While working with Rest API in SharePoint, you have to know about oData operators, ... $expand: This is interesting columns like person or group, Lookup field they're ... form the list item you will end up with potentially multiple values for the multi value column. ... If you need to expand nested entities, use the . dot notation.. I have created C# Web API to export data from activity entity. ... Now, I wanted to use this variable in odata query using WEB API by mapping the lookup field ...