title: Select a sum in Knex.js without using .raw
body: <p>I am trying to rewrite some MySQL queries in Knex.js, and I feel like I'm running into <code>.raw</code> at every turn, which feels counter to the reason I want to use Knex in the first place.</p>
  
  <p><strong>Is it possible to write the following query <em>without</em> using <code>.raw</code>?</strong></p>
  
  <pre><code>SELECT
     product,
     SUM(revenue)
  FROM orders
  </code></pre>
  
  <p>Using raw, it works to write:</p>
  
  <pre><code>knex()
     .select(
        'product',
        knex.raw('SUM(revenue)')
     )
     .from('orders')
  </code></pre>
  
  <p>but the idea of using Knex was to avoid using MySQL query strings, so I'm hoping there's another way. Or does everyone just use <code>.raw</code> everywhere, and I'm misunderstanding something? Very possible, I'm new to this.</p>