@prefix rr: <http://www.w3.org/ns/r2rml#> .
@prefix ex: <http://example.com/ns#> .

<#DeptTableView> rr:sqlQuery """
SELECT DEPTNO,
       DNAME,
       LOC,
       (SELECT COUNT(*) FROM EMP WHERE EMP.DEPTNO=DEPT.DEPTNO) AS STAFF
FROM DEPT
""".

<#TriplesMap2>
    rr:logicalTable <#DeptTableView>;
    rr:subjectMap [
        rr:template "http://data.example.com/department/{DEPTNO}";
        rr:class ex:Department;
    ];
    rr:predicateObjectMap [
        rr:predicate ex:name;
        rr:objectMap [ rr:column "DNAME" ];
    ];
    rr:predicateObjectMap [
        rr:predicate ex:location;
        rr:objectMap [ rr:column "LOC" ];
    ];
    rr:predicateObjectMap [
        rr:predicate ex:staff;
        rr:objectMap [ rr:column "STAFF" ];
    ].