Validate or Compair two Fields of SharePoint list Using Formula.(SharePoint 2010)

Introduction: This post, I’ll give some simple examples of how you might validate two date inputs by using formula,

For this example, I’m using two list fields Project Start Date and Project End Date, i want to ensure that project start date must be less or equal to project End date.

Procedure:

1. Create 1 sample List as with below fields:
   
   
   
   
2. Then Go to List Setting->Validation settings then set the formula,Give your custom error message and click on save ,
   
   button as like below image:
   
   
   
   
3. Now see validation result here :