Why does this SPARQL query generate an error

Question

My ontology IRI is "http://mycompany.com/ontologies/quality". I want to find "Find all subjects with a given object property (hasSolution)"

SELECT ?subject
    WHERE { ?subject hasSolution <http://mycompany.com/ontologies/quality#Issue> } LIMIT 10

It caused this error message:

Caused by: org.openrdf.query.parser.sparql.ast.TokenMgrError: Lexical error at line 8, column 30.  Encountered: " " (32), after : "hasSolution"
    at org.openrdf.query.parser.sparql.ast.SyntaxTreeBuilderTokenManager.getNextToken(SyntaxTreeBuilderTokenManager.java:3499)
    at org.openrdf.query.parser.sparql.ast.SyntaxTreeBuilder.jj_ntk(SyntaxTreeBuilder.java:8861)

Answer 1

I suspect the issue here is how you've expressed your predicate - it should be in IRI form, either using angle-brackets like this:

SELECT ?subject
    WHERE { 
    ?subject <http://mycompany.com/ontologies/hasSolution> <http://mycompany.com/ontologies/quality#Issue> 
    } 
    LIMIT 10

Or, using the PREFIX statement to give you something like this:

PREFIX  mycoont:  <http://mycompany.com/ontologies/>
SELECT  ?subject
WHERE   
{ 
?subject mycoont:hasSolution <http://mycompany.com/ontologies/quality#Issue>
}
LIMIT 10

Or, more generally, if you don't know what the predicate IRI is exactly, you can make it part of a query:

    SELECT ?subject ?predicate
    WHERE { 
    ?subject ?predicate <http://mycompany.com/ontologies/quality#Issue> 
    } 
    LIMIT 10

And explore the results - the returned ?predicate values should be expressed as being full IRIs, or, depending on your query engine, as some form of prefix:suffix arrangement.

On exploring the results, you should just be able to copy-paste the appropriate value into the ?predicate triple of your WHERE clause, and remove the ?predicate triple from your SELECT clause.