Only Count Customer buy selected products

[#1]

Dear All

I want to count only customer buy selected products

Here my sample dada

CUS_NAME	PRODUCT
John	A
John	B
Peter	D
Ken	A
Ken	C
Ken	D
Tony	A
Tony	B
Tony	C
Mary	B
Lisa	D

here is result I expected

if i chose PRODUCT = D, the result count customer = 2 (Peter and lisa), because Peter and lisa buy only product 'D' (Ken also buy D product but also bought A and B should not be counted)

if i chose Product =A and B, the result count customer = 1 (John) because John just buy two products A and B (Tony also bought one more product 'D' should not be counted)

I don't know how to do, please help me if possible

regards

An Pham

[#2]

Dear All

I found this thread Count customer that only buy one product

It solved my issue

Tks