title: Sum on subqueries on SQL Server
body: <p>I have a query with some subqueries inside and I want to add a sum query to sum them all.<br/>
  How can I do that?</p>
  
  <p>example:</p>
  
  <pre><code>Id,
  (SELECT COUNT(*) FROM table1 LEFT JOIN table2 on ...) as col1,
  (SELECT COUNT(*) FROM table3 LEFT JOIN table4 on ...) as col2,
  ** Sum of both col1 and col2 here **
  </code></pre>