for your second equation, you should have two results 1s and 0s
the 1s shoul dbe bothe the first duplicate and the unique records
are yoiu using autofilter to then select what you want or what are you doing
after you have applied the euation.

you could also use advanced filter to select a unique lis of serial numbers
and then use Vlookup t select the first instancwe of match.

"Gerry Verschuuren" wrote:

I am trying to use a computed/calculated filter for a list of records sorted
by the first column. The first column has SSNumbers with multiple duplicates.
I want to filter for just the first SSNs of those duplicates - so a unique
list of SSN and what comes with that record.

This is what I came up with:
1. =$A2<$A1 or =$A2<$A3 (but this leaves either the first or the last
unique entry out).
2. =COUNTIF(SA$2:A2,A2)=1 (but then I get all the first duplicates together,
and no other records).

What should I have done instead?

Thanks so much for your solution.

Gerry