title: mongodb php - how to do "INNER JOIN"-like query
body: <p>I'm using the Mongo PHP extension.</p>
  
  <p>My data looks like:</p>
  
  <pre><code>users
  {
    "_id": "4ca30369fd0e910ecc000006",
    "login": "user11",
    "pass": "example_pass",
    "date": "2010-09-29"
  },
  {
    "_id": "4ca30373fd0e910ecc000007",
    "login": "user22",
    "pass": "example_pass",
    "date": "2010-09-29"
  }
  
  news
  {
    "_id": "4ca305c2fd0e910ecc000003",
    "name": "news 333",
    "content": "news content 3333",
    "user_id": "4ca30373fd0e910ecc000007",
    "date": "2010-09-29"
  },
  {
    "_id": "4ca305c2fd0e910ecc00000b",
    "name": "news 222",
    "content": "news content 2222",
    "user_id": "4ca30373fd0e910ecc000007",
    "date": "2010-09-29"
  },
  {
    "_id": "4ca305b5fd0e910ecc00000a",
    "name": "news 111",
    "content": "news content",
    "user_id": "4ca30369fd0e910ecc000006",
    "date": "2010-09-29"
  }
  </code></pre>
  
  <p>How to run a query similar like this, from PHP?</p>
  
  <pre><code>SELECT n.*, u.* 
  FROM news AS n 
  INNER JOIN users AS u ON n.user_id = u.id
  </code></pre>