Formula Operators and Functions
BLANKVALUE(expression, substitute_expression) and replace expression with the expression you want evaluated; replace substitute_expression with the value you want to replace any blank values.
This formula returns the value of the Department field if the Department field contains a value. If the Department field is empty, this formula returns the word Undesignated.
(BLANKVALUE(Payment_Due_Date__c, StartDate +5)
This formula returns the date five days after the contract start date whenever Payment Due Date is blank. Payment Due Date is a custom date field.
Determines if an expression has a value and returns TRUE if it does not. If it contains a value, this function returns FALSE.
Determines if an expression is null (blank) and returns TRUE if it is. If it contains a value, this function returns FALSE.
Use ISBLANK instead of ISNULL in new formulas. ISBLANK has the same functionality as ISNULL, but also supports text fields. Salesforce is continuing to support ISNULL, so you do not need to change any existing formulas.