Average purchases by campaign

[debosul]

I have two tables with one to many relationship:

Table1: Sales:

Sales Id	Customer Id
9001	A
9002	B
9003	B
9004	A
9005	D
9006	E

Table2: Sales details:

Sales Id	Campaign Id
9001	C1
9001	C8
9002	C3
9002	C10
9002	C11
9003	C40
9004	C1
9004	C18
9005	C3
9006	C6
9006	C6
9006	C10

You should know that the column "Customer_Id" has blanks.

I want to calculate how many purchases a customer did by campaign. Any thoughts?
Thanks on advanced

[Whitewater100 · Accepted solution]

Hello: Here is the avg campaings/known customer. I hope this is what you are looking for.

https://drive.google.com/file/d/1VtPEjBK70Msz5hQcBtKZU4X9bl-eSQcT/view?usp=sharing 

[amitchandak]

@debosul , a measure like

AverageX(values(sales[customer ID]), calculate(count('sales details'[Campaign Id]) ) )

[debosul]

Thank you for your reply.

This is exactly what I'm after but I face a problem. The column "Customer ID" has blanks. I tried to replace "VALUES" with "DISTINCT" and "ALLNOBLANKROW" but it didn't solve it. Do you have any suggestion about this?

[amitchandak]

@debosul , replace null id's in power query with some value, that would be better