How to return a table in postgress ...?

I seldom use pgSQL, and mostly use it from .NET with the NpgSQL driver, but here are some examples. Sadly I got no output displayed in the pgAdmin window, but saving the results to a file worked.
Simple example from PostgreSQL wiki[^]

--DROP FUNCTION getemployees();
create function GetEmployees() returns setof employee as 'select * from employee;' language 'sql';
select * from GetEmployees();

Here is a more elaborate example from PL/pgSQL Declaration - w3resource[^]

CREATE FUNCTION get_employee(text) RETURNS text AS '
  DECLARE
     frst_name ALIAS FOR $1;
     lst_name employees.last_name%TYPE;
  BEGIN
     SELECT INTO lst_name last_name FROM employees 
	 WHERE first_name = frst_name;
     return frst_name || '' '' || lst_name;
  END;
' LANGUAGE 'plpgsql';

And then call it like this:

SELECT get_employee('John');

You can also call your functions in PgAdmin by right-clicking on them in the tree on the left and then use 'Scripts - Select Script', this way the output will be displayed in the output window.