Windows Functions - LAG() And LEAD()

In this article, I am going to discuss the other Windows Functions such as Lead, Lag, First_Value and Last_Value. These functions also work on the Window or Grouped Row Data Set or Partition created by Windows Functions in the T-SQL. For a better understanding I kindly request you to please read the previous article, mentioned above and then read this one.

source https://www.c-sharpcorner.com/article/windows-function-lag-and-lead/