title: How do I do a joined lookup with search.lookupFields()?
body: <p>I'm trying to get some information about an item, including the item's subsidiary's logo, which naturally requires joining the item to the subsidiary.</p>
  
  <p>The documentation for <code>search.lookupFields</code> says:</p>
  
  <blockquote>
    <p>You can use joined-field lookups with this method, with the following syntax:</p>
  
  <pre><code>join_id.field_name 
  </code></pre>
  </blockquote>
  
  <p>So, I duly request the fields I want, including a join on <code>subsidiary</code>:</p>
  
  <pre><code>require(['N/search'], function(search) {
      var item = search.lookupFields({
          type: search.Type.ITEM,
          id: 2086,
          columns: ['itemid', 'displayname', 'subsidiary.logo'],
      });
      log.debug(item);
  });
  </code></pre>
  
  <p><code>itemid</code> and <code>displayname</code> are fine, but when I try to join another record I get this error:</p>
  
  <pre><code>{
    "type":"error.SuiteScriptError",
    "name":"SSS_INVALID_SRCH_COLUMN_JOIN",
    "message":"An nlobjSearchColumn contains an invalid column join ID, or is not in proper syntax: logo.",
    "stack":["doLookupFields(N/search/searchUtil.js)","&lt;anonymous&gt;(adhoc$-1$debugger.user:2)","&lt;anonymous&gt;(adhoc$-1$debugger.user:1)"],
    "cause":{
      "type":"internal error",
      "code":"SSS_INVALID_SRCH_COLUMN_JOIN",
      "details":"An nlobjSearchColumn contains an invalid column join ID, or is not in proper syntax: logo.",
      "userEvent":null,
      "stackTrace":["doLookupFields(N/search/searchUtil.js)","&lt;anonymous&gt;(adhoc$-1$debugger.user:2)","&lt;anonymous&gt;(adhoc$-1$debugger.user:1)"],
      "notifyOff":false
    },
    "id":"",
    "notifyOff":false,
    "userFacing":false
  }
  </code></pre>
  
  <p>This seems to happen no matter which record and field I try to join. What am I missing?</p>