How to cascade delete from same MySQL table - mysql

Question

Is it possible to cascade delete from same MySQL table? I want to cascade delete in a table that references itself in relations.
Example:
I have a comments table that has comment_id and parent_id, where parent_id is the same id in comment_id.
Parent_id could be either another comment_id or null if it's a root
comment.
I want to be able to select any node in this tree and delete it. In the process, all child nodes and sub-child nodes should be deleted.
I have tried to alter my table using this query
ALTER TABLE `comment`
ADD FOREIGN KEY (`comment_id`)
REFERENCES `comment`(`parent_id`) ON DELETE CASCADE ON UPDATE RESTRICT;
but I end up with an error
Cannot add or update a child row: a foreign key constraint fails
(zendaya001.#sql-6c1_1044ab, CONSTRAINT comment_ibfk_3 FOREIGN
KEY (comment_id) REFERENCES comment (parent_id) ON DELETE
CASCADE ON UPDATE RESTRICT)
For reproduction, this is my comment table:
CREATE TABLE `comment` (
`comment_id` int NOT NULL,
`post_id` int UNSIGNED NOT NULL,
`user_id` int NOT NULL,
`parent_id` int DEFAULT NULL,
`content` text NOT NULL,
`type` varchar(50) DEFAULT NULL,
`count_replies` int NOT NULL DEFAULT '0',
`count_likes` int NOT NULL DEFAULT '0',
`timestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
--
-- Indexes for table `comment`
--
ALTER TABLE `comment`
ADD PRIMARY KEY (`comment_id`),
ADD KEY `user_id` (`user_id`),
ADD KEY `post_id` (`post_id`),
ADD KEY `parent_id` (`parent_id`);

Answer 1

You try to create the foreign key with incorrect direction.
Must be:
ALTER TABLE `comment`
ADD FOREIGN KEY (`parent_id`)
REFERENCES `comment`(`comment_id`) ON DELETE CASCADE ON UPDATE RESTRICT;
https://dbfiddle.uk/iJRlziwL
comment_id must be defined at least UNIQUE (maybe PRIMARY KEY).
I cannot insert a new record into the table even if ON UPDATE RESTRICT is also set to CASCADE – Freesoul
You do something wrongly.
https://dbfiddle.uk/rcUupB2b