php - MySQL/PHP 分页问题 - 不会转到第二页

Question

抱歉，如果这是一个愚蠢的问题，但我在这方面仍然是个新手，并且在不断尝试和犯错的过程中不断学习。

我有下面的分页脚本，它确实有效，但是当我单击“下一页”时，它不会在下一页上显示最后 2 个产品。它只是停留在第一页和原来的 3 页上。

• 数据库总记录 5

• 限制设置为每页 3 个(用于测试目的)

    <?php
   $dbhost = '*******';
   $dbuser = '*******';
   $dbpass = '*******';
  
   $rec_limit = 3;
   $conn = mysql_connect($dbhost, $dbuser, $dbpass);
  
   if(! $conn ) {
      die('Could not connect: ' . mysql_error());
   }
   mysql_select_db('********');
  
   /* Get total number of records */
   $sql = "SELECT count(id) FROM products ";
   $retval = mysql_query( $sql, $conn );
  
   if(! $retval ) {
      die('Could not get data: ' . mysql_error());
   }
   $row = mysql_fetch_array($retval, MYSQL_NUM );
   $rec_count = $row[0];
  
   if( isset($_GET{'page'} ) ) {
      $page = $_GET{'page'} + 1;
      $offset = $rec_limit * $page ;
   }else {
      $page = 0;
      $offset = 0;
   }
  
   $left_rec = $rec_count - ($page * $rec_limit);
   $sql = "SELECT id, name, description, price ". 
      "FROM products ".
      "LIMIT $offset, $rec_limit";
  
   $retval = mysql_query( $sql, $conn );
  
   if(! $retval ) {
      die('Could not get data: ' . mysql_error());
   }
  
   while($row = mysql_fetch_array($retval, MYSQL_ASSOC)) {
      echo "Product :{$row['name']}  <br> ".
         "Description : {$row['description']} <br> ".
         "Price : {$row['price']} <br> ".
         "--------------------------------<br>";
   }
  
   if( $page > 0 ) {
      $last = $page - 2;
      echo "<a href = \"$_PHP_SELF?page = $last\">Previous Page</a> |";
      echo "<a href = \"$_PHP_SELF?page = $page\">Next Page</a>";
   }else if( $page == 0 ) {
      echo "<a href = \"$_PHP_SELF?page = $page\">Next Page</a>";
   }else if( $left_rec < $rec_limit ) {
      $last = $page - 2;
      echo "<a href = \"$_PHP_SELF?page = $last\">Last Page</a>";
   }
  
   mysql_close($conn);
  ?>
  

Answer 1

Pagination in php is very simple concepts. You can learn easily. Just follow the below steps.

      1. Find the Start values based on page number:


 $limit=10;
 $page=$_GET['p'];
 if($page=='')
 {
  $page=1;
  $start=0;
 }
 else
 {
  $start=$limit*($page-1);
 }

     Where,
                  $limit is the number rows per page.
                  $page is page number.
                  $start is starting point of limit in mysql query.
If the page number is 1, then the start is 0 which is find by $start=$limit*($page-1).
                  $start=10*(1-1)
                  $start=10*(0)
                  $start=0

If the page number is 2, then the start is 10.
Similarly, if the page number is 3, then the start is 20.

                    2. Find total number of records in mysql table:

Then we need to calculate the total number of data in table. Then find the maximum pages using php script like below:

$tot=mysql_query("SELECT * FROM table1")  or die(mysql_error());
$total=mysql_num_rows($tot);
$num_page=ceil($total/$limit);


     Where,
                mysql_num_rows() returns the numbers results in numeric.
                ceil() returns the whole digit number. ie, ceil(2.3) => 3.
                $maxpage returns the number of pages.


                     3. Function for pagination:

        The php script for pagination function is:

function pagination($page,$num_page)
{
  echo'<ul ;
  for($i=1;$i<=$num_page;$i++)
  {
     if($i==$page)
{
 echo'<li ;
}
else
{
 echo'<li ;
}
  }
  echo'</ul>';
}      

           Where, 
                        You need to use for loop for display number of pages in mysql table.

Reference: http://www.phponwebsites.com/2014/04/php-mysql-pagination.html