Conditionnal formatting in two columns

Question

I am looking for information about conditional formatting in Google Sheets. I would like to put the cell in column L in red if it exists twice AND if the data in the same row in column K is the same.

By searching on the internet, I found how to put the cell in red if it exists more than once but I don't see how to add in addition a check on the K column ( =NB.SI($L2:$L;$L2)>1 ).

Below is a screenshot of my Sheets file.

You can see that the cells turn red and the data in the K columns are different.

Could you help me with this please? I am not comfortable with conditional formatting at all.

Answer 1

Try this formula in conditional formatting setting

=if(COUNTIF(L:L,L1)>1,countif(K:K,K1)>1)