Analytical Function as combo Lead | Lag

 Write a query to show salary, last_salary, next_salary, difference between last vs current salary, cumulative sum of salary.

select salary, lag(salary,1,0) over (order by employee_id desc) lag_sal,

       lead(salary,1,0) over (order by employee_id desc) lead_sal,

       salary -lag(salary,1,salary) 

       over (order by employee_id desc) diff_last_vs_current,

       sum(salary) over (order by employee_id desc)cumulative_sum

       from employees;