How many employees does each department have?
select count(departmentid) from department group by departmentid
Which department has the smallest number of employees?
select * from department group by departmentid order by count(departmentid) limit 1;
Tell me the name and position of the head of this department.
select t2.name, t2.position from department as t1 join physician as t2 on t1.head = t2.employeeid group by departmentid order by count(departmentid) limit 1;