title: How to do this aggregation in spring data mongo db?
body: <p>How to do this aggregation in Spring Data MongoDB?</p>
  
  <pre><code>db.order.aggregate([
      { $match: { quantity: { $gt:1 } } },
      { $group: { _id: "$giftCard", count: { $sum:1 } } }
  ])
  </code></pre>