PHP 无法动态构建 PDO 查询。答案

【问题标题】：PHP failing to build a PDO query dynamically.PHP 无法动态构建 PDO 查询。
【发布时间】：2012-06-24 18:43:39
【问题描述】：

所以我正在尝试使用 PDO 构建和准备动态的 mysql 查询。这是我的代码和调试信息。

$allowed_filters = array('hotels.star_rating', 'countries.id');

$where = 'WHERE 1 ';
if (!empty($data['filters'])){
    $where = 'WHERE';
    foreach ($data['filters'] as $field => $value){
        if (in_array($field, $allowed_filters)){
            $where .= " $field = :$field &&";
        }
        else unset($data['filters'][$field]);
    }

    $where = rtrim($where, '&&');
    $where = ($where == 'WHERE')? 'WHERE 1 ' : $where;
}

$st = $this->db->prepare("
    SELECT 
        hotels.code,
        hotels.name as name,
        hotels.star_rating,
        hotels.description,
        hotels.cover_image,
        countries.name as country,
        cities.name as city 
    FROM  
        hotels JOIN cities ON cities.id = hotels.city_id
        join countries on countries.id = cities.country_id
    $where
");

$st->execute($data['filters']);
var_dump($st->fetch());

就在 $st->execute($data['filters']) 行之前，我转储了 $st 和 $data['filters']。值如下。

$st 的价值

PDOStatement Object
(
    [queryString] => 
        SELECT 
            hotels.code,
            hotels.name as name,
            hotels.star_rating,
            hotels.description,
            hotels.cover_image,
            countries.name as country,
            cities.name as city 
        FROM  
            hotels JOIN cities ON cities.id = hotels.city_id
            join countries on countries.id = cities.country_id
        WHERE 
            hotels.star_rating = :hotels.star_rating && 
            countries.id = :countries.id 
)

$data['filters'] 的值

Array
(
    [hotels.star_rating] => 4 stars
    [countries.id] => 5
)

PDO 引发异常并失败并出现以下错误。

SQLSTATE[HY093]：参数号无效：参数未定义'

帮助？

【问题讨论】：

标签： php pdo

【解决方案1】：

您忘记了$data['filters'] 的键中的冒号:。应该是：

Array
(
    [:hotels.star_rating] => 4 stars
    [:countries.id] => 5
)

【讨论】：

确实如此。你能解释一下为什么有时它可以在没有冒号的情况下工作吗？例如，这很好用。 $st = $dbh->prepare('SELECT * FROM hotels WHERE id = :id'); $st->execute(array('id' => 1)); var_dump($st->fetch());