Php pdo 使用序列进行迭代

Question

我想按顺序显示问题和答案(先:问题然后答案)怎么可能？

$servername = "localhost";
$username = "someone";
$password = "someonepassword";
$dbname = "quiz_app";

$pdo = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);

$statement = $pdo->prepare("SELECT * FROM question");
$statement2 = $pdo->prepare("SELECT a.id as answer_id, a.*, 
                                    q.id as question_id, q.* 
                            FROM answer a 
                                inner join question q on a.question_id = q.id");


$statement->execute();
$statement2->execute();


$result = $statement->fetchAll(PDO::FETCH_ASSOC);
$result2 = $statement2->fetchAll(PDO::FETCH_ASSOC);

$i=0;
foreach ($result as $row) {
  $i++;
  echo "<h5>".$i.'.'.$row['question_text']. "</h5>";
    foreach ($result2 as $row2) {
      echo "<input name='group". $row2['id'] ."' type='radio' id='". $row2['answer_id'] ."' />" . "<label for='". $row2['answer_id'] ."'>".$row2['answer_text']."</label>";
     }
  echo "<br>";
 }

在此代码中，问题和答案的顺序不同(所有问题放在一起，然后是答案)我该如何解决它？

Answer 1

更逻辑地思考您正在处理的数据。第一个查询完全没有必要，您需要的一切都在第二个查询中。只需通过 q.id 和 a.id

订购即可

$stmt = $pdo->prepare("SELECT q.*,q.id as qid,
                              a.*, a.id as aid
                        FROM question q 
                            inner join answer a on a.question_id = q.id
                        ORDER BY qid, aid");

$q_and_a = $statement->fetchAll(PDO::FETCH_ASSOC);

$last_qid = NULL;
foreach ( $q_and_a as $i => $row) {
    if ( $last_qid == $row['qid'] ) {
        // we are starting a new question
        echo "<h5>{$row['question_text']}</h5>";
        $last_qid = $row['qid'];
    }
    // hear we are processing all the answer to the question
    echo "<input name='group{$row2['qid']}' type='radio' id='{$row['aid']}'/>" 
        . "<label for='{$row['aid']}'>{$row['answer_text']}</label>";
}

Not sure if I got the question id and answer id info in the right place in the output, but hopefully this will give you a nudge in the right direction and you can fix any little issues yourself