title: SQL Fill a column value based on two other columns
body: <p>This site has been a lifesaver way too many times. </p>
  
  <p>Need some help again from you guys.</p>
  
  <p>I am working on creating a query that will group all users to their respective group ids. Here is what I have:</p>
  
  <pre><code>UserID # UserLastName # GroupID # Section #
  
    01   #    Smith     #  999    #    1
  
    02   #    Smith     #  999    #    2
  
    03   #    White     #  999    #    1
  
    04   #    White     #  1000   #    2
  
    05   #    White     #  1000   #    3
  </code></pre>
  
  <p>and so forth...</p>
  
  <p>What I want to do is to automatically assign Smith to only one group and section without overwriting what I already have. The group would be something like 999-S (Section is now the last name). And since White only belongs to one section of 999 he would simply return a 999-W.</p>
  
  <p>I am thinking that a view or even a simple select should do this. </p>
  
  <p>Not sure where to begin though. Any help would be greatly appreciated!</p>