Obviously we can use Deluge script in custom function to calculate the age or difference between two date- But to trigger custom function we need to have ‘when event’. Instead of using workflow rules/custom function simply we can use formula field to show the calculated value all time. Lets see- how we can do this:
Consider a scenario where we want to know – how many days since the client(Patient) started treatment? Just use following formula for a formula field.
Datecomp(Now(),${Clients.Treatment Start Date})/60/24
And done!