PHP删除数据库中的项目不起作用

Question

I've a little script for deleting certificates by id number from my database but this is not working fine.

<?php
session_start();
include("config.php");
if(isset($_SESSION['username'])){
    $conn = mysqli_connect(host, db_user, db_pass, db);
    $id = htmlspecialchars($_GET['id']);
    $query = "DELETE FROM cert_details where certid = ". mysql_real_escape_string($id);
    $r = mysqli_query($conn, $query);
    mysqli_close($conn);
    header('location: dashboard.php');

}
else{
    header("location: index.php");
} ?>

This is what I am doing at HTML side

echo "<form method=\"POST\" action=\"deletecert.php?id=$certidd\" onSubmit=\"return confirm('Are you sure?')\">"; echo "<button name=\"del\" value=\"Delete\" type=\"submit\" class=\"btn btn-xs btn-danger\"><i class=\"fa fa-trash\"></i></button>"; echo "</form>";

This is having trouble on the remote hosting, but not on my local server.

Answer 1

Try this

<?php
session_start();
require "./config.php";

if (isset($_SESSION['username'])) {

    $mysqli = new mysqli(host, db_user, db_pass, db);

    /* check connection */
    if ($mysqli->connect_errno) {
        die("Connect failed: %s
", $mysqli->connect_error);
    }

    $id = htmlspecialchars($_GET['id']);
    $mysqli->query("DELETE FROM cert_details where certid = ". $mysqli->real_escape_string($id));
    mysqli->close();

    header('location: ./dashboard.php');

}else{
    header("location: ./index.php");
}
?>