Adding Column to Mark Most Recent Record w/o selecting or dropping records

[cmccranie21]

I have a file of records of agents and dates of meetings. The dataset can have multiple records per agent and I want to add a column that marks the date per agent as either Most Recent Or Past Observation. I've already sorted by Agent (Ascending) and Date (Descending). I have seen others use the Sample tool to select the most recent but I don't want to narrow/eliminate any results, just mark the most recent in a column while leaving all other records in tact.

What is the best way to mark the most recent record in a new column without selecting only those results or dropping any results like the Sample tool would do?

[aatalai]

@cmccranie21 

Instead of the sample try the multi row formula tool 

with if [agent:row] = [agent:row-1] then null() else "mark" endif

and this will be a new columns.

@cmccranie21 let me know if this helps