/*Write a query in SQL to display the first and last name, salary, and department ID for those employees whose salary is equal
 to the salary of the employee who works in that department which ID is 40.
*/

    SELECT first_name, last_name, salary, department_id   
     FROM employees  
      WHERE salary IN (  
                       SELECT salary   
                         FROM employees   
                           WHERE department_id = 40);