Codeigniter：尝试获取行的非对象属性（）

The error:

here's my code:

function get_modal_awal(){
     date_default_timezone_set('Asia/Jakarta');
     $sql = "SELECT modal_awal
             FROM trans_modal_awal 
           WHERE date_format(tanggal,'%Y-%m-%d') = '".date('Y-m-d')."'
           AND kode_kasir = ".$_SESSION['kode_user']."";
     return $this->db->query($sql)->row()->modal_awal; //the error goes here
 }

my view code like this:

<input readonly class="form-control" type="text" id="modal_awal"name="modal_awal" value="<?php echo $modal_awal;?>"></input>

my controller:

$data['modal_awal'] = $this->Modal_kasir_model->get_modal_awal();

What should I do?

You are assuming that your SQL always returns a row. If it doesn't, then there is no object to read. I would try to trap this:

function get_modal_awal(){
    date_default_timezone_set('Asia/Jakarta');
    $sql = "SELECT modal_awal
            FROM trans_modal_awal 
         WHERE date_format(tanggal,'%Y-%m-%d') = '".date('Y-m-d')."'
         AND kode_kasir = ".$_SESSION['kode_user']."";

    //Get row
    $result = $this->db->query($sql);
    if($result){
        $row = $result->row();
        if($row){
            //return row if set
            return $row->modal_awal;
        }
    }
    //return nothing, and deal with it in the calling code
    return false;

}

It's also not a bad idea to wrap your SQL calls in a try ... catch block.

function get_modal_awal()
{
   date_default_timezone_set('Asia/Jakarta');
    $sql = "SELECT modal_awal
    FROM trans_modal_awal 
    WHERE date_format(tanggal,'%Y-%m-%d') = '".date('Y-m-d')."'
    AND kode_kasir = ".$_SESSION['kode_user']."";
    $res = $this->db->query($sql);
    return $res->row('modal_awal');
  }

Use above code