SQL & PL/SQL :: Query To Get Overall Status For Clients

I have a clients table called CLIENTS. One of the fields in this table is called 'status'

I need to set this status field, depending on if the transactions for this client have passed.

The transactions are in a table called TXNS and has fields
client_id, txn_id, txn_status

txn_status can be 'success' or 'failed'

I need to somehow set the overall 'status' field on CLIENTS to success or fail depending on if any transactions failed or not

So for every client I want to list the status, any query that can possible list the overall status for the client?

select client_id, MAX(status)
from txns
group by client_id

but the max(status) bit needs to get the overall status part