Thanks Stefi for your quick reply but I don't understand your formula
completely. Maybe my question wasn't clear enough.
I have a large dataset (over 20,000 rows) with monthly performance of
certain companies.
column A is the date (A1-A12 january-december for company 1; A13-A24
january-december for company 2 etc.)
Column B is the company name(B1-b12 company 1; B13-B24 company 2 etc.)
Column C is the monthly performance.

Some companies only reported performance for the months (e.g.) March till
december. I want to exclude those companies that didn't report performance
during a whole year.
You said that I must choose an unused helper column, say D, but what formula
do I need to type exactly for that whole column?

I hope you can help me one more time

thanks and regards,

Bram

"Stefi" wrote:

Choose an unused helper column, say C, in C1 enter =COUNTIF(A:A,A1), then
apply autofilter in column C and click value 12.

regards,
Stefi

"Bram" wrote:

I have a large dataset of the monthly performance of certain companies.
example
a1:a12 contain January till december of company A
a13:a24 contain January till decmber of company B

Some companies only have data from March till december. How can I filter
these companies out of the dataset.

So I only want companies included that reported performance for a whole year

Thanks!!