PHP bind_param 错误

Question

When I start my script this Error appears:

Fatal error: Call to a member function bind_param() on a non-object in /Applications/XAMPP/xamppfiles/htdocs/Jil/login_skript.php on line 16

Here is the script:

$sql = "SELECT ID, vorname, nachname, username, email, passwort, profilBild, geschlecht, alter, wohnort, ueberSich FROM benutzer WHERE username LIKE '?' LIMIT 1;";
$stmt = $db->prepare($sql);
$stmt->bind_param("s", $username);

Answer 1

The problem is that 'alter' is a MySQL keyword. Enclose all your field names (or at least just 'alter') in backticks to fix this.

Also, don't put quotes around the '?'s in a prepared statement. They will be added for you.

$sql = "SELECT `ID`, `vorname`, `nachname`, `username`, `email`, `passwort`, `profilBild`, `geschlecht`, `alter`, `wohnort`, `ueberSich` FROM `benutzer` WHERE `username` LIKE ? LIMIT 1;";
$stmt = $db->prepare($sql);
$stmt->bind_param("s", $username);

Answer 2

This occurs because your select statement is invalid and the prepare returns NULL. You don't need the ' around the ? . There may be other errors as well that you can see by calling $db->error