准备的UPDATE语句PHP

Question

Hi I'm having a lot of trouble with these lines of code. I'm getting a "Call to a member function bind_param() on a non-object". I'm making exactly the same call right above, but instead of an update query I'm using the select statement to get $db_password and $db_salt. I have tried searching google and stackoverflow, but I can't find anyone so close but still so far. If somebody sees something i don't please give an advise. Thank you

if($passwordChange == $db_password) 
    {
        $stmt = $mysqli->prepare("UPDATE members SET username=? email=? WHERE id=?");
     $stmt->bind_param('ssi', $usernameInput, $emailInput, $user_id);
     $stmt->execute();
        return true;
        }

Answer 1

You have a syntax error. You're missing a comma between your update statements:

$stmt = $mysqli->prepare("UPDATE members SET username=? email=? WHERE id=?");
                                                     ^^^^
                                                     HERE    

Corrected:

$stmt = $mysqli->prepare("UPDATE members SET username=?, email=? WHERE id=?");