title: Oracle sql return true if exists question
body: <p>How do I check if a particular element exists in a table -  how can I return true or false?</p>
  
  <p>I have a table that has </p>
  
  <ul>
  <li>user_id</li>
  <li>user_password</li>
  <li>user_secretQ</li>
  </ul>
  
  <p>Verbally, I want to do this: If a particular <code>user_id</code> exists in the <code>user_id</code> column, then return true -- otherwise return false.</p>