while inside another while in php - php

Question

I have created a blog in php. Users can view posts of their friends and they can "like it", like you do in facebook. Under each post there is a link that when a user press it, the user can see all users like this certain post. Table comments holds all posts: comments(comments_id, comment, user) and table likes(like_id, user, the_comment_id) holds all likes for each post.
I have the following problem. Lets say that users 23, 30 like first post. User 30 likes second post. If I press on link for the first post to see pleople like it, it gives me 23 and 30. But if I click on second post, it gives 23, 30 and 30 and not only 30 as it should give me.
Probably the problem is with "while"... any idea how to fix this?
This is my php code for this:
<?php
$sql = mysql_query("SELECT * FROM comments");
// starts a while loop that prints all posts...
while ($row= mysql_fetch_assoc($sql)) {
$comment_id = $row['comments_id'];
//... prints post details succesfully
$comments .= ".$row['comment'].";
// here starts the process for the link, that user will press it, it will get all users likes this certain post
$favorites = mysql_query(" SELECT * FROM `likes` WHERE `the_comment_id`='{$row['comments_id']}' ");
while($e = mysql_fetch_array($favorites)){
$like_users = $e['user'];
$array[]=$like_users;
}
$arstring = implode('</br>',$array);
$comments .= <<<EOD
// here starts link, that press and see all people like this comment
$arstring
EOD;
} //end while

Answer 1

You should section off your like-array to be per-comment. Right now it's a single array for all comments/posts. So basically just clear it before starting the 2nd while loop.
You can do it like this:
<?php
$sql = mysql_query("SELECT * FROM comments");
// starts a while loop that prints all posts...
while ($row= mysql_fetch_assoc($sql)) {
$comment_id = $row['comments_id'];
//... prints post details succesfully
$comments .= ".$row['comment'].";
// here starts the process for the link, that user will press it, it will get all users likes this certain post
$favorites = mysql_query(" SELECT * FROM `likes` WHERE `the_comment_id`='{$row['comments_id']}' ");
$array = array(); // empty the list of any earlier users
while($e = mysql_fetch_array($favorites)){
$like_users = $e['user'];
$array[] = $like_users;
}
$arstring = implode('</br>',$array);
$comments .= <<<EOD
// here starts link, that press and see all people like this comment
$arstring
EOD;
} //end while
On a sidenote: you really should not use the mysql extension anymore. It is officially deprecated. Instead use the MySQLi or PDO extensions. These are both faster and safer.