title: How to use Union query with Laravel Eloquent?
body: <p>This MySQL query Has union and Normalized I don't Know how to write laravel Query.</p>
  
  <pre><code>SELECT DISTINCT val
  FROM
  (
      SELECT 'date' date_type, date val FROM user_presentation
      UNION
      SELECT 'accept_date', accept_date FROM user_presentation
      UNION
      SELECT 'question_date', question_date FROM user_presentation
      UNION
      SELECT 'success_date', success_date FROM user_presentation
  ) normalized;
  </code></pre>