flagging unique values based on specific date ranges

System

This discussion was created from comments split from: count distinct function in combination with Countifs?.

Hamid

Completely off the mark in my opinion...

I have a similar scenario where I have a main sheet with all the information with dates ranging a couple of years. I am interested in flagging only unique values in a given column based on specific date ranges.

For example: a list of customers (column A), a list of purchased items (column B), dates of pusrchase (column C) + other columns containing various information.

In the same sheet, I would like to flag unique customer names in a given month + flag unique items purchased in a given month, etc...

This is simple enough in excel but I can;t figure out how to do in Smartsheet... and unfortunately I am stuck with Smarsheet as I have a form feeding into the sheet, etc.