Count based on dates

[M_SBS_6]

Hi, I need to add some totals to a table based on dates. 

I have the following table

ID.     Cust.    Date_sent

1.   Kevin. 20/08/2024
2.   Barry.  20/08/2024
3.   Louise 21/08/2024

What I need is another column to see how many letters have been sent out within 6 months post and including today from date_sent.

The other column fields needed would be resp_date (the 6 month period) and count of resp_ID

So my table would look something like

ID.     Cust.    Date_sent.    Lettervol

1.   Kevin.  20/08/2024.     2
2.   Barry.  20/08/2024.     1
3.   Louise 21/08/2024.     7

Any idea what measure to use please?

[vojtechsima · Accepted solution]

Hello, @M_SBS_6 ,

given you want physical column, perhaps you can do it in DAX, even tho I would recommend having this as a measure.

the dim table:

lettervol = 
CALCULATE(
    COUNTROWS('fact'),
    DATESINPERIOD('calendar'[Date], dim[Date_sent],-6,MONTH)
)

fact:

Calendar is extra, I recommend having it as well.