What is the correct way to select all data (quads) from the triplestore that is composed of triples and quads?

[nguyenm100]

Wondering if I'm missing something here. I'm trying to retrieve all triples and quads from my 3s.

I have a data-set of 2 triples (quads):

<http://example.com/matt><http://example.com/knows><http://example.com/sara> .
<http://example.com/matt><http://example.com/knows><http://example.com/sara><http://example.com/graph1>.

I'd like a query that selects these 2 triples inclusive of graphname.

I've tried:

1. select * where {?s ?p ?o} which gives me:

<http://example.com/matt><http://example.com/knows><http://example.com/sara> 
<http://example.com/matt><http://example.com/knows><http://example.com/sara>

but I want the graphname.

2. select * where {{?s ?p ?o} union {graph ?g {?s ?p ?o}}} which gives me:

<http://example.com/matt> <http://example.com/knows> <http://example.com/sara>  
<http://example.com/matt> <http://example.com/knows> <http://example.com/sara>   
<http://example.com/matt> <http://example.com/knows> <http://example.com/sara> <http://example.com/graph1>

has an extra "sara" triple.

3. from rdf4j (

   rdf4j/core/repository/sparql/src/main/java/org/eclipse/rdf4j/repository/sparql/SPARQLConnection.java

   Line 90 in b33d914

   private static final String EVERYTHING_WITH_GRAPH = "SELECT * WHERE { ?s ?p ?o . OPTIONAL { GRAPH ?ctx { ?s ?p ?o } } }";

   )
   SELECT * WHERE { ?s ?p ?o . OPTIONAL { GRAPH ?ctx { ?s ?p ?o } } } which gives me:

<http://example.com/matt> <http://example.com/knows> <http://example.com/sara> <http://example.com/graph1>
<http://example.com/matt> <http://example.com/knows> <http://example.com/sara> <http://example.com/graph1>

is this a bug?

4. Bob Ducharme recommends (https://www.bobdc.com/blog/selectingall/):
   SELECT ?g ?s ?p ?o
   WHERE
   {
   { ?s ?p ?o
   MINUS { GRAPH ?g {?s ?p ?o} }
   }
   UNION
   { GRAPH ?g { ?s ?p ?o } }
   }

gives me:

<http://example.com/graph1> <http://example.com/matt> <http://example.com/knows> <http://example.com/sara>

??

5. The only one that works is:

SELECT distinct ?s ?p ?o ?g
WHERE
{
{ ?s ?p ?o }
UNION
{ GRAPH ?g { ?s ?p ?o } }
}

<http://example.com/matt> <http://example.com/knows> <http://example.com/sara>
<http://example.com/matt> <http://example.com/knows> <http://example.com/sara> <http://example.com/graph1>

[hmottestad]

Try to do two unions with named graph. The first with ?g and the second with the hardcoded <http://rdf4j.org/schema/rdf4j#nil> to represent the unnamed graph.