create or replace procedure helloworld(a1 in number,a2 in number,sum out number,sub out number)
as
begin
a1:=100;
sum:=a1+a2;
dbms_output.put_line(a1);
end;
/
create or replace procedure helloworld(a1 in number,a2 in number,sum out number,sub out number)
as
begin
sum:=a1+a2;
dbms_output.put_line(a1);
end;
/
传入的是产量不是变量，所以a1,a2不能重新赋值
但是sum,sub可以他们是输出参数
