PHP MySQL身份验证问题

Question

I was adding a delete function to my mysql database database but when i hit the submit button i get this Error message "DELETE command denied to user ''@'localhost' for table 'people" Ive taken a look at the user root to see and it has all priveleges added please help this is the code im working on

<?php

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "yoga";

$conn = new mysqli($servername, $username, $password, $dbname);

    if($conn -> connect_error){
        die("connection failed: ".$conn -> connect_error);
    }

        if(isset($_POST['delete'])){


        mysql_query("DELETE FROM `yoga`.`people` WHERE `people`.`id` =          '$_POST[deleteId]' ") or die(mysql_error());
        }

    ?>

Answer 1

Wonder your username is null as per the error message, which means username value is not passed

"DELETE command denied to user ''@'localhost' for table 'people"

---

If it is due to insufficient privileges. Check the result of

SHOW GRANTS FOR 'root'@'localhost';

Ensure you have the right privileges

GRANT DELETE ON `yoga`.`people` TO 'root'@'localhost';
or
GRANT DELETE ON `yoga`.* TO 'root'@'localhost';
FLUSH PRIVILEGES;

---

Also sometimes it is found that the queries which works in phpmyadmin may not work in server . To make that work in any platform, try this instead (omitting the database name)

schema_name.table_name to table_name

DELETE FROM people WHERE `people`.`id` = '$_POST[deleteId]' "

Answer 2

You don't use the connection you have created. Change the query line to this:

 $conn->query("DELETE FROM `yoga`.`people` WHERE `people`.`id` =          '$_POST[deleteId]' ") or die($conn->error);

I would also recommend that you use prepared statements, because now you are vulnerable to sql injection.