Update select statement result in a column conditioned by another column (Oracle SQL)

Question

I'm trying to write a Select query in Oracle SQL that will return first_name column as empty if last_name column is empty(Regarless what's in the first_name column value). For the first row "John" should be return as empty since he has no last_name I don't want to update the table, I just want a Select query that return empty first_name if last_name is empty. Thanks in advance!!!

THIS SHOULD BE THE OUTCOME.

Answer 1

You can use CASE expression:

SELECT customer_id,
       CASE
       WHEN last_name IS NULL
       THEN NULL
       ELSE first_name
       END AS first_name.
       last_name.
       age,
       country
FROM   table_name