title: Mysql regex doesn't start with alnum
body: <p>I am trying to remove records from my table which don't start with an alnum character. I've tried a number of different things but MySQL doesn't seem to play ball.</p>
  
  <p>My current query is:</p>
  
  <pre><code>SELECT *
  FROM central_store
  WHERE DomainName NOT REGEXP '^[[a-z|0-9]]'
  </code></pre>
  
  <p>I've also tried the <a href="https://www.safaribooksonline.com/library/view/mysql-cookbook/0596001452/ch04s08.html" rel="nofollow noreferrer"><code>:alnum</code></a> option, but my results still return records starting with a 0-9. I know this is probably basic but please can someone explain what I'm doing wrong.</p>