title: List of metacharacters for MySQL regexp square brackets
body: <p>Strangely I can't seem to find anywhere a list of the characters that I can't safely use as literals within MySQL regular expression square brackets without escaping them or requiring the use of a <code>[:character_class:]</code> thing. </p>
  
  <p>(Also the answer probably needs to be MySQL specific because MySQL regular expressions seem to be lacking compared those in Perl/PHP/Javascript etc).</p>