Updating a field of one table from another

I'm attempting to update a field on one table with a different field from another. Here's the query that I'd like to use

update FC_MOD m, FC f
set FC_MOD.parent_key= FC.tfn
where concat(F.ticker,'.CF')=M.ticker

this is based on this simple select

select f.tfn from FC f, FC_MOD M
where concat(F.ticker,'.CF')=M.ticker

I'm trying to update the parent_key field in the fc_mod table with the tfn of the fc table based on the joining statement concat(f.ticker,'.CF')=m.ticker

I'm not sure how to do this...I've done some research but haven't found anything that works based on the criteria of this Received on Thu May 09 2002 - 13:56:36 CDT