<?php
    $servername = "mysql.cba.pl";
    $username = "mmalewski";
    $password = "Haslo123";
    $dbname = "mmalewski";
    $conn = new mysqli($servername, $username, $password, $dbname);
    $sql = "DELETE FROM DB WHERE id= $_GET[id]";
    if ($conn->query($sql) === TRUE) {
    echo "Record deleted successfully";
} else {
    echo "Error deleting record: " . $conn->error;
}
$conn->close();
include "getdata.php";
?>

A wywołuje to:
<form> <input type='button' value='Usuń' onclick=window.location.href='delete.php?id=$idd' /> </form>