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', 'rookcu9gd122aelf37r0ka5iq1', '54.162.109.90', '1495803888', '1495803888', '/product_info.php?info=p579_Karlsson-Designer-Wanduhr---6-Motive.html')

[XT SQL Error]