calculate and display result from a row in codeignitor 3 - php

Question

I have a table where i need to subtract tow values in the same column and display the difference in another view table. I need to record daily total hour meter readings from 5 compressors and display the difference as daily running hours.
My table:
image output of crudtabe
SELECT a.cuidad_id,
a.bc100a,
Coalesce(a.bc100a - (SELECT b.bc100a
FROM cuidadrun b
WHERE a.cuidad_id = b.cuidad_id + 1), a.bc100a) AS
diffbc100a
FROM cuidadrun a
what is working great in phpmyadmin, please see image:
sql output
I cant workout my controller, model, and view to display the result.
also, can i save the result in another table?
My Controller
<?php
defined('BASEPATH') OR exit('No direct script access allowed');
class Cactushrs extends CI_Controller {
public function __construct()
{
parent::__construct();
$this->load->model('Cactushrs_model');
}
public function index()
{
$this->load->view('template/header');
$data = $this->Cactushrs_model->cactushrs();
$this->load->view('pages/cactushrs_view', $data);
$this->load->view('template/footer');
}
}
My Model
<?php
defined('BASEPATH') OR exit('No direct script access allowed');
class Cactushrs_model extends CI_Model
{
public function __construct()
{
parent::__construct();
$this->load->database();
}
public function cactushrs()
{
$query = $this->db->get ('SELECT a.cuidad_id, a.bc100a, COALESCE(a.bc100a - (SELECT b.bc100a FROM cuidadrun b WHERE a.cuidad_id = b.cuidad_id + 1), a.bc100a) AS differnce FROM cuidadrun a');
}
}
My view
<table id="cuidadhrs" class="table table-striped table-bordered dt-responsive nowrap" cellspacing="0" width="100%">
<thead>
<tr>
<th>cuidad_id</th>
<th>bc100a</th>
<th>diff100</th>
</tr>
</thead>
<tbody>
<tr>
<td><?php echo $this->db->get('differnce'); ?></td>
</tr>
</tbody>
DB Fiddle https://www.db-fiddle.com/f/vSM6hA2Wa3cpRJAqEoDMKZ/0

Answer 1

I did solved my question myself. The problem was in the model, controller and view.
controller.php
<?php
defined('BASEPATH') OR exit('No direct script access allowed');
class Cuidadhrs extends CI_Controller {
public function index()
{
$this->load->view('template/header');
$this->load->model('Cuidadhrs_model');
$hours['hours'] = $this->Cuidadhrs_model->cuidadhrs();
$this->load->view('pages/cuidadhrs_view', $hours);
$this->load->view('template/footer');
}
}
model.php
<?php
defined('BASEPATH') OR exit('No direct script access allowed');
class Cuidadhrs_model extends CI_Model
{
public function __construct()
{
parent::__construct();
$this->load->database();
}
public function cuidadhrs()
{
$sql = "SELECT a.cuidad_id, a.bc100a, COALESCE(a.bc100a - (SELECT b.bc100a FROM cuidadrun b WHERE a.cuidad_id = b.cuidad_id + 1), a.bc100a) AS diffbc100a FROM cuidadrun a";
$query = $this->db->query($sql);
return $query->result_array();
}
}
view.php
<table id="cuidadhrs" class="table table-striped table-bordered dt-responsive nowrap" cellspacing="0" width="100%">
<thead>
<th>ID</th>
<th>BC-100a Hourmeter</th>
<th>Daily Hrs.</th>
</thead>
<tbody>
<?php foreach($hours as $hrs){ ?>
<tr>
<td><?php echo $hrs['cuidad_id']; ?></td>
<td><?php echo $hrs['bc100a']; ?></td>
<td><?php echo $hrs['diffbc100a']; ?></td>
</tr>
</tbody>
<?php } ?>
<?php $this->output->enable_profiler(TRUE); ?>
</table>