无法在 Php 中添加标记 [关闭]

Question

我正在尝试从数据库中获取数据并添加一个名为 marks 的特定行

我成功地从数据库中获取了数据，在获取的数据中，有一个名为标记的列，现在我试图获取列中值的总和，但是当我运行代码时，它只显示第一个值 这是我的代码

<?php 
$select = "select subjectName, marks, studentId from tbl_subject, tbl_results, tbl_student where tbl_subject.id = tbl_results.SubjectId and studentId = tbl_results.stdntsId and studentId = $id";
        // $select = "select  from tbl_results";
        $execute = mysqli_query($conn, $select);
        $countRows = mysqli_num_rows($execute);
        if($countRows > 0){
          while($fetch = mysqli_fetch_array($execute)){
            $marks = $fetch['marks'];
            ?>
              <tbody>
                <tr>
                  <th scope="row">
                    <?php echo $fetch['subjectName'] ?>
                    
                  </th>
                  <td>
                    56
                  </td>
                  <td><?php echo $marks ?></td>
                  <td>D1</td>
                  <td>Good</td>
                  <td>O.B</td>
                </tr>
                
              
              </tbody>
            <?php
          }
          ?>
          <tr>
            <th>TOTAL</th>
            
            <td>
            34
            </td>
            <td>
              <?php 
                  $total_qty = 0;
                  // $a = $fetch['marks'];
                  $total_qty += $marks;
                  echo $total_qty;
              ?>
            </td>
            <td><b>AGGR: <span>5</span></b></td>
          </tr>
          <?php
          
        }
        
        
      ?>
    
    
  </table>

Answer 1

<table>
    <tbody>
<?php
$select = "select t1.subjectName, t2.marks, t3.studentId "
        . "from "
        . "tbl_subject t1, "
        . "tbl_results t2, "
        . "tbl_student t3"
        . "WHERE "
        . "t1.id = t2.SubjectId "
        . "AND "
        . "t2.studentId = t3.stdntsId "
        . "AND "
        . "t1.studentId = $id";
  

        $execute = mysqli_query($conn, $select);
        $countRows = mysqli_num_rows($execute);
        if($countRows > 0){
            $count = 0;
            $total_qty = 0;
            while($fetch = mysqli_fetch_array($execute)){
                $count++;
                $marks = $fetch['marks'];
                $total_qty += $marks;
            ?>
                <tr>
                    <td scope="row"><?=$fetch['subjectName'] ?></td>
                    <td>56</td>
                    <td><?=$marks ?></td>
                    <td>D1</td>
                    <td>Good</td>
                    <td>O.B</td>
                </tr>
            <?php
            }
          ?>
                <tr>
                    <td>TOTAL</td>
                    <td>34</td>
                    <td><?=$count;?> or <?=$total_qty;?></td>
                    <td><b>AGGR: <span>5</span></b></td>
                </tr>
          <?php
        }
        
      ?>
    </tbody>
    
  </table>

1. 我认为您的查询有问题，请尝试将您正在查询的表标记为 t1、t2 等

2. 放

   <tbody>

   外站循环

3. 如果你想显示重复次数你需要在循环之前声明

   $count = 0

   然后在循环内增加它

   $count++

4. 和总和

    $total_qty += $marks;

   你需要把它放在一个循环中。

希望有帮助