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', 'bsajmd84jvuks46o8pubn48i77', '216.73.216.113', '1775231810', '1775231810', '/product_info.php?XTCsid=38f09672db884903e3803adf9d076819&info=p17_20-Tissue-Napkins.html')

[XT SQL Error]