[Virtuoso-users] SPARQL sub-query to return a single result

[Sebastian Trüg]

Hi list,

in a query like this:

select distinct ?r where {
     graph ?g {
         ?r nie:url ?url .
     }  .
     ?g nao:maintainedBy ?app .
     ?app nao:identifier "nepomukindexer" .
}

I would like to use a sub-query to replace ?app since there is only
exactly one resource which has this identifier. The simplest possibility
is to use two queries and cache the resource URI of the app in the
client. But I figure there could be a fancy sub-query which allowed me
to query the app in-place.

Is that possible?

Cheers,
Sebastian