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MySQL循环语句实例教程 mysql while循环测试

Jun 01, 2016 pm 01:06 PM

在mysql数据库中操作同样有循环语句操作,标准的循环方式: while 循环 、 loop 循环和repeat循环。

还有一种非标准的循环: goto。 鉴于goto 语句的跳跃性会造成使用的的思维混乱,所以不建议使用。

这几个循环语句的格式如下:

WHILE……DO……END WHILE

REPEAT……UNTIL END REPEAT

LOOP……END LOOP

GOTO。

目前我只测试了 while 循环:

delimiter $$ // 定义结束符为 $$

drop procedure if exists wk; // 删除 已有的 存储过程

create procedure wk() // 创建新的存储过程

begin

declare i int; // 变量声明

set i = 1;

while i

insert into user_profile (uid) values (i);

set i = i +1;

end while;

end $$ // 结束定义语句

// 调用

delimiter ; // 先把结束符 回复为;

call wk();

delimter : mysql 默认的 delimiter是; 告诉mysql解释器,该段命令是否已经结束了,mysql是否可以执行了。

这里使用 delimiter 重定义结束符的作用是: 不让存储过程中的语句在定义的时候输出。(脚本学堂www.jbxue.com)

创建 MySQL 存储过程的简单语法为:

CREATE PROCEDURE 存储过程名称( [in | out | inout] 参数 )

BEGIN

Mysql 语句

END

调用存储过程:

call 存储过程名称() // 名称后面要加()

二 、 REPEAT 循环

delimiter //<p>drop procedure if exists looppc;</p><p>create procedure looppc()</p><p>begin</p><p>declare i int;</p><p>set i = 1;</p><p>repeat</p><p>insert into user_profile_company (uid) values (i+1);</p><p>set i = i + 1;</p><p>until i >= 20</p><p>end repeat;</p><p>---- 调用</p><p>call looppc()</p><p>三、 LOOP 循环</p><p>delimiter $$</p><p>drop procedure if exists lopp;</p><p>create procedure lopp()</p><p>begin</p><p>declare i int ;</p><p>set i = 1;</p><p>lp1 : LOOP // lp1 为循环体名称 LOOP 为关键字insert into user_profile (uid) values (i);set i = i+1;</p><p>if i > 30 then</p><p>leave lp1; // 离开循环体</p><p>end if;</p><p>end LOOP; // 结束循环</p><p>end $$</p>
    
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