Mysql带返回值与不带返回值的2种存储过程

1 drop procedure if exists proc_addNum;
2 create procedure proc_addNum (in x int,in y int,out sum int)
3 BEGIN
4 SET sum= x + y;
5 end

1 call proc_addNum(2,3,@sum);
2 select @sum;

1 drop procedure if exists proc_addNum;
2 create procedure proc_addNum (in x int,in y int)
3 BEGIN
4 DECLARE sum int;
5 SET sum= x + y;
6 SELECT sum;
7 end

1 call proc_addNum(2,3);