If you want to query a complete dataset with a single construct query.

dataset-construct-literal.sparql

PREFIX ex: <http://example.org/>

CONSTRUCT {
  ?s ?p ?o .
  ?g a ex:Graph ;
     ex:hasData ?datalit .
} WHERE {
  {
  	?s ?p ?o .
  } UNION {
    GRAPH ?g {
      ?gs ?gp ?go
      BIND(CONCAT("<", STR(?gs), "> <", STR(?gp), "> <", STR(?go), "> .") as ?datalit)
    }
  }
}

dataset-construct-reification.sparql

PREFIX ex: <http://example.org/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>

CONSTRUCT {
  ?s ?p ?o .
  ?g a ex:Graph ;
     ex:hasData [ a rdf:Statement ;
                    rdf:subject ?gs ;
                    rdf:predicate ?gp ;
                    rdf:object ?go ] .
} WHERE {
  {
    ?s ?p ?o .
  } UNION {
    GRAPH ?g {
      ?gs ?gp ?go
    }
  }
}