title: How to query virtual column using Sequelize?
body: <p>There is a Sage in Student table, I want to query the year of birth of a student using <code>2017-Sage</code>, but I don't know how to do it, I have tried to do like this:</p>
  
  <pre><code>db.Student.findAll({
          attributes: ['Sname','Ssex',[2017-Sequelize.col('Sage'),'Year of birth']],
          where: {
              Clno: {
                  $in: ['01311','10665']
              }
          }
      })
  </code></pre>
  
  <p>but it comes the error: </p>
  
  <pre><code>UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: attr[0].indexOf is not a function
  </code></pre>