Trying to create a loop in SQL to count every time the agent Id shows up in different month it would count one more than the previous month

Question

I'm trying to create a count where every time Agent Id shows up it would count one more than the previous month.

Image of end state:

Answer 1

You seem to be looking for row_number() :

select t.*, row_number() over(partition by name order by d_month desc) cnt
from mytable t