limited number of rows in a page - php

Question

Hi I'm retrieving my data from DB
my data is (pic & name ) when I retrieved them I put them in 4 columns
now I wanna limit the number of rows in each page , I want each page shows three rows only
and if there is more data I want to make it display in next page
my code :
<?php
$items_in_row = 4 ;
$index = 0 ;
?>
<table>
<tr>
<?php
while ($row = mysql_fetch_array( $result , MYSQL_ASSOC)){
$index++ ; ?>
<td>
<p>
<img id='g1' src='/<?php echo $row["img"] ;?>' width=130 height=130 onClick='f1()'>
</p>
<p> Name: <?php echo $row['name'] ; ?> </p>
<br>
</td>
<?php if ($index%$items_in_row == 0){ ?>
</tr>
<tr>
<?php }
} ?>
</tr>
</table>

Answer 1

One way to do this is to use the LIMIT() function in SQL, passing in variables that you are storing in the session in PHP. Let's say you want 3 rows of 4 pictures on each page, then you want 12 pictures. So you do something like
select * from pictures LIMIT(0,12)
This returns the first 12 items.
You can do it by just tracking page number. Maybe you have a $page variable in your PHP. If you are on page 2, $page contains 2. Use that to construct a dynamic SQL query with your PHP maybe like this...
$sqlQueryStatement = "select * from pictures LIMIT(". ($page-1)*12 . ", 12)";
What this does is for page 2, it produces the sql statement:
select * from pictures LIMIT(12,12)
See how that works? Now you execute that SQL, and you have the set of results that should be output for page 2.
You can use some further logic to take these basic concepts and run with them...extending them to uses like creating the clickable pagination numbers on the bottom of your results and so forth.

Answer 2

i develop my pagination jobs using the following algorithm:
...1) selecting the results
$page = 1; // what page to show, if you dont know 1 is default.
$maxthingsperpage = 5; // how many things (etc. what you show) per page
$offset = ($page * $maxthingsperpage) - $maxthingsperpage; // db id to start reading
$result = mysql_query("SELECT * FROM things LIMIT ".$offset.",".$maxthingsperpage);
...2) display the things into page
$numrows = mysql_num_rows($result);
$numthingstodisplay = ($numrows > $maxthingsperpage ? $maxthingsperpage : $numrows);
while ($row = mysql_fetch_array( $result , MYSQL_ASSOC)) {
... display here without worrying about when to break; num rows are exact
}
you can replace $maxthingsperpage with your $items_in_row