使用php从sql获取登录的用户信息。

$servername = "数据库服务器地址";
$username = "数据库用户名";
$password = "数据库密码";
$dbname = "数据库名";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接是否成功
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

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

$sql = "SELECT * FROM users WHERE username = '$username' AND password = '$password'";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 用户存在，可以获取用户信息
    $row = $result->fetch_assoc();
    $userId = $row['id'];
    $email = $row['email'];
    // 其他需要的用户信息

    // 输出用户信息
    echo "用户ID: " . $userId . "<br>";
    echo "邮箱: " . $email . "<br>";
    // 输出其他用户信息
} else {
    echo "用户名或密码错误";
}

$conn->close();