Errore: Unknown column 's.sess_agent' in 'where clause'

Query:
SELECT s.*, u.*, url.url_self AS user_url FROM sessions AS s
INNER JOIN users AS u ON (u.user_id = s.sess_uid)
INNER JOIN urls AS url ON (u.user_id = url.url_info_id AND url.url_info = 'user')
WHERE s.sess_key = '%s' AND s.sess_ip = '%s' AND s.sess_agent = '%s' LIMIT 1

Tabella:
CREATE TABLE sessions(
sess_key char(32) NOT NULL default '',
sess_ip varchar(50) NOT NULL default '',
sess_agent tinytext NOT NULL default '',
sess_time int(10) unsigned NOT NULL default '0',
sess_group tinyint(3) unsigned NOT NULL default '0',
sess_hidden enum('0', '1') NOT NULL default '0',
sess_uid mediumint(8) unsigned NOT NULL default '0',
sess_selfurl tinytext NOT NULL,
sess_infourl varchar(50) NOT NULL default '',
sess_titleurl tinytext NOT NULL,
PRIMARY KEY (sess_key)
)ENGINE=MyISAM;