Question

我有三个mysql表：clients，cars和insurance。每个客户可以拥有多辆汽车，每辆汽车都有多种保险政策。这是我的查询和sqlfiddle的链接：

SELECT
  a.*,
  b.id AS car_id, b.license_number, b.brand, b.model,
  c.id AS insurance_id, c.insurance_company, c.start_date, c.end_date, c.price
FROM clients a
LEFT JOIN cars b ON a.id = b.client_id
LEFT JOIN insurance c ON b.id = c.car_id

http://sqlfiddle.com/#!2/773a5/1

因此，对于两个客户，其中第一个客户有两辆车和三个保险单，第二个客户没有车，没有保险，查询将返回4行。

我无法弄清楚如何循环此查询以返回以下结构，同时避免重复的客户端条目。

Array
(
  [0] => Array
    (
      [id] => 1
      [first_name] => John
      [last_name] => Smith
      [cars] => Array
        (
          [id] => 1
          [license_number] => 'plate1'
          [brand] => 'BMW'
          [model] => 'E35'
          [insurance] => Array
            (
              [id] => 1
              [start_date] => '2015-02-10'
              [end_date] => '2016-02-10'
              [price] => '100'
            )

            (
              [id] => 2
              [start_date] => '2014-02-10'
              [end_date] => '2015-02-10'
              [price] => '50'
            )
        )

        (
          [id] => 2
          [license_number] => 'plate2'
          [brand] => 'VW'
          [model] => 'Golf'
          [insurance] => Array
            (
              [id] => 3
              [start_date] => '2015-02-10'
              [end_date] => '2016-02-10'
              [price] => '100'
            )
        )
    )

  [1] => Array
    (
      [id] => 1
      [first_name] => John
      [last_name] => Smith
      [cars] => NULL
    )
)

Answer 1

这很容易。它是关于使用assoc数组。您可以使用id，car_id和insurance_id作为数组键。

因此假设您将结果作为存储在$ rows变量中的获取的assoc行。简单的循环将是：

$result = array();
foreach($rows as $row) {
    $id    = $row['ID'];
    $carId = $row['CAR_ID'];
    $insId = $row['INSURANCE_ID'];

    $result[$id]['first_name'] = $row['FIRST_NAME'];
    $result[$id]['last_name']  = $row['LAST_NAME'];

    if(!isset($result[$id]['cars'])) {
        $result[$id]['cars'] = array();
    }

    if($carId && !isset($result[$id]['cars'][$carId])) {
        $car = array(
            'id'             => $row['CAR_ID'],
            'license_number' => $row['LICENSE_NUMBER'],
            'brand'          => $row['BRAND'],
            'model'          => $row['MODEL'],
            'insurance'      => array()
        );
        $result[$id]['cars'][$carId] = $car;
    }

    if($insId && isset($result[$id]['cars'][$carId]) && !isset($result[$id]['cars'][$carId]['insurance'][$insId])) {
        $insurance = array(
            'id'         => $row['INSURANCE_ID'],
            'start_date' => $row['START_DATE'],
            'end_date'   => $row['END_DATE'],
            'price'      => $row['PRICE']
        );
        $result[$id]['cars'][$carId]['insurance'][$insId] = $insurance;
    }
}

Answer 2

我不打算为你写出所有必要的字段，但它确实只归结为一个获取循环和一些if()逻辑来构建子数组：

$info = array()
while($row = fetch from db) {
    if(!isset($info[$row['userID']]) {
         $info[$row['userID']] = array(
              'first_name' => $row['first_name'],
              ...
              'cars' => array()
         );
    }
    if (!isset($info[$row['userID']]['cars'][$row['carID']]) {
         etc...
    }
}

对于您输入的每个子数组，您只需要另一个if()测试来初始化该子数组，然后从您提取的$row中填充它。

当你迭代行时，你会自然地建立你的结构。

从一对多的mysql结果创建多维数组

2 个答案: