New column depending on conditions sql

Question

Let's say that I have a table with 2 columns, like this:

And I want to add another column if the ID has the type credit card . How to do that?

Answer 1

If I get you correctly then you can use case expressions to add another column as following

select
  ID,
  Type,
  case 
    when Type = 'Credit Card' then yourValue
  end as yourColumnName
from yourTable

Answer 2

If I understand correctly, it would use window functions:

select t.*,
       max(case when type = 'Credit Card' then 1 else 0 end) over (partition by id) as has_credit_card
from t;