title: Exporting data from Postgres to json and renaming the columns of the fly
body: <p>How can I import only certain column from a table in json and rename them on the fly? That is:</p>
  
  <pre><code>MyTable (id, column1, column2, columns3)
  </code></pre>
  
  <p>And I want to export to json them as:</p>
  
  <pre><code>MyTable: {column11, column2, columns33}
  </code></pre>
  
  <p>So only 3 columns and 2 of them are renamed.</p>