I have sql query which creates trigger which contains comment with question mark.
CREATE TRIGGER `messages_for_users_au` AFTER
UPDATE ON `messages_for_users` FOR EACH ROW
-- oznaceni vlakna za neprectene
IF
NEW.lastReadTime IS NULL
AND OLD.lastReadTime IS NOT NULL
/* neprisel mezi tim dalsi vzkaz? */
AND OLD.lastReadTime >= (
SELECT lastSendTime
...
SqlPreprocesor catches the ? and requires to pass some parameter.