How to INNER JOIN 3 tables using CodeIgniter

Question

Can someone Tell me how to join 3 table with php? Example

SELECT FROM table1, table2,table on INNERJOIN -------------------

let I have 3 table.(question table ,answer table and category table) Here is example form my webpage.

Time remaining 30 minutes(I will get "30 minutes" form Category table)
1. Question (from question table)
2. answer (from answer table)

I don't know how to join 3 table.

Answer 1

it should be like that,

$this->db->select('*');    
$this->db->from('table1');
$this->db->join('table2', 'table1.id = table2.id');
$this->db->join('table3', 'table1.id = table3.id');
$query = $this->db->get();

as per CodeIgniters active record framework

Answer 2

I believe that using CodeIgniters active record framework that you would just use two join statements one after the other.
eg:

$this->db->select('*');
$this->db->from('table1');
$this->db->join('table1', 'table1.id = table2.id');
$this->db->join('table1', 'table1.id = table3.id');
$query = $this->db->get();

Give that a try and see how it goes.

Answer 3

I created a function to get an array with the values ​​for the fields and to join. This goes in the model:

  public function GetDataWhereExtenseJoin($table,$fields,$data) {
    //pega os campos passados para o select
    foreach($fields as $coll => $value){
        $this->db->select($value);
    }
    //pega a tabela
    $this->db->from($table);
    //pega os campos do join
    foreach($data as $coll => $value){
        $this->db->join($coll, $value);
    }
    //obtem os valores
    $query = $this->db->get();
    //retorna o resultado
    return $query->result();

}

This goes in the controller:

$data_field = array(
        'NameProduct' => 'product.IdProduct',
        'IdProduct' => 'product.NameProduct',
        'NameCategory' => 'category.NameCategory',
        'IdCategory' => 'category.IdCategory'
        );
    $data_join = array
                    ( 'product' => 'product_category.IdProduct = product.IdProduct',
                      'category' => 'product_category.IdCategory = category.IdCategory',
                      'product' => 'product_category.IdProduct = product.IdProduct'
                    );
    $product_category = $this->mmain->GetDataWhereExtenseJoin('product_category', $data_field, $data_join);

result:

echo '<pre>';
    print_r($product_category);
    die;