Question

我想在codeIgniter

中使用Active Record类从4个表中选择数据

我的表格 老师（id_teacher，姓名）学生（id_parent，name，id_teacher，id_class，id_school） class（id_class，libelle）学校（id_school，姓名）

这是我的代码：

$this->db->select("t.*, s.*, c.*, sh.*");
$this->db->from("teacher t");
$this->db->join("student s","t.id_teacher=s.id_teacher");
$this->db->join("class c","c.id_class=s.id_class");
$this->db->join("school sh","c.id_school=sh.id_school");

$query = $this->db->get();

但它不起作用。你能帮帮我吗？

Answer 1

您有两个from()我用join()

替换了第二个

public function test() {
    $this->db->select("t.*, s.*, c.*, sh.*");

    $this->db->from("teacher t");

    // $this->db->join("student s","t.id_teacher=s.id_teacher");

    $this->db->join('student s', 's.id_teacher = t.id_teacher' , 'LEFT');

    $this->db->join('class c', 'c.id_class = s.id_class', 'LEFT');

    // $this->db->from("school sh","c.id_school=sh.id_school");

    $this->db->join('school sh' ,"sh.id_school = c.id_school", 'LEFT');


    $query = $this->db->get();

    return $query->result_array(); 
}

如果需要特定类型的JOIN，可以通过函数的第三个参数指定它。选项包括：左，右，外，内，左外和右外。

//....
<form action="/servlet/UpdateUser" method="POST" accept-charset="utf-8" class="form" role="form">
//....        
   <button class="btn btn-lg btn-block signup-btn" type="submit" name="signup">Create my account</button>
</form>
//....

使用CodeIgniter中的Active Record Class从4个表中选择数据

1 个答案: