PHP从SQL获取带有子数组的数组

Question

我是编码新手，但我似乎无法理解这一点。非常感谢您提供一点帮助或提示。

基本上我想要一个带有问卷调查的数组，其中包含 id、name 和一个问题子数组。问题也由 id 和 name 组成。（1 Questionnaire 可以有多个问题） 我正在寻找这样的东西：

[{Questionnaires{id:x, name:x, questions:{id:x, name:x},{id:x2, name:x2}}]

这是我的查询

SELECT questionnaires.id QuestionnaireId, questionnaires.title QuestionnaireTitle, questions.id QuestionId, questions.text Question 
FROM questionnaires INNER JOIN questionnaireshasquestions qa ON qa.idQuestionnaire = questionnaires.id 
INNER JOIN questions ON questions.id = qa.idQuestion

还有我的 PHP 代码：

while ($row = $conn->fetch()) {
    
    if (!isset($data['questionnaires'][$row['QuestionnaireId']])) {
        
    $data['questionnaires'][] = array(
            'id' => $row['QuestionnaireId'],
            'title' => $row['QuestionnaireTitle'],
            'questions' => array(
                'id' => $row['QuestionId'],
                'text' => $row['Question']
            )
    ); 
    } else {
        $data['questionnaires'][$row['QuestionnaireId']][] = array(
           'questions' => array(
                'id' => $row['QuestionId'],
                'text' => $row['Question']
                )           
    );  
}

我得到的 JSON 数组格式错误/不正确：

{"questionnaires":[{"id":"1","title":"Are you hungry?","questions":{"id":"1","text":"How is your passion? "}},{"id":"1","title":"Are you hungry?","questions":{"id":"2","text":"Do you drink?"}},{"id":"2","title":"How are you feeling?","questions":{"id":"1","text":"How is your passion? "},"0":{"questions":{"id":"3","text":"Do you like fish?"}}},{"id":"5","title":"Is testing working?","questions":{"id":"4","text":"How is the testing?"}}]

如您所见，它对...内的每个问题重复相同的问卷调查

我希望我能很好地解释我在这里要做的事情:)

Answer 1

你的收集方法有点“坏”。

这应该可行：

while ($row = $conn->fetch()) {
    $id = $row['QuestionnaireId'];
    if (!isset($data['questionnaires'][$id])) {
        // First time we get this "QuestionnaireId" - 
        // define "container" that collects the related questions.  
        $data['questionnaires'][$id] = [
            'id'        => $row['QuestionnaireId'],
            'title'     => $row['QuestionnaireTitle'],
            'questions' => [],
        ];
    } else {
        // Already got this "container" -
        // put the question into the collection.
        $data['questionnaires'][$id]['questions'][] = [
            'id'   => $row['QuestionId'],
            'text' => $row['Question']
        ];
    }
}