title: MongoDB project the documents with count greater than 2
body: <p>I have a collection like </p>
  
  <pre><code>{
      "_id": "201503110040020021",
      "Line": "1", // several documents may have this Line value
      "LineStart": ISODate("2015-03-11T06:49:35.000Z"),
      "SSCEXPEND": [{
              "Secuence": 10,
              "Title": 1,
          },
          {
              "Secuence": 183,
              "Title": 613,
          },
          ...
      ],
  
  } {
      "_id": "201503110040020022",
      "Line": "1", // several documents may have this Line value
      "LineStart": ISODate("2015-03-11T06:49:35.000Z"),
      "SSCEXPEND": [{
              "Secuence": 10,
              "Title": 1,
          },
  
      ],
  
  }
  </code></pre>
  
  <p>SSCEXPEND is an array. I am trying to count the size of SSC array and project if the count is greater than or equal to 2. My query is something like this </p>
  
  <pre><code>db.entity.aggregate(
     [
        {
           $project: {
              SSCEXPEND_count: {$size: "$SSCEXPEND"}
           }
        },
        {
          $match: {
              "SSCEXPEND_count2": {$gte: ["$SSCEXPEND_count",2]}
           }
        }
     ]
  )
  </code></pre>
  
  <p>I am expecting the output to be only the the first document whose array size is greater than 2.</p>
  
  <p>Project part is working fine and I am able to get the counts but I need to project only those which has count greater than or equal to two but my match part is not working. Can any one guide me as where am I going wrong?</p>