SPARQL query and distinct count

Question

I have the following query:

SELECT ?tag WHERE {
  ?r ns9:taggedWithTag ?tagresource.
  ?tagresource ns9:name ?tag
}
LIM         


        

Answer 1

If you're using Java and Jena's ARQ, you can use ARQ's extensions for aggregates. Your query would look something like:

SELECT ?tag (count(distinct ?tag) as ?count)
WHERE {
    ?r ns9:taggedWithTag ?tagresource.
    ?tagresource ns9:name ?tag
}
LIMIT 5000

The original SPARQL specification from 2008 didn't include aggregates, but the current version, 1.1, from 2013 does.