I have two views with an ID and an id_code field. (The underlying table is the same.) How can I select all the ID's from view 1 that are not present in view two?

The following code returns the ID's if it exists, but the opposite returns no data. I know that there is data that is in view 1 but not view 2.

select
AZ.AN_ID,
AZ.ZIP_CODE,
from
AUTHOR_ZIPCODE AZ
WHERE exists
(select AN_ID from
AUTHOR_ZIPCODE_DUPES AZD
)


(Please forgive double posting if it happens...I can't see the 1st post)