CODEWITHSUNDEEP
mysqlsql
Fahardine Ben Fahardine
Fahardine Ben Fahardine

Reputation: 115

SQL How count all replies of a single comment on several levels

I am working on comment system, I have to count all replies of a single comment on several levels.

Like this:

Parent
    ->child
        -> child

Parent
    -> child
    -> child
        ->child

My Sql is :

CREATE TABLE IF NOT EXISTS `comment` (
  `id` bigint(11) NOT NULL AUTO_INCREMENT COMMENT 'This is primary key of the table',  
  `parent_id` bigint(11) NOT NULL, 
  `content` text NOT NULL,
  PRIMARY KEY (`comment_id`),
  KEY `user_id` (`user_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=unicode_ci AUTO_INCREMENT=8 ;



INSERT INTO `comments` (`id`, parent_id`, `content`) VALUES
(1, 0, 'Parent'),
(2, 1, 'child'),
(3,  2, 'child'),
(4,  3, 'child'),
(5,  1, 'child2'),
(6, 0, 'Parent2'),
(7,  6,'child of parent2');

Upvotes: 0

Views: 291

Answers (1)

Michał Turczyn
Michał Turczyn

Reputation: 37430

Try below query:

select count(*)
from comments c0
join comments c1 on c0.id = c1.parentid
-- in case if child comment doesn't have any children, we still need to keep it
left join comments c2 on c1.id = c2.parentid
where c0.id = 1 --particular id for which we want to count children

Upvotes: 1

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