SQL using If Not Null on a Concatenation

Question

If I have the table

SELECT (Firstname || \'-\' || Middlename || \'-\' || Surname)  AS example_column
FROM example_table

This will

Answer 1

One solution could be using case statement

select case Middlename is not null then (Firstname || '-' || Middlename || '-' || Surname) 
    else (Firstname || '-' || Surname) end AS example_column
from ....