title: how to assign NULL value in sql server 2008?
body: <pre><code>Cusid  Cusgroupid  Productid
  5      NULL        NULL
  
  ppid   cusgroupid       list    bulk     cost   billing
  854    NULL             45.00   42.00    42.00  42.00   
  855    2                39.00   36.00    33.00  30.00
  </code></pre>
  
  <p>I want to compare two table, 
  expect result is </p>
  
  <p>1, if cusgroupid is 2 only select that row </p>
  
  <pre><code>ppid   cusgroupid       list    bulk     cost   billing
  855    2                39.00   36.00    33.00  30.00
  </code></pre>
  
  <p>2, if cusgroupid is null only select that row </p>
  
  <pre><code>ppid   cusgroupid       list    bulk     cost   billing
  854    NULL             45.00   42.00    42.00  42.00   
  </code></pre>
  
  <p>Please help!</p>