title: How to find only id that has different values in MySQL?
body: <p>I have a table with two columns:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th style="text-align: left;">id</th>
  <th style="text-align: left;">num</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td style="text-align: left;">1</td>
  <td style="text-align: left;">2</td>
  </tr>
  <tr>
  <td style="text-align: left;">2</td>
  <td style="text-align: left;">8</td>
  </tr>
  <tr>
  <td style="text-align: left;">1</td>
  <td style="text-align: left;">7</td>
  </tr>
  <tr>
  <td style="text-align: left;">7</td>
  <td style="text-align: left;">3</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>I want to get as an answer to my query only ids that have more than 1 nums.
  For example in my table I would want to get as a result:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th style="text-align: left;">id</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td style="text-align: left;">1</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>How should I express my query?
  Thanks in advance.</p>