How to create Union based table type value set

Summary:

I am trying to create table based value set and also I need some constant value which is not exists in the table.

Content (required):

I am trying to create table based value set and also I need some constant value which is not exists in the table.

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):

select a.name from (select name, LEGAL_ENTITY_ID, status from per_legal_employers UNION ALL select 'Private Visa - Not sponsored by PFC' name, 123 LEGAL_ENTITY_ID, 'A' status from dual) a where STATUS = 'A'