title: Unsafe characters for programming and MySQL queries/databases
body: <p>Im limiting my clients from entering certain characters.</p>
  
  <p>Right now I allow:</p>
  
  <ul>
  <li><p>All the numbers</p></li>
  <li><p>All the english letters</p></li>
  <li><p>-</p></li>
  <li><p>_</p></li>
  </ul>
  
  <p>I do not allow:</p>
  
  <ul>
  <li>' </li>
  <li>" </li>
  <li>;</li>
  </ul>
  
  <p>What other safe characters and/or unsafe characters exist when doing a query via programming using a textbox or such?</p>