开始

set serveroutput on
define p_annual=6000

declare
  v_sal number(7,2):=&p_annual;
begin
  v_sal := v_sal/12;
  dbms_output.put_line('the monthly salary is ' || v_sal);
end;

script output 窗口可以看出:

anonymous block completed
the monthly salary is 500

结束