title: How to get simple Sum with JOOQ?
body: <p>What is the right way to get simple <code>sum</code> with JOOQ?</p>
  
  <pre><code>SELECT sum(PERSON.AGE) FROM PERSON;
  </code></pre>
  
  <p>I think about something like that:</p>
  
  <pre><code>BigDecimal sum = factory.select(sum(PERSON.AGE)).from(PERSON).fetch???;
  </code></pre>
  
  <p>?</p>