PHP Paging & Automatic Pagination Tutorial - Paging made easy

I have written a php paging tutorial before. Admittedly, it wasn't the greatest. I don't think I was as clear as I wanted to be. SO I'm trying again. At the end of this tutorial, there is a file named php-automatic-pagination.php.txt
Please download it! It will help you understand the following.

Here is what we will be making..nice, simple pagers! (Dont worry about the Image #x text, thats really not part of the tutorial)

Paging in php and automatic pagination is something every coder has to deal with when coding in php. I mean, you COULD show all results on 1 page and skip the php paging, but paging is necessary to reduce bandwidth and organize content. Paging is very easy to do and I will walk you through it step by step.

PHP automatic paging comes with a few questions:
Paging 1 : Page Size - How many results would you like to display per page?
Paging 2 : How can we bring back proper results in mysql?
Paging 3 : How can we print a pager that will help show the next items.

Decide on your page size - 10, 15, 25, 50, 100. It really depends on what you would like to do. For this tutorial I will use 15.

//we want 15 results per page

$pgsize=15;

//if there is a p variable in the query string e.g: page.php?p=5 we will get this value, else we will use 1 (page 1)

$pg=(is_numeric($_GET["p"]) ? $_GET["p"] : 1);

//lets determine where we would like to get results from
//if $pg is 1, this calculation results in 0 (we want to start from the first record in the database)
//if $pg is 2, this calculation will result in 1*15..which means we will start at the 15th index of the database (row 16)

$start=($pg-1)*$pgsize;

//let us query the database for our results
//you will notice LIMIT and $start and $pgsize.
//On page 1, this query will be SELECT * FROM image_table LIMIT 0,15 - this means return 15 rows starting at row-index 0 (row 1)
//On page 2, this query will be SELECT * FROM image_table LIMIT 15, 15 - this means we will return 15 rows starting at row-index 15 (row 16)
//On page 3, this query will be SELECT * FROM image_table LIMIT 30,15 - this means we will return 15 rows starting at row-index 30 (row 31)
GET IT?!?!?!

$imgs=mysql_query("SELECT * FROM image_table LIMIT $start, $pgsize");

//we will also need the total number of records in our table
//notice there is no limit? we want to know how many records are in the entire table!
//we can use COUNT(*), COUNT(1), or COUNT(fieldname), they will all return the same result

$img_total=mysql_query("SELECT COUNT(1) FROM image_table");

//mysql_query returns a resource id, we can use this to get the row it has returned

$img_total=mysql_fetch_row($img_total);

//the count will be the first field in this row

$img_total=$img_total[0];

//lets determine how many pages we will need
//WRONG!, this will cut off results..why?
//say we have 31 images, and our page size is 15. 31/15= ~2.x...We need to round this result up!

$max_pages=$img_total / $pgsize;

//use this line instead

$max_pages=ceil($img_total/$pgsize);

Once we have all this information, we can use a handy little function I have written named printPager. This function will print out a neat little pager. It uses a helper function named add_querystring_var which was from Added Bytes here:
http://www.addedbytes.com/code/querystring-functions/

Copy/paste this function into your page or into one of your includes:
This will print out your awesome little pager!

PHP Automatic Pagination Function

Print Pager is called like so:

PHP Pager Styles

Download this tutorials script! It will help you understand. Right click: php-automatic-pagination-tutorial.php and click Save as. Then get rid of the .txt extension and name it php if you would like to run it. You will need to setup a database table to use for the tutorial. It can have an id field and another field.

If you enjoyed this post please leave a comment! I like reading and responding to all my readers!
Thanks

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Easy & Simple Paging using PHP. Here is the result: (DB has 8records, Rows per page is set to 5, and we're on page 2)

Paging usually takes a while but here we will do it quickly and cleanly.

Your page will be named page.php. And when we want to switch pages we will make it page.php?pg=2.
Im sure you've seen this before. Anyways lets dive in.

I use shorthand to clean stuff up, but basically shorthand is

$returnvalue=(condition ? "true" : "false");
Example:

$is_loggedin=(isset($_SESSION["loggedin"]) ? 1 : 0);
After this statement, if the session variable is set, $is_loggedin will equal 1, else it will equal 0.

At the top of your PHP page type the following:

<?php
/*paging*/
Line 1: $pg=(isset($_GET["pg"]) && is_numeric($_GET["pg"]) && $_GET["pg"]>0 ? $_GET["pg"] : 1);
Line 2: $rowsperpage=10;
Line 3: $offset=($pg>1 ? ($pg-1)*$rowsperpage : 0 );
Line 4: $limitstr=" LIMIT $offset, $rowsperpage";
?>

Explanation:
First of all Limit is : LIMIT $startrowid, $number of entries to return
So LIMIT 55, 5 means start at row 55 and return 5 rows (55, 56, 57, 58, 59)

Line 1: If in the query string the pg is set e.g page.php?pg=4, and it is numeric, and greater than 0 we will assign the value of $_GET["pg"] to our $pg variable. If it is not set, or it is not numeric, or zero or less, we set the $pg variable to 1.
Line 2: We set our rows per page
Line 3: If the page is greater than 1, we set the offset to ($pg-1)*rowsperpage. If the page is 1 or less, we set offset to 0.
Line 4: We create the limit string for the sql statement. This will output something like LIMIT x, y.
(rowsperpage set to 10)

In this case page.php?pg=1
$pg = 1;
$offset = 0;
$rowsperpage=10;
$limitstr="LIMIT 0, 10"; //this string will pull 10 rows starting from row 0 (the first row) (rows 0-9)

In this case page.php?pg=3
$pg=3;
$offset= (3-1) * 10; //offset calculates to 20
$limitstr="LIMIT 20, 10"; //this string will pull 10 rows starting from and including row 20 (rows 20-29)

Ok. Now that we got that out of the way.

We will use a simple query, then we will attach our new limit string (looking at case 2 above)
$sql="SELECT * FROM MEMBERS $limitstr"; //sql = "SELECT * FROM MEMBERS LIMIT 20,10";
$res=mysql_query($sql);
while($row=mysql_fetch_array($res)){

//processing if you need to
}

We also need to know the total count for this table
$sql="SELECT COUNT(memberid) FROM MEMBERS";
$res=mysql_query($sql);
$row=mysql_fetch_array($res);
$total = $row[0];

Now we know the total count.

So we need to calculate the number of pages. That is done by this formula:
($total/$rowsperpage);
Now in the case of 26 members and 5 rows per page. Using this formula 26/5 = 5.2pages, so we need to round up!

$maxpage=ceil($total/$rowsperpage); //max page is now 6.

Ok, we got everything set up Just need to print out our paging!
Wherever you want your paging setup add this:

<?php
print '<div class="paging"><ul>';
for($i=1; $i<=$maxpage; $i++){
  if($pg==$i)
     print '<li><span>'.$i.'</span></li>';
  else
     print '<li><a href="?pg='.$i.'">'.$i.'</a></li>';
}
print "</ul></div>";
?>

Then we can do some nice styling (Mess around with margins to setup spacing)
CSS
div.paging {text-align: center; margin-top: 5px;}
div.paging span{font-weight: bold;}
div.paging ul{overflow: hidden;}
div.paging ul li{width: 10px; float: left; margin: 0px 10px 5px 0px;}

This will page across until it hits the edge of the div, then it will move to the next line.

ENJOY and comment !