1366 - Incorrect integer value: '' for column 'customer_id' at row 1

insert into whos_online (customer_id, full_name, session_id, ip_address, time_entry, time_last_click, last_page_url) values ('', 'Guest', 'i13dke3rovfgqsrdndi7d9vhg1', '216.73.216.130', '1761288646', '1761288646', '/index.php?XTCsid=2f0d32e80e0e3a7e9efdd2dc2a571c8d&cat=c5_Crockery.html')

[XT SQL Error]