Postgres how to implement calculated column with clause

Question

I need to filter by calculated column in postgres. It\'s easy with MySQL but how to implement with Postgres SQL ?

pseudocode:

select id, (cos(id) + c         


        

Answer 1

select id, (cos(id) + cos(id)) as op 
from selfies 
WHERE (cos(id) + cos(id)) > 1

You should specify the calculation in the where clause as you can't use a alias.