How to avoid this repetitive CASE WHEN pattern in postgres query?

Question

I have this postgres query that is validating if the columns are null or not based on one codition, this is a normal query that is not requiring function, could be overkill a functional approach because this is unique scenario in the collection.

The query is working as expected but I want to shrink the logic if is possible.

CASE WHEN LOWER(COALESCE(users.user_number, users.customer_number)) LIKE 'vip%' THEN NULL
    ELSE COALESCE(users.user_badge, users.customer_badge) END                              AS normal_badge,
CASE WHEN LOWER(COALESCE(users.user_number, users.customer_number)) LIKE 'vip%' THEN NULL
    ELSE users.expiration_date END                                                         AS expiration_date,
CASE WHEN LOWER(COALESCE(users.user_number, users.customer_number)) LIKE 'vip%' THEN NULL
    ELSE COALESCE(users.user_number, users.customer_number) END                            AS standard_user,

Answer 1

Try this using CTE:

WITH user_data AS (
    SELECT *,
           LOWER(COALESCE(user_number, customer_number)) AS lower_number
    FROM users
)
SELECT 
    CASE WHEN lower_number LIKE 'vip%' THEN NULL
         ELSE COALESCE(user_badge, customer_badge) 
    END AS normal_badge,
    CASE WHEN lower_number LIKE 'vip%' THEN NULL
         ELSE expiration_date 
    END AS expiration_date,
    CASE WHEN lower_number LIKE 'vip%' THEN NULL
         ELSE COALESCE(user_number, customer_number) 
    END AS coalesced_number
FROM user_data;