title: How to pull all elements from array in MongoDB without any condition
body: <p>I have a document as below, and I want to pull all the elements in this array <strong><em>without any condition</em></strong> just via one statement.  how can I do? </p>
  
  <pre><code>    "energy_sent" : [ 
          {
              "player_id" : "034010000093",
              "_id" : ObjectId("53675b8d251c20490d9679c6"),
              "time" : ISODate("2014-05-05T09:36:13.629Z"),
              "has_accepted" : 0,
              "energy_value" : 2
          }, 
          {
              "player_id" : "034010000094",
              "_id" : ObjectId("53675cfa251c20490d9679cc"),
              "time" : ISODate("2014-05-05T09:42:18.015Z"),
              "has_accepted" : 0,
              "energy_value" : 2
          }, 
          {
              "player_id" : "034010000116",
              "_id" : ObjectId("5367767889f8e3ee137dd239"),
              "time" : ISODate("2014-05-05T11:31:04.457Z"),
              "has_accepted" : 0,
              "energy_value" : 2
          }
      ]
  </code></pre>