PHP+Mysql development of page number paging

<html>
 <head>
     <meta http-equiv="CONTENT-TYPE" content="text/html;">
 </head>
 <body>
 <?php
 /** 1.传入页面 **/
 $page = $_GET['p'];
 /** 2.根据页面取出数据:php->mysql **/
 $host = "localhost";
 $username = 'root';
 $password = '123456789';
 $db = 'bbs2';
 $PageSize=5;
 $ShowPage=3;
 //连接数据库
 $conn = mysql_connect($host, $username, $password);
 if(!$conn){
     echo "数据库连接失败";
     exit;
 }
 
 //选择所要操作的数据库
 mysql_select_db($db);
 //设置数据库编码格式
 mysql_query('SET NAMES UTF8');
 //编写sql获取分页数据:SELECT * FROM 表名 LIMIT 起始位置 , 显示条数
 $sql = "SELECT*FROM test LIMIT ".($page-1)*$PageSize .",$PageSize";
 if(!$sql){
     echo "取出不成功";
 };
 //把sql语句传送到数据库
 $result = mysql_query($sql);
 //处理我们的数据
 echo "<table border=1 cellspacing=0 width=15% >";
 echo "<tr><td>ID</td><td>名字</td><td>性别</td></tr>";
 while($row = mysql_fetch_assoc($result)){
     echo "<tr>";
     echo "<td>{$row['id']}</td>";
     echo "<td>{$row['name']}</td>";
     echo "<td>{$row['sex']}</td>";
     echo "<tr>";
 }
 echo "</table>";
 //释放结果
 mysql_free_result($result);
 //获取数据总数
 $to_sql="SELECT COUNT(*)FROM test";
 $to_result=mysql_fetch_array(mysql_query($to_sql));
 $to=$to_result[0];
 //计算页数
 $to_pages=ceil($to/$PageSize);
 mysql_close($conn);
 /** 3.显示数据+分页条 **/
 $page_banner="";
 //计算偏移量
 $pageffset=($ShowPage-1)/2;
 if($page>1){
     $page_banner.="<a href='".$_SERVER['PHP_SELF']."?p=1'>首页</a>";
     $page_banner.="<a href='".$_SERVER['PHP_SELF']."?p=".($page-1)."'>上一页</a>";
 }
 //初始化数据
 $start=1;
 $end=$to_pages;
 if ($to_pages>$ShowPage){
     if($page>$pageffset+1){
         $page_banner.="...";
     }
     if ($page>$pageffset){
         $start=$page-$pageffset;
         $end=$to_pages>$page+$pageffset?$page+$pageffset:$to_pages;
     }else{
         $start=1;
         $end=$to_pages>$ShowPage?$ShowPage:$to_pages;
     }
     if ($page+$pageffset>$to_pages){
         $start=$start-($page+$pageffset-$end);
     }
 }
 for($i=$start;$i<=$end;$i++){
     $page_banner.="<a href='".$_SERVER['PHP_SELF']."?p=".($i)."'>{$i}</a>";
 }
 //尾部省略
 if ($to_pages>$ShowPage&&$to_pages>$page+$pageffset){
     $page_banner.="...";
 }
 if ($page<$to_pages){
     $page_banner.="<a href='".$_SERVER['PHP_SELF']."?p=".($page+1)."'>下一页</a>";
     $page_banner.="<a href='".$_SERVER['PHP_SELF']."?p=".($to_pages)."'>尾页</a>";
 }
 
 $page_banner.="共{$to_pages}页";
 echo $page_banner;
 ?>
 </body>
 </html>

When there is too much data, the page number will also be too long. At this time, it is necessary to hide the page number to achieve a beautiful effect

Code explanation

QQ截图20161026153352.png

##$ ShowPage=3; We only display 3 page numbers

$pageffset=($ShowPage-1)/2; Page offset We display 3 page numbers minus 1 divided by 2 to get 1, which means the previous one and the next one offset respectively.

$start=1;
 $end=$to_pages;
 if ($to_pages>$ShowPage){
     if($page>$pageffset+1){
         $page_banner.="...";
     }

The total number of pages is greater than the displayed number of pages, and the current page is greater than the offset + 1 display...Omitted


    if ($page>$pageffset){
         $start=$page-$pageffset;
         $end=$to_pages>$page+$pageffset?$page+$pageffset:$to_pages;

$start starting position if the current page is greater than the offset Shift, then the starting position displays the current page minus the offset

$end position. If the total number of pages is greater than the current page plus the offset, then the end position is the current page plus the offset. If not If it is greater, the last one will be displayed


else{
         $start=1;
         $end=$to_pages>$ShowPage?$ShowPage:$to_pages;
     }

If the current page is less than the offset, the starting position is 1


The end position of the current page is greater than the displayed number of pages. If it is greater, it will be displayed. The number of pages currently displayed, otherwise the total number of pages will be displayed

    if ($page+$pageffset>$to_pages){
         $start=$start-($page+$pageffset-$end);

If the page number plus offset is greater than the last page, the starting position is equal to the original starting position minus the current page plus offset minus Go to the end position.

}
 for($i=$start;$i<=$end;$i++){
     $page_banner.="<a href='".$_SERVER['PHP_SELF']."?p=".($i)."'>{$i}</a>";
 }

Display page number


//尾部省略
 if ($to_pages>$ShowPage&&$to_pages>$page+$pageffset){
     $page_banner.="...";
 }

When the total number of pages is greater than the displayed number of pages and the last page is greater than the current page plus the offset, it is omitted

Continuing Learning
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<html> <head> <meta http-equiv="CONTENT-TYPE" content="text/html;"> </head> <body> <?php /** 1.传入页面 **/ $page = $_GET['p']; /** 2.根据页面取出数据:php->mysql **/ $host = "localhost"; $username = 'root'; $password = '123456789'; $db = 'bbs2'; $PageSize=5; $ShowPage=3; //连接数据库 $conn = mysql_connect($host, $username, $password); if(!$conn){ // echo "数据库连接失败"; exit; } //选择所要操作的数据库 mysql_select_db($db); //设置数据库编码格式 mysql_query('SET NAMES UTF8'); //编写sql获取分页数据:SELECT * FROM 表名 LIMIT 起始位置 , 显示条数 $sql = "SELECT*FROM test LIMIT ".($page-1)*$PageSize .",$PageSize"; if(!$sql){ echo "取出不成功"; }; //把sql语句传送到数据库 $result = mysql_query($sql); //处理我们的数据 echo "<table border=1 cellspacing=0 width=15% >"; echo "<tr><td>ID</td><td>名字</td><td>性别</td></tr>"; while($row = mysql_fetch_assoc($result)){ echo "<tr>"; echo "<td>{$row['id']}</td>"; echo "<td>{$row['name']}</td>"; echo "<td>{$row['sex']}</td>"; echo "<tr>"; } echo "</table>"; //释放结果 mysql_free_result($result); //获取数据总数 $to_sql="SELECT COUNT(*)FROM test"; $to_result=mysql_fetch_array(mysql_query($to_sql)); $to=$to_result[0]; //计算页数 $to_pages=ceil($to/$PageSize); mysql_close($conn); /** 3.显示数据+分页条 **/ $page_banner=""; //计算偏移量 $pageffset=($ShowPage-1)/2; if($page>1){ $page_banner.="<a href='".$_SERVER['PHP_SELF']."?p=1'>首页</a>"; $page_banner.="<a href='".$_SERVER['PHP_SELF']."?p=".($page-1)."'>上一页</a>"; } //初始化数据 $start=1; $end=$to_pages; if ($to_pages>$ShowPage){ if($page>$pageffset+1){ $page_banner.="..."; } if ($page>$pageffset){ $start=$page-$pageffset; $end=$to_pages>$page+$pageffset?$page+$pageffset:$to_pages; }else{ $start=1; $end=$to_pages>$ShowPage?$ShowPage:$to_pages; } if ($page+$pageffset>$to_pages){ $start=$start-($page+$pageffset-$end); } } for($i=$start;$i<=$end;$i++){ $page_banner.="<a href='".$_SERVER['PHP_SELF']."?p=".($i)."'>{$i}</a>"; } //尾部省略 if ($to_pages>$ShowPage&&$to_pages>$page+$pageffset){ $page_banner.="..."; } if ($page<$to_pages){ $page_banner.="<a href='".$_SERVER['PHP_SELF']."?p=".($page+1)."'>下一页</a>"; $page_banner.="<a href='".$_SERVER['PHP_SELF']."?p=".($to_pages)."'>尾页</a>"; } $page_banner.="共{$to_pages}页"; echo $page_banner; ?> </body> </html>
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