :?child, then use the value of that placeholder to ask whether or not that child itself also has a child, which will be the :?grandchild.