PHP 警告：查询和获取

Question

警告：mysqli_query() 至少需要 2 个参数，1 个给定 警告：mysqli_fetch_assoc() 期望参数 1 为 mysqli_result，给定为空

我也有这些警告，我该如何解决？

public static function checklogin() {
    mysqli_connect();

    $username = $_SESSION['USER'];
    $password = $_SESSION['PASS'];

    $query = "
        SELECT 
            `account`.`id`,
            `account`.`status`
        FROM `account`.`account`
        WHERE `account`.`login` = '".$username."'
        AND `account`.`password`='".$password."'
    ";
    $exec = mysqli_query($query);
    $row = mysqli_fetch_assoc($exec);
    if($row['status'] == 'OK&apos
    {
        return true;
    }
    else
    {
        return false;
    }
}

Answer 1

您需要保存使用mysqli_connect 打开的数据库连接，并且为了实际连接到数据库主机配置。阅读连接文档here 以获得更好的解释。
使用数据库地址更新您的代码（确保您知道您的连接）

$db=mysqli_connect("127.0.0.1", "my_user", "my_password", "my_db");
if(!$db) {
  echo "ERROR connecting to my_db";
  return false;
}

// sanitize
$username = filter_var($_SESSION['USER'], FILTER_SANITIZE_STRING);
$password = filter_var($_SESSION['PASS'], FILTER_SANITIZE_STRING);

$query = "
    SELECT 
        `account`.`id`,
        `account`.`status`
    FROM `account`.`account`
    WHERE `account`.`login` = '".$username."'
    AND `account`.`password`='".$password."'
";
$exec = mysqli_query($db, $query);
$row = mysqli_fetch_assoc($exec);
...

看看mysqli_querydocs。