Blad bazy danych

Blad przy zapytaniu: SELECT zakladka_id FROM therma_zakladki WHERE zakladka_link='
Warning: Use of undefined constant bookmark_link - assumed 'bookmark_link' (this will throw an Error in a future version of PHP) in /home/therma/ftp/strona_www/templates/t_index.php on line 42
/deklaracja-dostepnosci'
Komunikat serwera: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'bookmark_link' (this will throw an Error in a future version of PHP) in /home' at line 1