The sparql markup allows to execute a query on the ontology repository. The result of the query will be rendered into the wiki page (instead of the query).
%%sparql...
The sparql markup allows full support of the SPARQL 1.1. query language specification, which can be found here: http://www.w3.org/TR/sparql11-query/
The following simple example shows a query selecting all instances of the class Person: