title: How to substitute ?column? from subqueries output
body: <p>How I can put name on subquery's output, instead of <code>?column?</code>?</p>
  
  <p>The <code>SELECT</code>'s output is:</p>
  
  <pre><code>._______.__________.__________.
  |__id___|_?column?_|_?column?_|
  |_31886_|____12____|____13____|
  </code></pre>
  
  <p>What I want is:</p>
  
  <pre><code>._______.__________.__________.
  |__id___|___ages___|_validate_|
  |_31886_|____12____|____13____|
  </code></pre>
  
  <p>What my <code>SELECT</code> look like:</p>
  
  <pre><code>SELECT g.id,
  (select dt from pcdhidro where nomepcd=31886 order by datahora asc limit 1),
  (select dt from pcdhidro_2003_96 where nomepcd=31886)
  FROM gestpcd_2 g
  WHERE g.tipo = 'HIDRO' and g.id = 31886
  </code></pre>