如何使用SQL更新记录

Question

I'm trying to update a username record, with the new one that comes from form.

After I execute the statement, a record in my database is deleted but it is NOT REPLACED with a new one, that comes from form. I can not figure out why.

index.php:

<form action="change.php">
    <input type="text" name="txtNewUsername" id="txtNewUsername" placeholder="new username"><br/>
    <button>Change username</button>
</form>

change.php:

<?php
session_start();
require_once __DIR__.'/connect.php';

$txtNewUsername = $_POST['txtNewUsername'];
$sUsername = $_SESSION['txtUsername'];

try{
    $stmt = $db->prepare('UPDATE users SET username = :sNewUsername WHERE username = :sOldUsername');
    $stmt->bindValue('sNewUsername', $txtNewUsername);
    $stmt->bindValue(':sOldUsername', $sUsername);
    $stmt->execute();

    echo $txtNewUsername;


}catch(PDOEXception $ex){
    echo $ex;
}

I would like to replace the username of connected user with the one coming from a form.

Answer 1

$stmt->bindValue('sNewUsername', $txtNewUsername);

I don't know if this is causing your problem but you are missing " : " sNewUsername