title: Sharepoint URL to reference a lookup
body: <p>I have two SharePoint lists used for Support case management. The first list contains Case Numbers and information about the case. The second list contains exhibits that support the case itself.</p>
  
  <p>We have a convention that the Case Number is a String supplied by the worker, ex 20150205-001. When the exhibits are joined to the Case it is through a Lookup. I want the Exhibit ID, a String, to be of the form Case Number + _[A-Z] -- and be auto-assigned.</p>
  
  <p>I want to use a Workflow (MS Sharepoint Designer 2013) to assign the Exhibit ID. The problem I face is that I cannot get the actual Case Number from the Lookup. The closest I have gotten so far is to get the ID (1, 2, etc) but not the actual String value represented.</p>
  
  <p>Tried working with the following URL:</p>
  
  <p><a href="http://[mySiteURL]/_api/web/lists/getbytitle([listName])/items" rel="nofollow">http://[mySiteURL]/_api/web/lists/getbytitle([listName])/items</a>?$select=Title,Case/Id&amp;$expand=Case/Id&amp;$filter=Case/Id%20eq%2020150205%45001</p>
  
  <p>substituted ascii: $filter=Case/ID eq 20150205-001</p>
  
  <p>without the filter I get all list items (understandably) but the filter does not work properly because the ID is not the actual lookup value.</p>