I've got a formula that requires me to use the createddate of the previous entry in a field. I think I've determined in order to do this, I need to create a new field (PriorDate) that records this value. I've searched the documentation but haven't yet seen how to do this. It's not an aggregated field, so I don't think I can use prevgroupval. I'm not a salesforce developer, just a reports user, so I'm not sure if this would be more suited for a developer to tackle somewhere in the backend.
This simplified example in excel is what I'm aiming to do. For each case action sharing a parent case, I've created a sequencenum field that orders each case action. For sequencenum 1, the priordate field would be null, but for the rest, I'd want to take the createdDate value of the previous sibling and save it to priordate for the current value. I just need a way to reference the case action for sequencenum n-1, and I'm not finding an easy way to do that. Is this possible using a formula field? I've seen that a salesforce formula object can't reference a sibling directly within a formula, but I figured there must be a way if I assign it as its own object first.