开始
1、建立一张学生表
DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(256) DEFAULT NULL,
`class` varchar(256) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO `student` VALUES ('1', '张三', '1班');
INSERT INTO `student` VALUES ('2', '李四', '2班');
INSERT INTO `student` VALUES ('3', '王五', '3班');
INSERT INTO `student` VALUES ('4', '麻子', '1班');
INSERT INTO `student` VALUES ('5', '老王', '3班');
2、建立存储过程
DROP PROCEDURE IF EXISTS whileFor;
DELIMITER $$
CREATE PROCEDURE whileFor(OUT namess VARCHAR(1024))
BEGIN
DECLARE a VARCHAR(500);
DECLARE i , j , Done INT DEFAULT 0 ;
-- 申明游标
DECLARE rs CURSOR FOR SELECT NAME FROM student;
DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET Done = 1 ;
SET namess = '' , i = 0 , j = 1;
-- 循环四次
WHILE (j < 5) DO
-- 如果不是第一次,我们这里加一个|区分
IF(j > 1) THEN
SELECT CONCAT(namess,'|') INTO namess;
END IF;
-- 打开游标
OPEN rs;
FETCH NEXT FROM rs INTO a;
REPEAT
SET i = i + 1 ;
IF(i != 1 ) THEN
SELECT CONCAT(namess,',' , a) INTO namess;
ELSE
SELECT CONCAT(namess , a) INTO namess;
END IF;
FETCH NEXT FROM rs INTO a;
UNTIL Done END REPEAT;
CLOSE rs;
SET j = j + 1;
SET Done = 0 ;
SET i = 0 ;
END WHILE;
END
3、调用存储过程
CALL whileFor(@names);
SELECT @names;
执行结果为:
张三,李四,王五,麻子,老王|张三,李四,王五,麻子,老王|张三,李四,王五,麻子,老王|张三,李四,王五,麻子,老王