Ajax :: Mysql Is Inserting The Id Of The Last Created Playlist - Not The First

I have a question about ajax, php si mysql.. In mysql i have a table playlists and here is the code for php:

<?php
$playlist_result = mysql_query("SELECT *, COUNT(playlist_id) AS NumOccurrences FROM playlists WHERE created_by=$user_id GROUP BY playlist_id HAVING ( COUNT(playlist_id) > 0 ) ORDER BY date DESC");
$playlist_result_count=mysql_num_rows($playlist_result);
$i=0;
if($playlist_result_count > 0)
{
[Code]...

It`s working fine but in mysql is inserted the id of the last created playlist, not the one that I clicked. What am I doing wrong?