I have an Excel file listing 326k records representing 263k clients. When multiple records represent the same client, they have an identical rel_key. I've used COUNTD(rel_key) to get the accurate number of clients, but now I'm looking for the amount of checks deposited (checks_dep) by all of these clients, ignoring the duplicate records.
Logically, I would write this out as sum of checks_dep for only the first occurrence of each rel_key. How would I write that out in a Tableau formula?