jena-sdb/testing/Algebra/two-nested-opt.rq - jena - Git at Google

 PREFIX :    <http://example/>

 SELECT *
 {
     :x1 :p ?v .
 ##    FILTER( ?v = 1 )
     OPTIONAL
     {
       :x3 :q ?w .
       OPTIONAL { :x2 :p ?v }
     }
 }
	PREFIX : <http://example/>

	SELECT *
	{
	:x1 :p ?v .
	## FILTER( ?v = 1 )
	OPTIONAL
	{
	:x3 :q ?w .
	OPTIONAL { :x2 :p ?v }
	}
	}