PREFIX ocds: <http://data.tbfy.eu/ontology/ocds#>
PREFIX dct: <http://purl.org/dc/terms/>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX tbfy: <http://data.tbfy.eu/ontology/tbfy#>

SELECT ?qid ?qtitle ?qdescription ?qstatus ?releasepublisheddate
WHERE {
	?qid a ocds:Tender .
	OPTIONAL { ?qid dct:title ?qtitle } .
	OPTIONAL { ?qid dct:description ?qdescription } .
	OPTIONAL { ?qid ocds:tenderStatus ?qstatus } .
	OPTIONAL { ?contproc a ocds:ContractingProcess .
    ?contproc ocds:hasTender ?qid .
    ?contproc ocds:hasRelease ?release .
    ?release tbfy:releasePublishedDate ?releasepublisheddate ;
             tbfy:releaseURI ?releaseURI }.  
	FILTER ( ?status = xsd:string("_empty_") || regex( ?qstatus, ?status, "i") ) .
  FILTER ( ?title = xsd:string("_empty_") || regex( ?qtitle, ?title, "i") ) .
  FILTER ( ?description = xsd:string("_empty_") || regex( ?qdescription, ?description, "i") ) .
	FILTER ( ?start_dt = xsd:string("_empty_") || ?releasepublisheddate > ?start_dt ) .
	FILTER ( ?end_dt = xsd:string("_empty_") || ?releasepublisheddate < ?end_dt ) .
}