ARQ - Sub Queries

ARQ includes support for nested SELECTs. This was previously an ARQ extension but is now legal SPARQL 1.1


A SELECT query can be placed inside a graph pattern to produce a table that is used within the outer query. A nested SELECT statement is enclosed in {} and is the only element in that group.

Example: find toys with more than five orders:

PREFIX : <http://example/>
  ?x a :Toy .
  { SELECT ?x ( count(?order) as ?q ) { ?x :order ?order } GROUP BY ?x }
  FILTER ( ?q > 5 )

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