Count unique values if adjacent cell meets criteria

Hi all,

I need a little help with perfecting my formula. In the picture below, I need a formula in column E to count the unique occurrences in column A (excluding blanks) if its corresponding value in column B (B1 value) matches that in column D (B2 value). Currently column E is showing the values I would want the formula to return.
Capture.PNG

At the moment I have a formula as below:

=SUMPRODUCT(--(B:B=$D2),--(A:A<>""))

this will do a countif in column A if column B matches the value in column D, but would not weed out duplicates for me.

I need some help modifying my formula, or ideas on a solution. I have attached the sample workbook below for your convenience.

Book1.xlsx

Any help is very much appreciated in advance.

Many thanks.

Not sure if your results are as per expectation

There are 4 unique values for 666 and 2 for 777

Try
=SUMPRODUCT(($B$2:$B$10=D2)/COUNTIFS($A$2:$A$10,$A$2:$A$10&"",$B$2:$B$10,$B$2:$B$10&""))

Try

=SUMPRODUCT(($A$2:$A$10<>"")*($B$2:$B$10=D2)/COUNTIFS($A$2:$A$10,$A$2:$A$10&"",$B$2:$B$10,$B$2:$B$10&""))

It ensures the blank cells do not give you a #DIV/0 error

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