Appending data to existing file and making sure rows have no duplicates

[DC21]

Hi

I run data off specific dates each time for a work flow.

e.g.

one run- jan month end 31/1

2nd run- feb month end 26/2

Each run currently goes to a file with the same name e.g ABC

and I choose the append option so it adds to the file each time I run

However, how can I ensure I don't append duplicate rows. So for example if I run

one run- jan month end 31/1

2nd run- jan month end 31/1

How do I ensure that my append doesn't duplicate the rows so i don't see Jan data twice?

[Qiu]

@DC21 
This issue looks simple but actually complicated one I believe.
So far I can think of is to have a time stamp stored in the output data, if allowed, with the function of "DateTimeToday".

Then use a Branching Tool to seperate the data by comparing last stored Time Stamp and current Run Time Stamp.

The Branching tool would be a macro.

https://community.alteryx.com/t5/Alteryx-Designer-Discussions/Conditional-branching-of-workflow/m-p/...