PHP分页效率终结版(推荐)_php技巧
以前人们常用的PHP分页技术,通常都需要先统计出数据库中总信息条数才能判断出总页数并对其进行分页,,也就是说,每次分页要对数据库进行两次调用,在面临大数据量,高并发查询情况下是很不效率的,曾经一直为这个问题烦恼但都没想到合适的解决方法,今天突然在睡梦中 遇见奇迹...具体分析原理如下:(红色部分为优化后的区别,思路采用最原始的代码书写,为了照顾新人)
原始分页技术:包括许多开源程序也在使用的技术;
一般都是对数据库信息进行统计,然后调用分页类,进行分页,,每次都要经过2次数据库查询操作
例(原始分页技术): 每次都要进行2次数据库查询
$sqlstr="select count(*) as total from tablename";
$sql=mysql_query($sql) or die("error");
$info=mysql_fetch_array($sql); //第一次 数据库调用
$total=$info["total"];//每次翻页都要进行 总信息条数 的数据库查询操作
$pagesize=10; //每页显示数量
$page=$_GET["page"]?max(intval($_GET["page"]),1):1;//当前页
if($total){,
$sql="select * from tablename limit "($page-1)*$pagesize",$pagesize";
$sql=mysql_query($sql) or die("error");//第二次数据库查询操作
$info=mysql_fetch_array($sql);
do{
...............
}while($info=mysql_fetch_array($sql));
include("page_class.php");//调用分页类
$url="url.php?page=" //假设当前页为 URL.PHP
echo $get_page=new get_page($url,$total,$pagesize,$page); //URL 为要分页的URL地址
}
//优化后的分页技术(只需在第一次调用时进行信息统计即可)
if(isset($_GET["total"])){ //只需要进行一次总信息条数的统计即可
$total=intval($_GET["total"]);
//以后的的总信息数量通过GET传递即可,节省了1/2的数据库负荷,,,,
}else{
$sqlstr="select count(*) as total from tablename";
$sql=mysql_query($sql) or die("error");
$info=mysql_fetch_array($sql); //第一次 数据库调用
$total=$info["total"];
}//总信息条数
$pagesize=10; //每页显示数量
$page=$_GET["page"]?max(intval($_GET["page"]),1):1;//当前页
if($total){
$sql="select * from tablename limit "($page-1)*$pagesize",$pagesize";
$sql=mysql_query($sql) or die("error");//第二次数据库查询操作
$info=mysql_fetch_array($sql);
do{
...............
}while($info=mysql_fetch_array($sql));
include("page_class.php");//调用分页类
$url="url.php?total=$total&page=" //假设当前页为 URL.PHP
echo $get_page=new get_page($url,$total,$pagesize,$page); //URL 为要分页的URL地址
}

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