Blog script problem(2)

[pcman10]

Hi guys!
I have an other problem in posts.inc.php.Warning: mysql_fetch_assoc(): supplied argument is not a valid MySQL result resource in /core/inc/posts.inc.php on line 42

There is the code:
[syntax=php]<?php

// checks if the given post id is in the table.
function valid_pid($pid){
$pid = (int)$pid;

$total = mysql_query("SELECT COUNT(`post_id`) FROM `posts` WHERE `post_id` = {$pid}");
$total = mysql_result($total, 0);

if ($total != 1){
return false;
}else{
return true;
}
}

// fetches a summery of all the blog posts.
function get_posts(){
$sql = "SELECT
`posts`.`post_id` AS `id`
`posts`.`post_title` AS `title`,
LEFT(`posts`.`post_body~, 512) AS `preview`,
`posts`.`post_user` AS `user`,
DATE_FORMAT(`posts`.`post_date`, '%d/%m/%Y %H:%i:%s') AS `date`,
`comments`.`total_comments`,
DATE_FORMAT(`comments`.`last_comment`, '%d/%m/%Y %H:%i:%s) AS `last_comment`
FROM `posts`
LEFT JOIN (
SELECT
`post_id`,
COUNT(`comment_id`) AS `total-comments`,
MAX(`comment_date`) AS `last_comment`
FROM `comments`
GROUP BY `post_id`
) AS `comments`
ON `posts`.`post_id` = `comments`.`post_id`
ORDER BY `posts`.`post_date` DESC";

$posts = mysql_query($sql);

$rows = array();
while (($row = mysql_fetch_assoc($posts)) !== false){
$rows[] = array(
'id' => $row['id'],
'title' => $row['title'],
'preview' => $row['preview'],
'user' => $row['user'],
'date' => $row['date'],
'total_comments' => ($row['total_comments'] === null) ? 0 : $row['total_comments'],
'last_comment' => ($row['last_comment'] === null) ? 'never' : $row['last_comment']
);
}
return $rows;
}

// fetches a single post from the table.
function get_post($pid){
$pid = (int)$pid;

$sql = "SELECT
`post_title` AS `title`,
`post_body` AS `body`,
`post_user` AS `user`,
`post_date` AS `date`
FROM `posts`
WHERE `post_id` = {$pid}";

$post = mysql_query($sql);
$post = mysql_fetch_assoc($post);

$post['comments'] = get_comments($pid);

return $post;
}

// adds a new blog entry.
function add_post($name, $title, $body){
$name = mysql_real_escape_string(htmlentities($name));
$title = mysql_real_escape_string(htmlentities($title));
$body = mysql_real_escape_string(nl2br (htmlentities($body)));

mysql_query("INSERT INTO `posts` (`post_user`, `post_title`, `post_body`, `post_date`) VALUES '{$name}', '{$title}', '{$body}', NOW()");
}

?>[/syntax]

[Helx]

Line 22 of the code you supplied.

You put a tilde (~) where you should have a grave/backtick (`).