Discussions posts details returned as an RDF Graph

PREFIX sioc: <http://rdfs.org/sioc/ns#>
PREFIX sioct: <http://rdfs.org/sioc/types#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX dcterms: <http://purl.org/dc/terms/>
CONSTRUCT
{
  ?post dcterms:created ?created .
  ?post sioc:link ?link .
  ?post sioc:title ?title .
}
WHERE
  {
    ?forum a sioct:Discussion  .
    ?post sioc:has_container ?forum .
    OPTIONAL{ ?post dcterms:created ?created } .
    OPTIONAL{ ?post sioc:link ?link } .
    OPTIONAL{ ?post sioc:title ?title }
  }