Absence Fast Formula Code for null values

Summary

Absence Fast Formula Code for null values

Content

Hi Experts,

I am writing a fast formula where it has to consider 3 fields to validation.

One custom Attribute, Contract Type and Union Flag. There are multiple combinations where i have to write the FF. If the employee only having Custom Attribute and not having any values against Contract type and Union Flag. I m looking for the code when Contract type and Union flag is not populated any value then how to write the code in the Fast formula.

I used 'null' in the fast formula but it did not worked for me. I given the one which i used in FF.