如何从3个表中获取数据库中的所有数据？

Question

My problem is, i am getting the datas which is present in all the 3 tables.But i want to display the data which is not present in any one of the table(that is empty space or 0 is printed on that item if it's not present in anyone of the table)..i googled and found that it can be done by fullouter join but i don't know how to use it.. Controller Code:

   public function St_statement(){

        $startdate = $this->input->post('SDate');
        $enddate = $this->input->post('EDate');
        $date = str_replace('/', '-', $startdate);
        $newDate = date("Y-m-d", strtotime($date));
        $date2 = str_replace('/', '-', $enddate);
        $newDate2 = date("Y-m-d", strtotime($date2));
        $data['startdate'] = $startdate;
        $data['enddate'] = $enddate;
        if ($this->input->post('all'))
        {
        $this->db->where('billdate >=', $newDate);
        $this->db->where('billdate <=', $newDate2);
        $this->db->where('billdte >=', $newDate);
        $this->db->where('billdte <=', $newDate2);
        $this->db->select("Item");
        $this->db->select("pgroup");
        $this->db->select_sum("Stock");
        $this->db->select_sum("quantity");
        $this->db->select_sum("Qty");
        $this->db->from('opstock');
        $this->db->group_by("Item");
        $this->db->order_by("pgroup",'asc');

        $this->db->join('purchaseitem',' purchaseitem.Prdtname = opstock.Item','OUTER');
         $this->db->join('salesitem','salesitem.Prdtname =  purchaseitem.Prdtname','OUTER');
          $this->db->join('itemmaster','itemmaster.itemname =  purchaseitem.Prdtname','OUTER');
         $this->db->join('pgroup','pgroup.pgroupid = itemmaster.catcode','OUTER');

        $query = $this->db->get();
  $data['query'] = $query;

        $this->load->view('Inventory/St_Stmt', $data);
        //$this->load->view('Inventory/St_Stmt1', $data);
    }
    if($this->input->post('selected'))
    {
        if($name = $this->input->post('businessType'))
        {
        $this->db->where('billdate >=', $newDate);
        $this->db->where('billdate <=', $newDate2);
        $this->db->where('billdte >=', $newDate);
        $this->db->where('billdte <=', $newDate2);
        $this->db->where('pgroup',$name);
        $this->db->select("Item");
        $this->db->select("pgroup");
        $this->db->select_sum("Stock");
        $this->db->select_sum("quantity");
        $this->db->select_sum("Qty");
        $this->db->from('opstock');
        $this->db->group_by("Item");

        $this->db->join('purchaseitem',' purchaseitem.Prdtname = opstock.Item','OUTER');
         $this->db->join('salesitem','salesitem.Prdtname =  purchaseitem.Prdtname','OUTER');
          $this->db->join('itemmaster','itemmaster.itemname =  purchaseitem.Prdtname','OUTER');
         $this->db->join('pgroup','pgroup.pgroupid = itemmaster.catcode','OUTER');

        $query = $this->db->get();
  $data['query'] = $query;

        $this->load->view('Inventory/St_Stmt', $data);


    }

}
}

Answer 1

$query = "SELECT Item , pgroup , SUM( Stock ) AS Stock , SUM( quantity ) AS quantity , SUM( Qty ) AS Qty FROM opstock LEFT JOIN purchaseitem ON purchaseitem . Prdtname = opstock . Item LEFT JOIN salesitem ON salesitem . Prdtname = purchaseitem . Prdtname LEFT JOIN itemmaster ON itemmaster . itemname = purchaseitem . Prdtname LEFT JOIN pgroup ON pgroup . pgroupid = itemmaster . catcode WHERE billdate >= '".$newDate."' AND billdate <= '".$newDate2."' AND billdte >= '".$newDate."' AND billdte <= '".$newDate2."' GROUP BY Item ORDER BY pgroup ASC UNION SELECT Item , pgroup , SUM( Stock ) AS Stock , SUM( quantity ) AS quantity , SUM( Qty ) AS Qty FROM opstock RIGHT JOIN purchaseitem ON purchaseitem . Prdtname = opstock . Item LEFT JOIN salesitem ON salesitem . Prdtname = purchaseitem . Prdtname LEFT JOIN itemmaster ON itemmaster . itemname = purchaseitem . Prdtname LEFT JOIN pgroup ON pgroup . pgroupid = itemmaster . catcode WHERE billdate >= '".$newDate."' AND billdate <= '".$newDate2."' AN D billdte >= '".$newDate."' AND billdte <= '".$newDate2."' GROUP BY Item ORDER BY pgroup ASC SELECT Item , pgroup , SUM( Stock ) AS Stock , SUM( quantity ) AS quantity , SUM( Qty ) AS Qty FROM opstock LEFT JOIN purchaseitem ON purchaseitem . Prdtname = opstock . Item RIGHT JOIN salesitem ON salesitem . Prdtname = purchaseitem . Prdtname LEFT JOIN itemmaster ON itemmaster . itemname = purchaseitem . Prdtname LEFT JOIN pgroup ON pgroup . pgroupid = itemmaster . catcode WHERE billdate >= '".$newDate."' AND billdate <= '".$newDate2."' AND billdte >= '".$newDate."' AND billdte <= '".$newDate2."' GROUP BY Item ORDER BY pgroup ASC UNION SELECT Item , pgroup , SUM( Stock ) AS Stock , SUM( quantity ) AS quantity , SUM( Qty ) AS Qty FROM opstock LEFT JOIN purchaseitem ON purchaseitem . Prdtname = opstock . Item LEFT JOIN salesitem ON salesitem . Prdtname = purchaseitem . Prdtname RIGHT JOIN itemmaster ON itemmaster . itemname = purchaseitem . Prdtname LEFT JOIN pgroup ON pgroup . pgroupid = itemmaster . catcode WHERE billdate >= '".$newDate."' AND billdate <= '".$newDate2."' AND billdte >= '".$newDate."' AND billdte <= '".$newDate2."' GROUP BY Item ORDER BY pgroup ASC";

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