php用户注册常用检测、写入

        //        判断数据库是否已经存在
        $check_sql = "select * from user where idNumber='$idNumber'";
        $check_query = $conn->query($check_sql);
        if ($check_query->num_rows > 0) {
            echo "该用户名已经存在，请输入其他用户名";
            return;
        }

//插入数据库
        $password = $_POST['password'];
        $hashPassword = password_hash($password, PASSWORD_DEFAULT);
        $insert_sql = "insert into user (roleNum,password,idNumber,userStatus) values ( 0,'$hashPassword','$idNumber',1)";
        $insert_query = mysqli_query($conn, $insert_sql);
        $insert_id = mysqli_insert_id($conn);
        if ($insert_id > 0) {
            //插入成功
            echo "添加成功：" . $idNumber;
        } else echo "Error: " . mysqli_error($conn);
        mysqli_close($conn);

//批量输出
$select_sql = "select * from user where roleNum=0 ";
$select_query = mysqli_query($conn, $select_sql);
while ($row = mysqli_fetch_array($select_query)) {
    // print_r( $row);
    foreach ($row as $key => $value) {
        if (is_int($key)){
            echo $value;
            echo " | ";
        }
    }
    echo "<br>";
}