title: How to select non "unique" rows
body: <p>I have the following table, from which i have to fetch non unique rows</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th style="text-align: left;">id</th>
  <th style="text-align: left;">idA</th>
  <th style="text-align: left;">infos</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td style="text-align: left;">0</td>
  <td style="text-align: left;">201</td>
  <td style="text-align: left;">1899</td>
  </tr>
  <tr>
  <td style="text-align: left;">1</td>
  <td style="text-align: left;">205</td>
  <td style="text-align: left;">1955</td>
  </tr>
  <tr>
  <td style="text-align: left;">2</td>
  <td style="text-align: left;">207</td>
  <td style="text-align: left;">1955</td>
  </tr>
  <tr>
  <td style="text-align: left;">3</td>
  <td style="text-align: left;">201</td>
  <td style="text-align: left;">1959</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>I'd like fetch all the rows for the column <code>infos</code>, that have a same <code>idA</code> value in at least two rows.</p>
  <p>Output of the query for the above table must be</p>
  <pre><code>infos
  1899
  1959 
  </code></pre>
  <p>I've tried the following requests with no success :</p>
  <ul>
  <li><code>SELECT idA FROM XXX WHERE NOT EXISTS(SELECT * FROM XXX GROUP BY idA)</code></li>
  <li><code>SELECT * FROM XXX a WHERE NOT EXISTS(SELECT * FROM XXX b WHERE a.RVT_ID=b.RVT_ID GROUP BY idA)</code></li>
  </ul>