title: SQL query to identify seasonal sales items
body: <p>I need a SQL query that will identify seasonal sales items. </p>
  
  <p>My table has the following structure - </p>
  
  <pre><code>ProdId    WeekEnd     Sales
  234       23/04/09    543.23
  234       30/04/09     12.43
  432       23/04/09      0.00
  etc
  </code></pre>
  
  <p>I need a SQL query that will return all ProdId's that have 26 weeks consecutive 0 sales.  I am running SQL server 2005. Many thanks!</p>
  
  <p><strong>Update:</strong> A colleague has suggested a solution using rank() - I'm looking at it now...</p>