mysql中的游标使用案例

DELIMITER $$

DROP PROCEDURE IF EXISTS `curTest`$$

CREATE PROCEDURE curTest(IN _myId INT)
BEGIN
DECLARE ids VARCHAR(20);
-- 遍历数据结束标志
DECLARE done INT DEFAULT FALSE;
-- 定义游标
DECLARE cur CURSOR FOR SELECT GROUP_CONCAT(id) FROM detail WHERE splitFlag=1 AND myId=_myId GROUP BY code;
-- 将结束标志绑定到游标
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
-- 打开游标
OPEN cur;
updateLoop:LOOP
FETCH cur INTO ids;
-- 跳出循环
IF done THEN
LEAVE updateLoop;
END IF;
-- 业务开始
UPDATE detail a,
(SELECT nos,id FROM detail WHERE FIND_IN_SET(id,ids) ORDER BY LENGTH(nos) DESC LIMIT 0,1) b
SET a.nos= b.nos WHERE FIND_IN_SET(a.id,ids);

END LOOP;
CLOSE cur;
END$$

DELIMITER ;

注意：

1.变量的定义不要和你的select的列的键同名！不然，fetch into 会失败！

2.变量定义顺序不对会报错 “

Variable or condition declaration after cursor or handler declaration

”

报错参见：http://stackoverflow.com/questions/18780974/mysql-error-1337

参考：http://www.cnblogs.com/trying/p/3296793.html