除非你告诉我们你犯了什么错误，而不是让我们猜。但是嘿，这样更有趣！
当你宣布接受一个程序时 IN 还有两个 OUT 参数：

create or replace procedure cust_name_limit(
  i_customer_num in customer.customer_num%type,
  i_customer_name out customer.customer_name%type,
  i_credit_limit out customer.credit_limit%type)
as
begin
  select customer_name, credit_limit
  into i_customer_name, i_credit_limit
  from customer
  where customer_name = i_customer_name;
end;

您在调用它时也必须这样做：

declare
  l_custname customer.customer_name%type;
  l_credlim  customer.credit_limit%type;
begin
  CUST_NAME_LIMIT('126', l_custname, l_credlim);

  dbms_output.put_line(l_custname ||' - '|| l_credlim);
end;
/

在程序中显示结果没有多大意义；一旦它返回值就这样做。