PHP使用mysql与mysqli连接Mysql数据库用法示例

<?php  /**  * @Author:   HTL  * @Description: Description  */  // 降低PHP默认的错误级别  // 只显示除禁用以外的所有错误  // 解决因为PHP5.3+版本太高而导致在使用mysql_connect时出现的弃用警告“Deprecated: mysql_connect(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead”  error_reporting(E_ALL ^ E_DEPRECATED);  $db_host="localhost";  $db_user="root";  $db_passwd="";  $db_name="mysql";  echo("<BR>---------------------------mysql_connect------------------------<BR><BR>");  $query = "SELECT SESSION_USER(), CURRENT_USER(),now();";  $conn = mysql_connect($db_host, $db_user,$db_passwd);  if (!$conn)  {   die('Could not connect: ' . mysql_error());  }  mysql_select_db($db_name, $conn);  $result = mysql_query($query);  while($row = mysql_fetch_array($result)){   var_dump($row);  }  mysql_close($conn);  echo("<BR>---------------------------mysqli_connect------------------------<BR><BR>");  $conn = mysqli_connect($db_host, $db_user, $db_passwd,$db_name) ;  if (!$conn)  {   die('Could not connect: ' . mysqli_error());  }  //execute the query.  $result = mysqli_query($conn, $query);  //display information:  while($row = mysqli_fetch_array($result)) {    var_dump($row);  }  mysqli_close($conn);  exit();?>