Hello

I just try to analyze how the uniue formula works which I got on an
internet page i.e.
=SUMPRODUCT((1/COUNTIF(A1:A5;A1:A5&"")))

This counts all unique entries in A1:A5. But how deos the
COUNTIF(A1:A5;A1:A5&"") work here? Interesting is the criteria part. A
range as criteria? I Can anybody tell me what this criteria and
especially the '&""' does here?

Thanks
Mark Egloff