为什么这样写只能连接到数据库，不能输出表里的值？

Question

<?php	
  $DBServer = '121.0.0.1';
  $DBUser = 'root';
	$DBPass = 'Zjy9201141217';	
	$DBname='test';
  $mysqli = new mysqli($DBServer,$DBUser,$DBPass,$DBname);
  $mysqli->query("SET NAMES utf8");
  if($mysqli){
    echo "连接成功";
    echo "<br>";
  }
  $sql_1 = "SELECT Usersname,Passwords FROM Users where Usersname='zjy'";
	$result_1 = $mysqli->query($sql_1);	
  echo '<ol>';
  while(list($Usersname,$Passwords)=$result_1->fetch_row()){
    echo '<li>'.$Usersname.':'.$Passwords.'<li>';
  }
  echo '<\ol>';
  $result_1->close();
  $mysqli->close();
?>

Answer 1

参照如下代码写：

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
 
// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
} 
 
$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = $conn->query($sql);
 
if ($result->num_rows > 0) {
    // 输出数据
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
    }
} else {
    echo "0 结果";
}
$conn->close();
?>

引用地址：https://www.runoob.com/php/php-mysql-select.html