Jqgrid Pagination not working due to query - php

Question

I am trying to set up a jqgrid and I am having difficulty in constructing the controller that generates the json data to populate the grid. I am using codeigniter 2.0+ and I am not sure how to build the query for php in codeigniter.
I followed this guid under "Loading Data -> JSON Data" for the jqgrid. I also consulted codeigniter docs on data selection. The thing is I am not sure how to write the second query to sort and limit according to the jqgrid paramiters. Here is my controller.
public function applicantdata(){
$page = $this->input->get('page');// get the requested page
$limit = $this->input->get('rows');// get how many rows we want to have into the grid
$sidx = $this->input->get('sidx');// get index row - i.e. user click to sort
$sord = $this->input->get('sord');// get the direction
if(!$sidx){ $sidx =1; }
$this->db->select('*');
$this->db->from('applicant');
$this->db->join('transaction', 'transaction.applicant_id = applicant.id');
$query = $this->db->get();
$count = $query->num_rows();
$limit = 10;
if( $count > 0 ) {
$total_pages = ceil($count/$limit);
} else {
$total_pages = 0;
}
if ($page > $total_pages){ $page=$total_pages; }
$start = $limit*$page - $limit; // do not put $limit*($page - 1)
//NOT SURE HOW TO DO THIS IN CODEIGNITER ENVIRONMENT
//$SQL = "SELECT a.id, a.invdate, b.name, a.amount,a.tax,a.total,a.note FROM invheader a, clients b WHERE a.client_id=b.client_id ORDER BY $sidx $sord LIMIT $start , $limit";
//$result = mysql_query( $SQL ) or die("Couldn t execute query.".mysql_error());
$result = $query->result_array();
$responce->page = $page;
$responce->total = $total_pages;
$responce->records = $count;
$i=0;
foreach ($result as $myrow){
$responce->rows[$i]['id']=$myrow['id'];
$responce->rows[$i]['cell']=array($myrow['id'],$myrow['firstname'],$myrow['lastname'],$myrow['amount'],$myrow['status']);
$i++;
}
echo json_encode($responce);
}
With the above code, the grid is populating and its is working to a greater extent. Only thing is the pagination stuff not working properly in that the data on page one shows when I move to page 2, 3, etc.

Answer 1

Her is the final working thing. For anyone who may need it.
public function applicantdata(){
$page = $this->input->get('page');// get the requested page
$limit = $this->input->get('rows');// get how many rows we want to have into the grid
$sidx = $this->input->get('sidx');// get index row - i.e. user click to sort
$sord = $this->input->get('sord');// get the direction
if(!$sidx){ $sidx =1; }
$this->db->select('firstname');
$this->db->from('applicant');
$this->db->join('transaction', 'transaction.applicant_id = applicant.id');
$query = $this->db->get();
$count = $query->num_rows();
if( $count > 0 ) {
$total_pages = ceil($count/$limit);
} else {
$total_pages = 0;
}
if ($page > $total_pages){ $page=$total_pages; }
$start = $limit*$page - $limit; // do not put $limit*($page - 1)
$this->db->select('*');
$this->db->from('applicant');
$this->db->join('transaction', 'transaction.applicant_id = applicant.id');
$this->db->order_by("applicant.id", $sord);
$this->db->limit($limit, $start);
$query2 = $this->db->get();
$result = $query2->result_array();
$responce->page = $page;
$responce->total = $total_pages;
$responce->records = $count;
$i=0;
foreach ($result as $myrow){
$responce->rows[$i]['id']=$myrow['id'];
$responce->rows[$i]['cell']=array($myrow['id'],$myrow['firstname'],$myrow['lastname'],$myrow['amount'],$myrow['status']);
$i++;
}
echo json_encode($responce);
}