php mssql 分页SQL语句优化 持续影响_php教程-查字典教程网
php mssql 分页SQL语句优化 持续影响
php mssql 分页SQL语句优化 持续影响
发布时间:2016-12-29 来源:查字典编辑
摘要:复制代码代码如下:

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('/bASCb|bDESCb/i', '', $order));

}

$sql = preg_replace('/^SELECTs/i', 'SELECT TOP ' . ($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;

}

}

?>

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