The Sales Order 'External ID' is not available in the OData Service "Customer_order_collection".
SAP Cloud for Customer
External ID is not directly available in the Sales order Odata.
External ID is stored as a BTD reference in the sales order. Query the CustomerOrderBusinessTransactionDocumentReferenceCollection and then write a filtering logic to get the ID field where the RoleCode = 6.
Customer_Order, customer order, sales order, odata, collection , KBA , LOD-LE-CQP-CO , Lean Sales Orders , LOD-CRM-INT-API , OData API (C4C Only) , Problem