title: Does using WHERE IN hurt query performance?
body: <p>I've heard that using an IN Clause can hurt performance because it doesn't use Indexes properly.  See example below:</p>
  
  <pre><code>SELECT ID, Name, Address 
  FROM people
  WHERE id IN (SELECT ParsedValue FROM UDF_ParseListToTable(@IDList))
  </code></pre>
  
  <p>Is it better to use the form below to get these results?</p>
  
  <pre><code>SELECT ID,Name,Address
  FROM People as p
  INNER JOIN UDF_ParseListToTable(@IDList) as ids
  ON p.ID = ids.ParsedValue
  </code></pre>
  
  <p>Does this depend on which version of SQL Server you are using?  If so which ones are affected?</p>