DREAMWEAVER MX -- HOW TO WRITE MySQL UPDATE SET QUERY...

Trying to write a MySQL UPDATE SET query in DW MX but can't make it work.

Here is what I have:

SELECT *
FROM t_dontn_new
UPDATE t_dontn_new
SET t_dontn_new.amt_adm = 5
WHERE t_dontn_new.dontn_id = 254

Another variant would be:

SELECT *
FROM t_dontn_new
UPDATE t_dontn_new
SET t_dontn_new.amt_adm = t_dontn.amt * 0.15
WHERE t_dontn_new.dontn_id = 254

This should be pretty simple, but does not work (for me) in DW MX.

Any help you can offer will be greatly appreciated.