title: Non-integer constants in the ORDER BY clause
body: <p>Upgrade advisor says:</p>
  
  <blockquote>
    <p>Non-integer constants are not allowed in the <code>ORDER BY</code> clause in 90 or later compatibility mode".</p>
  </blockquote>
  
  <p>But, when I try the below statement in <code>SQL Server 2008</code>, it works just fine. So, my questions is: What exactly is a non-integer constant?</p>
  
  <pre><code>SELECT
      COALESCE( fi.Payee, -1 ) AS 'Payee',
      COALESCE( p.ProvNo, '' ) AS 'ProviderNo'
  FROM
      dbo.tbl_Emp
  ORDER BY
      'Payee',
      'ProviderNo' 
  </code></pre>