title: How to group in mongodb withtout including _id
body: <p>so I want to result as :</p>
  
  <pre><code>{
      "id" : 888789999,
      "name" : "Malaysian with Attendance Allowance",
  }
  </code></pre>
  
  <p>but I tried</p>
  
  <pre><code>{$group : {
      'id' : '$profiles.id',
      'name' : {$first:'$profiles.name'},
  }}
  </code></pre>
  
  <p>an I get an error :</p>
  
  <blockquote>
    <p>"errmsg" : "The field 'id' must be an accumulator object",</p>
  </blockquote>