php - MySQL 查询 PHP "sorry...query failed, please click me"错误

Question

我在 Marketplace php 脚本上工作，每次当我想登录用户帐户时，我只会收到此错误:抱歉...查询失败，请点击我主页

query("SELECT * FROM `users` WHERE `username`='" . $mysqli->real_escape_string($useroremail) . "' and `password`='" . md5($password) . "' and `userlevel`='".($vendor==true ? 30 : 20)."'LIMIT 1;") or die('sorry...query failed, please click me <a href="./index.php">home</a>');     $row_cnt = $result->num_rows;
        if($row_cnt==1){
        $row = $result->fetch_assoc();
        if ($vendor==true){
        setcookie('lite_engine', $gbhgbhgbh->encrypt('['.(time()+86400).';'.$row['username'] . ']2','/'),  time()+86400);
        }else{
        setcookie('lite_engine', $gbhgbhgbh->encrypt('['.(time()+86400).';'.$row['username'] . ']1','/'),  time()+86400);
        }

希望有人能帮助我。

Answer 1

要查看查询出了什么问题，请尝试对其进行调试，以下是我调试查询的方法

1. 将查询回显到屏幕
2. 从屏幕上复制打印的查询
3. 在数据库管理器 (phpmyadmin) 中执行查询
4. 阅读 SQL 错误(在这里您将看到查询出了什么问题)并

5. 相应地更改您的查询

   $query = "SELECT * FROM `users` WHERE `username`='" . $mysqli->real_escape_string($useroremail) . "' and `password`='" . md5($password) . "' and `userlevel`='".($vendor==true ? 30 : 20)."'LIMIT 1;";
   echo $query;