Count unique value of a field but exclude specific value from the count

[PaReD_SF85]

I need to count the number of customers with unique values in one field while excluding a specific value at the same time.  I feel I am close but being new, I am missing something likely very simple.

Using the sample data,  I want to exclude '333' from the count of unique IDs per Customer.

Sample:

Customer	ID
a	666
a	666
a	333
b	111
b	222
c	111
c	111
c	222
c	333
Summary Counts I need:
a	1
b	2
c	2

Thank you for your help!

[QFabian · Accepted solution]

Hi @PaReD_SF85 , try this expression it uses some set analysis :

count({<ID -= {333} >} distinct ID)

[PaReD_SF85 · Accepted solution]

Thank you QFabian!  This works perfectly.