Select all records don't meet certain conditions in a joined table

Question

Let\'s say we have two tables here , posts and comments, the relations is one to many, there has a field call comment_date in the comments table.

Now I am struggle t

Answer 1

SELECT  *
FROM    posts
WHERE   post_id NOT IN 
        (
        SELECT  comment_post
        FROM    comments
        WHERE   comment_date >= @deadline
        )

Answer 2

SELECT *
FROM posts p
WHERE NOT EXISTS(
    SELECT 1
    FROM comments c
    WHERE c.comment_date >= 'deadline'
    AND p.post_id = c.post_id
)