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', 'r8iu8ggjml8tb4fh7r72auk3l4', '216.73.216.9', '1758130090', '1758130090', '/index.php?XTCsid=ee199fdb171da456469b100b0e4b3f11&cat=c5_Crockery.html')

[XT SQL Error]