Distinct COUNTIF in Filtered Table

[torkaman]

I have the below table in Excel with 3 columns. I need to do a distinct count for type 1 and type 2 on the SN column with the filter working. Duplicate values are in Red, they shouldn't be counted two times and just count visible cells in the table.

in the below screenshot, the Class A filter is applied:

in the below screenshot, the Class B filter is applied:

 

[Fluff]

Hi & welcome to MrExcel.
For type 1 how about

=IFERROR(ROWS(UNIQUE(FILTER(Table2[SN],(Table2[Type]=1)*(BYROW(Table2[Type],LAMBDA(br,SUBTOTAL(3,br)))=1)))),0)

 

[torkaman]

Hi & welcome to MrExcel.
For type 1 how about

=IFERROR(ROWS(UNIQUE(FILTER(Table2[SN],(Table2[Type]=1)*(BYROW(Table2[Type],LAMBDA(br,SUBTOTAL(3,br)))=1)))),0)

You're AWSOME!!!
It works perfectly. I didn't know about the LAMBDA function at all.
I was wondering if you could walk me through the calculation.

 

[Fluff]

The BYROW effectively "loops" through the range one row at a time & the SUBTOTAL returns either 1 or 0 depending on whether that row is visible or not.