How to use the keyword after AS in WHERE

Question

I am calculating the total year that a member have been registered. I need to return the result how many member registered more than 5 years but I am having error when I run the code.

It shows "duration" invalid identifier in line 3

select floor(months_between(SYSDATE,RegistrationDate)/12) as "Duration"

from member

where duration > 5;

Answer 1

You can use a subquery:

select *
from
(
    select floor(months_between(SYSDATE,RegistrationDate)/12) as "Duration"
    from member
)
where "Duration" > 5;