title: SQL Server: how can I change this query to use subquery with date column?
body: <p>I have a query that has about 20 columns, for brevity I'm showing <code>*</code></p>
  
  <pre><code>SELECT TOP 1
      *
  FROM 
      [Frontier].[dbo].[tblLoadFile]
  WHERE
      TN = 4132644856
  ORDER BY 
      CallTime DESC
  </code></pre>
  
  <p>I am told that I should use a <code>max</code> on <code>calldate</code> in a <code>subquery</code> as it is the "faster" and "proper" way to write the query. </p>
  
  <p>How and where would I put in a <code>max(calldate)</code> subquery?</p>
  
  <p>This is for SQL Server / T-SQL</p>