小编Mar*_*lis的帖子

我有以下PHP代码,用于应用程序的投票系统.它是一个问答应用程序,用户可以投票选出已发布的问题和答案.

在我的PHP代码中,我首先检查用户是否已投票给某个特定问题.这将存在于QVOTES表中,其中包含电子邮件和正在投票的问题的ID.

执行此检查时,我不确定如何查看$ result是否为空集,以便在尚未对该问题进行投票时提交用户的投票.

我怎样才能使这个工作？非常感谢所有帮助.

<?php

$con=mysqli_connect("127.2.1.1","S837","887","D887");
if (mysqli_connect_errno($con))
{
   echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$qid = $_POST['qid'];
$email = $_POST['email'];
$result = mysqli_query($con, "SELECT * FROM QVOTES WHERE QID = $qid AND EMAIL = '$email'");
if (!mysqli_num_rows($result) ){
    if ($result = mysqli_query($con, "INSERT INTO QVOTES (QID, EMAIL) VALUES     ($qid, '$email')")) {
            mysqli_query($con, "Update QUESTIONS SET VOTES = VOTES +1 WHERE     QID = $qid");
            echo "Update successful";
        } else{
            echo "Update unsuccessful";
        }
            } else{ …