Compare 2 Columns, if they are the same, display the text from a 3rd column

Hi,

I have a problem. I would like to update some old ID with new ID and
new names.

I have 3 columns at the moment, Say ColA is the old ID numbers, Col C
is new ID numbers and Col B are names of the new ID numbers

I want to check if the ID numbers in Col A is equal to Col C. If this
is the case, I want to display the relevant names in Col B.
otherwise, display 0.

Can i do a conditional formatting where if A1=C1, display B1? otherwise
zero?

But ColB and ColC are relevant to each other, how can i do that?

Thanks very much.