javascript - 如何循环JSON上的所有数据

Question

您好，我尝试循环 json_encode() 来获取根据我的查询相关的所有数据脚本工作正常，但循环部分不行

这是我到目前为止所拥有的:

$con3 = new PDO("mysql:host=". db_host .";dbname=db", db_username , db_password);
$con3->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );

$con4 = new PDO("mysql:host=". db_host .";dbname=chat_db", db_username , db_password);
$con4->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
$sql5 = "SELECT * FROM users WHERE id = :rid LIMIT 1";
$stmt6=$con4->prepare($sql5);
$stmt6->bindValue( 'rid',$_GET['rid'], PDO::PARAM_STR);
$stmt6->execute();
    foreach($stmt6->fetchAll()as $res)
        {
            $usern = $res['username'];
            $user_lvl = $res['ulvl'];
        }

$comb = $usern . $_GET['name'];


  $sql6="SELECT msgid FROM thread WHERE combination1=:msgids OR combination2=:submsgids";
  $msg_id = $con4->prepare($sql6);
  $msg_id->bindParam(':msgids', $comb, PDO::PARAM_STR);
  $msg_id->bindParam(':submsgids', $comb, PDO::PARAM_STR);
  $msg_id->execute();
  $msgd = $msg_id->fetchColumn();
  $tbpre = $msgd;
    $sql7 = "SELECT   message_content, username , message_time, recipient FROM ".$tbpre."chat_conversation WHERE msgid=:chat";

    $stmt7=$con3->prepare($sql7);
    $stmt7->bindValue( 'chat', $msgd, PDO::PARAM_STR);
    $stmt7->execute();



  $message_query = $stmt7;


if(count($message_query) > 0) {
    while($message_array = $stmt7->fetchAll(PDO::FETCH_ASSOC)) {
        echo json_encode($message_array);
    }
}

它只从我的数据库返回一项数据..

这是我的 javascript，用于从我的 php 端检索:

        function AjaxRetrieve()
        {
          var rid = document.getElementById('trg').value,
    data = {chat: uid, rid: rid, name: user};

$.get('includes/getChat.php', data, function (result) {
    var res = $([]);

    $.each(result[0], function(key, value) {
        res = res.add($('<div />', {text : value}));
    });

    $("#clog").html(res);

}, 'json');
        }

Answer 1

您只需在每次循环迭代时继续覆盖 $json_string 即可。

您想要做的是将数据库数据保存到数组中然后进行编码。

$array = array();
if(count($message_query) > 0) {
    while($message_array = $stmt7->fetchAll(PDO::FETCH_ASSOC)) {
        $array[] = $message_array;   
    }
}
$json_string = json_encode($array);
echo $json_string;

在您的 AJAX 成功处理函数中，您似乎没有正确迭代数组。

请注意，您仅对返回结果集的第一个数组元素调用 $.each():

$.each(result[0], function(key, value) {
    res = res.add($('<div />', {text : value}));
});

我认为您会想要像这样迭代整个结果集:

$.each(result, function(rowKey, row) {
    // row is single row of result set from database
    // rowKey is numerical index of the row in the result set
    // rowKey is probably not useful here
    // You can just append new div to #clog with
    // whatever content from row which you desire
    // for example, this would insert message_content value
    // in child div to #clog
    $("#clog").append('<div>' + row.message_content + '</div>');
});