Delete button after every post (php, sql) - php

Question

I need some help with PHP and SQL. Im doing a website where you can post notes in different subjects (Work, Home, School, and so on). After every note that being selected from my database I want a button that can delete that specific post when it's not needed anymore. I can make it delete but is deletes wrong note, always the one above or below. I don't know whats wrong with my code? Please help me.
<?php
$query = "SELECT * FROM notes WHERE subject='Work' order by id desc";
$result = mysql_query($query);
while ($row = mysql_fetch_array($result)) {
$id = $row['id'];
$subject = $row['subject'];
$date = $row['date'];
$note = $row['note'];
print "<p><strong>$subject</strong> ($id), $date </p>";
print "<p> $note </p>";
?>
//delete button starts here here
<form id="delete" method="post" action="">
<input type="submit" name="delete" value="Delete!"/>
<?php
if(isset($_POST['delete'])){
$query = "DELETE FROM notes WHERE id=$id";
$result = mysql_query($query);
}
?>
</form>
<?php
}
?>
And when I press delete I get this:
Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in /home/mirho663/www-pub/webbpage/menu2.php on line 40
What does that mean and how do I fix it?

Answer 1

I updated your script below, try it if it works.
<?php
if(isset($_POST['delete'])){
$id = $_POST['delete_rec_id'];
$query = "DELETE FROM notes WHERE id=$id";
$result = mysql_query($query);
}
$query = "SELECT * FROM notes WHERE subject='Work' order by id desc";
$result = mysql_query($query);
while ($row = mysql_fetch_array($result)) {
$id = $row['id'];
$subject = $row['subject'];
$date = $row['date'];
$note = $row['note'];
print "<p><strong>$subject</strong> ($id), $date </p>";
print "<p> $note </p>";
?>
//delete button starts here here
<form id="delete" method="post" action="">
<input type="hidden" name="delete_rec_id" value="<?php print $id; ?>"/>
<input type="submit" name="delete" value="Delete!"/>
</form>
<?php
}
?>