我在找出下面的代码的while和foreach循环中在做什么时遇到了一些主要困难。我倾向于混合使用面向对象和过程性的mqsqli,但是每次我认为正确时,都会出错。

在这段代码中的循环中我在做什么错?

现在我得到这个错误

Warning: mysqli::query() expects parameter 1 to be string,


完整代码

try {
$con = new mysqli("localhost", "", "", "");
if (mysqli_connect_errno()) {
    throw new Exception("Connect failed: %s\n", mysqli_connect_error());
    exit();
}
$cid = $_GET['cid'];
$tid = $_GET['tid'];
$userid = ( isset( $_SESSION['user'] ) ? $_SESSION['user'] : "" );
    echo $cid . "<br>";
    echo $tid;
//Prepare
if ($stmt = $con->prepare("SELECT * FROM forum_topics WHERE `category_id`=? AND `id`=? LIMIT 1")) {

    $stmt->bind_param("ii", $cid, $tid);
    //$stmt->fetch();

    if (!$stmt) {
        throw new Exception($con->error);
    }
}
$stmt->store_result();
$numrows = $stmt->num_rows;
if($numrows == 1){
    echo "<table width='100%'>";
    if ( $_SESSION['user'] ) {
        echo "<tr><td colspan='2'><input type='submit' value='Add Reply' onclick=\"window.location =
    'forum_post_reply.php?cid=".$cid."$tid=".$tid."'\"> <hr />";
    } else {
        echo "<tr><td colspan='2'><p>Please log in to add your reply</p><hr /></td></tr>";
    }

foreach($stmt as $row) {

    //Prepared SELECT stmt to get forum posts
    if($stmt2 = $con->prepare("SELECT * FROM forum_posts WHERE `category_id`=? AND `topic_id`=?")) {
    //var_dump($stmt2);

        $stmt2->bind_param("ii", $cid, $tid);
        $stmt2->execute();
    }
    if ($result = $con->query($stmt)) {
        while ($row2 = $result->fetch_assoc() ) {
            echo "<tr><td valign='top' style='border: 1px solid #000000;'>
            <div style='min-height: 125px;'>".$row['topic_title']."<br />
            by ".$row2['post_creator']." - " .$row2['post_date']. "<hr />" . $row2['post_content'] ."</div></td>
            <td width='200' valign='top' align='center' style='border: 1px solid #000000;'>User Info Here!</td></tr>
            <tr><td colspan='2'><hr /></td></tr>";
        }
}
}
}   else {
    echo "<p>This topic does not exist.</p>";
    }

最佳答案

if ($stmt = $con->prepare("SELECT * FROM forum_topics WHERE `category_id`=? AND `id`=? LIMIT 1")) {

$stmt->bind_param("ii", $cid, $tid);
//$stmt->fetch();

if (!$stmt) {
    throw new Exception($con->error);
}
}

    $stmt->store_result();
    $numrows = $stmt->num_rows;


在遍历$stmt之前,您实际上根本没有执行过foreach($stmt as $row) {

您将要把它扔在那里:

$stmt->execute()

您的逻辑遍布各处。您看起来好像遍历了从未执行过的查询结果,然后尝试在此处重新查询原始的$stmt

if ($result = $con->query($stmt)) {

编辑:与您聊天后,您需要编辑原始查询以查询特定列,以便可以像这样引用它们:

if ($stmt = $con->prepare("SELECT topic_creator FROM forum_topics WHERE `category_id`=? AND `id`=? LIMIT 1")) {


...

$stmt->bind_result($topic_creator);
while ($stmt->fetch()) {
   echo "TC: " . $topic_creator . "<br>";
}


您可以将其应用于while循环中的子查询。

关于php - 在带循环的预备语句后发出输出数据,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/31570715/

10-11 22:35
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