PHP SQL从两个表中删除

Question

我遇到了一个我无法解决的错误，我尝试了多种方法，但没有结果。

我想从2个表中删除。首先删除答复。

存在：

if(isset($_POST['delete'])){
    // Get form data

    $delete_id = mysqli_real_escape_string($Conn, $_POST['delete_id']). " ";

    $query = 'DELETE FROM replies WHERE parent_id =' .$delete_id.";" .
             'DELETE FROM topics WHERE topic_id =' .$delete_id ;



    if(mysqli_query($Conn, $query)){
        header('Location:' .'../forum/'.'');
    } else {
        echo 'ERROR: ' .mysqli_error($Conn);
    }
}

|

    if(isset($_POST['delete'])){
    // Get form data

    $delete_id = mysqli_real_escape_string($Conn, $_POST['delete_id']). " ";

    $query = 'DELETE * FROM replies, topics FROM replies LEFT JOIN topics WHERE parent_id = {$delete_id} AND topic_id= {$delete_id}';



    if(mysqli_query($Conn, $query)){
        header('Location:' .'../forum/'.'');
    } else {
        echo 'ERROR: ' .mysqli_error($Conn);
    }
}

|

if(isset($_POST['delete'])){
    // Get form data

    $delete_id = mysqli_real_escape_string($Conn, $_POST['delete_id']). " ";

    $query1 = 'DELETE FROM replies WHERE parent_id =' .$delete_id.;
    $query2 = 'DELETE FROM topics WHERE topic_id =' .$delete_id ;

    $query = $query1 . ";" . $query2;

    if(mysqli_query($Conn, $query)){
        header('Location:' .'../forum/'.'');
    } else {
        echo 'ERROR: ' .mysqli_error($Conn);
    }
}