MySQL計算眾數(只回傳一筆，非平均)

select employee.dno, employee.Salary
from employee
inner join(
        select dno, max(Cou) as MaxCount
        from(
                select dno, count(*) as Cou
                from employee
                group by dno, Salary
                ) A
        group by dno
        ) B on employee.dno = B.dno
group by employee.dno, employee.Salary, B.MaxCount
having count(*) = B.MaxCount