As Woody already told you, the result is correct.

just adding a DESC "somewhere" won't order every field descending. You
have to add DESC for every field you want to order descending, otherwise
it will be deaulted by an ascending order.

order by DATE_ADMIN,TIME_ADMIN
will first order by DATE_ADMIN ASC and then by TIME_ADMIN ASC

order by DATE_ADMIN,TIME_ADMIN desc
will first order by DATE_ADMIN ASC and then by TIME_ADMIN DESC

You need:
order by DATE_ADMIN DESC,TIME_ADMIN DESC



Luc.