title: Get another row's data from same table
body: <p>I have a <code>categories</code> table:</p>
  
  <pre><code>| cat_id | cat_name | cat_desc | child_cat
  </code></pre>
  
  <p>What I want to accomplish is to get the cat name of <code>child_cat</code> if it exists.</p>
  
  <p>sample data:</p>
  
  <pre><code>| cat_id | cat_name | cat_desc | child_cat
      1        test      testd       0
      2        test2     testd2      1
  </code></pre>
  
  <p>When I get the info of <code>cat_id = 2</code>, I also want to get the <code>cat_name</code> of <code>child_cat</code>.</p>
  
  <p>Expected output:</p>
  
  <pre><code>| cat_id | cat_name | cat_desc | child_cat_name
      1        test2     testd2        test
  </code></pre>
  
  <p>Which method should I use?</p>