Codeigniter联接多个表

Question

I'm having a little trouble in retrieving data in multiple tables using codeigniter.

This is the code i'm using to retrieve data in my model which is working well.

function retrieve_experience($alumni_id)
{
$this->db->select('*');
$this->db->from('experience');
$this->db->where('alumni_id',$alumni_id);
$query = $this->db->get();
return $query;  
}

function retrieve_education($alumni_id)
{
$this->db->select('*');
$this->db->from('education');
$this->db->where('alumni_id',$alumni_id);
$query = $this->db->get();
return $query;
}

Now i tried using a simplified code but fails to display the data. here is the code in my model

function retrieve_all_data($alumni_id)
{
$this->db->select('*');
$this->db->from('experience');
$this->db->join('education','education.alumni_id=experience.alumni_id');
$this->db->where('experience.alumni_id',$alumni_id);
$query=$this->db->get();
return $query->result_array();
}

In my controller, i used this code to retrieving data in my model

function display()
{
$alumni_id = $this->session->userdata('alumni_id');
$data['all_data'] = $this->Alumni_model->retrieve_all_data($alumni_id);
$data['main_content'] = 'alumni_home';
$this->load->view('includes/template', $data);
}

and for the display i used this code

foreach($all_data as $results)
{
/** data from experience table **/
$results['company_name']; 
$results['company_address'];
/** data from education table **/
$results['school_name'];
$results['field_of_study'];
}

I cant display anything at all. Please help

Answer 1

Hope below mentioned function should return data that you expected.

function retrieve_all_data($alumni_id)
{
  $this->db->select('*');
  $this->db->from('experience ex');
  $this->db->join('education ed','ed.alumni_id=ex.alumni_id');
  $this->db->where('ex.alumni_id',$alumni_id);
  $query=$this->db->get();
  return $query->result_array();
}

Answer 2

Try the below code,

I believe you'll want something like this:

function retrieve_all_data($alumni_id)
{
  $this->db->select("e.*,edu.*");
  $this->db->from("experience e");
  $this->db->join("education edu", "edu.alumni_id = e.alumni_id",'left');
  $this->db->where('e.alumni_id',$alumni_id);
  $this->db->group_by('e.exp_id');
  $query = $this->db->get();
  return $query->result_array();
}