连接数据库

<?php
try{
    $pdo = new PDO('mysql:locahost=127.0.0.1;dbname=php','root','123456');
 }catch(PDOException $e){
  echo '没有连接' . $e->getMessage();
 }
 $pre = $pdo -> prepare('SELECT * FROM `user`');
 $exe = $pre -> execute();
 $data = $pre -> fetchAll();
 ?>

用户信息

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>用户信息</title>
</head>
<body>
    <?php 
         require_once "db.php";
        $sql='SELECT * FROM `user`';
        $pre=$pdo->prepare($sql);
        $pre -> bindColumn('id',$id);
        $pre -> bindColumn('account',$account);
        $pre -> bindColumn('email',$email);
        $pre -> bindColumn('add_time',$add_time);
        $pre -> bindColumn('last_time',$last_time);
        $pre -> bindColumn('status',$status);
        $exec=$pre->execute();
        ?>
    <div class="user">
        <table>
            <caption>用户信息</caption>
            <thead>
                <tr>
                    <th><input type="checkbox" id="check_all"></th>
                    <th>ID</th>
                    <th>账号</th>
                    <th>邮箱</th>
                    <th>注册时间</th>
                    <th>登录时间</th>
                    <th>状态</th>
                </tr>
            </thead>
            <tbody>
                <?php while ($pre->fetch(PDO::FETCH_ASSOC)):?>
                <tr>
                    <td><input type="checkbox" class="chk_item"></td>
                    <td class="id"><?=$id?></td>
                    <td><a href="edit.php ?id=<?=$id?>" title="点击修改"><?=$account?></a></td>
                    <td><?=$email?></td>
                    <td><?=date('Y-m-d',$add_time)?></td>
                    <td><?=date('Y-m-d',$last_time)?></td>
                    <td><?=$status==1?'开启':'关闭'?></td>
                </tr>
                <?php endwhile ?>
            </tbody>
            <tfoot>
                <tr>
                    <td colspan="3"><button onclick="del()">删除</button></td>
                    <td><a href="add.php">注册用户</a></td>
                </tr>
            </tfoot>
        </table>
    </div>
    <script>
    const chkAll = document.querySelector("#check_all");
    const chkItems = document.querySelectorAll(".chk_item");
    chkAll.onchange = ev => chkItems.forEach(item => item.checked = ev.target.checked);
    chkItems.forEach(item => item.onchange = () => chkAll.checked = [...chkItems].every(item => item.checked));
    function del() {
        if (confirm('确定要删除吗？')) {
            const chkItems = document.querySelectorAll(".chk_item");
            chkItems.forEach(item => {
                if (item.checked) {
                    const id = item.parentElement.nextElementSibling.textContent;
                    let isDel = delOpt(id);
                    if (isDel) {
                        item.parentElement.parentElement.remove();
                    }
                }
            })
        } else {
            alert("NO");
        }
    }
    async function delOpt(id) {
        const response = await fetch("del.php?id=" + id);
        const comments = await response.json();
        return comments;
    }
    </script>
</body>
</html>

用户添加

<?php
require_once "db.php";
$sql='SELECT * FROM `user`';
?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>添加用户</title>
</head>
<body>
    <form method="post">
        账户：<input name="account" type="text" /><br />
        密码：<input name="password" type="password" /><br />
        邮箱：<input name="email" type="text" /><br />
        <input type="submit" value="注册" />
    </form>
</body>
</html>
<?php
    if(!empty($_POST)){
        if(empty($_POST['account'])){
            echo '<div style="color:blue;margin-top:20px;">请输入账户</div>';
            exit;
        }
        if(empty($_POST['password'])){
            echo '<div style="color:red;margin-top:20px;">请输入密码</div>';
            exit;
        }
        $pdo = new PDO('mysql:localhost=127.0.0.1;dbname=php','root','123456');
        $sql = 'INSERT INTO `user` SET `account` = "' . $_POST['account'] . '", `password` = "' . md5($_POST['password']) .'"';
        if(!empty($_POST['email'])){
            $sql .= ', `email` = "' . $_POST['email'] . '"';
        }
        $sql .= ', `last_time` = ' . time();
        $sql .= ', `status` = 1';
        $pre = $pdo->prepare($sql);
        $pre -> execute();
        if($pre->rowCount() > 0){
           echo '<script>alert("注册成功");window.location.href="list.php"</script>';
            exit;
        }else{
            echo '<div style="color:blue;margin-top:20px;">注册失败，请重试</div>';
            exit;
        }
    }
?>

用户修改

<?php
    if(!empty($_POST)){
        if(empty($_POST['account'])){
            echo '<div style="color:blue;margin-top:20px;">请输入账户</div>';
            exit;
        }
        if(empty($_POST['password'])){
            echo '<div style="color:red;margin-top:20px;">请输入密码</div>';
            exit;
        }
        $pdo = new PDO('mysql:localhost=127.0.0.1;dbname=php','root','123456');
        $sql = 'UPDATE `user` SET `account` = "' . $_POST['account'] . '", `password` = "' . md5($_POST['password']) .'"';
        if(!empty($_POST['email'])){
            $sql .= ', `email` = "' . $_POST['email'] . '"';
        }
        $sql .= ', `last_time` = ' . time();
        $sql .= ', `status` = 1';
        $pre = $pdo->prepare($sql);
        $pre -> execute();
        if($pre->rowCount() > 0){
           echo '<script>alert("修改成功");window.location.href="list.php"</script>';
            exit;
        }else{
            echo '<div style="color:blue;margin-top:20px;">修改失败，请重试</div>';
            exit;
        }
    }
?>

用户删除

<?php
    require_once "db.php";
    $id=$_GET['id'];
    $sql="DELETE FROM `user` WHERE id=$id";
    $pre=$pdo->prepare($sql);
    $exec=$pre->execute();
    if($exec){
        echo 1;
    }else{echo 0;}

用户添加，修改，删除

连接数据库

用户信息

用户添加

用户修改

用户删除

运行效果