如何使用Codeigniter和MySQL获得单个值

Question

我需要通过使用此代码从数据库获取service_price字段。

public function get_service_price($id) { 
 $this->db->select('*');
  $this->db->from('service');
    $this->db->where('id', $id);
    $query = $this->db->get('service');
    return $query->row('service_price');  
}

在这里，我称这个功能为功能。

 public function vat($vat=14.5)

 {
  $id = $this->uri->segment(4);
  $data['service_price'] = $this->service_model->get_service_price($id);
  $price_with_vat=0;
  $price_with_vat = $data + ($vat*($data/100));
  //$price_with_vat=78.005;
  $price_with_vat = round($price_with_vat, 2);
  $this->load->view('admin/service/vat', $price_with_vat);
  }

有一些错误。 请帮我

Answer 1

要获得第一行，请使用以下命令

$query = $this->db
->where('id', $id);
->get('service');
$firstRow = $query->first_row();
return $firstRow->service_price;

Answer 2

在模型中

public function get_service_price($id) {
    $query = $this->db->query("SELECT * FROM service WHERE id='$id'");
    $result = $query->result_array();
    return $result;
}

在控制器中

$id = $this->uri->segment(4);
$data['service_price'] = $this->service_model->get_service_price($id);
$price_with_vat=0;
$price_with_vat = $data[0]['table_field_name'] + ($vat*($data[0]['table_field_name']/100)); //$price_with_vat=78.005;
$price_with_vat = round($price_with_vat, 2);
$this->load->view('admin/service/vat', $price_with_vat);

鉴于

foreach ($service_price as $new_service_price)
{
    echo $new_service_price['table_field_name'];//exapmle echo $new_service_price['service_price']
}

Answer 3

使用此代码为您的模型：

  public function get_service_price($id) { 
    $this->db->select('service_price');
    $this->db->from('service');
    $this->db->where('id', $id);
    $query = $this->db->get();
    return $query->row();  
 }