title: Get the only one sub-subdocument
body: <p>I have a collection of documents like this:</p>
  
  <pre><code>{
    "_id" : ObjectId("532d4e7d569c9e4574d5156e"),
    "title" : "Book Title"
    "author" : "Book Author",
    "owner" : "532d4e7c569c9e4574d51568",
    "pages" : [
      {
        "texts" : [
          {
            "_id" : ObjectId("532d4e7d569c9e4574d51572"),
            "paragraphs" : [ ],
            "format" : [ ],
            "position" : {
              "y" : 0,
              "x" : 0
            }
          }
        ],
        "images" : [
          {
            "_id" : ObjectId("532d4e7f569c9e4574d51573"),
            "position" : {
              "y" : 0,
              "x" : 0
            }
          }
        ],
      },
      {
        "_id" : ObjectId("532d4e7d569c9e4574d51571"),
        "videos" : [ ],
        "audios" : [ ],
        "images" : [ ],
        "texts" : [ ],
        "animations" : [ ]
      }
    ]
  }
  </code></pre>
  
  <p>and I want to get the only <code>text</code> subdocument with <code>_id</code>:</p>
  
  <pre><code>db.projects.find({'pages.texts._id': ObjectId("532d4e7d569c9e4574d51572")}, {'pages.$.texts.$': 1}).pretty()
  </code></pre>
  
  <p>but it's not works.</p>
  
  <p>I want to get only this part of document: </p>
  
  <pre><code>{
    "_id" : ObjectId("532d4e7d569c9e4574d51572"),
    "paragraphs" : [ ],
    "format" : [ ],
    "position" : {
      "y" : 0,
      "x" : 0
    }
  }
  </code></pre>