Assign integer value based on customer email + date

Question

Context: I have 2 columns of data: Col 1: date Col 2: customer email address

The same customer orders multiple times on different days

Problem: I want to understand how to assign based on date, and customer email address, whether it's their first time, second time etc.

I have not figure it out and looking for some help :)

Thanks a lot!

Example spreadsheet:

https://docs.google.com/spreadsheets/d/1LE7hO0ot22N1R-i35cDqG8OWDlZg2x1gE_kCHGdyruA/edit#gid=0

Answer 1

What I tried is to make a running count using COUNTIFS():

Formula in E2:

=INDEX(IF(B2:B="","",COUNTIFS(C2:C,C2:C,B2:B,"<="&B2:B)))