I'm trying to calculate the date difference from one row to the next but I would like to group it according to its unique key but its not keeping it within the unique key group.
Eg. =iif(previous(Fields!action_date.Value) is nothing, nothing, datediff(“d”,previous(Fields!action_date.Value), Fields!action_date.Value))
it works well for items with the unique key group but if that row is below another record group it will pull values from the date value prior to it.