(aql-query
   ( select "s1" ( property any "root" subject ) )
   ( select "p1" ( property any "root" predicate ) )

   ( select "s2" ( property any "left1" subject ) )
   ( select "p2" ( property any "left1" predicate ) )

   (join left ("left1") (comp-eq (property any "root" object) (property any "left1" subject)))
)
