php - php mySQL 无序列表(流程图)

Question

我想用 php 和 mySQL 创建一个带有无序列表的流程图。

表格 - 问题

id |问题|答案id

表格 - 答案

id |答案| Question_id

每个问题都引用一个answer_id。 answer_id 引用了 Question_id(参见附图)。

到目前为止的 php:

// Starts with the first question (answer_id=0)
$sql = db_query("SELECT * FROM questions WHERE answer_id='0'");
while ($row = mysqli_fetch_assoc($sql)){ ?>

<ul>
    <li>
      <?php echo $row['question'];
      $question_id = $row['id'];
  }

  $sql = db_query("SELECT * FROM answers WHERE question_id='$question_id'");
  while ($row = mysqli_fetch_assoc($sql)){ 
  $question_id = $row['id'];
  ?>
      <ul>
          <li>
            <?php echo $row['answer'];?>

      <?
      $answer_id = $row['id'];

      $sqlf = db_query("SELECT * FROM questions WHERE answer_id='$answer_id'");
      while ($rowf = mysqli_fetch_assoc($sqlf)){ ?>
        <ul>
            <li>
                <?php echo $rowf['question'];?>
            </li>

          <?
          $question_id = $rowf['id'];
          $sqls = db_query("SELECT * FROM answers WHERE question_id='$question_id'");
          while ($rows = mysqli_fetch_assoc($sqls)){ ?>
              <ul>
                <li>
                    <?php echo $rows['answer'];?>
                </li>
          </ul>
          <?
          }   
      }
  }

我对此完全脑子一片空白。如何获得一个循环来打印带有子答案和子问题等的问题？

Answer 1

这对我有帮助! Printing down all row elements as tree in PHP

感谢 Naruto 对递归函数的指导:)