database链接检测 ``` <?php $dbhost = 'localhost'; // mysql服务器主机地址 $dbuser = 'root'; // mysql用户名 $dbpass = '123456'; // mysql用户名密码 $conn = mysqli_connect($dbhost, $dbuser, $dbpass); if(! $conn ) { die('Could not connect: ' . mysqli_error()); } echo '数据库连接成功！'; mysqli_close($conn); ``` SQL查询 ``` <?php $dbhost = 'localhost:3306'; // mysql服务器主机地址 $dbuser = 'root'; // mysql用户名 $dbpass = '123456'; // mysql用户名密码 $conn = mysqli_connect($dbhost, $dbuser, $dbpass); if(! $conn ) { die('连接失败: ' . mysqli_error($conn)); } // 设置编码，防止中文乱码 mysqli_query($conn , "set names utf8"); echo '数据库连接成功！'; $sql = 'SELECT username, email FROM users'; mysqli_select_db( $conn, 'test' ); $retval = mysqli_query( $conn, $sql ); if(! $retval ) { die('无法读取数据: ' . mysqli_error($conn)); } echo '<h2>mysqli_fetch_array demo<h2>'; echo '<table border="1"><tr><td>Username</td><td>email</td></tr>'; while($row = mysqli_fetch_array($retval, MYSQLI_ASSOC)) { echo "<tr><td> {$row['username']}</td> ". "<td>{$row['email']} </td> ". "</tr>"; } echo '</table>'; mysqli_close($conn); ```