title: SELECT from an UNION ALL in SQL
body: <p>When I do a :</p>
  
  <pre><code>SELECT id FROM table1
  UNION ALL
  SELECT id FROM table2
  </code></pre>
  
  <p>I get a new table with all the ids, and it's perfect.
  But when I try a :</p>
  
  <pre><code>SELECT * FROM (
                 SELECT id FROM table1
                 UNION ALL
                 SELECT id FROM table2
                 )
  </code></pre>
  
  <p>It doesn't work, It doesn't return me anything.</p>
  
  <p>May anyone help me ? I've tried a lot of things, and this is a very small code so I can't understand why it doesn't work.</p>
  
  <p>Thank's a lot.</p>