Mysqli_query SELECT返回false

Question

我目前正在尝试根据学生编号和密码获得某个用户...问题是mysqli_query一直返回false（？）语句。虽然我通过在PHPMyAdmin中测试它来检查查询。这是我的疑问：

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

$sql = "SELECT studentNumber FROM student where studentNumber = '$number'" ;
$result = mysqli_query($conn, $sql) or die(mysqli_error());;

if(!$result){
    echo "FAIL";
}
else if($result > 0){
    header("register.html");    
}else{
    $sql = "INSERT INTO 'sampleDB'.'student'('userID', 'studentNumber', 'password') VALUES ('', $number, $password)";
    header("login.html");
}

这是我的代码连接部分：

$conn = new mysqli($servername, $username, $password);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

Answer 1

首先获取结果并在您的条件下使用它。

$result2 = mysql_fetch_array($result);