从phpmyadmin数据库中删除数据

<?php
include_once("FTMdatabase.php");
$id = $_GET['AccountID'];
$sql = "DELETE FROM personaldetails WHERE AccountID = '$id'";
$result = mysql_query($sql, $conn);
$msg = "Data Has Been Removed";
confirm($msg);
mysql_close();
?>
<?php
function confirm($msg)
{
echo "<script language=\"javascript\">
alert(\"".$msg."\");
document.location.href='FTMlogin.php';
</script>";
}
?>

I try this code. But I got an error that says 'AccountID' undefined index. My 1st row in the database is AccountID. Why does it happen?

<?php
include_once("FTMdatabase.php");
$sql="SELECT * FROM personaldetails";
$result = mysql_query($sql, $conn);
while($row = mysql_fetch_array($result))
{
$id = $row['AccountID'];
$name = $row['Name'];
$phone = $row['Phone'];
$car = $row['Car'];
$comment = $row['Comment'];
?>
<table border="1">
<tr><td width="10"><?php echo $id; ?></td>
<td width="10"><?php echo $name; ?></td>
<td width="300"><?php echo $phone; ?></td>
<td width="100"><?php echo $car; ?></td>
<td width="100"><?php echo $comment; ?></td>
</tr>
<td><a href="FTMdelete.php?id=<?php echo $id;?>">
Delete</a>
</table>
<?php

This is where to get $id. The reason I use $_GET['AccountID']

The error you are facing is not database error it's an php warning.

'AccountID' undefine index is because of this line

$_GET['AccountID'];

this is because you do not pass the AccountID to the page. You should use like this

if($isset($_GET['AccountID'])){
   echo "No value for AccountID given";
exit;
}

If you are using mysql_query(); then there is no need of connection so

the line

$result = mysql_query($sql, $conn);

Should be like this

$result = mysql_query($sql);

By the way mysql is deprecated so use mysqli.

So the final result code will look like this

<?php
include_once("FTMdatabase.php");
if($isset($_GET['AccountID'])){
   echo "No value for AccountID given";
   exit;
}
$id = $_GET['AccountID'];
$sql = "DELETE FROM personaldetails WHERE AccountID = '$id'";
$result = mysql_query($sql);
if($result){
  $msg = "Data Has Been Removed";
  confirm($msg);
} else {
  echo "error on query";
}

mysql_close();

function confirm($msg)
{
 echo "<script language=\"javascript\">
 alert(\"".$msg."\");
 document.location.href='FTMlogin.php';
 </script>";
}
?>