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php实现只保留mysql中最新1000条记录_PHP

May 30, 2016 am 08:44 AM
mysql php

<&#63;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!";
}
&#63;>

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test.sql

-- phpMyAdmin SQL Dump
-- version 3.1.5-rc1
-- http://www.phpmyadmin.net
--
-- 主机: localhost
-- 生成日期: 2010 年 08 月 19 日 05:47
-- 服务器版本: 5.0.18
-- PHP 版本: 5.2.8

SET SQL_MODE="NO_AUTO_VALUE_ON_ZERO";


/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;

--
-- 数据库: `test`
--

-- --------------------------------------------------------

--
-- 表的结构 `news`
--

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;
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