我正在尝试获取特定（已登录用户）用户的数据，但无法执行此操作。我编写了一个代码，可以读取完整的数据，但是我只想读取特定用户的数据。
我曾尝试使用WHERE username="$username"和其他可能的方法，但对我来说都不起作用
<?php
include_once 'server.php';
$result = mysqli_query($db,"SELECT * FROM users");
?>
<!DOCTYPE html>
<html>
<head>
<title> Admin Panel</title>
<link rel="stylesheet" type="text/css" href="style.css">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>
<body>
<h2>Welcome Admin</h2><hr>
<?php
if (mysqli_num_rows($result) > 0) {
?>
<table id="students">
<tr>
<th>ID</th>
<th>First Name</th>
<th>Last Name</th>
<th>Gender</th>
<th>DateOfBirth</th>
<th>Contact Number</th>
<th>Username</th>
<th>Email id</th>
</tr>
<?php
$i=0;
while($row = mysqli_fetch_array($result)) {
?>
<tr>
<td><?php echo $row["id"]; ?></td>
<td><?php echo $row["fname"]; ?></td>
<td><?php echo $row["lname"]; ?></td>
<td><?php echo $row["gender"]; ?></td>
<td><?php echo $row["dob"]; ?></td>
<td><?php echo $row["contact"]; ?></td>
<td><?php echo $row["username"]; ?></td>
<td><?php echo $row["email"]; ?></td>
</tr>
<?php
$i++;
}
?>
</table>
<?php
}
else{
echo "No result found";
}
?>
<form method="GET" action="index.php?logout='1'">
<button type="submit" class="button" name="logout">Logout</button>
</form>
</body>
</html>
这是server.php，我能够提取所有用户数据，但是我想根据登录者来确定特定的用户数据
<?php
session_start();
// variable declaration
$id = "";
$fname = "";
$lname = "";
$gender="";
$dob = "";
$contact = "";
$username = "";
$email = "";
$errors = array();
$_SESSION['success'] = "";
// connect to database
$db = mysqli_connect('localhost', 'root', '', 'registration');
// REGISTER USER
if (isset($_POST['reg_user'])) {
// receive all input values from the form
$fname = mysqli_real_escape_string($db, $_POST['fname']);
$lname = mysqli_real_escape_string($db, $_POST['lname']);
$gender = mysqli_real_escape_string($db, $_POST['gender']);
$dob = mysqli_real_escape_string($db, $_POST['dob']);
$contact = mysqli_real_escape_string($db, $_POST['contact']);
$username = mysqli_real_escape_string($db, $_POST['username']);
$email = mysqli_real_escape_string($db, $_POST['email']);
$password_1 = mysqli_real_escape_string($db, $_POST['password_1']);
$password_2 = mysqli_real_escape_string($db, $_POST['password_2']);
// form validation: ensure that the form is correctly filled
if (empty($fname)) { array_push($errors, "Firstname is required"); }
if (empty($lname)) { array_push($errors, "Lastname is required"); }
if (empty($dob)) { array_push($errors, "Date of Birth is required"); }
if (empty($contact)) { array_push($errors, "Contact Number is required"); }
if (empty($username)) { array_push($errors, "Username is required"); }
if (empty($email)) { array_push($errors, "Email is required"); }
if (empty($password_1)) { array_push($errors, "Password is required"); }
if ($password_1 != $password_2) {
array_push($errors, "The two passwords do not match");
}
// register user if there are no errors in the form
if (count($errors) == 0) {
$password = md5($password_1);//encrypt the password before saving in the database
$query = "INSERT INTO users (fname, lname, gender, dob,contact, username, email, password)
VALUES('$fname', '$lname','$gender', '$dob','$contact', '$username', '$email', '$password')";
mysqli_query($db, $query);
$_SESSION['username'] = $username;
$_SESSION['success'] = "You are now logged in";
header('location: index.php');
}
}
// ...
// LOGIN USER
if (isset($_POST['login_user'])) {
$username = mysqli_real_escape_string($db, $_POST['username']);
$password = mysqli_real_escape_string($db, $_POST['password']);
if (empty($username)) {
array_push($errors, "Username is required");
}
if (empty($password)) {
array_push($errors, "Password is required");
}
if (count($errors) == 0) {
$password = md5($password);
$query = "SELECT * FROM users WHERE username='$username' AND password='$password'";
$results = mysqli_query($db, $query);
if (mysqli_num_rows($results) == 1) {
$_SESSION['username'] = $username;
$_SESSION['success'] = "You are now logged in";
header('location: index.php');
}else {
array_push($errors, "Wrong username/password combination");
}
}
}
那么您可以在php中使用会话或cookie函数。在您的登录页面中，输入命令
setcookie('user', $user, time() + (the time for the user must be logged in), '/');
然后在要显示用户数据的页面中，分配变量，如
$user = $_COOKIE['user'];
和SQL查询：
select * from table_name where user = $user
我希望这可以解决您的问题