Find max and second max salary for a employee table MySQL

Question

Suppose that you are given the following simple database table called Employee that has 2 columns named Employee ID and Salary:

  Employee
  Employee ID    S         


        

Answer 1

You can write SQL query in any of your favorite database e.g. MySQL, Microsoft SQL Server or Oracle. You can also use database specific feature e.g. TOP, LIMIT or ROW_NUMBER to write SQL query, but you must also provide a generic solution which should work on all database. In fact, there are several ways to find second highest salary and you must know a couple of them e.g. in MySQL without using the LIMIT keyword, in SQL Server without using TOP and in Oracle without using RANK and ROWNUM.

Generic SQL query:

SELECT
    MAX(salary)
FROM
    Employee
WHERE
    Salary NOT IN (
        SELECT
            Max(Salary)
        FROM
            Employee
    );

Another solution which uses sub query instead of NOT IN clause. It uses < operator.

SELECT
    MAX(Salary)
FROM
    Employee
WHERE
    Salary < (
        SELECT
            Max(Salary)
        FROM
            Employee
    );