Hi!

I'm new in Semantics and using SPARQL as a query language.

I'm trying to execute a SELECT query into my sesame repository.
The simple version of my SELECT is working fine. The problem is adding the FILTER clause.

I want to get the most recent value of a set of Measures. This is a brief specification of my ontology...

Measure -hasValue- float
-hasDateTime- dateTime

Here is the query I'm trying to run:

.........
Prefixes
..........

" SELECT ?value"+
" WHERE {"+
" ?measure rdf:type ismed:Measure;"+
" ismed:hasValue ?value;"+
" ismed:hasDateTime ?dateTime ."+
" OPTIONAL {"+
" ?measure2 rdf:type ismed:Measure;"+
" ismed:hasDateTime ?dateTime2 ."+
" FILTER (?dateTime2 > ?dateTime) ."+
" }."+
" FILTER (!BOUND(?dateTime2)) ."+
" }";

Every time I execute this query get all the measure values stored in the repository, not just the most recent one.
Someone may help me with this??

Thank you so much!