I have the following tables:

posts (post_id, content, etc) 

comments (comment_id, post_id, content, etc)

posts_categories (post_category_id, post_id, category_id)

and this query:

SELECT `p`.*, COUNT(comments.comment_id) AS cmts, posts_categories.*,comments.* 
FROM `posts` AS `p` 
LEFT JOIN `posts_categories` 
ON `p`.post_id = `posts_categories`.post_id 
LEFT JOIN `comments` 
ON `p`.post_id = `comments`.post_id 
GROUP BY `p`.`post_id`

There are three comments on post_id=1 and four in total. In posts_categories there are two rows, both assigned to post_id=1. I have four rows in posts.

But if I query the statement above I get a result of 6 for COUNT(comments.comment_id) at post_id=1. How is this possible? I guess the mistake is somewhere in the GROUP BY clause but I can't figure out where.

Any suggestions?