Mysql procedure does not execute as expected

Using mysql 5.7, when I execute this procedure:

DELIMITER $$
CREATE PROCEDURE tres()
BEGIN
    DECLARE maxid INT;
    DECLARE x INT;
    SET maxid = 655;
    SET x=1;
    WHILE x<= maxid DO 
        INSERT INTO `forum_topicresponder` (topic_id, username, reply_id) SELECT p.topic_id, p.creator_name, p.id  FROM forum_post AS p  WHERE p.topic_id=x;
     SET  x = x + 1; 
     END WHILE;
END$$

I get

mysql> call tres();
Query OK, 0 rows affected (3.49 sec)

However when I execute the INSERT for a certain values inside the loop range:

 INSERT INTO `forum_topicresponder` (topic_id, username, reply_id) SELECT p.topic_id, p.creator_name, p.id  FROM forum_post AS p  WHERE p.topic_id=42;

I see that the results are inserted without problem.

The table schemas:

CREATE TABLE `forum_topicresponder` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `topic_id` int(10) NOT NULL DEFAULT '0',
  `username` varchar(300) CHARACTER SET utf8mb4 NOT NULL DEFAULT 'na',
  `reply_id` int(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=94 DEFAULT CHARSET=latin1;

And

CREATE TABLE `forum_post` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `body` varchar(16000) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL,
  `topic_id` int(11) NOT NULL DEFAULT '0',
  `creator_id` int(11) NOT NULL DEFAULT '0',
  `creator_name` varchar(30) NOT NULL DEFAULT 'NA',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6264595 DEFAULT CHARSET=utf8;

So what could be wrong here and how can I fix it?

Answer

You need to check the value of x in the procedure, It might be not matched with your topic_id of the forum_post table.

If topic_id not matched then no data will copy to the forum_topicresponder table.

You need to set the proper value of x, (from min to max) depends on topic_id of forum_post table