Querying against WooCommerce endpoints only accepts certain parameters, which are not fields in the vendor response body so it can be a little confusing to structure successful CEQL queries against WooCommerce. We are analyzing the possibility of normalizing query against the WooCommerce endpoints further, but for the time being the documented WooCommerce query syntax must be used.
For instance to query the /orders endpoint for a specific customer_id=1 the Where clause must be made like customer=1, and querying the /products endpoint for a specific product id=1651 must be made with a Where clause of include=1651.
WooCommerce has documented the available parameters for querying their endpoints including /orders and /products:
/orders available parameters: context, page, per_page, search, after, before, exclude, include, offset, order, orderby, parent, parent_exclude, status, customer, product, dp.
/products available parameters: context, page, per_page, search, after, before, exclude, include, offset, order, orderby, parent, parent_exclude, slug, status, type, sku, featured, category, tag, shipping_class, attribute, attribute_term, tax_class, in_stock, on_sale, min_price, max_price.