Mysql×Ö·ûÌõ¼þ²éѯÎÊÌâ

SQL code:

DROP TABLE IF EXISTS `t_aaaa`;
CREATE TABLE `t_aaaa` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(30) NOT NULL DEFAULT 'N/A',
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

INSERT INTO `t_aaaa` VALUES (1,'aaa');
INSERT INTO `t_aaaa` VALUES (2,'bbb');
INSERT INTO `t_aaaa` VALUES (3,'ccc');

CREATE DEFINER=`root`@`%` PROCEDURE `sp_aaaa`(
p_name varchar(30)
)
begin
declare v_id int;
select id into @v_id from t_aaaa where name=p_name;
set v_id=@v_id;
select v_id;
end;


call sp_aaaa('aaa');

call sp_aaaa('ddd');



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call sp_aaaa('ddd');
ΪNULL

CREATE PROCEDURE `sp_aaaa`(
p_name varchar(30)
)
begin
declare v_id int;
select id into @v_id from t_aaaa where name=p_name;
set v_id=@v_id;
select v_id;
end;

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ÔÚÖмä¼ÓÒ»¶ÎSQL code

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