Sparql - Conditional Output - sparql

Question

I am very new to the semantic web and sparql. I have an internal ontology that uses SmartLogic in order to manage the data.
I am writing some simple queries to get started.
PREFIX skos: <http://www.w3.org/2004/02/skos/core#> # Simple Knowledge Organization System - https://www.w3.org/2004/02/skos/
PREFIX skosxl: <http://www.w3.org/2008/05/skos-xl#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <https://www.w3.org/TR/rdf-schema/>
prefix owl: <http://www.w3.org/2002/07/owl#>
prefix ap: <http://cv.ap.org/ns>
SELECT DISTINCT
?subjectPrefLabel ?p ?o ?oL
WHERE {
{
?subject skosxl:prefLabel ?subjectLabel .
?subjectLabel skosxl:literalForm ?subjectPrefLabel .
?subject ?p ?o .
OPTIONAL {?o skos:prefLabel ?oL}
}
FILTER regex(?subjectPrefLabel, "Trump", 'i')
} order by ?subjectPrefLabel
This query returns results that look like :
I am trying to merge the ?o and ?oL fields, so that it will replace the ?o field, if and only if there is a valid ?oL Field
I haven't been able to figure it out quite yet. If there is any suggestions please let me know.

Answer 1

A bit difficult without data for testing the query, but in SPARQL 1.1 you can use BIND(IF(condition,then,else) as ?result ):
PREFIX skosxl: <http://www.w3.org/2008/05/skos-xl#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX rdfs: <https://www.w3.org/TR/rdf-schema/>
PREFIX ap: <http://cv.ap.org/ns>
SELECT DISTINCT ?subjectPrefLabel ?p ?o
WHERE
{ ?subject skosxl:prefLabel ?subjectLabel .
?subjectLabel
skosxl:literalForm ?subjectPrefLabel .
?subject ?p ?o_tmp
OPTIONAL
{ ?o_tmp skos:prefLabel ?oL }
BIND(if(bound(?oL), ?oL, ?o_tmp) AS ?o)
FILTER regex(?subjectPrefLabel, "Trump", "i")
}
ORDER BY ?subjectPrefLabel