# filename: ex202.rq

PREFIX dm:  <http://learningsparql.com/ns/demo#> 

ASK 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 ) )))   
}