for $y in document('v-depts.xml')/departments/department
where
$y/deptno/date(@tend) >= date('1999-01-01') and
$y/deptno/date(@tstart) <= date('1999-01-01')
return (element department{$y/deptno, element counting{count(
for $x in document('v-emps.xml')/employees/employee
where
$x/deptno/text() = $y/deptno/text() and
$x/deptno/date(@tend) >= date('1999-01-01') and
$x/deptno/date(@tstart) <= date('1999-01-01')
return $x)}})