title: Is it possible to do a $lookup aggregation between two databases in Mongodb?
body: <p>I'm trying to do something like this: </p>
  
  <pre><code>use user; 
  
  db.user.aggregate([
      {
        $lookup:
          {
            from: "organization.organization",
            localField: "organizationId",
            foreignField: "uuid",
            as: "user_org"
          }
     }
  ])
  </code></pre>
  
  <p><code>user</code> and <code>organization</code> are in two different databases. </p>
  
  <p><em>If this is not possible, what are the alternatives?</em></p>