[Tracker] Tracker-sparql queries

[John stacy <tracker indexer gmail com>]

Hello Team,

I am trying to construct few sparql queries for artist, album, genre information. I am able to fetch the information successfully. with the below queries 

UUID <--> FILE PATH <--> ARTIST NAME <--> ALBUM NAME <-->GENRE <--> BITRATE

tracker-sparql -q "SELECT ?x (SELECT nie:url(?url) {?x nie:isStoredAs ?url }) 
(SELECT nmm:artistName(?artist) { ?x nmm:performer ?artist } ) 
(SELECT nmm:albumTitle(?album) { ?x nmm:musicAlbum ?album } ) 
(SELECT ?genre { ?x nfo:genre ?genre } ) 
(SELECT ?title { ?x nie:title ?title } ) WHERE { ?x a nmm:MusicPiece }"



Now my question is I want to Fetch all albums or artists or Genre belongs to the files present in a particular folder or mountpath. 
How to do this? 

I am fetching the file names belongs to a particular folder with the below query.

tracker-sparql -q "SELECT ?uri nfo:fileName(?uri) WHERE {?uri a nmm:MusicPiece . ?uri nie:url ?url FILTER(fn:starts-with(?url, 'file:///home/JOHN)) }"

but unable to fetch the albums/artists/genre information for the files which are present on a particular folder or mountpath.

Can some one help me in framing the query? 

Thanks,
Prafulla