PDO INSERT with WHERE clause

Question

I want to INSERT data into an existing table using MySQL with PDO. I have no idea how to use the WHERE statement inside the INSERT INTO query. My code:

if(isset($url)){
        if(preg_match($pattern, $url) ){
            $user = $_SESSION['user'];
            try {
                // prepared statement to insert user data
                $sql = "INSERT INTO user (website) where username = :username VALUES (:website)";
                $stmt = $conn->prepare($sql);
                $stmt->bindParam(':website', $url);
                $stmt->bindParam(':username', $user);
                $stmt->execute();
            }
            //Exception handling
            catch(PDOException $e)
            {
                $urlError =  $e->getMessage();
            }

Each time i try to INSERT it fails. I am new with php so don't go too hard on me please.

Answer 1

I'm going to guess that you don't want insert . You really want update :

UPDATE user
    SET website = :website
    WHERE username = :username;

UPDATE changes columns in existing rows. INSERT adds new rows into a table.

Answer 2

Check this:

if(isset($url)){
    if(preg_match($pattern, $url) ){
        $user = $_SESSION['user'];
        try {
            // prepared statement to insert user data
            $sql = "UPDATE user SET website = :website WHERE username = :username";
            $stmt = $conn->prepare($sql);
            $stmt->bindParam(':website', $url);
            $stmt->bindParam(':username', $user);
            $stmt->execute();
        }
        //Exception handling
        catch(PDOException $e)
        {
            $urlError =  $e->getMessage();
        }
    }
}