SELECT posts.post_id, posts.name, posts.ctime, posts.author, posts.post, COUNT(comment.comment_id)
FROM posts, comment
WHERE comment.post_id=posts.post_id
GROUP BY comment.post_id
SELECT posts.post_id, posts.name, posts.ctime, posts.author, posts.post
, (select COUNT(*) from comment WHERE comment.post_id=posts.post_id ) as COUNT
FROM posts
SELECT posts.post_id, posts.name, posts.ctime, posts.author, posts.post, count(comment.comment_id)
FROM posts
LEFT JOIN comment ON posts.post_id = comment.post_id
GROUP BY posts.post_id
SELECT posts.post_id, posts.name, posts.ctime, posts.author, posts.post, COUNT(comment.comment_id)
FROM posts
LEFT JOIN comment USING(post_id)
GROUP BY posts.post_id