php+mysql prepare 与普通查询的性能对比实例讲解

<?php 
class timer {   
    public $starttime = 0;   
    public $stoptime = 0;   
    public $timespent = 0;   
      
    function start(){   
      $this->starttime = microtime();   
    }   
      
    function stop(){   
      $this->stoptime = microtime();   
    }   
      
    function spent() {   
      if ($this->timespent) {   
      return $this->timespent;   
 
      } else {  
        // http://www.manongjc.com
        $startmicro = substr($this->starttime,0,10);   
        $startsecond = substr($this->starttime,11,10);   
        $stopmicro = substr($this->stoptime,0,10);   
        $stopsecond = substr($this->stoptime,11,10);   
        $start = floatval($startmicro) + $startsecond;   
        $stop = floatval($stopmicro) + $stopsecond;   
        $this->timespent = $stop - $start; 
         
      return round($this->timespent,8).'秒';   
      }  
    }  
  
} 
 
$timer = new timer;   
$timer->start();  
 
$mysql = new mysqli('localhost','root','root','ganbaobao_ucenter'); 
 
/* 
$query = $mysql->query("select username,email from uc_members where uid < 100000"); 
$result = array(); 
http://www.manongjc.com/article/1194.html
while($result = $query->fetch_array()) 
{ 
  $result[] = array('name'=>$result['username'],'email'=>$result['email']); 
} 
*/ 
$query_prepare = $mysql->prepare("select username,email from uc_members where uid < ?"); 
 
$id = 100000; 
$query_prepare->bind_param("i",$id); 
 
$query_prepare->execute(); 
$query_prepare->bind_result($username,$email); 
 
$result = array(); 
while($query_prepare->fetch()) 
{ 
  $result[] = array('name'=>$username,'email'=>$email); 
} 
 
$timer->stop();  
echo '</br>预查询mysql运行100000条数据时间为: '.$timer->spent();  
unset($timer);  
//var_dump($result);