Incorrect integer value: '' for column 'is_wholesaler' at row 1

update tbl_session set 	user_id = NULL,  is_wholesaler = '', items_in_cart = '0', cart_total = '0.00', original_total = '0.00', estimated_total = '0.00', cart_ship_method_id = '', cart_usps_insurance = '', cart_ups_insurance = '', cart_shipping_zip = '', cart_shipping_country = '762', shipping_id = '', billing_id = '', order_id = '', state_id = '', voucher_id = '', gift_certificate_id = '', order_complete = '', pwpp_token = '', pwpp_payer_id = '', date_time_modified = NOW() where unique_session_id = 'c002256dade34e2ce73b83cd9f1b4665'