I think having the query return empty string is easy solution:
SELECT td_duckbill_accounts.platypus_no,
IIF(ISNULL(t_accounts.name),'',t_accounts.name) AS name
FROM t_accounts
INNER JOIN td_duckbill_accounts ON t_accounts.account_no = td_duckbill_accounts.account_no
ORDER BY td_duckbill_accounts.platypus_no
This should also work but I can't test it right now:
SELECT td_duckbill_accounts.platypus_no,
Nz(t_accounts.name,'') AS name
FROM t_accounts
INNER JOIN td_duckbill_accounts ON t_accounts.account_no = td_duckbill_accounts.account_no
ORDER BY td_duckbill_accounts.platypus_no