title: Return null rows if not found in where mysql
body: <p>Imagine have a request Like :</p>
  <pre><code>Select product_id,category, price  FROM mytable
  WHERE category IN('fish', 'chips', 'nuggets')
  </code></pre>
  <p>But no products_id has a 'chips' category. Then it will return something like:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>Product_id</th>
  <th>category</th>
  <th>price</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>001</td>
  <td>fish</td>
  <td>1,3</td>
  </tr>
  <tr>
  <td>001</td>
  <td>nuggets</td>
  <td>1,4</td>
  </tr>
  <tr>
  <td>002</td>
  <td>fish</td>
  <td>4,1</td>
  </tr>
  <tr>
  <td>002</td>
  <td>nuggets</td>
  <td>3,1</td>
  </tr>
  <tr>
  <td>003</td>
  <td>fish</td>
  <td>1,41</td>
  </tr>
  <tr>
  <td>003</td>
  <td>nuggets</td>
  <td>44,1</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>But I want display null for each conditions not found in where conditions:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>Product_id</th>
  <th>category</th>
  <th>price</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>001</td>
  <td>fish</td>
  <td>1,3</td>
  </tr>
  <tr>
  <td>001</td>
  <td>nuggets</td>
  <td>1,4</td>
  </tr>
  <tr>
  <td>001</td>
  <td>chips</td>
  <td>NULL</td>
  </tr>
  <tr>
  <td>002</td>
  <td>fish</td>
  <td>4,1</td>
  </tr>
  <tr>
  <td>002</td>
  <td>nuggets</td>
  <td>3,1</td>
  </tr>
  <tr>
  <td>002</td>
  <td>chips</td>
  <td>NULL</td>
  </tr>
  <tr>
  <td>003</td>
  <td>fish</td>
  <td>1,41</td>
  </tr>
  <tr>
  <td>003</td>
  <td>nuggets</td>
  <td>44,1</td>
  </tr>
  <tr>
  <td>003</td>
  <td>chips</td>
  <td>NULL</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>How can I do that??</p>