Writing SQL query for getting maximum occurrence of a value in a column

Question

I have an emp table with the records below:

INSERT into emp(EmpId,Emp name, Manager)
Values(1,A,M1)
values(2,B,M1)
values(3,C,M2)
values(4,D,M3)         


        

Answer 1

SELECT
    count(e.last_name) count,
    d.last_name
FROM
    employees e
LEFT OUTER JOIN employees d ON e.manager_id = d.employee_id
GROUP BY
    d.last_name
ORDER BY
    count DESC;