How to make the Rich Text Field Mandatory by a Validation Rule

If you want to make the Rich Text Field Mandatory in SFDC by a Validation rule then ISNULL, ISBLANK  functions will not work. You will require to use the LEN (Length) Function and make sure the validation rule looks like

                        IF LEN (Rich Text Field) == 0 then fire the Validation Rule

with this approach the validation rule will make sure the Rich Text field always has the value.

Business Case:- Make Other (Rich Text Field) Mandatory when the Reason (Picklist Field) is selected as Others.


Note:- ISNULL was previously used for the Numeric fields whereas Length function was used for Text field. Now ISBLANK is a new function which can be used for both the Text as well as the Number field.