two-nested-opt-alt.rq

来自「jena2.5.4推理机系统的一种最基本实现 HP实验室出品」· RQ 代码 · 共 11 行

PREFIX :    <http://example/>

## The nested optional example, rewritten to a form that is the same
## for the SPARQL algebra and the declarative semantics.
SELECT *
{ 
    :x1 :p ?v .
    OPTIONAL { :x3 :q ?w }
    OPTIONAL { :x3 :q ?w  . :x2 :p ?v }
}