title: how to calculate profit in the select query
body: <p>Following is my select query for calculating monthly income and expense </p>
  
  <pre><code>select sum(dr)exp,sum(cr) inc 
  from vMonthlyExpenses
  </code></pre>
  
  <p>and this will return</p>
  
  <pre><code>exp              inc 
  $14,751,199.09   $14,800,985.09
  </code></pre>
  
  <p>so my question is how to get profit value along with the above select, Expected result is</p>
  
  <pre><code>exp              inc            profit
  $14,751,199.09   $14,800,985.09 $49,786.00
  </code></pre>