MySQL存储过程和"Cursor"的使用方法
                        
                            时间:2021-07-01 10:21:17
                            帮助过:93人阅读
							                        
                     
                    
                    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: 
 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()