简单sql操作语句

<?php

// header("Content-type: text/html; charset=utf-8"); 

// function vertifyUser($usern, $passw){

    $serverN = "localhost";

    $serverUN = "root";

    $serverPS = "root";

        $serverDB = "myDB";

    $conn = new mysqli($serverN, $serverUN, $serverPS,$serverDB);

        if($conn->connect_error){

            die("连接失败". $conn->connect_error);

        }

//        $sql = "create table Students ("

//                . "id int(6) unsigned auto_increment primary key,"

//                . "firstname varchar(30) not null,"

//                . "lastname varchar(30) not null,"

//                . "phone int(11))";

        // $sql = "insert into Students (firstname, lastname, phone) values"

        //        . "('姓', '名', '1352566363')";

        // if($conn->query($sql) === TRUE){

        //    echo "创建成功";

        // }  else {

        //    echo "创建失败". $conn->error;

        // }

    // $stmt = $conn->prepare("insert into Students (firstname, lastname, phone) values (?, ?, ?)");

    // $stmt->bind_param("ssi", $first, $last, $pho);

    // $first = "ce";

    // $last = "shi";

    // $pho = 999999;

    // $stmt->execute();

    // $first = "ce1";

    // $last = "shi1";

    // $pho = 8888;

    // $stmt->execute();

    // $stmt->close();

        // $sql = "select id, firstname, lastname, phone from Students";

        // $result = $conn->query($sql);

        // if ($result->num_rows > 0)  {

        //    while ($row = $result->fetch_assoc()) {

        //        echo $row["id"]. "--". $row["firstname"]. "--". $row["lastname"]. "--". $row["phone"]. "
";

        //    }

        // }else{

        //    echo "失败";

        //    var_dump($result);

        // }

        // $sql = "select * from Students order by firstname asc";

        // $result = $conn->query($sql);

        // // echo $result->num_rows;

        // if ($result->num_rows > 0)  {

        //    while ($row = $result->fetch_assoc()) {

        //        echo $row["id"]. "--". $row["firstname"]. "--". $row["lastname"]. "--". $row["phone"]. "
";

        //    }

        // }

        $sql = "select * from Students where firstname regexp '[学]'";

        $result = $conn->query($sql);

        // echo $result->num_rows;

        if ($result->num_rows > 0)  {

            while ($row = $result->fetch_assoc()) {

                echo $row["id"]. "--". $row["firstname"]. "--". $row["lastname"]. "--". $row["phone"]. "
";

            }

        }

        $conn->close();

?>