define function employeeIn ($deptno, $ts, $te) {
  if (date($ts) <= date('2002-03-24')) then (
    for $x in document('v-emps.xml')/employees/employee
    where
      $x/deptno/text() = $deptno and
      (($x/deptno/date(@tstart) >= date('2002-03-24') and
        $x/deptno/date(@tstart) <= date($te)) or
       ($x/deptno/date(@tend) >= date('2002-03-24') and
        $x/deptno/date(@tend) <= date($te)) or
       ($x/deptno/date(@tend) >= date($te) and
        $x/deptno/date(@tstart) <= date('2002-03-24')))
    return $x
  ) else (
    for $x in document('v-emps.xml')/employees/employee
    where
      $x/deptno/text() = $deptno and
      (($x/deptno/date(@tstart) >= date($ts) and
        $x/deptno/date(@tstart) <= date($te)) or
       ($x/deptno/date(@tend) >= date($ts) and
        $x/deptno/date(@tend) <= date($te)) or
       ($x/deptno/date(@tend) >= date($te) and
        $x/deptno/date(@tstart) <= date($ts)))
    return $x
  )
}
for $y in document('v-depts.xml')/departments/department/mgrno
where
$y/date(@tstart) >= date('2002-03-24') or
($y/date(@tstart) <= date('2002-03-24') and
 $y/date(@tend) >= date('2002-03-24'))
return(
  element manager{
      $y,
      element counting{count(employeeIn($y/../deptno/text(),$y/@tstart,$y/@tend))}
  }
)