mysql 存储过程

Question

1.问题描述：我想要从一个表中查找数据，然后取其中一些字段批量存到另一张表中，刚学习用存储过程，但是一直显示影响0行，不知道是哪里错了，请各位帮帮忙。谢谢了！
2.代码：

BEGIN
    #Routine body goes here...
    DECLARE id INT DEFAULT 0;
  DECLARE user_Id INT DEFAULT 0;
  DECLARE course_id INT DEFAULT 0;
  DECLARE playercount INT DEFAULT 0;
  DECLARE course_name VARCHAR(255);
  DECLARE play_time INT DEFAULT 0;
  DECLARE finish INT DEFAULT 0;
    DECLARE _done TINYINT(1) DEFAULT 0; 
  DECLARE mian_cur CURSOR FOR SELECT user_id,course_id,SUM(playercount) AS playercount,SUM(play_time) AS play_time,course_name FROM `edu_course_studyhistory` WHERE user_id = userId GROUP BY course_id ;
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET _done = 1; 
  OPEN mian_cur;
  loop_xxx:LOOP 
        FETCH FROM mian_cur INTO user_id,course_id,playercount,play_time,course_name;
        IF _done=1 THEN  
            LEAVE loop_xxx;  
        END IF;
        INSERT INTO edu_course_history VALUES(NULL,user_id,course_id,playercount,course_name,now(),play_time,0);
  END LOOP;
END

3.错误信息

Answer 1

从这个edu_course_studyhistory这个表取数据插入edu_course_history这个表么？
1.先确认下有没有数据：

SELECT
    user_id,
    course_id,
    SUM(playercount) AS playercount,
    SUM(play_time) AS play_time,
    course_name
FROM
    `edu_course_studyhistory`
WHERE
    user_id = userId
GROUP BY
    course_id;

2.试试执行能成功么？

INSERT INTO edu_course_history
VALUES
    (
        NULL,
        user_id,
        course_id,
        playercount,
        course_name,
        now(),
        play_time,
        0
    );

Answer 2

看起来没必要用存储过程吧？维护起来还麻烦。

INSERT INTO table1
(field1, field2, ...)
SELECT field1, field2 FROM table2
WHERE ...