<?php

mysql_connect("localhost","root","root");

mysql_select_db("test");

//保留最新的1000条记录

$limit=1000;

$query="select `id` from `news`";

$result=mysql_query($query);

$num=mysql_num_rows($result);

if($num>$limit){

$query="select `id` from `news` order by `id` desc limit ".$limit;

$result=mysql_query($query);

mysql_data_seek($result,$limit-1);

$data=mysql_fetch_array($result);

$query="delete from `news` where `id`<'$data[id]'";

if(mysql_query($query)){

echo "数据库中原有".$num."条记录，多余的".($num-$limit)."条记录被成功删除，现在还剩余".$limit."条记录！";

}

}else{

echo "数据记录不足".$limit."条！没有必要删除！";

}

?>

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CREATE TABLE IF NOT EXISTS `news` (

`id` int(11) unsigned NOT NULL auto_increment,

`title` varchar(256) NOT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB DEFAULT CHARSET=gb2312;