Sparql use filter with selecting invidual

Question

I want to retrieve all movies that actor play in. I'm not sure how to specify for which actor(individual in protege) I want results. Below code returns empty table.

PREFIX f: <http://imdb.com/movie.owl#>

SELECT ?title
WHERE {
    ?movie a f:Movie .
    ?movie f:Title ?title .
    ?actor a f:Actor .
    ?actor f:playsIn ?movie .
    FILTER(?actor = "Actor_1")
}

Answer 1

OWL individuals are identified by IRIs, thus, you have to use the full or prefixed IRI in the query and not a string literal:

PREFIX f: <http://imdb.com/movie.owl#>

SELECT ?title
WHERE {
    ?movie a f:Movie .
    ?movie f:Title ?title .
    ?actor a f:Actor .
    ?actor f:playsIn ?movie .
    FILTER(?actor = <http://imdb.com/movie.owl#Actor_1>)
}

Update

As @Joshua Taylor correctly pointed out, if SPARQL 1.1 is supported you should use the VALUES feature which is probably more what is intended here compared to a FILTER:

PREFIX f: <http://imdb.com/movie.owl#>

SELECT ?title
WHERE {
    VALUES ?actor { f:Actor_1 }
    ?movie a f:Movie ;
           f:Title ?title .
    ?actor a f:Actor ;
           f:playsIn ?movie .

}