学步园

以经典的阶乘算法为例。

Oracle：

create or replace procedure factorial(n in number, b out number)
is
    c_in number;
    c_out number;
begin
    if n!=1 then
        c_in := n-1;
        factorial(c_in,c_out);
        b := n*c_out;
    else
        b := 1;
    end if;
end;
/

--调用
variable r number;
exec factorial(6,:r);
print r;

MySQ：

drop procedure if exists factorial;
set @@session.max_sp_recursion_depth=99;
delimiter $$

create procedure factorial (in n bigint, out b bigint)
begin
    declare c_in bigint;
    declare c_out bigint;
    if n!=1 then
        set c_in := n-1;
        call factorial(c_in,c_out);
        set b:=n*c_out;
    else
        set b:=1;
    end if;
end$$

delimiter ;

--调用
call factorial(6,@r);
select @r;