sparql - 如何从查询结果

Question

PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX base: <http://www.cs7is1.com/ireland-school-county#>

SELECT ((COUNT(?school))/?a AS ?density) 
WHERE {
 ?school base:inCounty base:DUBLIN.
  base:area ?a
}
GROUP BY ?a

我运行此查询，查询很好，但我得到的结果是这样的

"0.47776812"^^<http://www.w3.org/2001/XMLSchema#float>

我想删除XML内容，我试图绑定它不起作用