I\'m looking to provide some summary stats for a data set and I want to list the different types of edge entities and node(vertex) entities in the graph.
For example:
You can use the UNION
clause to combine two patterns in conjunction with a FILTER
clause using the IsLiteral()
function to omit literals e.g.
SELECT DISTINCT ?vertex
WHERE
{
{
?vertex ?p []
}
UNION
{
[] ?p ?vertex
FILTER(!IsLiteral(?vertex))
}
}
The []
is an anonymous variable because you don't care about the some of the positions on either side of the UNION
so by giving them an anonymous variable we match any value but don't carry those values out in the query.
The FILTER
clause in the RHS of the union is used to filter out objects which are literals. It is not necessary to have this in the LHS because RDF forbids literal subjects so any ?vertex
value from the LHS must be a resource i.e. a URI/blank node