如何修复PHP中的无响应mysql连接

我试图从mySQL表中获取一个变量到PHP代码中。我正在使用mysqli_查询命令。当我尝试回显结果时，它什么也不回显，甚至其他回显语句也不回显

我已经确保$conn是正确的并且可以工作，并且通过直接在PHPmyAdmin中运行Sql查询来确保它是正确的

<?php
session_start(); 

include_once("includes/dbh.inc.php");

    $UID = $_POST['userIdVariable'];

    $UID = $_SESSION['u_uid'];

    $balance = "SELECT account_balance FROM `users` WHERE user_uid = \"$UID\"";//this line probably works

$result = mysqli_query($conn, $balance);

echo "$result";

---

您需要使用mysqli_fetch函数从$result对象中获取结果列

while ($data = mysqli_fetch_assoc($result)) {
    printf("%s \n", $data["account_balance"]);
}

不要在查询中的字段名或表名中使用引号。

$balance = "SELECT account_balance FROM users WHERE user_uid = '$UID'";

请检查数据库连接。可能缺少数据库名称之类的内容。

$balance = "SELECT account_balance FROM users WHERE user_uid = '$UID'";

并打印$UID。可能没有身份证。

$balance = "SELECT account_balance FROM users WHERE user_uid = '$UID'";

要打印数据，请使用print_r（）

试试这个：

session_start(); 
$servername = "localhost";
$username = "username";
$password = "password";
// Create connection
$conn = new mysqli($servername, $username, $password,"databasename");
     $UID=1;
     $balance = "SELECT account_balance FROM users WHERE user_uid =$UID"; 
    $result = mysqli_query($conn, $balance); 
    if (mysqli_num_rows($result)) { 
        while ($row = mysqli_fetch_assoc($result)) { 
            echo $row['account_balance'];
        } 
    }

mysqli\u query
返回true\false\object，而不是查询结果添加到@tim：您需要以某种方式获得结果，以便使用（显示）结果集。请参阅以了解您拥有的选项