title: mongodb move documents from one collection to another collection
body: <p>How can <strong>documents</strong> be <strong>moved from one collection to another collection</strong> in <strong>MongoDB</strong>?? For example: I have lot of documents in collection A and I want to move all 1 month older documents to collection B (these 1 month older documents should not be in collection A).</p>
  
  <p>Using <strong>aggregation</strong> we can do <strong>copy</strong>. But what I am trying to do is <strong>moving</strong> of documents.
  What method can be used to move documents?</p>