title: Postgresql - Opposite of string_agg
body: <p>I'm looking for a postgresql function that will do the opposite of <code>string_agg</code>. </p>
  
  <p>I have a movies table where the tags column contains values such as </p>
  
  <pre><code>Action|Adventure|Drama|Horror|Sci-Fi
  Action|Horror|Sci-Fi
  </code></pre>
  
  <p>I would like to get a distinct list of tags from this column, for example</p>
  
  <pre><code>Action
  Adventure
  Drama
  Horror
  Sci-Fi
  </code></pre>