Calculate the average age of employee in each department and state which department has the youngest employees.
Average = Divide(Sum(Substract(year(@today),year(BirthDate))),Count(BusinessEntityID) by each Department ID; youngest employee refers to Min(BirthDate);
SELECT STRFTIME('%Y', CURRENT_TIMESTAMP) - STRFTIME('%Y', T1.BirthDate) + 1 , T3.Name FROM Employee AS T1 INNER JOIN EmployeeDepartmentHistory AS T2 USING (BusinessEntityID) INNER JOIN Department AS T3 USING (DepartmentID) ORDER BY T1.BirthDate DESC LIMIT 1