Mysql高级编程_存储过程类型(in/out/inout)
标签：编程 localhost mys ota begin class current 参数表 变量
Mysql高级编程_存储过程类型(in/out/inout)
create procedure p1()
begin
declare i int default 10;
select concat (‘i的取值是:‘,i) as QuZhi;
end $
delimiter $
create procedure p2(width int, hegit int)
begin
select concat(‘它的面积是:‘,width * hegit) as area;
if width > hegit then
select ‘比较瘦‘ as Xingzhuang ;
elseif width < hegit then
select ‘比较方‘ as Xingzhuang ;
end if;
end $
------>这里求的是1+100之间的和，这里是固定的求和
delimiter $
create procedure p3()
begin
declare total int default 0 ;
declare num int default 0 ;
while num <= 100 do
set total := total+num;
set num := num +1;
end while;
select concat(‘total的大小是:‘,total) as total;
end $
--->需求：如果这里想要计算1+N ?
--->in型参数表示往存储过程中传输参数
delimiter $
create procedure p4(in n int)
begin
declare total int default 0 ;
declare num int default 0 ;
while num <= n do
set total := total+num;
set num := num +1;
end while;
select concat(‘total的大小是:‘,total) as total;
end $
---看看out型参数？
create procedure p5(in n int,out total int)
begin
declare num int default 0 ;
set total := 0;
while num <= n do
set total := total+num;
set num := num +1;
end while;
end $
--看看inout型参数？
delimiter $
create procedure p6(inout age int)
begin
set age := age + 10;
end $
--具体操作--
root@localhost 22:57: [liulin]> set @current=18 $ --这里先要设置一个变量--
Query OK, 0 rows affected (0.00 sec)
root@localhost 22:58: [liulin]> call p6(@current) $ --然后再将这个变量传入存储过程中inout类型中--
Query OK, 0 rows affected (0.00 sec)
root@localhost 22:58: [liulin]> select @current $ --最后再查看该变量是否修改--
+----------+
| @current |
+----------+
| 28 |
+----------+
1 row in set (0.00 sec)