# filename: ex207.rq

PREFIX dm:  <http://learningsparql.com/ns/demo#> 
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

CONSTRUCT
{
  ?item dm:problem dm:prob44 .
  dm:prob44 rdfs:label "Expenditures over 100 require grade 5 approval." . 
}

WHERE
{
  ?item dm:cost ?cost ;
        dm:amount ?amount .
  OPTIONAL 
  {
    ?item dm:approval ?approvingEmployee . 
    ?approvingEmployee dm:jobGrade ?grade . 
  }

  BIND (?cost * ?amount AS ?totalCost) .
  FILTER ((?totalCost > 100) &&
          ( (!(bound(?grade)) || (?grade < 5 ) )))   
}