2 answers
Hi L G,
You will need to do the below
Create a custom Date or Datetime field on the Case Object (Date field if you want to calculate the time in Days, Date/Time field if you want to calculate the time either in Days, Hours, Minutes )
Create a Workflow to update this field when the Support Engineer is assigned to the field
as part of immediate actions update the Date field with the Date or DatetimeCreate a custom formula field of return type number and the formula will be
Custom_Date_Time_Field__c - CreatedDate
if your custom field is Date field the formula will be
Custom_Date_Field__c - DATEVALUE(CreatedDate)
Workflow Setup:
Evaluation Criteria: Created and anytime its subsequently edited to meet the Criteria (3rd Option)Rule Criteria: formula evaluates to True and formula is
NOT(ISBLANK(Support_Engineer__c))
Immediate Action: Field Update
Field to Update: Custom Date or DateTime field
use formula to set the new value and the formula isIf its Date field
TODAY()
if its Date Time field
NOW()
Save,Done and Activate the Workflow rule