How to make query on two different ontologies?

Question

I have two different ontologies: one for movie genre and another for movie certification. I want to write a query in SPARQL that can find those movies having certification x (say PG-13) and genre y (say action). Both ontologies are different and I upload them in Apache Jena.

These are my ontologies:

PREFIX o2: <http://www.semanticweb.org/administrator/ontologies/2016/11/genre_ontology#>
PREFIX o1: <http://www.semanticweb.org/administrator/ontologies/2016/11/certification_ontology#>

I want to find movies having genre and certification. my query is

SELECT ?x ?z
WHERE {
    ?x o1:hasCertificationOf ?y.
   ?z o2:hasGenre ?a.

  FILTER regex(str(?y),"R_") FILTER regex (str(?a),"Adventure")
} 

here R is Restricted certification

Query result contain movies in x and z, but i only want common movie in x and z?

Answer 1

You should always try to provide a minimal example along with your question.

You might want to look at Multiple triple patterns:

?s cert:level cert:PG13 .  
?s genres:genre genres:Action . 

As you see, we use two namespaces (for 2 ontologies). You can reference them like this (before your SPARQL query):

PREFIX cert: <http://example.com/cert/1.0/>
PREFIX genres: <http://example.com/genres/1.0/>

Final query might look like this:

PREFIX cert: <http://example.com/cert/1.0/>
PREFIX genres: <http://example.com/genres/1.0/>

SELECT ?s ?p ?o
WHERE {
    ?s ?p ?o .
    ?s cert:level cert:PG13 .
    ?s genres:genre genres:Action .
}

NB: in order to apply multiple graph patterns in a single query, you must use the same variable in those patterns (?s in the last 2 graph patters).

I have no affiliation to the authors, but I think you might benefit from taking https://www.futurelearn.com/courses/linked-data.