I'm using prestashop webservice for an integration,
I'm sending throw POST
with this xml
<![CDATA[[SQL Error] Column 'id_product_attribute' cannot be null. From CartCore->setWsCartRows() Query was : INSERT INTO `ps_cart_product`(`id_cart`, `id_product`, `id_product_attribute`, `id_address_delivery`, `quantity`, `date_add`, `id_shop`) VALUES (18, 0, NULL, 0, 0, NOW(), 1)]]>
Your XML es wrong formed. Notice that in query error id_product and id_product_attribute values are 0 and NULL, so data you are passing into XML never find correct destination in webservice.
If you have SKU you must first get products filtered by reference (or ean13 or UPC or the field that SKU represent in Prestashop). That way you will have id_product and id_product_attribute yo pass it to webservice in your XML.