When I run this page, it says You couldn’t execute the query. I think there is a syntax problem, but I cannot see the problem.

The variables look fine when I echo them. I added the column names as a code comment. All the columns are VARCHAR.

I don’t believe it is a connection problem since I can perform SELECT AND DELETE operations from other php pages.

`<?php include “header.php”;
if(isset ($_POST [‘submit’])) {
include “config.php”;

$user_id = $_POST ['user_id'];
$fname = $_POST ['f_name'];
$lname = $_POST ['l_name'];
$usern = $_POST ['user_name'];

$sql = "UPDATE user SET first_name='$fname', last_name='$lname', username='$usern' WHERE user_id='$user_id'";
$result = mysqli_query ($conn, $sql) or die ("Query Failed");
if (mysqli_num_rows ($result) > 0) {
    echo "<p style='margin:10px 0; color:red; text-align:center;'>Username already exists.</p>";
}
else{
    $sql1 = "INSERT INTO user (first_name, last_name, username) 
        VALUES ( '{$fname}', '{$lname}' , '{$username}')";

    if (mysqli_query ($conn, $sql1)) {
        header ("location: {$hostname}/admin/users.php");
    }

}

}`