数据库连接

$sql=new mysqli('localhost','root','','test');
print_r($sql);

if($sql->connect_errno){
    die('CONNECT ERROR:'.$sql->connect_errno);
};

<?php
header('content-type:text/html;charset=utf-8');
//1.连接MySQL
$link=mysqli_connect('localhost','root','root') or die('数据库连接失败<br/>ERROR '.mysqli_connect_errno().':'.mysqli_connect_error());
//2.设置字符集
mysqli_set_charset($link, 'UTF8');
//3.打开指定数据库
mysqli_select_db($link, 'test1') or die('指定数据库打开失败<br/>ERROR '.mysqli_errno($link).':'.mysqli_error($link));