3702506 - System queries are not working for GET requests on OData V4 API

When calling a GET request for an OData V4 API, the system queries inserted in the URL don't have any effect. 

Using the API Customer Return (A2X, OData V4) as an example: when calling the URL <host>/sap/opu/odata4/sap/api_customerreturn/srvd_a2x/sap/customerreturn/0001/CustomerReturn?top=10&expand=_Item,_Partner,_Text, the queries top and expand don't have any effect: there are more results than specified on top (+10) and the sub-entities item, partner and text are not present in the response.

SAP S/4HANA Cloud Public Edition

The queries are not working due to the malformed syntax of the URL. In OData V4, system query options must be prefixed with a dollar sign ($).

By omitting the $, the SAP Gateway treats expand and top as custom query parameters rather than system commands, so it simply ignores them. So this explains why the main order data is received (the request succeeds) but without the sub-entities (the expansion logic is never triggered).

Add the dollar sign ($) before the commands:

• <host>/sap/opu/odata4/sap/api_customerreturn/srvd_a2x/sap/customerreturn/0001/CustomerReturn?$top=50&$expand=_Item,_Partner,_Text

Note: to use the _PricingElement in the expand query, the sales document number must be specified.

Customer Return (A2X, OData V4) | SAP Help Portal

OData Version 4.01. Part 1: Protocol

odata v4, _Item, _Partner, _PricingElement, _Text, navigation, association, customer return, api_customerreturn, SalesOrder, system query options, top, expand, filter, orderby, select, count , KBA , SD-SLS-API-2CL , API (Public Cloud) , Problem