mysql LIMIT并不断检索行[重复]

I will do a project for my database class (new in databases). I will use php. The tables are created in mysql. I have to display a webpage with some information:

attr1 | atrr2 | atrr3 | atrr4 
      |       |       |
      |       |       |

But I want to display the last inserted 20 rows. Then, if the user wants to see the other rows inserted, the webpage will have a next page button showing the following 20 rows (not the same ones).

I know that I can use something like:

select (attributes) from tbl ORDER BY 'ID' DESC LIMIT 20

1- But then, How I can retrieve (with php programming) the other 20 rows? If I use the same query it will display the same information.

2- I was thinking to just query all the data and somehow store it, but I don't know if it is a good choice to store all the data even if the user does not want to see it. I want to do it as my first question because I have to retrieve other information from other tables in the database.

What do you suggest? And how I can retrieve the data as I want in my first question?

</div>

I made one of these recently in a project. I used the Bootstrap pagination class to style it:

<div class="pagination" style="text-align:center">
<ul>

<?php

        if($firstPage)
        {
            $relative = "./";
        }
        else
            $relative = "../";

        if($page != 1)
        {
            echo "<li><a href=\"".$relative."page/$page\">&laquo;</a></li>";
        }
        for($i = 1; $i <= ceil($numRows / $numItems); $i++)
        {
            if($i == $page)
                echo "\t<li><a href=\"".$relative."page/$i"."\" style=\"background-color:#e5e5e5;color:#AAAAAA;\"><b>".$i."</b></a></li>";
            else
                echo "\t<li><a href=\"".$relative."page/$i\">".$i."</a></li>";
        }
        if(($page+1) <= ceil($numRows / $numItems))
            echo "\t<li><a href=\"".$relative."page/".($page+1)."\">&raquo;</a></li>";
?>
</ul>
</div>

Then in the controller, I form the query:

$numItems = 20;  // Number of results to show per page
$q = "SELECT * FROM --- WHERE ---- = $-----";
$q .= " LIMIT ".(($page_number-1)*$numItems).','.($numItems*($page_number));

This concept is called pagination. In this -

1st) LIMIT 20,0    (from 1 to 20)
2nd) LIMT 20,20    (from 21 to 40)
3rd) LIMIT 20,40   (from 41 to 60) 
4th) LIMIT 20,60   (from 61 to 80)

It is a combination of limit and offset. 1st, 2nd, 3rd... are the page and the (LIMIT 20,0) are the addons to the query, and offset parameter you'll get from $_GET (from URL)