标签：循环 statement _id rom 局部变量 blog href its 游标
测试表 level ;
create table test.level (name varchar(20));
再 insert 些数据 ;代码,初始化
drop procedure if exists useCursor //
建立 存储过程 create
CREATE PROCEDURE useCursor() BEGIN
局部变量的定义 declare
declare tmpName varchar(20) default ‘‘ ; declare allName varchar(255) default ‘‘ ; declare cur1 CURSOR FOR SELECT name FROM test.level ;
MySQL 游标 异常后 捕捉
并设置 循环使用 变量 tmpname 为 null 跳出循环。
declare CONTINUE HANDLER FOR SQLSTATE ‘02000‘ SET tmpname = null;
开游标
OPEN cur1;
游标向下走一步
FETCH cur1 INTO tmpName;
循环体 这很明显 把MySQL 游标查询出的 name 都加起并用 ; 号隔开
WHILE ( tmpname is not null) DO set tmpName = CONCAT(tmpName ,";") ; set allName = CONCAT(allName ,tmpName) ;
游标向下走一步
FETCH cur1 INTO tmpName;
结束循环体:
END WHILE;
关闭游标
CLOSE cur1;
选择数据
select allName ;
结束存储过程
END;//
调用存储过程：
call useCursor()//
运行结果：
mysql> call useCursor()// +--------------------------------------+ | allName | +--------------------------------------+ | f1;c3;c6;c5;c2;c4;c1;f1;f3;f4;f2;f5; | +--------------------------------------+ 1 row in set (0.00 sec)
loop循环游标：
DELIMITER $$ DROP PROCEDURE IF EXITS cursor_example$$ CREATE PROCEDURE cursor_example() READS SQL DATA BEGIN DECLARE l_employee_id INT; DECLARE l_salary NUMERIC(8,2); DECLARE l_department_id INT; DECLARE done INT DEFAULT 0; DECLARE cur1 CURSOR FOR SELECT employee_id, salary, department_id FROM employees; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1; OPEN cur1; emp_loop: LOOP FETCH cur1 INTO l_employee_id, l_salary, l_department_id; IF done=1 THEN LEAVE emp_loop; END IF; END LOOP emp_loop; CLOSE cur1; END$$ DELIMITER ;
repeat循环游标：
/*创建过程*/ DELIMITER // DROP PROCEDURE IF EXISTS test // CREATE PROCEDURE test() BEGIN DECLARE done INT DEFAULT 0; DECLARE a VARCHAR(200) DEFAULT ‘‘; DECLARE c VARCHAR(200) DEFAULT ‘‘; DECLARE mycursor CURSOR FOR SELECT fusername FROM uchome_friend; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1; OPEN mycursor; REPEAT FETCH mycursor INTO a; IF NOT done THEN SET c=CONCAT(c,a);/*字符串相加*/ END IF; UNTIL done END REPEAT; CLOSE mycursor; SELECT c; END // DELIMITER ;
/*******************************************循环语句************************************************/ /*(1).WHILE循环*/ [ label: ] WHILE expression DO statements END WHILE [ label ] ; /*(2).LOOP循环*/ [ label: ] LOOP statements END LOOP [ label ] ; /*(3).REPEAT UNTIL循环*/ [ label: ] REPEAT statements UNTIL expression END REPEAT [ label ] ;
原文地址：http://www.jb51.net/article/38317.htm
标签：循环 statement _id rom 局部变量 blog href its 游标
原文地址：http://www.cnblogs.com/mqxs/p/6018766.html
