title: Self join query: how to return children and parent row?
body: <p>I have this table:</p>
  
  <pre><code>Content:
  - id
  - parent_id
  - slug
  - creation_date
  </code></pre>
  
  <p>parent_id is a foreign key pointing to the same table (content.id).</p>
  
  <p>I want to select all the rows in the table that are children of a parent_id in the same table. I would like the parent row to be returned too. </p>
  
  <p>Right now I have these two queries, both of which work only returning the child rows:</p>
  
  <pre><code>SELECT a.* 
  FROM content a 
  JOIN content b ON a.parent_id = b.id
  WHERE b.slug = 'some-slug'
  ORDER BY creation_date
  </code></pre>
  
  <p>and:</p>
  
  <pre><code>SELECT content.* 
  FROM content 
  WHERE content.parent_id = (SELECT id FROM content WHERE slug= 'some-slug')
  ORDER BY creation_date
  </code></pre>
  
  <p>How can I return the child rows as well as the parent row ordered by creation_date?</p>
  
  <p>Thanks!</p>