删除文件夹中的图像，但在PHP中图像路径不会更新为null

I have created a code to delete image which is in a folder and to update image_path to null in the database. Although the image deletes the image, the path does not get updated to null. I spent hours to catch my mistake. But I could not. Any help would be grateful!

This is my code

<?php
//this is were images displayed
$sql    = "SELECT * FROM services WHERE user_name='wendi'";
$result = $con->query($sql);
if ($result->num_rows > 0) {
    // output data of each row
    while ($row = $result->fetch_assoc()) {
?>
                   <a href="delete.php?delete=<?= $row['id'] ?>" onclick = "return confirm('Are you sure you want to delete?')"><img src="images/template/delete.png" id="AEDbutton">delete</a>

<?php
        echo "<img border=\"0\" src=\"" . $row['image_path4'] . "\" width=\"200\"  height=\"100\">";
        echo "<br>";
    }
}


?>

this is delete.php

<?php
include('config.php');


$sql    = "SELECT * FROM services WHERE user_name='wendi'";
$result = $con->query($sql);

while ($row = $result->fetch_assoc()) {
    $image = $row['image_path4'];
    unlink($image);

}
$sql    = "UPDATE image_path4=null, file_name4=null FROM services WHERE user_name='wendi'";
$result = $con->query($sql);


?>

It seems your UPDATE query is malformed, the syntax should be like this:

UPDATE {table} SET {column}={value} WHERE {column2}={value2}

So in your case this would be:

UPDATE services SET image_path4=null, file_name4=null WHERE user_name='wendi'

Your query should be like this:

$sql = "UPDATE services SET image_path4 = null, file_name4 = null WHERE user_name = 'wendi' ";

After uplink function assign $image to null:

$image = null;

And use update query below:

$sql = "UPDATE  `services ` SET  `image_path4` = ' ". $image." ', `file_name4` = ' ". $image." ' WHERE `user_name` = 'wendi' ";