Q4：mysql declare cursor只能放在前面吗
本文中介绍了一个MySQL的存储过程，其中涉及Cursor的使用
示例如下：
复制代码
代码如下:
CREATE PROCEDURE `justifyGroupNum`()
NOT DETERMINISTIC
SQL SECURITY DEFINER
COMMENT
BEGIN
/*how to run:call justifyGroupNum()*/
DECLARE p_group_id int;
declare p_num int;
declare stopFlag int;
DECLARE cursor_name CURSOR
FOR select c_group_id,count(*) as num
from `t_group_member`
where
c_valid in (3,4)
group by c_group_id;
DECLARE CONTINUE HANDLER FOR NOT
FOUND set stopFlag=1;
OPEN cursor_name;
REPEAT
FETCH cursor_name
INTO p_group_id,p_num;
begin
update t_groupinfo set
c_member_number=p_num where c_group_id=p_group_id;
end;
UNTIL stopFlag =
1
END REPEAT;
CLOSE cursor_name;
END;
总结：
1、注意设置游标的countinue handler：DECLARE CONTINUE HANDLER FOR NOT FOUND set
stopFlag=1;
2、注意REPEAT和UTILE [停止条件] END REPEAT的使用，否则不会循环；
3、如何RUN，输入并执行：call justifyGroupNum()
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