title: Error converting data type varchar to bigint using union
body: <p>Query:</p>
  
  <pre><code>SELECT TOP (1) '-1' AS hrempid, 'All employees' AS fullname
  FROM employee
  UNION
  SELECT fullname, hrempid
  FROM employee AS employee1 
  order by fullname
  </code></pre>
  
  <p>Error:
  Error converting data type varchar to bigint.</p>