title: how to show databases in mysql using regexp
body: <p>In Mysql db, I have many databases, like </p>
  
  <pre><code>msgnotify_0,msgnotify_1....msgnotify_20,msgnotify_21.......msgnotify_98,msgnotify_99.
  </code></pre>
  
  <p>I want to only get database name including </p>
  
  <pre><code>msgnotify_0,msgnotify_1....msgnotify_20,msgnotify_21,msgnotify_48,msgnotify_49
  </code></pre>
  
  <p><strong>not including</strong> 
  <code>msgnotify_50,msgnotify_51.....msgnotify_98,msgnotify_99.</code></p>
  
  <p>Execute <code>show databases</code> will give me all the databases in the db,</p>
  
  <p>Execute <code>show databases like 'msgnotify_%'</code> also give me all the databases.</p>
  
  <p>how can I get the only previous 50 database names? </p>
  
  <p><strong>using regexp? how?</strong></p>