title: Merge 2 rows into one row
body: <p>I have this query : </p>
  
  <pre><code>Select ID, Groucode
  from mytable
  </code></pre>
  
  <p>which returns this result:  </p>
  
  <pre><code>ID  GroupCode
  ---------------
  60  00        
  60  01         
  70  00         
  80  00
  80  01
  90  00
  </code></pre>
  
  <p>What I want is to shows only the rows with '00' and '01', like this: </p>
  
  <pre><code>ID   GroupCode
  ---------------
  60    00  
  60    01    
  80    00
  80    01      
  </code></pre>