ARQ - SELECT Expressions

The SELECT statement of a query can include expressions, not just variables. This was previously a SPARQL extension but is now legal SPARQL 1.1

Expressions are enclosed in () and can be optionally named using AS. If no name is given, and internal name is allocated which may not be a legal SPARQL variable name. In order to make results portable in the SPARQL Query Results XML Format, the application must specify the name so using AS is strongly encouraged.

Expressions can involve group aggregations.

Expressions that do not correctly evaluate result in an unbound variable in the results.  That is, the illegal expression is silently skipped.


PREFIX : <http://example/>

SELECT (?p+1 AS ?q)
  :x :p ?p


PREFIX rdf: <>
PREFIX :    <http://example/>

SELECT (count(*) AS ?count)
  :x rdf:type :Class

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