How, depending on the value of the author's type attribute, to select a name from different tables (WHEN, CASE)?

Question

PostgreSQL

There is a view in which I display the id, the author's name and the text of the message.
In the table with messages, I entered the author's id and author's type attributes.
How to get name values ​​from different tables depending on the different type of author.

SELECT 
messages.id
messages.text
    case messages.typeauthor	
      when '1'
      
      when '2'
      
 FROM messages

Author id value
messages.authorid
In the first case, you need to make such a request

SELECT idmc.name
FROM idmc
WHERE idmc.id = messages.authorid

In the second

SELECT suppliers.name
FROM suppliers
WHERE suppliers.id = messages.authorid

Answer 1

SELECT
  m.id,
  m.text,
  CASE m.typeauthor
    WHEN '1' THEN
      (SELECT name FROM idmc WHERE id = m.authorid)
    WHEN '2' THEN
      (SELECT name FROM suppliers WHERE id = m.authorid)
  END
FROM messages m