Count if with Multiple conditions

Hi,

I have 2 columns, A has names and B has yes or no in it.

I need to count the number of times a particular name appears in A where B=Yes.

I've tried every variation of CountIF I can think of and even tried sums with embedded IF's... nothing seems to work.

Any help is appreciated!!

=sumproduct((a$1:$a$100="name")*($b$1:$b$100="yes"))

Thats great! Works perfectly thanks.

Can I just ask why does multiplying the two conditions create the correct answer?