| PREFIX : <http://example/> | |
| PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> | |
| PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> | |
| PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> | |
| # Variable spans block. | |
| SELECT ?v ?p | |
| WHERE | |
| { ?x :p ?v | |
| OPTIONAL | |
| { | |
| :x ?p ?x . | |
| FILTER regex(?v, "^A") | |
| } | |
| } |