teste.psql

-- calcula_valor(operacao)

-- CREATE OR REPLACE FUNCTION test(p int, n int)
-- RETURNS setof users AS $$
-- BEGIN
--   IF p = 1 THEN
--     return query SELECT * FROM users u where u.id=n;
--   else
--    UPDATE users  set salario=salario*1.1 where id=n;
--    return query SELECT * FROM users u where u.id=n;
--   END IF;
--   RETURN;
-- END;
-- $$ LANGUAGE plpgsql;

-- insert into users values (1, 'Maria', 5151.50), (2, 'Joao', 5454.40), (3, 'Joaninha', 4444.55);

-- CREATE OR REPLACE FUNCTION calcula_valor(valor int) RETURNS void AS $$
-- BEGIN
--    if valor = 1 then
--        UPDATE users SET salario = salario*1.10;
--    else
--       if valor =2 then
--           UPDATE users SET salario = salario*0.90; 
--       end if; 
--    end if;   
-- END;
-- $$
-- LANGUAGE 'plpgsql';

-- select * from calcula_valor(3);

-- CREATE OR REPLACE FUNCTION 

-- CREATE TABLE employee (id int, name varchar(50), BirthYear int, salary float);
insert into employee values (1, 'Alex', 2000, 5000.50), ;