php - 如何在 html 中呈现多级 mysql 查询（codeIgniter）

Question

这是mysql查询

SELECT * 
FROM users AS up
JOIN users AS u ON up.id = u.parent_id
JOIN users AS uc ON u.id = uc.parent_id
WHERE up.id =16

这是视图文件中的输出

   <?php foreach($query->result() as $q): ?>
    <?php echo $q->id; ?>

    <?php endforeach; ?>

mysql 结果给出了 3 个级别的结果，但在 html 中它只输出 1 个级别，并且是最后一个级别，但我需要在层次结构中呈现它

Answer 1

将您的查询更改为：

SELECT up.id AS id1, u.id AS id2, uc.id AS id3
FROM users AS up
JOIN users AS u  ON up.id =  u.parent_id
JOIN users AS uc ON  u.id = uc.parent_id
WHERE up.id = 16

然后您可以访问三个级别id1：id2和id3：

<?php
  foreach($query->result() as $q) {
    echo $q->id1;
    echo $q->id2;
    echo $q->id3;
  }
?>