title: Select multiple rows with the same value(s)
body: <p>I have a table, sort of like this:</p>
  
  <pre><code>ID  |  Chromosome | Locus | Symbol | Dominance |
  ===============================================
  1   |      10     |   2   |   A    |   Full    |
  2   |      10     |   2   |   a    |   Rec.    |
  3   |      10     |   3   |   B    |   Full    |
  4   |      10     |   3   |   b    |   Rec.    |
  </code></pre>
  
  <p>I'd like to select all rows with the same locus and chromosome.  For example, rows 3 and 4.  There may be more than 2 at a time and they may not be in order.</p>
  
  <p>I tried this: </p>
  
  <pre><code>SELECT *
  FROM Genes
  GROUP BY Locus
  HAVING Locus='3' AND Chromosome='10'
  </code></pre>
  
  <p>But it always returns row 3, never row 4, even when repeated.  I think I'm missing something obvious and simple, but I'm at a loss.  </p>
  
  <p>Can someone help?</p>