call function in postgresql

I made a simple function as part of my homework but for the life of me I can't figure out how to call it and test it. Can anyone tell me how?

    -- Procedure
CREATE OR REPLA开发者_开发知识库CE FUNCTION addDoctor (
    a INT,
    b VARCHAR (20),
    c VARCHAR (20)
) RETURNS VOID
LANGUAGE plpsql
AS $BODY$
BEGIN
    INSERT INTO doctor
    VALUES (a,b,c);
END;
$BODY$

---

Use SELECT:

SELECT function_name();

---

CREATE or REPLACE FUNCTION analyzer(character varying, character varying)
  RETURNS boolean AS
$BODY$
--
begin
--
    execute 'analyze '||quote_ident($1)||'.'||quote_ident($2) ;
return 1 ;
--
end ;
$BODY$
  LANGUAGE plpgsql VOLATILE SECURITY DEFINER;

---

if you need to call function just to check for exceptions that can occur there go perform:

PERFORM f_foo(i);

if you need a result, go select

SELECT function_name();