How to clear graphs which are related to empty graphs? The following example demonstrates how to remove graphs which are related to empty graphs: PREFIX nrl:<http://www.semanticdesktop.org/ontologies/2007/08/15/nrl#> SELECT ( bif:exec(bif:sprintf("SPARQL CLEAR GRAPH<%s>", str(?mg)))) WHERE { ?mg nrl:coreGraphMetadataFor ?g . FILTER(?g in ( <urn:nepomuk:local:8a9e692a> )) . FILTER ( !bif:exists((SELECT (1) WHERE { GRAPH ?g { ?s ?p ?o . } . })) ) . } Related Virtuoso Tips and Tricks Collection