从 CodeIgniter 中查询的第一行获取单个字段值

发布于 2024-10-06 00:45:45 字数 265 浏览 8 评论 0原文

我正在使用 CodeIgniter 的活动记录类，查询如下所示：

$query = $this->db
    ->get_where('Table', array('field' => $value));

What's the fast way to get a field value from the 第一行？

$query->first_row->field; 有效吗？

原文

I'm using CodeIgniter's active record class and the query looks something like this:

$query = $this->db
    ->get_where('Table', array('field' => $value));

What's the fastest way to get a field value from the first row?

Would $query->first_row->field; work?

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羞稚 2024-10-13 00:45:45

虽然速度快固然很棒，但错误却不是！确保在尝试使用 ($query->num_rows() > 0) 访问结果之前始终检查结果

最快（最简洁）的方式：

$query = $this->db->get_where('Table', array('field' => $value));

echo(($query->num_rows() > 0) ? $query->first_row()->field : 'No Results');

本质上相同：

$query = $this->db->get_where('Table', array('field' => $value));
if($query->num_rows() > 0)
{
    echo $query->first_row()->field;
}
else
{
    echo 'No Results';
}

对于多个字段使用：

$query = $this->db->get_where('Table', array('field' => $value));

if ($query->num_rows() > 0)
{
    $row = $query->row(); 

    echo $row->title;
    echo $row->name;
    echo $row->body;
}

Though fast is wonderful, errors aren't! Make sure you always check for results before trying to access them with ($query->num_rows() > 0)

Fastest (most concise) way:

$query = $this->db->get_where('Table', array('field' => $value));

echo(($query->num_rows() > 0) ? $query->first_row()->field : 'No Results');

Essentially the same as:

$query = $this->db->get_where('Table', array('field' => $value));
if($query->num_rows() > 0)
{
    echo $query->first_row()->field;
}
else
{
    echo 'No Results';
}

For multiple fields use:

$query = $this->db->get_where('Table', array('field' => $value));

if ($query->num_rows() > 0)
{
    $row = $query->row(); 

    echo $row->title;
    echo $row->name;
    echo $row->body;
}

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﹏雨一样淡蓝的深情 2024-10-13 00:45:45

$query->first_row()->field

$query->first_row()->field

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酒几许 2024-10-13 00:45:45

如果您对 ->row() 返回的值进行 null 合并，则无需检查 num_rows()。 row() 返回一个对象或null。

return $this->db
    ->get_where('Table', ['field' => $value])
    ->row()
    ->field ?? null;

或者，更简洁地使用空安全属性访问。

return $this->db
    ->get_where('Table', ['field' => $value])
    ->row()
    ?->field;

如果没有行或者第一行中的field值为null，以上两者都会返回null。如果 row() 生成的对象中没有 field 属性，故障安全脚本将发出警告。

You won't need to check num_rows() if you null coaleace the returned value from ->row(). row() return an object or null.

return $this->db
    ->get_where('Table', ['field' => $value])
    ->row()
    ->field ?? null;

Or, more concisely use null-safe property access.

return $this->db
    ->get_where('Table', ['field' => $value])
    ->row()
    ?->field;

Both of the above will return null if there are no rows or the field value in the first row is null. The fail-safe script will emit a Warning if there is no field property in the object generated by row().

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