Mysql: Perform of NOT EXISTS. Is it possible to improve perfomance?

Question

I have two tables posts and comments. Table comments have post_id attribute. I need to get all p

Answer 1

No idea whether it is faster, you could check it out:

SELECT * FROM posts
LEFT JOIN comments 
ON comment.postid = post.id
AND comment.comment_type='good'
WHERE comment.postid IS NULL

Assuming postid is never NULL / a non NULLable column.