Having an issue with deleting entry from database on my website - php

Question

I have echoed my database table onto my website and have tick option next to the table where you can tick it and delete any of the entries from the website, it should delete it from the database. For some reason its not working, I'm a beginner and any help would be greatly appreciated thanks.
<form method="" action="tester.php">
<?php
include 'connect_to_mysql.php';
$count=mysql_num_rows($result);
$result = mysql_query("SELECT * FROM booking ORDER BY ID ASC");
echo "<table border='1'>
<tr>
<th>DEL</th>
<th>Name</th>
<th>Email ID</th>
<th>Phone Number</th>
<th>Collection Address</th>
<th>Collection Date</th>
<th>Collection Time</th>
<th>Make & Model</th>
<th>Message</th>
</tr>";
while($row = mysql_fetch_array($result))
{
?>
<td align="center" bgcolor="#FFFFFF"><input name="delete_these[]" type="checkbox" id="checkbox[]" value="<?php echo $row['ID']; ?>"></td>
<?php
echo "<td>" . $row['name'] . "</td>";
echo "<td>" . $row['email'] . "</td>";
echo "<td>" . $row['phonenumber'] . "</td>";
echo "<td>" . $row['collectionaddress'] . "</td>";
echo "<td>" . $row['collectiondate'] . "</td>";
echo "<td>" . $row['collectiontime'] . "</td>";
echo "<td>" . $row['makemodel'] . "</td>";
echo "<td>" . $row['message'] . "</td>";
echo "</tr>";
}
echo "</table>";
?> <br>
<td colspan="5" align="center" bgcolor="#FFFFFF"><input name="delete" type="submit" id="delete" value="Delete"></td>
</tr>
<?php
// Check if delete button active, start this
if(isset($_GET['delete'])) {
for($i=0;$i<$count;$i++){
$id = $checkbox[$i];
print_r($_GET['delete_these']);
$ids = implode(', ', $_POST['delete_these']);
$sql = "DELETE FROM booking WHERE id IN($ids)";
echo "<br />SQL: $sql<br />";
$result = mysql_query($sql);
}
// if successful redirect to delete_multiple.php
if($result){
}
}
mysql_close();
?>
</form>

Answer 1

you have add method in your form tag--
<form method="post" action="tester.php" >
and also replace if(isset($_GET['delete'])) to if(isset($_POST['delete']))

Answer 2

Replace your form tag by:
<form method="post" action="tester.php">
then these 3:
if(isset($_POST['delete']))
$id =(int)$_POST['delete_these'][$i];
$sql = "DELETE FROM booking WHERE id=$id";
at the place of these 3:
if(isset($_GET['delete']))
$id = $checkbox[$i];
$sql = "DELETE FROM booking WHERE id IN($ids)";
Your $id = $checkbox[$i]; works only if register_globals directive is on, which is now deprecated (and removed as of PHP 5.4) because of security issues it causes, and if it exists in the version of PHP you are using most hosting services turn it off.
You'll be sending the data through post so you access them through $_POST. the (int) before the $_POST is to cast anything to integer so if the user try to send a string it will become 0, this will protect you from sql injection.
SIDE NOTE you should stop using mysql_* functions as they are deprecated. Check out PDO or mysqli