如何删除 id 是 post id、sql、php 的位置

Question

Thanks in advance. I am just learning php. I am trying to delete a post from blog I created. I should delete post by post_id which is auto incremented primary key.

But how I use post_id to WHERE clause?

my code is:

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "travelogy";
try{
    $conn = new PDO("mysql:host=$servername; dbname=$dbname", $username, $password);

    //  $post_id_location->bindValue(':post_id', $post_id);
    $delete_query = "DELETE FROM post_p WHERE id ="$_POST['post_id'];
    //   $delete_query = "DELETE FROM post_p WHERE id = $post_id_location";
    $conn->exec($delete_query);
    echo "Record deleted.";
    }catch(PDOException $e){
        echo $delete_query."<br>".$e->getMessage();
    }
$conn = null;

---

BUT Error Notice: Undefined variable: post_id_location in C:\\xampp\\htdocs\\CMS_project\\pdo.php on line 10 Fatal error: Uncaught Error: Call to a member function bindValue() on null in C:\\xampp\\htdocs\\CMS_project\\pdo.php:10 Stack trace: #0 {main} thrown in C:\\xampp\\htdocs\\CMS_project\\pdo.php on line 10

Answer 1

Change:

$delete_query = "DELETE FROM post_p WHERE id ="$_POST['post_id'];

To:

$delete_query = "DELETE FROM post_p WHERE id = " . $_POST['post_id'];

Or:

$post_id = $_POST['post_id'];
$delete_query = "DELETE FROM post_p WHERE id = '$post_id'";