codeigniter-如何在表列中添加值 [英] codeigniter - how to add up values in table column

问题描述

试图从我的表（non_clinical_total_tests）中获取在列（af_am_msm）中输入的值的总和。我想在html表中显示总计。

Trying to get the sum of the values entered within a column (af_am_msm) from my table (non_clinical_total_tests). I want to display that total within an html table.

我的错误消息是：

遇到PHP错误-严重性：注意-消息：数组到字符串的转换

A PHP Error was encountered - Severity: Notice - Message: Array to string conversion

我的模型：

public function af_am_sum()
{
    $this->db->select_sum('af_am_msm');
    $query = $this->db->get('non_clinical_total_tests');
    return $query->result();
}

我的控制器：

public function index()
{
    $data['af_am_total'] = $this->Page_model->af_am_sum();

    $data['pages'] = $this->Page_model->get_list();

    $this->template->load('admin', 'default', 'district1', $data);

}

我的观点：

<td><?php echo $af_am_total; ?></td>

推荐答案

Codeigniter的 result（）函数始终返回对象数组。在您的视图中，您将其作为字符串回显，因此出现错误。为避免产生结果行，请在数组中循环，或：

Codeigniter's result() function always returns an array of objects. In your view you echo it out as a string, hence the error. In order to avoid that you either produce result rows, looping through the array, or:

如您的示例所示，因为您期望只有一行（一列的总和），所以您有可能获得该结果行（而不用需要遍历它）与 row（）-> the_name_of_your_column 。为了简化输出，我们可以为mysql sum创建一个别名，将其命名为第二个参数：

like in your example, as you are expecting only one row (the sum of a column) you have the possibility to get this result row (without the need to loop through it) with row()->the_name_of_your_column. To simplify the output we can create an alias for the mysql sum, naming it as second parameter:

$this->db->select_sum('af_am_msm','my_sum');
$query = $this->db->get('non_clinical_total_tests');
return $query->row()->my_sum;

这会在您的视图中以假装的形式出现

which echos in your view as pretended

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