I'm having troubles working something out. I have just used a threaded comment example online, tested it against manually inputted data and works perfectly.
But this setup is kind of strange. It uses a PATH method, so the first comment has a path of 01, a reply to that comment has a path of 01_01 and another reply to the first comment would have 01_02. You can see the relative paths in my screenshot (above), next to each name.
This method performs really well, as I have tested it against many, many comments. The problem I have is calculating the next reply path. For example, let's say my user clicks [reply] on Jeremy Clarkson's comment, which has a path of 01_01_01. The next sequence to this would be 01_01_02, but that has already been used by Kim Bauer's comment. I thought I could do a little query SELECT * FROM comments WHERE path LIKE '01_01_%' and select the last row and add 1 to it, but the comment from Chloe O'Brien has 01_01_01_01, which would affect this result.
Can somebody please explain how I can calculate the next correct path for a reply?
My Fix:
I calculate the next available path by doing this:
SELECT path
FROM blog_comments
WHERE path LIKE '01_01___'
ORDER BY path DESC
LIMIT 1
$last_path = $row[0];
$last_path_suffix = substr($last_path,strrpos($last_path,'_')+1);
$next_path_suffix = str_pad($last_path_suffix+1,2,'0',STR_PAD_LEFT);
$next_path = substr($last_path,0,strlen($last_path)-strlen($last_path_suffix)).$next_path_suffix;
If anybody would like to use this method, the printing goes something like this:
$SQL = "SELECT * FROM comments ORDER BY path ASC;";
while($row = $STH->fetch()) {
$nesting_depth = strlen($row['path']) - strlen(str_replace('_','',$row['path']));
$left_margin = $nesting_depth * 40; // 40 pixels nesting indent
echo '<div class="comment_item" style="margin-left:'.$left_margin.'px;">';
echo '<strong>'.htmlspecialchars($row['author_name']).'<br>';
echo htmlspecialchars($row['comment']).'<br>';
echo '</div>';
}