使用 php 和 mysqli 将数组传回 Ajax

Question

我目前正在做一个小型项目，我有 2 个 mysql 数据库表（问题和答案）。答案表包含 questionid。我在 ajax 调用中使用以下查询选择一个问题和 4 个相关答案，它可以工作但不确定它是否正确？

然后我将其作为数组传回以显示在我的网页上。正在显示问题，但没有显示答案，但我可以在控制台窗口的回复中看到值在那里。我在想可能是因为问题和答案在同一个数组中？

非常感谢任何帮助。

php/mysqli：

$sql= 'SELECT question FROM questions where difficulty = 1
UNION ALL
SELECT answer FROM answers a right join questions q on q.id = a.questionid WHERE q.difficulty = 1';
$result = $mysqli->query($sql) or die($mysqli->error.__LINE__);

if($result->num_rows > 0){
    $array = array(); // initialize
    while($row = $result->fetch_array(MYSQLI_BOTH)){
        $array[] = array(
        'question' => $row[0],
        'answer' => $row[1],
        'answer' => $row[2],
        'answer' => $row[3],
        'answer' => $row[4]
        );  
    }

}
header('Content-Type: application/json',true);
echo json_encode($array);   
$result->free();
$mysqli->close();

Ajax 成功响应：

function response(json){
  console.log(json);
  var quest = json[0].question;
  var ans1 = json[1].question;
  var ans2 = json[2].question;
  var ans3 = json[3].question;
  var ans4 = json[4].question;
  $("#questionBox").html('<h2>Q: ' + quest);
  $("#answerBox").html('<h2>Q: ' + ans1);
}

Ajax 响应：

[{"question":"Is this an easy question?","answer":null},
{"question":"Yes","answer":null},
{"question":"No","answer":null},
{"question":"Maybe","answer":null},
{"question":"Who Knows","answer":null}]

直接从浏览器响应：

[{"question":"Is this an easy question?","answer":null},
{"question":"Yes","answer":null},
{"question":"No","answer":null},
{"question":"Maybe","answer":null},
{"question":"Who Knows","answer":null}]

Answer 1

var ans1 = json[1].question;

不应该是这样的：

var ans1 = json[0].answer;

此外，您用于创建数组的 PHP 代码也具有相同的 answer 键 4 次，我想这意味着即使您设置了 4 个答案，您也只能在响应中得到 1 个答案。您可能希望将其更改为：

  $array[] = array(
        'question' => $row[0],
        'answer1' => $row[1],
        'answer2' => $row[2],
        'answer3' => $row[3],
        'answer4' => $row[4]
        ); 

然后在javascript中：

var ans1 = json[0].answer1;
var ans2 = json[0].answer2;

等等