sanitize POST arrays

You can use array_map like this:

$room_types = isset( $_POST['room_types'] ) ? (array) $_POST['room_types'] : array();

$room_types = array_map( 'esc_attr', $room_types ); // Replace esc_attr with your desire sanitization

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)