1366 - Incorrect integer value: '' for column `CP_as15`.`whos_online`.`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', 'lsudfcc6buc79667ao34ak6q13', '52.14.223.221', '1738997851', '1738997851', '/index.php?XTCsid=rvhpma4g2refpn33qk2f07nfb7&cat=c26_PDA---Handheld-Akku.html')

[XT SQL Error]