Sparql - 条件输出

Question

我是语义网和sparql的新手。我有一个内部本体，使用 SmartLogic 来管理数据。

我正在编写一些简单的查询来开始。

CalendarContract.Instances._ID
CalendarContract.Instances.EVENT_ID
CalendarContract.Instances.TITLE
CalendarContract.Instances.BEGIN
CalendarContract.Instances.END
CalendarContract.Instances.ALL_DAY
CalendarContract.Instances.DESCRIPTION
CalendarContract.Instances.EVENT_LOCATION
CalendarContract.Instances.EVENT_COLOR
CalendarContract.Instances.CALENDAR_COLOR
CalendarContract.Instances.OWNER_ACCOUNT
CalendarContract.Instances.VISIBLE
CalendarContract.Instances.CALENDAR_ID
CalendarContract.Reminders.EVENT_ID
CalendarContract.Reminders.MINUTES
CalendarContract.Reminders.METHOD
CalendarContract.Attendees.EVENT_ID
CalendarContract.Attendees.ATTENDEE_EMAIL
CalendarContract.Attendees.ATTENDEE_NAME
CalendarContract.Attendees.ATTENDEE_STATUS
CalendarContract.Attendees.ATTENDEE_RELATIONSHIP

此查询返回如下所示的结果：

我正在尝试合并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 字段，以便当且仅当有?o and ?oL字段

时才会替换?o字段

我还没有能够搞清楚。如果有任何建议请告诉我。

Answer 1

没有用于测试查询的数据有点困难，但在SPARQL 1.1中，您可以使用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