title: Group By Except For Certain Value
body: <p>I'm trying to create a (sqlite) query that will perform a GROUP BY but will not group anything with the value 'unknown'.  For example, I have the table:</p>
  
  <pre><code>id |   name  | parent_id | school_id |
   1 | john    |   1       |    1      |
   2 | john    |   1       |    1      |
   3 | john    |   1       |    1      |
   4 | nick    |   2       |    2      |
   5 | nick    |   2       |    2      |
   6 | nick    |   3       |    3      |
   7 | bob     |   4       |    4      |
   8 | unknown |   5       |    5      |
   9 | unknown |   5       |    5      |
   10| unknown |   5       |    5      |
  </code></pre>
  
  <p>With the proper query with 'GROUP BY name, parent_id, school_id' I need the following rows returned:</p>
  
  <pre><code>id |   name  | parent_id | school_id |
   1 | john    |   1       |    1      |
   3 | nick    |   2       |    2      |
   4 | nick    |   3       |    3      |
   5 | bob     |   4       |    4      |
   6 | unknown |   5       |    5      |
   7 | unknown |   5       |    5      |
   8 | unknown |   5       |    5      |
  </code></pre>
  
  <p>Any help would be greatly appreciated.  Thanks!</p>