Mysqli准备的语句错误？

debugcn 发表于 Dev

泰勒·史蒂文斯（Taylor Stevens）

我在使用预准备语句时遇到了这个错误，我刚开始使用预准备语句，所以请对我轻松一点，以下是错误：

警告：mysqli_stmt :: bind_result（）：绑定变量数与第31行的C：\ wamp \ www \ darkhorizons \ login.php中已准备好的语句中的字段数不匹配

这是我的代码：

if (isset($_POST['submit'])){

$username = $_POST['username'];
$password = $_POST['password'];

if(isset($username) && isset($password)) {

   $mysqli = new mysqli("localhost","root","","phplogin") or die("Couldnt connect!");
    if(mysqli_connect_errno()){
        echo "Connection failed: ". mysqli_connect_errno();
        exit();
    }

    if($stmt = $mysqli -> prepare("SELECT * FROM users WHERE username =? AND password      =? LIMIT 1")){
    $stmt -> bind_param("ss", $username, $password);
    $stmt -> execute();

    $stmt -> bind_result($result);
    $stmt -> fetch();



    $numrows = mysqli_num_rows($result);

} else {
    die("Please enter a username and password!");
}

if($numrows == 1){

    $_SESSION['username'] = $_POST['username'];
    $_SESSION['loggedin'] = true ;

    $query = "SELECT adminflag FROM users WHERE username = '{$_SESSION['username']}' LIMIT 1;";
    $result2 = mysqli_query($connect, $query);
    $numrows2 = mysqli_num_rows($result2);

    if ($numrows2 == 1) {
        $_SESSION['isadmin'] = true;
    }

    header("Location: {$pageLoc}");
    exit(); //It's good to use exit or die (same thing) AFTER using header to redirect

} else {


}

    }
    }

附带说明，请忽略准备好的语句下面的代码中的任何错误，请重做我一直在学习的登录脚本。

蜂蜜

遍历代码后，您实际上并不需要两次查询数据库，您应该adminflag在同一选择中阅读。

SELECT * 永远不要选择总是选择特定字段。

而且我还注意到您使用的是两种不同的样式，建议您坚持使用面向对象的方法。

<?php
if (isset($_POST['submit'], $_POST['username'] , $_POST['password'])){

$username = $_POST['username'];
$password = $_POST['password'];

$mysqli = new mysqli("localhost","root","","phplogin");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

$query = "SELECT adminflag FROM users WHERE username = ? AND password = ? LIMIT 1";
if ($stmt = $mysqli->prepare($query)) {
    $stmt -> bind_param("ss", $username, $password);
    $stmt->execute();

        $stmt->store_result();
        $numrows = $stmt->num_rows;
        printf("Number of rows: %d.\n", $numrows );

    if($numrows == 1){
        $stmt->bind_result($admin_flag);
        $stmt->fetch();
        session_start();
        if ($admin_flag== 1) {
            $_SESSION['isadmin'] = true;
        }
        $_SESSION['username'] = $username;
        $_SESSION['loggedin'] = true ;
        header("Location: {$pageLoc}");
    }else{
        echo 'user not found';
    }

}
$stmt->close();
$mysqli->close();
}else{
    echo 'required field missing';
}
?>

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