title: get posts that I have commented on with new comments?
body: <p>I have a typical MySQL database set up for this: post table, user table, comment table.</p>
  
  <p>What is the best way to query something like "Get posts where I commented that have new comments since my last comment"? I'm having trouble arriving out how to merge the other users comment_timestamp being greater than my comment_timestamp condition into the query below:</p>
  
  <p>I have roughly </p>
  
  <pre><code>SELECT * FROM posts 
  WHERE posts.id IN 
  ( SELECT DISTINCT posts.id FROM posts,users,comments WHERE comments.post_id = post.id AND comments.user_id = $current_user_id ) AND .. something to filter only comments where timestamp is greater than mine
  </code></pre>
  
  <p>I realize I could loop through one set and filter outside of MySQL, but I'd prefer to have it all done in MySQL if possible. I know there's probably a better way to do this with a join, but I'm lost on how to move the comment_timestamp for "my" last comment amongst both parts of the join</p>
  
  <pre><code>user table
  -----
  id
  
  posts table
  ------
  id
  user_id
  
  comments table
  -------
  id
  user_id
  post_id
  comment_timestamp
  </code></pre>