有没有办法使用 PDO 获取按指定列的值分组的关联数组?

问题描述

例如，让我们使用一些简单的数据集

For example, let's use some simple data set

+---------+------+------+------------+
| name    | age  | sex  | position   |
+---------+------+------+------------+
| Antony  |   34 | M    | programmer |
| Sally   |   30 | F    | manager    |
| Matthew |   28 | M    | designer   |
+---------+------+------+------------+

我们想要得到的是这样组织的数组

What we are trying to get is array organized this way

Array
(
  [Antony] => Array
    (
      [age] => 34
      [sex] => M
      [position] => programmer
    )

  [Sally] => Array
    (
      [age] => 30
      [sex] => F
      [position] => manager
    )

  [Matthew] => Array
    (
      [age] => 28
      [sex] => M
      [position] => designer
    )
)

作为粗略的近似，我们可以使用

As a rough approximation we can use

$pdo->query('SELECT * FROM employee')->fetchAll(PDO::FETCH_GROUP|PDO::FETCH_ASSOC);

但结果是我们有不必要的嵌套层

But as result we have unnecessary nesting level

Array
(
    [Antony] => Array
        (
            [0] => Array
                (
                    [age] => 34
                    [sex] => M
                    [position] => programmer
                )

        )

    [Sally] => Array
        (
            [0] => Array
                (
                    [age] => 30
                    [sex] => F
                    [position] => manager
                )

        )

    [Matthew] => Array
        (
            [0] => Array
                (
                    [age] => 28
                    [sex] => M
                    [position] => designer
                )

        )

)

我试图通过使用回调函数摆脱这种不必要的嵌套层

I tried to get rid of this unnecessary nesting level by using callback function

$stmt->fetchAll(PDO::FETCH_GROUP|PDO::FETCH_ASSOC|PDO::FETCH_FUNC, 'current');

但由于某些原因它没有通过

But for some reasons It passes not

Array
  (
   [0] => Array
    (
        [age] => 34
        [sex] => M
        [position] => programmer
    )
  )

但只是一堆标量 34, 'M', 'programmer' 到回调函数:(

but just a bunch of scalars 34, 'M', 'programmer' to callback function :(

可以使用回调等函数查看

You can see it using such function as callback

function what_do_you_pass_me() {

  $numargs = func_num_args();
  $arg_list = func_get_args();
  for ($i = 0; $i < $numargs; $i++) {
    echo "Argument $i is: " . $arg_list[$i] . "\n";
  };
  echo "\n\n";
};

那么有没有办法在获取结果后使用 PDO::FETCH_* 模式而不使用 array_map('current', $result) 获得所需的结果集?>

So is there a way to get desired resultset using PDO::FETCH_* modes without using array_map('current', $result) after fetching results ?

推荐答案

这是一个很老的话题，但我找到了很简单的解决方案:

It's quite old topic, but I found very easy solution:

->fetchAll(\PDO::FETCH_GROUP|\PDO::FETCH_UNIQUE)

第一个列将被设置为键，其余将被设置为值.

First col will be set as key, rest will be set as value.

无需遍历数组或使用 array_map.

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