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', '4354ee7552e185c1fee354aa596361d1', '44.202.209.105', '1711714934', '1711714934', '/product_info.php/info/p63_de-Immenwaechter-0-75-l-lieblich-aus-Kornblume-und-Bluetenhonig.html')

[XT SQL Error]