Quick Q - I have to use this in the data load editor on a table that has about 15 other columns.
Meaning, I can only use your expression via a "Group By" clause correct ?
Do you know how that expression could be written in the data load editor without havintg to use the Group by Clause?
It's just guessing from your screenshot what do you want to do and I could imagine that you need something like this:
load Name, [Service Date], autonumber(Name &'|' & [Service Date]) as [Day #]
resident PreviousFromLoad order by Name, [Service Date];
left join (Table)
load Name, max([Service Date]) - min([Service Date]) as [Total Stay]
resident Table group by Name;
whereby it's important to sort (could be only applied by a resident-load) the data properly within the first load.