当前位置: 首页 > 图文教程 > 网络编程 > PHP > php mssql 分页SQL语句优化 持续影响

PHP
同台服务器使用缓存APC效率高于Memcached的演示代码
GBK的页面输出JSON格式的php函数
在字符串指定位置插入一段字符串的php代码
php 数组二分法查找函数代码
php htmlspecialchars加强版
支持数组的ADDSLASHES的php函数
判断是否为指定长度内字符串的php函数
php 读取文件乱码问题
PHP+ajax 无刷新删除数据
php microtime获取浮点的时间戳
php 魔术函数使用说明
php 高效率写法 推荐
PHP 学习路线与时间表
php中理解print EOT分界符和echo EOT的用法区别小结
Search File Contents PHP 搜索目录文本内容的代码
收藏的PHP常用函数 推荐收藏保存
PHP 伪静态隐藏传递参数名的四种方法
PHP实现域名whois查询的代码(数据源万网、新网)
php 用checkbox一次性删除多条记录的方法
php str_pad() 将字符串填充成指定长度的字符串

PHP 中的 php mssql 分页SQL语句优化 持续影响


出处:互联网   整理: 软晨网(RuanChen.com)   发布: 2009-09-13   浏览: 303 ::
收藏到网摘: n/a

经过SQL优化后的分面查询速度能够得到大幅提高。

复制代码 代码如下:

<?php
/**
* @Filename :page.sql.class.php
* @CreatTime :2009-01-06
* @Descrition :此类为SQL语句处理类。
* @UpdateTime-1 :null
* @Version :jswweb1.0.0
* @Author :fkedwgwy
* @Dome :
$sql//SQL语句
$allcount//总记录数
$pagesize//页面显示记录条数
$page//当前页
$sqlc= new sqlpage($sql,$allcount,$pagesize,$page);
$sql=$sqlc->getsql();
优化后的语句:
SELECT * FROM (SELECT TOP 10 * FROM (SELECT TOP 270 Lsh,Ztm,Dyzrsm,Dyzzfs,Cbsm,Cbny,Ssh,Fbsl,jcsl from ts_gcb where Ssh like 'C%' order by Lsh asc) AS inner_tbl ORDER BY Lsh DESC) AS outer_tbl ORDER BY Lsh asc
*/
class sqlpage{
function sqlpage($sql,$allcount,$pagesize,$page){
$this->sql= $sql;//查询语名
$this->allcount= intval($allcount);//总记录数
$this->pagesize= intval($pagesize);//页面大小(显示记录数)
$this->page= intval($page);//当前页
$this->getpage();
$this->gettop();
}
function getpage(){ //获取当前页
$this->allpage=ceil( $this->allcount/$this->pagesize);//去当前小数的最大整数
if ($this->page=="" or $this->page>$this->allpage or $this->page<0 or $this->page==0){
$this->page2=1;
}else{
$this->page2=intval($this->page);//将页码转换为数字
}
}
function gettop(){ //获取子查询2的TOP大小
if ($this->page2<$this->allpage){
$this->top2=$this->pagesize;
}else{
$this->top2=$this->allcount-$this->pagesize*($this->allpage-1);
}
}
/* function getsql(){//获取SQL语句
$this->s=preg_replace("/select/i","",$this->sql);
$this->top1=$this->pagesize*$this->page2;
$this->sql1="SELECT TOP $this->top1 $this->s";
if (strpos($this->sql,"asc")){//升序
$this->sql_e="select * from ( select TOP $this->top2 * FROM ( $this->sql1 ) as aSysTable ORDER BY $this->order DESC ) as bSysTable ORDER BY $this->order ASC";
}else
//$this->sql_e="select * from ( select TOP $this->top2 * FROM ( $this->sql1 ) as aSysTable ORDER BY $this->order DESC ) as bSysTable ORDER BY $this->order ASC";
if (strpos($this->sql,"desc")){//降序
$this->sql_e="select * from ( select TOP $this->top2 * FROM ( $this->sql1 ) as aSysTable ORDER BY $this->order asc ) as bSysTable ORDER BY $this->order desc";
}else{//不处理排序的情况
$this->sql_e="select * from ( select TOP $this->top2 * FROM ( $this->sql1 ) as aSysTable ORDER BY $this->order DESC ) as bSysTable ORDER BY $this->order ASC";
}
// echo $this->sql_e;
return $this->sql_e;
}*/
function getsql()
{
$sql=$this->sql;
$this->top1=$this->pagesize*$this->page2;
$orderby = stristr($sql, 'ORDER BY');
if ($orderby !== false) {
$sort = (stripos($orderby, ' desc') !== false) ? 'desc' : 'asc';
$order = str_ireplace('ORDER BY', '', $orderby);
$order = trim(preg_replace('/\bASC\b|\bDESC\b/i', '', $order));
}
$sql = preg_replace('/^SELECT\s/i', 'SELECT TOP ' . ($this->top1) . ' ', $sql);
$sql = 'SELECT * FROM (SELECT TOP ' . $this->top2 . ' * FROM (' . $sql . ') AS inner_tbl';
if ($orderby !== false) {
$sql .= ' ORDER BY ' . $order . ' ';
$sql .= (stripos($sort, 'asc') !== false) ? 'DESC' : 'ASC';
}
$sql .= ') AS outer_tbl';
if ($orderby !== false) {
$sql .= ' ORDER BY ' . $order . ' ' . $sort;
}
echo $sql;
return $sql;
}
}
?>