title: SQL Grouping with null rows
body: <p>I've searched around a bit and couldn't find anything that addressed my exact issue</p>
  
  <p>I have a table (MSSQL), and the data looks like this:</p>
  
  <pre><code>Source table:
  
  RID    FullName FirstName   LastName    Email               Address
  -------------------------------------------------------------------------------
  1      NULL     [BOB]       NULL        NULL                NULL
  1      NULL     NULL        [BOB]       NULL                NULL
  1      NULL     NULL        NULL        [bob@bob.com]       NULL
  2      NULL     [JAY]       NULL        NULL                NULL
  2      NULL     NULL        [JAY]       NULL                NULL
  2      NULL     NULL        NULL        [jerry@jerry.com]   NULL
  3      NULL     [RICK]      NULL        NULL                NULL
  3      NULL     NULL        [RICK]      NULL                NULL
  3      NULL     NULL        NULL        [rick@rick.com]     NULL
  </code></pre>
  
  <p>But I need to transform the data to look like this:</p>
  
  <pre><code>Results table:
  
  RID     FullName             Email                Address
  ---------------------------------------------------------
  1       [BOB] [BOB]        [bob@bob.com]          NULL
  2       [JAY] [JAY]        [jerry@jerry.com]      NULL
  3       [RICK] [RICK]      [rick@rick.com]        NULL
  </code></pre>
  
  <p><strong>NOTE:</strong>  If Fullname from the source table is NULL, then we combine FirstName and LastName.  (If both FirstName and LastName are NULL, then we simply have a NULL FullName result, which is completely fine).</p>
  
  <p>Thanks in advance for any help on this!</p>